Trắc nghiệm ôn tập - Môn Tế bào sinh học phân tử| Đại học Y dược Cần Thơ

CELLS & MOLECULAR BIOLOGY PART 1: EXAM
1. The “fluid” and “mosaic” terms in the fluid mosaic model of membrane structure refer to the ___ and ___, respectively.
A. inside of the membrane; outside of the membrane B. lipids; proteins C. proteins; lipids
D. fatty acid chains; polar groups
2. Which of the following proteins is likely to contain one or more hydrophobic segments, 20-30 amino acids long?
A. Integral membrane protein.
B. Peripheral membrane protein. C. Lipid-anchored protein. D. Cytoplasmic protein.
3. Which of the following would most readily cross a lipid bilayer by simple diffusion? A. Oxygen B. Glucose C. Chloride ions D. Proteins
4. The voltage-gated potassium channels associated with an action potential provide an example of what type of membrane transport? A. Simple diffusion.
B. Facilitated diffusion. C. Coupled transport. D. Active transport.
5. You are studying the entry of a small molecule into red blood cells. You determine the rate of movement
across the membrane under a variety of conditions and make the following observations:
i. The molecules can move across the membrane in either direction.
ii. The molecules always move down their concentration gradient.
iii. No energy source is required for the molecules to move across the membrane.
iv. As the difference in concentration across the membrane increases, the rate of transport reaches a maximum.
The mechanism used to get this molecule across the membrane is most likely: A. simple diffusion.
B. facilitated diffusion. C. active transport.
D. There is not enough information to determine a mechanism.
6. A particular cell has an internal chloride ion concentration of 50 mM, while outside the cell the chloride
ion concentration is 100 mM. The free energy change associated with chloride transport into the cell (DG) is
+970 cal/mol. Which choice below is the best explanation for this data?
A. Cl- ion movement into the cell is energetically favorable.
B. Both the concentration gradient and electrical gradient favor movement of Cl- ions into the cell.
C. The concentration gradient for Cl- ions favors movement into the cell, but the electrical gradient
opposes inward movement of Cl-.
D. Both the electrical and chemical gradients for Cl- ions favor outward movement of Cl- ions.
7. Place the following steps in an action potential in the correct order.
1. Sodium channels become inactivated and potassium channels are opened.
2. Sodium and potassium channel gates are closed; membrane potential is 60 – mV.
3. Sodium channel gates open in response to change in membrane potential.
4. Potassium rapidly leaves the cell; membrane potential drops to 75m – V.
5. Sodium rushes into the cell; membrane potential reaches +40mV. A. 2, 1, 4, 3, 5, 2. B. 2, 1, 3, 4, 5, 2. C. 2, 3, 4, 1, 5, 2. D. 2, 3, 5, 1, 4, 2.
8. How are neurotransmitters released into a synapse in response to an action potential?
A. They pass through voltage-gated neurotransmitter channels.
B. They diffuse through the cell when the action potential reverses membrane potential.
C. They pass through gap junctions into the post-synaptic cell.
D. They are released by membrane fusion of vesicles in response to increased calcium concentration.
9. The neurotransmitter g-amino butyric acid (GABA) binds to receptors that are ligand-gated Cl- ion
channels. What affect will this neurotransmitter have on the post-synaptic cell?
A. Cl- ions will rush into the cell leading to hyperpolarization and a reduced likelihood of an action potential.
B. Cl- ions will rush into the cell leading to depolarization and an increase in the chance for an action potential.
C. Cl- ions bind to GABA and inhibit it from interacting with the receptor, stimulating an action potential.
D. There will be no significant effect on the post-synaptic cell; only the pre-synaptic cell is affected by neurotransmitters.
10. Which of the following is the most likely immediate affect of G-protein activation?
A. Receptors are stimulated to bind to their ligands.
B. Enzymes are activated that catalyze second messenger formation.
C. GTP is depleted from the cell.
D. G-proteins bind to DNA and activate gene expression.
11. Proteins with SH2 domains are important in intracellular signaling pathways. What is the function of these domains?
A. They bind to activated tyrosine kinase receptors.
B. They bind to DNA and activate gene transcription.
C. They regulate the activity of voltage-gated ion channels.
D. They hydrolyze GTP to inactivate the pathway.
12. Platelet activation at the site of a wound is a example of: A. endocrine signaling.
B. paracrine signaling.
C. intracellular receptor activation. D. apoptosis.
13. Apoptosis is mediated by signal transduction pathways that lead to the programmed death of the cell.
How is cell death achieved during apoptosis?
A. Aqueous channels form in the cell membranes leading to inward movement of water and lysis of the cell.
B. Gene expression is activated that leads to the synthesis of inhibitors of respiratory enzymes.
C. The Na+/K+ ATPase is inactivated, leading to the loss of membrane potential which the cell needs to survive.
D. Caspases are activated that lead to hydrolysis of many cellular macromolecules.
14. Which of the following statements is NOT true of tyrosine kinase-linked receptors?
A. Monomeric receptors are often induced to dimerize upon ligand binding.
B. The activated receptors attract and activate G proteins to continue the signal pathway.
C. The cytoplasmic side of the receptor contains a kinase enzyme domain that is activated upon ligand binding.
D. Activated receptors autophosphorylate themselves to attract SH2 domain proteins.
15.What mechanism is used to regulate the spontaneous assembly of collagen protein into a collagen fiber?
A. Different fibroblasts secrete different components for each collagen fiber.
B. Inhibitory protein domains are removed by an extracellular protease.
C. Covalent cross-links between proteins are only made outside the cell.
D. Complete collagen fibers are exported from the cell only as they are needed.
16. Which choice below describes the major function of proteoglycans in the extracellular matrix?
A. They provide a hydrated, gel-like medium for lubrication, cushioning, and embedding other ECM components.
B. They provide high strength fibers required to withstand mechanical stress.
C. They provide a highly elastic support to resist tension.
D. They create the dense, hard support structures of bone tissue.
17. Fibroblasts attach the extracellular matrix to the cytoskeleton via: A. focal adhesions. B. tight junctions. C. hemidesmosomes. D. gap junctions.
18. Which of the following classes of molecules is not involved in direct cell-to-cell contact? A. Cadherins B. N-CAMs C. Selectins D. Fibronectins
19. The cell junction that prevents the two different types of glucose transporters from mixing in the plasma
membrane of intestinal epithelial cells is the: A. gap junction. B. tight junction. C. adherens junction. D. desmosome.
