Category: Cell Biology Objective Questions

Cell Biology Multiple Choice Questions on “Cellular Membranes – Lipids and Fluidity”.

1. Fluidity and viscosity are the same.
A. True
B. False
Answer: B
Clarification: Fluidity and viscosity are not the same and they are inversely related. Fluidity is a measure of ease of flow and viscosity is the resistance to flow.

2. Which of the following attributes of the membrane is most affected at the transition temperature?
A. size
B. fluidity
C. internal composition
D. internal environment
Answer: B
Clarification: At the transition temperature, the bilayer distinctly changes from liquid crystalline phase to crystalline gel. This occurs when the temperature is lowered from a standard warm temperature of 37⁰C.

3. The ___________ the degree of unsaturation of the fatty acids of the bilayer, the ___________ the temperature before the bilayer gels.
A. greater, lower
B. greater, more
C. lesser, higher
D. lesser, higher
Answer: A
Clarification: When the number of unsaturated fatty acids in the membrane is more, lower the transition temperature at which the membrane gels.

4. Which of the following molecules affects the mobility of fatty acyl chains in the plasma membrane?
A. starch
B. glycogen
C. cholesterol
D. carbohydrates
Answer: C
Clarification: Cholesterol disrupts the packing between fatty acyl chains and interferes with their mobility. It makes the membrane durable while decreasing the permeability of the membrane.

5. Which of the following occurs in the membrane, when the temperature is lowered?
A. denaturation
B. desaturation
C. saccharification
D. glycolysis
Answer: B
Clarification: When the temperature of the surrounding is lowered, the cells respond metabolically. Membrane remodeling takes place to make the cell more cold resistant. This takes place by desaturation of fatty acyl chains to form double bonds.

6. Lipid rafts are patches of cholesterol and ________________
A. carbohydrates
B. amino acids
C. lipids
D. sphingolipids
Answer: D
Clarification: Lipid rafts are the patches of cholesterol and sphingolipids. When membrane lipids are extracted from the membranes to synthesize artificial membranes in vitro, cholesterol and sphingolipids tend to self-assemble.

7. Cell fusion can be performed on two cells from different species.
A. True
B. False
Answer: A
Clarification: Cell fusion is a technique to fuse two cells from different species to form one cytoplasm and one single continuous plasma membrane.

8. In the experiments to demonstrate the mobility of membrane proteins, which cells were fused with human cells?
A. mouse cells
B. drosophila cells
C. tumor cells
D. bacterial cells
Answer: A
Clarification: The first experiments to demonstrate that membrane proteins can move within the plane of the membrane used fused cells of human and mouse. These were performed in 1970 at the John Hopkins University.

9. Which phenomena are made use of in the technique FRAP?
A. electrostatic
B. photothermal
C. hybridization
D. fluorescence
Answer: D
Clarification: Fluorescence recovery after photobleaching (FRAP) is a technique in which integral membrane proteins are labeled with a fluorescent dye, after which they are irradiated by a laser beam.

10. Which type of molecules are used in SPT?
A. organic dye
B. inorganic dye
C. antibodies
D. gold particles
Answer: D
Clarification: In the technique of single-particle tracking (SPT), individual membrane proteins are labeled with antibody conjugated gold particles and their movement is traced using computer-enhanced microscopy.

11. The use of optical tweezers in membrane biology was done to confirm the ________________ nature of membranes.
A. self-replicating
B. elastic
C. inelastic
D. photo-responsive
Answer: B
Clarification: The integral membrane proteins are tagged with antibody-coated beads that provide for handles that can be gripped by laser beam. The experiments concluded that membrane barriers are elastic in nature.

12. The sperm cell is covered by a _____________
A. sheath
B. cell wall
C. continuous membrane
D. discontinuous membrane
Answer: C
Clarification: Of all the cells in mammals, sperms are the most highly differentiated. A mature sperm is divided into three regions head, midpiece and tail; all having their specific functions. The sperm is covered by a continuous plasma membrane that contains a mosaic of specialized domains.

13. Hemolysis is associated with which type of cells?
A. hepatocytes
B. germ cells
C. somatic cells
D. red blood cells
Answer: D
Clarification: Hemolysis is the phenomenon when red blood cells are placed in a dilute hypotonic solution which makes the uptake water and resultant swelling. When they swell up, they become leaky and the contents flow out of the cells.

