CELL : THE UNIT OF LIFE
Different shapes of cells
- Round and biconcave : Red blood cells
- Amoeboid : White blood cells
- Long and narrow : Columnar epithelial cells
- Branched and long : Nerve cell
- Elongated : A tracheid
- Round and oval : Mesophyll cells
Different size of cells
- Smallest cells : Mycoplasma (0.3 μm in length)
- Bacteria : 3-5 μm, RBC : 7.0 μm in diameter
- A typical eukaryotic cell : 10-20 μm
- Typical bacteria : 1-2 μm
- PPLO : about 0.1 μm
- Viruses : 0.02-0.2 μm
- Largest isolated single cell : Egg of ostrich
- Longest cells : Nerve cell
Prokaryotic Cells
- Bacteria, blue-green algae, mycoplasma & PPLO (Pleuro Pneumonia Like Organisms)
- Shape & Size : Bacillus, Coccus, Vibrio and Spirillum (Bacteria)
- Chromatophores : Cyanobacteria (Prokaryotes)
Inclusion Bodies
- Phosphate granules, cyanophycean granules, glycogen granules & gas vacuoles
Membrane less organelles : Ribosome, Centrosome, Inclusion Bodies & Nucleolus
Eukaryotic Cells
- Cellmembrane: RBC = 52% protein + 40% lipid
- Contractile vacuole : Amoeba
- Food vacuoles : Protists
- Amyloplasts : Starch, Elaioplasts : Oil and fats
- Aleuroplasts : Proteins
- Chloroplasts : Their number varies from 1 (e.g. Chlamydomonas) to 20-40 per cell in the mesophyll
Chromosome Type : Based on position of centromere
- Metacentric
- Sub-metacentric
- Acrocentric
- Telocentric
Question 1: Which of the following scientists first observed and described a live cell?
(a) Robert Hooke.
(b) Anton Von Leeuwenhoek.
(c) Robert Brown.
(d) Rudolf Virchow.
Answer: (b) Anton Von Leeuwenhoek.
Question 2: The concept of 'Omnis cellula-e cellula' was proposed by Rudolf Virchow in which year?
(a) 1838.
(b) 1839.
(c) 1855.
(d) 1898.
Answer: (c) 1855.
Question 3: Theodore Schwann, based on his studies on plant tissues, concluded that the presence of ______ is a unique character of plant cells.
(a) Plasma membrane.
(b) Cell wall.
(c) Large central vacuole.
(d) Plastids.
Answer: (b) Cell wall.
Question 4: Which of the following is an exception to the traditional cell theory?
(a) Bacteria.
(b) Blue-green algae.
(c) Viruses.
(d) Mycoplasma.
Answer: (c) Viruses.
Question 5: What is the main arena of various cellular activities in both plant and animal cells?
(a) Nucleus.
(b) Cytoplasm.
(c) Plasma membrane.
(d) Mitochondria.
Answer: (b) Cytoplasm.
Question 6: Which of the following is the smallest cell, measuring only 0.3 µm in length?
(a) Bacteria.
(b) Mycoplasma.
(c) Ostrich egg.
(d) Human RBC.
Answer: (b) Mycoplasma.
Question 7: The genomic DNA of a prokaryotic cell is typically:
(a) Linear and double stranded.
(b) Circular and single stranded.
(c) Circular and double stranded.
(d) Linear and single stranded.
Answer: (c) Circular and double stranded.
Question 8: In addition to genomic DNA, many bacteria have small circular DNA outside called:
(a) Nucleoid.
(b) Plasmid.
(c) Episome.
(d) Mesosome.
Answer: (b) Plasmid.
Question 9: Which structure in prokaryotes provides resistance to antibiotics?
(a) Genomic DNA.
(b) Plasmid DNA.
(c) Mesosomes.
(d) Inclusion bodies.
Answer: (b) Plasmid DNA.
Question 10: The prokaryotic cell envelope consists of a tightly bound three-layered structure. Arrange them from outermost to innermost:
(a) Glycocalyx, Cell wall, Plasma membrane.
(b) Cell wall, Glycocalyx, Plasma membrane.
(c) Plasma membrane, Cell wall, Glycocalyx.
(d) Glycocalyx, Plasma membrane, Cell wall.
Answer: (a) Glycocalyx, Cell wall, Plasma membrane.
Question 11: A loose sheath of glycocalyx in bacteria is called a:
(a) Capsule.
(b) Slime layer.
(c) Mesosome.
(d) Pili.
Answer: (b) Slime layer.
Question 12: Which of the following structures is a specialized differentiated form of cell membrane in prokaryotes?
(a) Ribosome.
(b) Mesosome.
(c) Nucleoid.
(d) Flagella.
Answer: (b) Mesosome.
Question 13: Which of the following is NOT a function of the mesosome?
(a) Cell wall formation.
(b) DNA replication.
(c) Protein synthesis.
(d) Respiration and secretion.
Answer: (c) Protein synthesis.
Question 14: In cyanobacteria, there are other membranous extensions into the cytoplasm which contain pigments, called:
(a) Mesosomes.