20. Polarized epithelial cells:
A. have a reversed membrane potential from most other cells.
B. maintain distinct membrane domains through the action of tight junctions.
C. do not have gap junctions so they are isolated from their neighbors.
D. are found only in animals such as polar bears, walruses and penguins. PART 2: LESSON
THE OVERVIEW OF CELLS: STRUCTURES AND FUNCTIONS
1/ Who was the first person to see cells under the microscope and give them a name? A. Anton van Leeuwenhoek B. Robert Hooke C. Theodor Schwann D. Matthias Schleiden
2/ Which of the following is NOT one of the main components of the cell theory? A. cells must contain DNA
B. all living things are made of cells
C. cells can only come from other cells
D. cells are the basic unit of life
3/ What do protists, plants, fungi, and animals have in common? A. Multicellular B. Eukaryotic C. Prokaryotic D. Consumers
4. Which one of the following eukaryotic cell structures does not contain DNA? A. a nucleus B. a mitochondrion
C. the endoplasmic reticulum D. a chloroplast
5. A centriole is an organelle that is:
A. present in the center of a cell's cytoplasm
B. composed of microtubules and important for organizing the spindle fibers C. surrounded by a membrane D. part of a chromosome
6. Differential staining of bacteria on Gram staining is due to:
A. Difference in the cell wall layer components of Gram positive and Gram negative bacteria
B. Difference in the cell structure of Gram positive and Gram negative bacteria
C. Difference in mode of nutrition of Gram positive and Gram negative bacteria
D. Difference in plasma membrane components of Gram positive and Gram negative bacteria 7. What is a cell?
a) smallest and advanced unit of life
b) smallest and basic unit of life
c) largest and basic unit of life
d) largest and advanced unit of life
8. Which of the following is a functional unit of a body? a) Mitochondria b) Cytoplasm c) Spleen d) Cell
9. Which of the following is used by cells to interact with other cells? a) Cell tubules b) Cell junctions c) Cell adhesions d) Cell detectors
10. In which of the following type of cells the cell junction is abundant? a) Cardiac cells b) Prokaryotic cells c) Hepatic cells d) Epithelial cells
11. What is epithelial mesenchymal transistion?
a) Loss of migration and gain of adhesion
b) Formation of mesenchymal cells
c) Loss of adhesion and gain of migration d) Lysis of cell
12. In which of the following type of cells the Gap junctions are absent? a) Sperm cells b) Brain cells c) Reproductive cells d) Cardiac cells
13. In which of the following type of cells Sarcoplasmic reticulum is found? a) muscle cells b) liver cells c) kidney cells d) neurons
Explanation: Smooth endoplasmic reticulum sequesters calcium ions within the cytoplasm of the cell and
controlled release of Ca2+ from the SER of cardiac and skeletal muscle cells triggers contraction. Smooth
endoplasmic reticulum (SER) in the aforementioned cells is known as sarcoplasmic reticulum.
14. Which of the following are phagocytic cells? a) neutrophils, mast cells b) mast cells, macrophages c) mast cells, antibodies
d) neutrophils, macrophages
10. Which of the following is known as the powerhouse of a cell? a) Mitochondria b) Cytoplasm c) Lysosome d) Nuclei
Explanation: The mitochondria, also known as the “powerhouse of the cell,” are the organelles that produce
energy within the cell. The mitochondria are the major site for ATP generation and play a significant role in cellular respiration.
11. Which of the following is known as the suicide bag of a cell? a) Mitochondria b) Golgi Complex c) Lysosome d) Nuclei
Explanation: The digesting enzymes are found in lysosomes. When lysosomes rupture, digestive enzymes
are released, which begin digesting the body’s own cells. That’s why they’re referred to as suicidal bags.
12. Lysosomes are produced by which of the following cell organelles? a) Mitochondria b) Endoplasmic Reticulum c) Golgi Complex d) DNA
Explanation: They are produced by the Golgi body. The fusion of vesicles from the Golgi complex with endosomes produces lysosomes.
13. Which of the following cell organelle is responsible for transporting, modifying, and packaging proteins and lipids? a) Mitochondria b) Endoplasmic Reticulum c) Golgi Complex d) DNA
Explanation: The Golgi apparatus, also known as the Golgi complex, is a factory where proteins from the
ER are further processed and sorted before being transported to their final destinations: secretion,
lysosomes, or the plasma membrane.
14. Which of the following cell doesn’t contain a cell wall? a) Plant cell b) Bacteria c) Fungi d) Animal cell
Explanation: Plant cells require a cell wall, but animal cells do not, as plants require a stiff framework in
order to grow up and out. Cell membranes are present in all cells and are flexible. Plant cells only have the
shapes of their cell walls, but animal cells can have a variety of shapes.
15. Who is the father of cell biology? a) George N. Papanicolaou b) George Emil Palade c) Robert Hooke d) None of the above
16. DNA is stored in which of the following cell organelle? a) Cell wall b) Cell Membrane c) Nucleus d) Cytoplasm
17. In which of the following cell nucleus is not present? a) Eukaryotic cell b) Prokaryotic cell c) Both of the above d) None of the above
18. Which of the following organisms doesn’t have a cell? a) Virus b) Bacteria c) Fungi d) Algae
Explanation: Viruses aren’t made up of cells. Their genetic material is protected by a protein covering
(either DNA or RNA). However, they lack a cell membrane and other organelles seen in cells.
19. Who proposed the cell theory?
a) Theodor Schwann, Watson and Robert Hooke
b) Theodor Schwann, Matthias Schleiden and Robert Hooke
c) Theodor Schwann, Matthias Schleiden and Rudolf Virchow
d) NTheodor Schwann, Rudolf Virchow and Robert Hooke
20. RNA is present in which of the following cell organelles? a) Cell wall b) Ribosome c) Nucleus d) Cytoplasm d) Golgi complex
Explanation: Ribosomes are tiny organelles that contain RNA and specific proteins within the cytoplasm.
21. A cell organelle that is present in animal cells but not present in plant cells is? a) Cytoplasm b) Centrosome c) Mitochondrial d) Golgi complex
Explanation: Plant cells lack a centrosome and lysosomes, while animal cells do. Animal cells lack a cell
wall, chloroplasts, and other specialized plastids, as well as a big central vacuole, but plant cells do.