14. Band 3 and glycophorins are membrane proteins that contain ________________
A. carbohydrates
B. sterols
C. lipids
D. nucleic acids
Answer: A
Clarification: Band 3 and glycophorins are carbohydrate-containing membrane proteins. Band 3 gets its name from the position in electrophoretic gel; it is present in the membrane as a homodimer.

15. Which is the first membrane protein to have its amino acid sequence determined?
A. Glycophorin A
B. Glycophorin B
C. Glycophorin C
D. Glycophorin D
Answer: A
Clarification: Glycophorin A is the first membrane protein to have its amino acid sequence determined. Other glycophorins are present in lesser amount in the membranes. Glycophorin A has carbohydrates attached that account for 60% of its weight.

Cell Biology Multiple Choice Questions on “Chloroplast Structure and Function – Chloroplast and Photosynthetic Pigments”.

1. Who first discovered chloroplast?
A. J Rhodin
B. Robert Porter
C. Camillo Golgi
D. Konstantin Mereschkowski
Answer: D
Clarification: Chloroplast are small cell organelles found in both eukaryotic and some prokaryotic photosynthetic organisms. They were first discovered by Konstantin Mereschkowski in 1905.

2. What is the diameter of a chloroplast?
A. 1 – 2 micrometer
B. 2 – 4 micrometer
C. 4 – 6 micrometer
D. 6 – 10 micrometer
Answer: C
Clarification: Chloroplasts are generally 4 – 6 micrometer in diameter and 2 – 4 micrometer in thickness. These chloroplasts are round, oval and disc shaped organelles.

3. The mass of chloroplast DNA is __________
A. 10 – 15 million daltons
B. 50 – 100 million daltons
C. 80 – 130 million daltons
D. 25 – 125 million daltons
Answer: C
Clarification: The chloroplasts have their own DNA, which is circular in shape that forms a ring like structure. A single chloroplast DNA has a mass of about 80 – 130 million daltons.

4. The number of chloroplasts found in Arabidopsis thaliana is _____________
A. 100
B. 150
C. 50
D. 200
Answer: A
Clarification: Arabidopsis thaliana commonly known as mouse-ear cress has around 100 chloroplasts in each cell. The number of chloroplasts in each organism differ from species to species depending on the need of energy from photosynthesis.

5. Identify A and B from the below figure.

A. A – Lumen; B – Thylakoids
B. A – Thylakoids; B – Lumen
C. A – Stroma; B – Grana
D. A – Grana; B – Stroma
Answer: B
Clarification: Thylakoids resemble the structure of a coin, a stack of thylakoids looks like a stack of coins known as grana. The lumen is a connection between two or more grana.

6. The sunlight is captured by the membrane of thylakoids.
A. True
B. False
Answer: A
Clarification: The membrane of thylakoids is responsible for photosynthesis. They entrap the solar energy and provide it for the photosynthesis.

7. Which pigment is responsible for the process of sunlight?
A. Chlorophyll a
B. Chlorophyll b
C. Xanthophyll
D. Anthocyanin
Answer: A
Clarification: Chlorophyll a is the pigment, which primarily helps in photosynthesis. Xanthophyll and Anthocyanin are the pigments responsible for yellow and blue colour in plants respectively.

8. Which pigment constitutes majorly in absorbing sunlight for photosynthesis?
A. Chlorophyll a
B. Chlorophyll b
C. Xanthophyll
D. Anthocyanin
Answer: B
Clarification: Chlorophyll b is a pigment, which is yellow in colour. This pigment is responsible for the vast absorption of sunlight. It is present in the light absorbing antenna of the plants.

9. Which of the following organisms has photosynthetic pigments in it?
A. Yeast
B. Nitrosomonas
C. Spirulina
D. Phosphobacter
Answer: C
Clarification: The spirulina, which belongs to the community of cyanobacteria, commonly known as blue green algae, has photosynthetic pigments in it. They predominantly contain chlorophyll a.

10. What is the chemical formula of chlorophyll a?
A. C₄₅H₇₂MgN₄O₅
B. C₅₅H₇₂MgN₄O₅
C. C₅₅H₇₂MnN₄O₅
D. C₄₅H₇₂MnN₄O₅
Answer: B
Clarification: The chlorophyll a contains a magnesium ion complex, which forms a ring structure called the Chlorin ring. It has a molar mass of 893.51 g•mol⁻¹.

11. Chloroplast divide by binary fission.
A. True
B. False
Answer: A
Clarification: Chloroplasts cannot be synthesized by the cell itself. They have their own DNA and it divides by binary fission process like prokaryotes.