(b) Chromatophores.
(c) Chloroplasts.
(d) Leucoplasts.
Answer: (b) Chromatophores.
Question 15: Bacterial flagellum is composed of three parts. Which of the following is the longest portion?
(a) Hook.
(b) Basal body.
(c) Filament.
(d) Pili.
Answer: (c) Filament.
Question 16: Which surface structures of bacteria do not play a role in motility but help in attachment?
(a) Flagella and Pili.
(b) Pili and Fimbriae.
(c) Flagella and Fimbriae.
(d) Chromatophores.
Answer: (b) Pili and Fimbriae.
Question 17: In prokaryotes, ribosomes are associated with the:
(a) Nucleus.
(b) Plasma membrane.
(c) Mesosome.
(d) Cell wall.
Answer: (b) Plasma membrane.
Question 18: What is the size of a typical prokaryotic ribosome?
(a) 10 nm by 15 nm.
(b) 15 nm by 20 nm.
(c) 20 nm by 25 nm.
(d) 5 nm by 10 nm.
Answer: (b) 15 nm by 20 nm.
Question 19: Several ribosomes may attach to a single mRNA and form a chain called:
(a) Polysome.
(b) Nucleosome.
(c) Lysosome.
(d) Centrosome.
Answer: (a) Polysome.
Question 20: Reserve material in prokaryotic cells are stored in the cytoplasm in the form of:
(a) Vacuoles.
(b) Inclusion bodies.
(c) Mesosomes.
(d) Nucleoids.
Answer: (b) Inclusion bodies.
Question 21: Which of the following is NOT an inclusion body found in prokaryotes?
(a) Phosphate granules.
(b) Cyanophycean granules.
(c) Glycogen granules.
(d) Lipid vacuoles.
Answer: (d) Lipid vacuoles.
Question 22: Gas vacuoles are found in which of the following?
(a) Green photosynthetic bacteria.
(b) Purple and green photosynthetic bacteria.
(c) Blue-green algae.
(d) All of the above.
Answer: (d) All of the above.
Question 23: The detailed structure of the membrane was studied only after the advent of the ______ in the 1950s.
(a) Compound microscope.
(b) Electron microscope.
(c) Phase-contrast microscope.
(d) Fluorescent microscope.
Answer: (b) Electron microscope.
Question 24: In the plasma membrane, the lipids are arranged within the membrane with the:
(a) Polar heads towards the inner side.
(b) Hydrophobic tails towards the outer side.
(c) Polar heads towards the outer side and hydrophobic tails towards the inner part.
(d) Random arrangement of heads and tails.
Answer: (c) Polar heads towards the outer side and hydrophobic tails towards the inner part.
Question 25: The lipid component of the membrane mainly consists of:
(a) Triglycerides.
(b) Phosphoglycerides.
(c) Cholesterol only.
(d) Glycoproteins.
Answer: (b) Phosphoglycerides.
Question 26: In human beings, the membrane of the erythrocyte has approximately ______ protein and ______ lipids.
(a) 40% protein, 52% lipids.
(b) 52% protein, 40% lipids.
(c) 50% protein, 50% lipids.
(d) 20% protein, 80% lipids.
Answer: (b) 52% protein, 40% lipids.
Question 27: Depending on the ease of extraction, membrane proteins can be classified as:
(a) Small and large.
(b) Polar and non-polar.
(c) Integral and peripheral.
(d) Primary and secondary.
Answer: (c) Integral and peripheral.
Question 28: The fluid mosaic model of cell membrane was proposed by:
(a) Schleiden and Schwann.
(b) Singer and Nicolson.
(c) Camillo Golgi.
(d) Robert Brown.
Answer: (b) Singer and Nicolson.
Question 29: According to the fluid mosaic model, the quasi-fluid nature of ______ enables lateral movement of proteins.
(a) Proteins.
(b) Lipids.
(c) Carbohydrates.
(d) Cholesterol.
Answer: (b) Lipids.
Question 30: The fluid nature of the membrane is important for functions like:
(a) Cell growth and secretion.
(b) Endocytosis and cell division.
(c) Formation of intercellular junctions.
(d) All of the above.
Answer: (d) All of the above.
Question 31: Movement of water by diffusion across a selectively permeable membrane is called:
(a) Active transport.
(b) Facilitated diffusion.
(c) Osmosis.
(d) Pinocytosis.
Answer: (c) Osmosis.
Question 32: In active transport, molecules are moved across the membrane:
(a) Along the concentration gradient without energy.
(b) Against the concentration gradient using ATP.
(c) Through simple diffusion.
(d) By osmosis.
Answer: (b) Against the concentration gradient using ATP.
Question 33: The cell wall of algae is made of cellulose, galactans, mannans and minerals like:
(a) Magnesium carbonate.
(b) Calcium carbonate.
(c) Sodium chloride.
(d) Calcium phosphate.
Answer: (b) Calcium carbonate.
Question 34: The cell wall of a young plant, the ______ wall, is capable of growth.
(a) Secondary.
(b) Middle lamella.
(c) Primary.
(d) Tertiary.