22. Which of the following cell is found in the brain? a) Neuron b) Hepatocyte c) Nephron d) Epithelial cell
23. Protein synthesis takes place in which of the following cell organelle? a) Cell wall b) Ribosome c) Nucleus d) Cytoplasm
24. Which of the following cells are found in the intestinal lining? a) RBCs b) Neurons c) Epithelial cells d) Hepatocytes
Explanation: Epithelial cells line the intestine and are responsible for the uptake and absorption of nutrients
from the digestive tract. Microvilli are located at the apical end of these cells and mitochondria are located at the basal end.
25. Which of the following polysaccharide is not present in the eukaryotic plant cell wall? a) Chitin b) Hemicellulose c) Pectin d) Cellulose
Explanation: Chitin is a polysaccharide that is present mainly in exoskeletons of Arthropods and are not a
component of plant cell wall. Plant cell wall is majorly composed of cellulose, hemicelluloses and pectin.
26. Which of the following is the process of synthesis of glucose? a) saccharification b) glycolysis c) gluconeogenesis d) neogenesis
Explanation: The anabolic pathway that leads to the formation of glucose is referred to as gluconeogenesis.
A cell can synthesize glucose at the same it as utilizing glucose as the source of chemical energy.
27. Which of the following site is represented by Loops in lampbrush chromosomes? a) Crossing over b) Cell division c) Replication d) Transcription
Explanation: Lampbrush chromosomes are a type of giant chromosomes found in the growing oocytes of
amphibians. Twin loops arise on either side of the chromosome in the meiotic prophase. This is due to the
active transcription of many genes.
28. Which of the following part of a neuron receives information from other neurons? a) myelin sheath b) dendrites c) cell body d) axon
Explanation: The fine extensions from the cell body of the neurons are called dendrites which receive
information from external sources, usually other neighboring neurons.
29. Which of the following is not a component of cell membranes?
a) Phosphotriglycerides b) Cholesterol c) Sphingolipids d) Phosphodiglycerides
Explanation: Phospholipids present in cell membrane are diglycerides and not triglycerides. Triglycerides
have three fatty acids and are not ampipathic in nature. It also consists of sphingolipid and cholesterol.
30. Which of the following promote curvature of cell membrane? a) Phosphatidyl serine (PS) b) Phosphatidyl inositol(PI) c) Phosphatidyl choline (PC)
d) Phosphatidyl ethanolamine (PE)
31. Which of the following is not a type of chromosomal aberration? a) duplication b) translocation c) mutations d) inversion
32. Which of the following cells release insulin when glucose levels elevate in the body? a) gamma cells b) beta cells c) alpha cells d) zeta cells
33. Which of the following cells are pluripotent?
a) embryonic stem cells b) nucleosomes c) hepatocytes d) neurons
34. Which of the following cells do not lack the ability to divide? a) red blood cells b) muscle cells c) skin cells d) nerve cells
Explanation: Only highly specialized cells of the body such as nerve cells, muscle cells and red blood cells
lack the ability to divide, once they have differentiated they remain in that state till the end of their life cycles.
35. Which of the following cells do not usually divide but can be induced to divide? a) liver cells b) red blood cells c) hair cells d) hair follicles
Explanation: Liver cells do not usually grow and divide but can be made to do so under specific conditions
such as liver surgery. Lymphocytes can also be induced to regrow and divide by interaction with a proper antigen.
36. A scientist observes a new organism through a microscope. Which of the following observations tells
her that the organism is eukaryotic? A. The organism has ribosomes
B. The organism has a membrane bound nucleus
C. The organism is unicellular
D. The organism has a cell membrane
37. What is the main function of cytoplasm in a cell?
A. Suspending cellular structures and providing a place for cellular functions to take place
B. Regulating the transport of molecules into and out of the cell
C. Synthesizing proteins in the cell
D. Packaging and sending out proteins and lipids
38. Lysosomes can be expected to be present in large numbers in cells which…. A. carry out phagocytosis B. are actively dividing C. are migrating D. secrete peptide hormones
39. He advanced the cell theory with his conclusion that cells could only come from other cells?
40._____________ are inherited metabolic diseases characterized by an abnormal build-up of various toxic
materials in the body’s cells as a result of enzyme deficiencies.
A. Lysosomal storage diseases B. Mitochondrial diseases
C. Endoplasmic reticulum diseases D. Plasma membrane diseases
(____________ là bệnh chuyển hoá di truyền được mô tả bởi sự tích tụ của các vật chất độc hại trong các tế
bào của cơ thể do kết quả của thiếu enzyme) A. Các bệnh lysosome B. Các bệnh ti thể
C. Các bệnh mạng lưới nội chất
D. Các bệnh màng tế bào)
41. Which of the following statement is FALSE about mitochondrial diseases
A. occur when mitochondria fail to produce enough energy
B. are often chronic and genetic
C. can affect almost any part of the body but the parts of your body that need the most energy are most affected
D. the affected child is always inherited the disease from the affected mother
42. SARS-CoV-2 consists of 4 structural proteins, which of them provides specificity for cellular entry receptors: A. spike (S) protein B. envelope (E) protein C. membrane (M) protein D. nucleocapsid (N) protein
43. Một tế bào có một đột biến làm cho nó không thể tổng hợp protein một cách phù hợp. Chức năng của
bào quan nào sau đây có thể bị ảnh hưởng bởi đột biến này nhất A. Màng tế bào B. Lục lạp C. Ribosome D. Ti thể
TRANSPORT ACROSS CELL MEMBRANE
1/ Which of the following describes the fluid mosaic model of the plasma membrane structure?
A. phospholipid monolayer with embedded proteins
B. phospholipid bilayer with embedded protein
C. phospholipid bilayer with embedded lipids
D. triglyceride bilayer with embedded proteins
2/ Which of the following ions has a higher concentration outside the cell than inside the cell A. Na+, Cl-, H+, Mg2+ B. Na+, Cl-, K+, Mg2+ C. Na+, Ca2+, K+, Mg2+ D. Na+, Ca2+, Cl-, Mg2+
3/ In coupled transport processes, sugars can be brought into the cell against their concentrations gradients
A. because ATP powers the pump that brings them in
B. because they follow sodium ions into the cell which are traveling down their concentration gradients
C. because they follow potassium in through the sodium-potassium pump D. through endocytosis
4/ The opening of axon membrane voltage-gated potassium channels is responsible for which part of the action potential?