12. What disease is caused by the dysfunction of chloroplast?
A. Leaf spot
B. Blight spot
C. Leaf variegation
D. Powdery mildew
Answer: C
Clarification: Leaf variegation is caused by the deficiency of chloroplast due to mutation. Blight spot, Leaf spot and Powdery mildew are caused by fungi.

Cell Biology Multiple Choice Questions on “Cytoplasmic Membrane Systems – Golgi Complex”.

1. Golgi complex has a cisternae of diameter _________
A. 0.5-1 mm
B. 0.5-1 nm
C. 0.5-1 pm
D. 0.5-1 μm
Answer: D
Clarification: The Golgi complex was discovered by Camillo Golgi for which he was awarded Nobel Prize in 1908. It consists of flattened, disk-like membranous cisternae of diameter 0.5 to 1 μm.

2. Cis-Golgi network (CGN) is closer to the endoplasmic reticulum than the trans-Golgi network (TGN).
A. True
B. False
Answer: A
Clarification: Cis-Golgi network is the entry face closes to endoplasmic reticulum (ER) and trans-Golgi network is the opposite face to the ER. The CGN primary functions to sort out the proteins that are to be sent back to ER and those that proceed further in the Golgi complex.

3. Which of the following parts of Golgi complex directs the proteins to their final intracellular destinations?
A. tubules
B. cis-Golgi network
C. trans-Golgi network
D. medial cisternae
Answer: C
Clarification: Trans-Golgi network (TGN) is the final station in the Golgi complex where the proteins are sorted out based on their final intracellular destinations.

4. Which protein families do not mechanically support the Golgi complex?
A. Keratin
B. Actin
C. Spectrin
D. Ankyrin
Answer: A
Clarification: The Golgi complex is mechanically supported by a scaffold or a peripheral membrane skeleton consisting of a variety of protein families – ankyrin, actin, spectrin.

5. Newly synthesized membrane proteins enter the cis face of the Golgi complex and leave from the trans face.
A. True
B. False
Answer: A
Clarification: The newly synthesized membrane and lysosomal proteins from the endoplasmic reticulum enter the Golgi complex through the cis face and reach the trans face, getting modified throughout the way.

6. Which of the following is located at the trans end of the Golgi stack?
A. ascorbic acid
B. methanoic acid
C. sialyl-transferase
D. dehydrogenase
Answer: C
Clarification: The enzyme sialyl-transferase is located at the trans face of the Golgi stack and it places sialic acid at the terminal position of the glycoprotein chains.

7. Which of the following is not completely synthesized in the Golgi complex of a cell?
A. Pectins
B. Hemicellulose
C. N-linked oligosaccharides
D. O-linked oligosaccharides
Answer: C
Clarification: Pectins and hemicelluloses found in the plant cell wall as well as O-linked oligosaccharides are synthesized completely in the Golgi complex. The synthesis of N-linked oligosaccharides begins in the endoplasmic reticulum (ER).

8. How many models of movement of materials through the Golgi complex exist?
A. 1
B. 2
C. 3
D. 4
Answer: B
Clarification: There two models with contrasting views on the movement of materials through the Golgi complex namely “Cisternal maturation model” and “Vesicular transport model”.

9. What is responsible for the transport of materials from the cis cisternae to the trans cisternae of the Golgi complex?
A. active diffusion
B. passive diffusion
C. translocon
D. transport vesicles
Answer: D
Clarification: The materials such as membrane proteins and other proteins are transported from the cis cisternae to the trans cisternae by means of vesicles that bud from the rims of cisternae stack.

10. While moving from cis cisternae to the trans cisternae, which molecule does not leave the cisternal lumen?
A. membrane proteins
B. procollagen
C. oligosaccharides
D. lysosomal proteins
Answer: B
Clarification: Procollagen molecules are the precursors of extracellular collagen found in fibroblasts. They move from cis cisternae to the trans cisternae without ever leaving the cisternal lumen.

Cell Biology Multiple Choice Questions on “Chemical Basis of Life – Carbohydrates”.

1. Heptoses are __________
A. sugars
B. proteins
C. amino acids
D. monomers
Answer: A
Clarification: Heptoses are carbohydrates that contain 7 atoms of carbon. The sugars of importance in cellular metabolism contain 3 to 7 carbon atoms.

2. Fructose is a _____________
A. aldose sugar
B. ketose sugar
C. monosaccharide
D. polymer
Answer: B
Clarification: Fructose is a ketose sugar because the carbonyl group (C==O) is located in an internal position to form a ketone group. If the carbonyl bond is located at one end of the sugar it is called aldose sugar.