A. Depolarisation of the membrane
B. Repolarisation of the membrane
C. Contraction of the post synaptic muscle fibre
D. Signalling vesicular release of neurotransmitters
5/ The term "voltage - gated" means that in the membrane
A. ion channels open and close with changes in the membrane potential.
B. potential is controlled by the Na+/K+ pumps.
C. potential is controlled by light energy
D. potential can only be controlled by the binding of specific ligands to their receptors
2. In which type of signaling, the cell that expresses messenger molecules also produces receptors? a) autocrine b) heterocrine c) paracrine d) endocrine
Explanation: In autocrine signaling, the cells that express messenger molecules also synthesize surface
receptors. Surface receptors can respond to the messengers synthesized by the cell itself.
3. Cell signaling is a process by which cells communicate. a) True b) False
4. Paracrine messenger molecules are usually ________________ a) large b) stable c) unstable d) amphoteric
5. Endocrine messengers are also called ___________________ a) hormones b) receptors c) antibody d) antigen
6. The primary messenger molecules bind to the transmembrane receptors. a) True b) False
7. Protein kinases and phosphatases act by altering ______________ of the signaling proteins. a) basicity b) conformation c) acidity d) siz e
Explanation: Protein kinases are enzymes that add phosphate groups while protein phosphatases remove
phosphate groups. These enzymes alter the conformation of signaling proteins.
8. To which of the following residues of the protein, the protein kinases do not add phosphate groups? a) serine b) cytosine c) threonine d) tyrosine
Explanation: The protein kinases usually add phosphate groups to serine and threonine residues of their
target proteins. A very important class of kinases also adds phosphate groups to the tyrosine residues.
9. The process by which extracellular messages translate into intracellular changes is termed _________________ a) cell signaling b) cell adhesion c) signal transduction d) cell transformation
Explanation: The process by which extracellular messenger molecules transform into intracellular changes
such as apoptosis, metabolism, transcription etc. is called signal transduction.
10. The a, b, and c respectively in the following image are _________________________
a) autocrine, paracrine, endocrine
b) autocrine, endocrine, paracrine
c) endocrine, paracrine, autocrine
d) endocrine, autocrine, paracrine
Explanation: The signaling pathways in the figure shown are autocrine, paracrine and endocrine signaling
pathways respectively. All the three are stimulation pathways in which messenger molecules reach cell surface receptors.
11. Steroids are derived from ________________ a) estrogen b) cholesterol c) proteins d) carbohydrates
12. Which messenger molecules are derived from arachidonic acid? a) eicosanoids b) terpenoids c) corticoids d) steroids
13. G-protein coupled receptors contain ________ transmembrane alpha helices. a) 2 b) 5 c) 7 d) 9
Explanation: The G-protein coupled receptors (GPCRs) are a family of cell surface receptors that consist of
7 transmembrane alpha helices. These receptors translate the binding of extracellular messengers to the
activation of intracellular GTP-binding proteins.
____ 1. In the yeast signal transduction pathway, after both types of mating cells have released the
mating factors and the factors have bound to specific receptors on the correct cells,
a. binding induces changes in the cells that lead to cell fusion.
b. the cells then produce the a factor and the factor.
c. one cell nucleus binds the mating factors and produces a new nucleus in the opposite cell.
d. the cell membranes fall apart, releasing the mating factors that lead to new yeast cells.
e. a growth factor is secreted that stimulates mitosis in both cells. ____ 2. Paracrine signaling
a. involves secreting cells acting on nearby target cells by discharging a local regulator into the extracellular fluid.
b. requires nerve cells to release a neurotransmitter into the synapse.
c. occurs only in paracrine yeast cells.
d. has been found in plants but not animals.
e. involves mating factors attaching to target cells and causing production of new paracrine cells.
3. From the perspective of the cell receiving the message, the three stages of cell signaling are
a. the paracrine, local, and synaptic stages.
b. signal reception, signal transduction, and cellular response.
c. signal reception, nucleus disintegration, and new cell generation.
d. the alpha, beta, and gamma stages.
e. signal reception, cellular response, and cell division.
____ 4. When a cell releases a signal molecule into the environment and a number of cells in the
immediate vicinity respond, this type of signaling is a. typical of hormones. b. autocrine signaling. c. paracrine signaling. d. endocrine signaling. e. synaptic signaling.
____ 5. Synaptic signaling between adjacent neurons is like hormone signaling in which of the following ways?
a. It sends its signal molecules through the blood.
b. It sends its signal molecules quite a distance. c. It requires calcium ions.
d. It requires binding of a signaling molecule to a receptor.
e. It persists over a long period.
____ 6. A small molecule that specifically binds to another molecule, usually a larger one
a. is called a signal transducer. b. is called a ligand. c. is called a polymer.
d. seldom is involved in hormonal signaling.
e. usually terminates a signal reception.
____ 7. Which of the following is (are) true of ligand-gated ion channels?
a. They are important in the nervous system.
b. They lead to changes in sodium and calcium concentrations in cells.
c. They open or close in response to a chemical signal. d. Only A and B are true. e. A, B, and C are true.
____ 8. Of the following, a receptor protein in a membrane that recognizes a chemical signal is most similar to
a. the active site of an allosteric enzyme in the cytoplasm that binds to a specific substrate.
b. RNA specifying the amino acids in a polypeptide.
c. a particular metabolic pathway operating within a specific organelle.
d. an enzyme with an optimum pH and temperature for activity.
e. genes making up a chromosome.
____ 9. G proteins and G-protein-linked receptors
a. are found only in animal cells, and only embedded in or located just beneath the cell's membrane.
b. are found only in bacterial cells, embedded in the cell's plasma membrane only.
c. are thought to have evolved very early, because of their similar structure and function in a wide variety of modern organisms.
d. probably evolved from an adaptation of the citric acid cycle.
e. are not widespread in nature and were unimportant in the evolution of eukaryotes.
____ 10. Membrane receptors that attach phosphates to specific animo acids in proteins are a. not found in humans.
b. called receptor tyrosine-kinases.
c. a class of GTP G-protein signal receptors.
d. associated with several bacterial diseases in humans.
e. important in yeast mating factors that contain amino acids.