3. The compounds which have same chemical reactivity but structures which are mirror images of each other are known as ____________
A. isoforms
B. allotropes
C. enantiomers
D. isomers
Answer: C
Clarification: Enantiomers or stereoisomers are the compounds having similar chemical reactivity and their structures are mirror images of each other.

4. Which of the following conventions is used to denote the presence of carbonyl group in left/right in the chemical structure of a carbohydrate?
A. Positive/ negative
B. -1/ +1
C. L/ R
D. L/ D
Answer: D
Clarification: When carbonyl group as in ketone or aldehyde is located on the left side the molecule is represented with a prefix ‘L-‘, for example L- glyceraldehyde; if present on the right prefix ‘D-‘ is added.

5. Enzymes in a cell can distinguish between L and D forms of sugar.
A. True
B. False
Answer: A
Clarification: Enzymes present in a living cell can differentiate between the D and L forms of sugar. Therefore, a cell uses only one of the stereoisomers. For example, only D-glucose is used.

6. Which types of bonds are found in sugars?
A. amide
B. acidic
C. glycosidic
D. non-covalent
Answer: C
Clarification: Sugars are joined to one another by covalent glycosidic bonds that play a major role in the formation of large sugar moieties. In these bonds carbon of one sugar molecule bonds with the hydroxyl group of another sugar generating a –C-O-C- linkage.

7. Sucrose and lactose are _____________
A. monosaccharides
B. disaccharides
C. pentoses
D. polyssaccharides
Answer: B
Clarification: Disaccharides provide the readily available stores of energy. Sucrose is found in plant sap and has the function of carrying chemical energy from one part of the plant to another. Lactose is found in milk of mammals and has the role of nourishing the new born with fuel for growth and early development.

8. Enzyme lactase is found in ______________
A. nucleus
B. ribosome
C. plasma membrane
D. golgi complex
Answer: C
Clarification: The enzyme lactase is responsible for hydrolyzing lactose. It is found in the plasma membrane of cells lining the walls of the intestine.

9. Which type of carbohydrates lead to the formation of glycolipids and glycoproteins?
A. Oligosaccharides
B. Monosaccharides
C. Glycogen
D. Glucose
Answer: A
Clarification: Oligosaccharides are formed when sugar molecules link to form small chains (oligo means few). These form covalent bonds with lipids and proteins generating glycolipids and glycoproteins.

10. Which of the following polysaccharide is not entirely composed of glucose subunits?
A. Lactose
B. Starch
C. Glycogen
D. Cellulose
Answer: A
Clarification: Lactose is a disaccharide molecule found in milk. Glycogen, starch and cellulose are all polysaccharides composed entirely of glucose subunits. They have same constitution but different chemical and physical properties.

Cell Biology Multiple Choice Questions & Answers (MCQs)on “Cellular Membranes – Plasma Membrane”.

1. Transverse diffusion (flip-flop) is the movement of _____________
A. cholesterol molecule
B. amino acid
C. protein
D. phospholipid
Answer: D
Clarification: In case of a membrane phospholipid, two types of movements are possible: lateral shift i. e. movement from one place in the bilayer membrane to the other within the same leaflet; and transverse diffusion is movement of the phospholipid from one side of the membrane to the other, which is a relatively long process.

2. The mobility of integral proteins can be measured by physical state of the ______________
A. amino acids
B. external phospholipids
C. membrane phospholipids
D. membrane appendages
Answer: C
Clarification: Since integral proteins are embedded in the phospholipid bilayer of the membrane, the mobility of the integral proteins is determined largely by the physical state of membrane phospholipids.

3. Two cells can be operated in such a way that leads to a common continuous plasma membrane of both.
A. True
B. False
Answer: A
Clarification: In a technique called cell fusion, two cells from different species can be fused to have a common cytoplasm and a single continuous membrane.

4. Which of the following can not be used to mediate the fusion of plasma membranes of two different cells?
A. electric shock
B. inactivated viruses
C. Polyethylene glycol
D. emulsifier
Answer: D
Clarification: There are various techniques that can be used to fuse two different cells and all of these are basically used to either modify the surface of plasma membrane or attach to it (inactivated viruses). Emulsifiers however do neither and are hence not used in cell fusion.

5. FRAP can be used to analyze living cells.
A. True
B. False
Answer: A
Clarification: FRAP is a technique that can be used to monitor the movements of molecules across the plasma membranes of a living cell under a light microscope.