____ 11. Up to 60% of all medicines used today exert their effects by influencing what structures in the cell membrane? a. tyrosine-kinases receptors
b. ligand-gated ion channel receptors c. growth factors d. G proteins e. cholesterol
____ 12. Which of the following are chemical messengers that pass through the plasma membrane of
cells and have receptor molecules in the cytoplasm? a. insulin b. testosterone c. cAMP d. epinephrine 1. A agen n
t secreted by a cell that can influence the properties of another cell: a. Receptor b. Antigen c. Pheromone d. Ligand Answer: d. Ligand
2. Hormones are signaling molecules of which system? a. Nervous system b. Endocrine system c. Immune system d. Circulatory system Answer: b. Endocrine system 3. In human beings, U l
V ight acts as an incoming signal to promote the synthesis of a protective pigment called: a. Melanin b. Bilirubin c. Urochrome d. Pheromone Answer: a. Melanin
4. Which of the following transmit information both electrically and chemically? a. Neurons b. Nephrons c. Dendrocytes d. All of these Answer: a. Neurons
5. Which of the following is not a local regulator? a. Growth factor b. Histamine c. Prostaglandins d. Oxytocin Answer: d. Oxytocin
6. A signaling molecule that diffuses through the interstitial fluid and acts on nearby cells is called: a. Motor neuron b. Local regulator c. Transporter d. Transmitter Answer: b. Local regulator
7. In many signaling cascades in prokaryotic and animal cells, the second messenger is? a. cAMP b. cATP c. NO d. G proteins Answer: a. cAMP
9. Specialized receptors in the vertebrate eye that respond to light signals are: a. Rhodopsin b. Phytochrome c. Cryptochromes d. Melanophores Answer: a. Rhodopsin
10. Cell surface receptors represent about…………..of all human proteins: a. 30% b. 50% c. 60% d. 80% Answer: a. 30%
11. Which of the following ligands binds to the extracellular receptors? a. Nitric oxide b. Growth hormones c. Steroid hormones d. Thyroid hormones Answer: b. Growth hormones
12. The largest family of human cell surface receptors is the:
a. G protein-coupled receptors
b. Ion channel-linked receptors c. Enzyme-linked receptors d. Receptor Tyrosine Kinase
Answer: a. G protein-coupled receptors
13. The sequence of changes in a series of different molecules that occurs during cell signaling is: a. Nerve impulse b. Reflex arc
c. Signal transduction pathway d. Reflex action
Answer: c. Signal transduction pathway
14. Chemicals that take information about nerve impulse from one neuron to another neuron are called: a. Hormones b. Pheromones c. Neurotransmitters d. Transducers Answer: c. Neurotransmitters
15. Which of the following is used for long-distance signaling in both plants and animals? a. Hormones b. Protein kinases c. Transducers d. Ligand binding proteins Answer: a. Hormones
16. There are how many categories of cell signaling? a. Two b. Ten c. Seven d. Four Answer: d. Four
Explanation: There are four main types of cell signaling found in multicellular organisms: paracrine,
autocrine, endocrine, and signaling by direct contact.
17. Which of the following type of signaling is involved in Paracrine s gn i aling? a. Autostimulation of cell b. Hormonal Communication c. Synaptic transmission d. Chemical signaling Answer: d. Chemical signaling
18. Which of the following statements is true regarding cell signaling?
a. Cell signaling has four basic categories
b. is used to study the context of human diseases
c. In plants cell signaling occurs through phytohormones d. All of these Answer: d. All of these
19. The target cells of a lipid-soluble hormone such as cortisol, are able to respond to it becaus of e :
a. They have membrane-bound cell surface receptors
b. Only target cells express appropriate cytosolic receptors
c. Their genome includes the appropriate transcriptional response d. All of these
Answer: b. Only target cells express appropriate cytosolic receptors
20. Which of the following signal molecules is NOT used for extracellular signaling? a. Cyclic AMP b. Endocrine c. Autocrine d. Paracrine Answer: a. Cyclic AMP
21. Which signal molecules does NOT interact with cell surface receptor? a. Testosterone b. Glucagon c. Gastrin d. Insulin Answer: a. Testosterone
22. Which of the following guanine nucleotide-binding proteins (G-protein) takes part in the regulation of vision? a. Gs family b. Gq family c. Gi family d. Golf Answer: c. Gi family
23. Which of the following signaling pathway is followed by the T lymphocyte’s response to antigenic stimulation? a. Juxtacrine signaling b. Autocrine signaling c. Paracrine signaling d. Endocrine signaling
Answer: b. Autocrine signaling 24. What molecules c n
a directly convert extracellular signals into intracellular signals? a. transmembrane proteins b. Cell-surface receptors c. GPCRs d. All of these Answer: d. All of these
25. Choose the correct statement about the paracrine messenger molecules:
a. The messenger molecules are unstable
b. The messenger molecules are stable
c. The messenger molecules are short
d. The messenger molecules are large
Answer: a. The messenger molecules are unstable
26. Which of the following messenger molecules are derived from the fatty acid arachidonic acid? a. Eicosanoids b. Terpenoids c. Corticoids d. Steroids Answer: a. Eicosanoids
27. Which of the following type of signaling the cell that expresses messenger molecules also produces receptors? a. Paracrine b. Heterocrine c. Endocrine d. Autocrine Answer: d. Autocrine
28. How many transmembrane helices are present in the GPCRs (G-protein coupled receptors)? a. One b. Fiver c. Four d. Seven Answer: d. Seven
29. All steroid hormones are derived from: a. Chemicals b. Hormones c. Cholesterol d. Carbohydrates Answer: c. Cholesterol
30. Which of the following signaling molecules are used by simple nerve reflexes? a. Proteases b. G proteins c. Neurotransmitters d. Nitric oxides Answer: c. Neurotransmitters
2. Normal cells can be converted to cancer cells by treatment with _____________
a) carcinogenic compounds b) endonucleases c) exonucleases d) kinases
Explanation: Normal cells can be converted to cancer cells by treatment with carcinogenic compounds (such
as X-rays) that can induce mutations in the genome of normal cells, making them malignant.
3. The normal cells tend to remain in monolayer when their _____________ decreases. a) pH b) volume c) genomic content d) growth rate
Explanation: The normal cells tend to remain in single layer of cells, termed monolayer when their growth
rate decreases. The decrease in growth rate is caused due to inhibitory influences from the environment.