6. The erythrocyte has a _________________ shape.
A. spherical
B. convex
C. concave
D. bi-concave
Answer: D
Clarification: The peripheral proteins of the plasma membrane of an erythrocyte are located on the internal surface and make up a fibrillar membrane skeleton, which plays a major role in determining the bi-concave shape of an erythrocyte.

7. Which of the following genetic diseases is caused by mutations in a membrane protein?
A. Alzheimer’s disease
B. Parkinson’s disease
C. Anemia
D. Hemolytic anemia
Answer: D
Clarification: Hemolytic anemia is caused by the abnormal shapes of erythrocytes which have been traced to the mutations in ankyrin or spectrin which are plasma membrane proteins found in erythrocytes.

8. Glycophorin is involved in which of the following disease?
A. viral fever
B. common cold
C. asthma
D. malaria
Answer: D
Clarification: Glycophorin is the receptor utilized by the protozoan that causes malaria, providing a path for entry into the blood cells. Consequently, those who lack glycophorin A and B are immune against the disease.

Cell Biology Questions and Answers for Campus interviewson “Chloroplast Structure and Function – Photosynthetic Units and Reaction Centres”.

1. In which part of the plant, does photosynthesis takes place?
A. Peroxisomes
B. Glyoxisomes
C. Quantosomes
D. Lysosomes
Answer: C
Clarification: Quantosomes are sub cellular organelles present in the membrane of thylakoid in the chloroplast. Their function is to absorb light energy and start the photosynthesis mechanism.

2. Which pigment protects the photosystem from ultraviolet radiation?
A. Chlorophyll a
B. Chlorophyll b
C. Carotenoids
D. Anthocyanin
Answer: C
Clarification: Carotenoids are coloured pigments found in plants and some other prokaryotic algal cells. Carotenoids do not directly contribute to the photosynthesis, but they protect the plants from UV radiation.

3. What is the name of the book written by Jan Ingenhousz, which explains the basis of photosynthesis?
A. Experiments upon Fruits
B. Experiments upon Vegetables
C. Experiments upon Plants
D. Experiments upon Animals
Answer: B
Clarification: Jan Ingenhousz in the year 1779 carried out around 500 experiments to prove the mechanism of photosynthesis. He observed that plants absorb carbon di oxide and evolve oxygen with the help of light energy.

4. Photosystem II happens before photosystem I.
A. True
B. False
Answer: A
Clarification: Photosystem II happens before photosystem I but the name I and II denotes the order of their discovery. The electrons usually flow from photosystem II to photosystem I.

5. Which of the following amino acid is helpful in the synthesis of plastoquinone?
A. Valine
B. Isoleucine
C. Leucine
D. Tyrosine
Answer: D
Clarification: Plastoquinone is a branched chain unsaturated quinone, which helps in the electron transport chain of photosynthesis. P-hydroxyphenylpyruvate is synthesized from tyrosine which then converts finally to plastoquinone.

6. What is the other name of Plastoquinol – plastocyanin reductase?
A. Cytochrome b₄f complex
B. Cytochrome b₅f complex
C. Cytochrome b₆f complex
D. Cytochrome b₅g complex
Answer: C
Clarification: Plastoquinol – plastocyanin reductase is also known as the Cytochrome b₆f complex. It is an enzyme that helps to transfer electrons from Photosystem II to Photosystem I.

7. What is the maximum wavelength of light photosystem II can absorb?
A. 680nm
B. 450nm
C. 700nm
D. 230nm
Answer: A
Clarification: Photosystem II primary donor or P680 is a complex of many pigments which has the potentiality to absorb maximum light at 680nm. It is also known to be the strongest biological oxidizing agent.

8. Which of the following Vitamins act as an electron acceptor in light dependent photosynthesis?
A. Vitamin A
B. Vitamin D
C. Vitamin E
D. Vitamin K
Answer: D
Clarification: Vitamin K also known as phylloquinone acts as an electron acceptor during photosynthesis. It donates a hydrogen molecule and helps in the electron transport chain.

9. During photosynthesis, how many chlorophyll molecules are required to produce one oxygen molecule?
A. 1000
B. 2000
C. 2500
D. 3000
Answer: C
Clarification: Scientists Emerson and Arnold found that in a photosynthetic reaction 2500 molecules of chloroplast is required to produce one molecule of oxygen. They also require eight photons in the process of producing one molecule of oxygen.

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