5. The two important compounds of serum that are necessary for cell culture are __________________
a) insulin, epidermal growth factor
b) insulin, phosphatidylserine
c) tumor necrosis factor, epidermal growth factor
d) epidermal growth factor, phosphatidylserine
Explanation: The two important compounds those are required for the culture of normal mammalian cells,
are insulin and epidermal growth factor, present as components of the serum’s fluid fraction. However, these
are not required for the culturing of cancer cells.
6. The immortality exhibited by the cancer cells is due to presence of _____________________ a) telomerase b) nuclease c) kinase d) protease
Explanation: In culture, the cancer cells possess the capability of growing infinitely unlike normal cells that
do not grow beyond a certain number of mitotic divisions. This immortality exhibited by the cancer cells is
due to the presence of enzyme telomerase.
7. The cancer cells are protected from ___________________ a) transcription b) mutation c) apoptosis d) contamination
Explanation: The cancer cells are protected from apoptosis and usually do not activate a cell destruction
pathway even when there is a presence of aberrant chromosome number and inhibitory signals from the environment.
8. Cancer cells depend on _________________ metabolic pathway. a) Effectors b) Primary messengers c) Secondary messengers d) G-proteins
Explanation: Arrestins are a small group of proteins that bind to the G-protein coupled receptors. To bind to
these receptors, the arrestins compete with heterotrimeric G-proteins. In the process of desensitization,
arrestin binding prevents further activation of the G-proteins.
11. For the development of cancer, which of the following is the most influential component of the genome? a) EGF b) Cytochrome c c) TP53 d) T53 12. p53 is a _________ a) translation factor b) polymerase c) endonuclease
d) transcription factor
Explanation: p53 is a protein transcription factor that is also called the guardian of the genome because of its
role in tumour suppression by causing apoptosis. p53 has also been used to treat onset of certain tumours.
13. p53 is capable of binding to which family of proteins? a) Bcl-1 b) Bcl-2 c) Bcl-3 d) Bcl-4
Explanation: p53 is a transcription factor that activates the expression of proteins involved in cell cycle
regulation and apoptosis. In addition to that, it can also bind directly to the Bcl-2 family of proteins and initiate apoptosis.
CELL CYCLE, CELL DIVISION AND CELL DEATH
1. Which term is used to refer to a period between the cell divisions? a) M phase b) G0 phase c) Interphase d) Resting phase
2. There are ______ major phases in a cell cycle. a) 1 b) 2 c) 3 d) 4
Explanation: Cells in vivo and in vitro pass through a series of defined stages, constituting the cell cycle.
The two major phases of the cell cycle are M phase (constituting mitosis and cytokinesis) and interphase.
4. Asynchronous cultures are the ones whose cells are _______________________ a) of different origin
b) randomly distributed through the cell cycle
c) have different genomic content
d) have different nutrient requirements
Explanation: Asynchronous culture is the term used for cultures that have cells that are randomly distributed
throughout the cell cycle i.e. all the cells might be at different stages of their life.
5. DNA replication can be monitored by incorporation of ______________________ a) tyrosine b) thymidine c) cytosine d) nitite
Explanation: DNA replication can be monitored by incorporating [3H]thymidine in the strands of double
helix. In this way, microscopy can be used to illustrate how the cells pass through each stage of the cell cycle.
6. DNA replication occurs during _________________ of the cell cycle. a) S phase b) Interphase c) G2 phase d) G0 phase
7. Which of the following cells do not lack the ability to divide? a) skin cells b) nerve cells c) muscle cells d) red blood cells
Explanation: Only highly specialized cells of the body such as nerve cells, muscle cells and red blood cells
lack the ability to divide, once they have differentiated they remain in that state till the end of their life cycles.
8. Which of the following cells do not usually divide but can be induced to divide? a) red blood cells b) liver cells c) hair cells d) hair follicles
Explanation: Liver cells do not usually grow and divide but can be made to do so under specific conditions
such as liver surgery. Lymphocytes can also be induced to regrow and divide by interaction with a proper antigen.
9. Which of the following cells are capable of asymmetric cell division? a) Hepatocytes b) Epithelial cells c) Stem cells d) Neurons
10. Cells that have stopped dividing and are arrested in a state preceding that of DNA synthesis, are said to be in the__________ a) S phase b) G1 phase c) G0 phase d) G2 phase
Explanation: Cells that have stopped dividing either temporarily or permanently are referred to as being in
the G0 state, to distinguish them from cells in the G1 phase that are about to enter the synthesis phase.
12. What will happen if a G2 phase cell is fused with an M phase cell?
a) premature chromosome compaction b) chromosome aggregation c) gene transcription
d) inhibition of transcription
Explanation: If a G1 cell and M phase cell are fused together, premature chromosome compaction takes
place. If G2 and M phase cell are fused together G2 chromosomes will appear visibly doubled and undergone premature gene compaction.
13. The entry of a cell into M phase is initiated by _________________ a) interleukin factor
b) maturation promoting factor c) transcription factor d) necrosis factor
Explanation: The entry of a cell into mitotic (division or M phase) phase is initiated by the maturation
promoting factor (MPF). It consists of two subunits o
– ne with kinase activity and the other with regulatory activity.
14. The regulatory subunit of maturation-promoting factor (MPF) is called _______________ a) kinase b) cyclin c) tetracyclin d) interleukin
Explanation: The regulatory subunit of maturation-promoting factor (MPF) is called cyclin. The
concentration of this regulatory protein changes in a predictable pattern. When the cyclin concentration is low, the enzyme is inactive.
15. Cyclin binding leads to a change in the _________________ of kinase. a) pH b) temperature c) concentration d) conformation
Explanation: Cyclin binding leads to a change in the conformation of catalytic subunit of kinase enzyme by
binding to its catalytic site. This binding allows the cyclin dependent kinase (CDK) to phosphorylate its substrates.
DNA STRUCTURE, REPLICATION, AND REPAIR
1/ Process of genetic information flowing from DNA to RNA to proteins is called A. gene annealing B. gene mutation C. gene expression D. gene therapy
2/ 5-Flurouracil is a chemotherapeutic agent used in the treatment of many cancers. It works by inhibiting
the S-phase of the cell cycle through inhibiting the synthesis of: A. dUMP from dTMP B. dTMP from dUMP C. dAMP from dGMP D. dGMP from dAMP
3, What is the structure indicated below? A. Adenosine B. Deoxyadenosine C. Guanosine D. Cytidine
4/ Dyskeratosis congenital (DKC) is a genetically inherited disease in which the proliferative capacity of
stem cells is markedly impaired. The defect has been traced to inadequate production of an enzyme needed
for chromosome duplication in the nuclei of rapidly dividing cells. Structural analysis has shown that the
active site of this protein contains a singlestranded RNA that is required for normal catalytic function.
Which step in DNA replication is most likely deficient in DKC patients?
A. Synthesis of Okasaki fragments B. Synthesis of RNA primers
C. Synthesis of telomeres D. Removal of RNA primers
5/ Newly synthesized DNA contains A. both new strands B. both old strands
C. one new strand and one old strand D. only one strand
6, In patients with hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome, which of the
following repair mechanisms is defective:
A. Nucleotide-excision repair (NER) B. Mismatch repair C. Base-excision repair (BER) D. All of the above
7. An nucleic acid contains: 15%A, 55%C, 30%T, 20%G. What is the most likely source of this nucleic acid: A. bacterial plasmid B. mitochondrial chromosome C. nuclear chromosome
D. viral genome (bộ gen virus)
8. Endonuclease activation and chromatin fragmentation are characteristic features of eukaryotic cell death
by apoptosis. Which of the following chromosome structures would most likely be degraded first in an apoptotic cell? A. 10-nm fiber B. 30-nm fiber C. centromere D. heterochromatin 9. Which is correct?
TRANSCRIPTION AND TRANSLATION
3/ To start transcription, RNA polymerase recognizes nucleotide sequences in what region of the DNA? A. Promoter region B. Template region C. G-C rich region D. Terminator region
4/ A geneticist isolates a gene for a specific trait under study. She also isolates the corresponding mRNA.
Upon comparison, the mRNA is found to contain 1,000 fewer bases than the DNA sequence. Did the
geneticist isolate the wrong DNA?
A. yes, mRNA is made from a DNA template and should be the same length as the gene sequence
B. yes, the mRNA should contain more bases than the DNA sequence because bases flanking the gene are also transcribed
C. no, the final mRNA contains only exons, the introns were removed
D. no, the mRNA was partially degraded after it was transcribed
5/ A 10-year-old boy with severe progressive skin ulceration, decreased resistance to infection, and impaired
cognitive ability has been diagnosed with a genetic deficiency of the enzyme prolidase. Mutat ion analysis
has identified a single base substitution at the 3’ end of intron 6 of the mutant allele as well as deletion of a
45-base exon (exon 7) in the prolidase cDNA. Which type of gene mutation was most likely inherited by this boy? A. Splice-site mutation B. Frame-shift mutation C. Missense mutation D. Nonsense mutation
6/ What is the role of chaperone proteins in protein synthesis?
A. Assisting correct folding of the newly formed polypeptide chain.
B. Correct formation of disulphide bridges in protein folding.
C. Release of completed proteins from the ribosome.
D. Switching peptide bonds that involve proline residues between the cis and the trans configurations
7/ Proteins directed to which of the following organelle is synthesized by ribosomes attached to the rough endoplasmic reticulum? A. Cell membrane B. Mitochondria C. Nucleus D. Peroxisomes
8/ Parahemophilia is an autosomal recessive bleeding disorder characterized by a reduced plasma
concentration of the Factor V blood coagulation protein. Deficiency arises from a 12 base-pair deletion in
the Factor V gene that impairs the secretion of Factor V by hepatocytes and results in an abnormal
accumulation of immunoreactive Factor V antigen in the cytoplasm. In which region of the Factor V gene
would this mutation most likely be located? A. Last exon B. First exon
C. 5’ Untranslated region D. 3’ Untranslated region
9/ Bằng cách nào ribosome của nhân sơ bám vào vị trí chính xác trên chuỗi mRNA để bắt đầu dịch mã:
A. Nó bám vào đầu 5’ tự do của mRNA
B. Nó nhận diện và bám vào codon khởi đầu AUG
C. Các protein của ribosome nhận diện và bám vào 1 trình tự ngay phía trước điểm khởi đầu
D. RNA của ribosome bắt cặp đặc hiệu với một trình tự bazo nằm ngay trước điểm khởi đầu
10/ Which type of Covid-19 vaccine below having translation of viral protein (spike protein) occurring in human body cells? A. mRNA vaccines B. Protein-based vaccine
C. Inactivated virus-based vaccine D. Lipid-based vaccine
GENE REGULATION IN EUKARYOTES AND PROKARYOTES 1. Eukaryotic entities
(a) in the presence of a cAMP molecule, it carries out protein synthesis
(b) have only operons assisting in gene expression
(c) transcription takes place in the nucleus and translation in the cytoplasm
(d) transcription occurs in the cytoplasm and translation in nucleus
2. A genomic DNA possesses functioning units, a group of genes under the influence of promoters known as (a) genes (b) operons (c) anticodon (d) codon
3. All regulatory proteins possess a common DNA binding motif that is specific flexes in their protein
chains permitting them to interlock with
(a) the outside groove of DNA helix
(b) the major groove of DNA helix
(c) the minor groove of DNA helix
(d) the inner groove of DNA helix
4. Regulatory proteins turn transcription off through binding to a site rapidly at the front of the
promoter and many times even overlaps the promoter, this site is the (a) regulatory site (b) operator site (c) suppressor site
(d) transcriptional control site
5. Seemingly, the vertebrate cells contain a protein which binds to clusters of 5-methylcytosine
ensuring that the bound gene stays in the “off” position. This regulation on the role of gene regulation is an outcome of (a) Methylation (b) Translation (c) Enhancer expression (d) operator suppression
6. The transcriptional gene control in eukaryotes is mediated by
(a) metabolites that bind to the cis-acting elements
(b) trans-acting factors failing to bind to cis-acting elements
(c) trans-acting factors binding to cis-acting elements
(d) repressor proteins that bind to operator sites
7. Basic tools of genetic regulation are the ability of some proteins to bind to specific
(a) regulatory DNA sequences (b) regulatory RNA sequences (c) enzymes of cells
(d) promoter portions of genes
8. In the regulation of gene expression, this is an incorrect statement
(a) in the bacteria, it permits to replicate with no control
(b) in the bacteria, it permits to adapt to changing environments
(c) permits the maintenance of homeostasis in multicellular entities
(d) permits the functioning of multicellular entities on the whole
9. There are these many histones in the core of a nucleosome (a) 8 (b) 6 (c) 4 (d) 2
10. In eukaryotes and bacteria, the most common form of regulation is (a) promoter control (b) translation control (c) repressor control
(d) transcriptional control
11. Expression of gene is controlled in eukaryotes At many places in the cell
12. Which one of the following is not a component of lac operon model? A. Promoter gene B. Structural gene C. Primer gene D. Regulator gene
13. Which molecule is not produced by E. Coli in the lactose medium?
A. lactose dehydrogenase
B. thiogalactoside transacetylase C. beta-galatosidase D. lactose permease
14. The lactose operon consists of five genes one i –
nhibitor, one operator and three structural genes
15. Aporepressor is inactive repressor in tryptophan repressible operon system. It is generally a protein
16. Addition of lactose in a culture of E. Coli induces enzymes to breakdown the lactose into glucose
and galactose B-galactosidase (tổng hợp bởi gene Z), permease, transacetylase
38. Choose the wrong one out for insertion sequence.
(a) Insertion sequences are transposons
(b) Insertion sequences range from 5kb to 30kb
(c) Insertion sequences only carry genes for their transposition
(d) Insertion sequences have terminal IR
Ans. (b) Insertion sequences range from 5kb to 30kb
Explanation: Insertion sequences are very short transposons which range from 768 bp to 5 kb.
39. Which of the following is wrong option?
(a) Transposons have trasposase along with other genes
(b) Transposons lack inverted terminal repeats
(c) Transposons have insertion sequences within it
(d) Class III transposons are called MITES
Ans. (b) Transposons lack inverted terminal repeats
40. Which of the following is not true about conservative transposition?
(a) It creates direct repeat sequences on either side
(b) It is Copy-Paste mechanism
(c) Transesterification reaction takes place
(d) Class II transposons have this mechanism
Ans. (b) It is Copy-Paste mechanism
Explanation: Conservative or non-replicative transposition acts through cut and paste mechanism. The donor
site loses the transposon which is inserted in the recipient generating direct repeats. It is seen in class II transposons.
41. Which of the following enzyme is seen in copy-paste method, but not seen in cut-paste transposition? (a) Resolvase (b) Strand transfer (c) Transposase (d) Synaptic complex Ans. (a) Resolvase
42. choose wrong one about Inversion:
(a) Inverted chromosomes are generally viable
(b) Inversion can cause chromosome breakage
(c) Two DNA strands with an inverted segment will not pair
(d) Inversion including centromere is known as pericentric
Ans. (c) Two DNA strands with an inverted segment will not pair
43. Consider this sequence A—O—B —C—D—E—F, be a DNA sequence where O is the centromere.
Which of the following will be a pericentric inversion? (a) A—O—B—D—E—F (b) B—O—A—D—E—F (c) D—B—O—A—E—F (d) A—O—E—D—B—F
Ans. (d) A—O—E—D—B—F
Explanation: Pericentric inversion is the inversion that doesn’t involve the centromere. Here in option A
there is no change at all, option B and C are including the centromere. Only option D doesn’t involve the
centromere in the inverted sequence, so it is pericentric.
44. What are the results of pericentric inversion with single crossing over?
(a) Two normal, one dicentric and one acentric chromosome
(b) 2 dicentric and 2 acentric chromosomes
(c) Four normal chromosomes with centriomere in different positions
(d) 3 normal chromosome, one abnormal acentric chromosome
Ans. (a) Two normal, one dicentric and one acentric chromosome
Explanation: Recombination in the paracentric region will take place between only two strands, so the other
two strands will be normal. This recombination will result in one dicentric chromosome and another acentric chromosome.
45. In drosophila male there is no cross over suppression due to pericentric inversion as:
(a) They have only one set of chromosome
(b) They always have double cross over (c) They never recombine
(d) They don’t undergo meiosis
Ans. (c) They never recombine
46. Which of the following is an example of inversion? (a) Chromosome 22 and 9 (b) Chromosome 8 (c) Chromosome 14 (d) Chromosome 3 Ans. (d) Chromosome 3
Explanation: In chromosome 3 of human there is duplication-deletion which leads to inversion.
47. In pericentric inversion, the inversion loop involves __________ strands. (a) 1 (b) 2 (c) 3 (d) 4 Ans. (d) 4
48. Which of the following case of duplication involves more than one chromosome? (a) Tandem duplication
(b) Reverse tandem duplication (c) Displaced (d) Transposed Ans. (d) Transposed
49. Tandem duplication creates ____________ and reverse tandem creates_____________ (a) Buckling, looping (b) Hairpin, buckling (c) Buckling, Hairpin (d) Loop with turn, hairpin
Ans. (c) Buckling, Hairpin
Explanation: In case of tandem repeat the same sequence in same order is repeated. As parent chromosome
has only one copy of that sequence the daughter bulges out. This, causes buckling. In reverse tandem the
duplication is inverted in sequence which leads to formation of hairpin.
50. Which of the following explains Streisinger’s model? (a) Transition Frame shifts (b) Transposition (c) Inversion (d) Frame shifts Ans. (d) Frame shifts
Explanation: Streisinger’s model explains that the Frame shift mutations are more frequent in repetitive
sequences. This causes duplicative insertion and also at times deletion. 51. 52. 53. 54. 55. 56. SINGLE GENE DISORDERS
1/ Traits produced by a gene can be either dominant or recessive. A trait is dominant when the trait appears
when only one copy of the gene is present. A trait is recessive when the trait only appears when two copies
of the gene for that trait are present. Which of the following is the term used for people who have only one
copy of an abnormal gene for a recessive trait? A.Carriers B.Codominants C.Non-X-linked inheritors D.X-linked inheritors
2/ To inherit a recessive disorder, a person usually must receive two abnormal genes, one from each parent.
If both parents have one abnormal and one normal gene, neither parent has the disorder. However, each
parent has a 50% chance of passing the abnormal gene to their children. Which of the following is the
likelihood each child has of inheriting two normal genes? A.25% B.50% C.66% D.75%
3/ Human chromosomes contain a long strand of DNA and many genes. With the exception of sperm and
egg cells, how many pairs of chromosomes are contained in each human cell? A. 8 B. 15 C. 23. D. 30 4/ 5/ 6/ 7/ 8/ 9/ 10/ 11/ 12/