Answer: (c) Primary.
Question 35: The middle lamella is a layer mainly of ______ which holds the different neighboring cells together.
(a) Calcium pectate.
(b) Cellulose.
(c) Hemicellulose.
(d) Lignin.
Answer: (a) Calcium pectate.
Question 36: Which structures traverse the cell wall and middle lamella to connect the cytoplasm of neighboring cells?
(a) Desmosomes.
(b) Plasmodesmata.
(c) Gap junctions.
(d) Tight junctions.
Answer: (b) Plasmodesmata.
Question 37: Which of the following organelles is NOT considered part of the endomembrane system?
(a) Endoplasmic Reticulum.
(b) Golgi complex.
(c) Mitochondria.
(d) Vacuoles.
Answer: (c) Mitochondria.
Question 38: The network of tiny tubular structures scattered in the cytoplasm is called:
(a) Golgi body.
(b) Endoplasmic Reticulum.
(c) Cytoskeleton.
(d) Microtubules.
Answer: (b) Endoplasmic Reticulum.
Question 39: Rough Endoplasmic Reticulum (RER) is frequently observed in cells actively involved in:
(a) Lipid synthesis.
(b) Protein synthesis and secretion.
(c) Steroid hormone synthesis.
(d) Carbohydrate metabolism.
Answer: (b) Protein synthesis and secretion.
Question 40: Smooth Endoplasmic Reticulum (SER) is the major site for synthesis of:
(a) Proteins.
(b) Lipids.
(c) Ribosomes.
(d) DNA.
Answer: (b) Lipids.
Question 41: In animal cells, lipid-like steroidal hormones are synthesized in:
(a) RER.
(b) SER.
(c) Golgi apparatus.
(d) Lysosomes.
Answer: (b) SER.
Question 42: Camillo Golgi first observed densely stained reticular structures near the nucleus in the year:
(a) 1855.
(b) 1898.
(c) 1950.
(d) 1838.
Answer: (b) 1898.
Question 43: The Golgi cisternae are concentrically arranged near the nucleus with a convex ______ face and a concave ______ face.
(a) Trans, Cis.
(b) Cis, Trans.
(c) Forming, Maturing.
(d) Both (b) and (c).
Answer: (d) Both (b) and (c).
Question 44: The Golgi apparatus principally performs the function of:
(a) Protein synthesis.
(b) Packaging materials.
(c) ATP production.
(d) Water storage.
Answer: (b) Packaging materials.
Question 45: Which organelle is the important site for the formation of glycoproteins and glycolipids?
(a) Endoplasmic Reticulum.
(b) Golgi apparatus.
(c) Lysosome.
(d) Vacuole.
Answer: (b) Golgi apparatus.
Question 46: Lysosomal vesicles are rich in almost all types of ______ enzymes.
(a) Oxidative.
(b) Hydrolytic.
(c) Reductive.
(d) Synthetic.
Answer: (b) Hydrolytic.
Question 47: The pH at which lysosomal enzymes are optimally active is:
(a) Basic.
(b) Neutral.
(c) Acidic.
(d) Highly alkaline.
Answer: (c) Acidic.
Question 48: In plant cells, the vacuole can occupy up to ______ of the volume of the cell.
(a) 50%.
(b) 70%.
(c) 90%.
(d) 30%.
Answer: (c) 90%.
Question 49: The vacuole is bound by a single membrane called:
(a) Tonoplast.
(b) Plasma membrane.
(c) Anthocyanin.
(d) Elaioplast.
Answer: (a) Tonoplast.
Question 50: In Amoeba, the ______ vacuole is important for excretion.
(a) Food.
(b) Contractile.
(c) Gas.
(d) Sap.
Answer: (b) Contractile.
Question 51: Mitochondria are often called the 'powerhouses' of the cell because they produce cellular energy in the form of:
(a) AMP.
(b) ADP.
(c) ATP.
(d) GTP.
Answer: (c) ATP.
Question 52: The number of mitochondria per cell depends on the:
(a) Size of the cell.
(b) Shape of the cell.
(c) Physiological activity of the cell.
(d) Age of the cell.
Answer: (c) Physiological activity of the cell.
Question 53: The inner membrane of mitochondria forms a number of infoldings called:
(a) Cisternae.
(b) Thylakoids.
(c) Cristae.
(d) Grana.
Answer: (c) Cristae.
Question 54: Mitochondria possess their own:
(a) Circular DNA and 70S ribosomes.
(b) Linear DNA and 80S ribosomes.
(c) Circular DNA and 80S ribosomes.
(d) RNA only.
Answer: (a) Circular DNA and 70S ribosomes.
Question 55: Mitochondria divide by:
(a) Mitosis.
(b) Meiosis.
(c) Fission.
(d) Budding.
Answer: (c) Fission.
Question 56: Plastids are found in all plant cells and in:
(a) Bacteria.
(b) Euglenoids.
(c) Fungi.
(d) Cyanobacteria.
Answer: (b) Euglenoids.
Question 57: Which type of plastids store carbohydrates (starch)?
(a) Elaioplasts.
(b) Aleuroplasts.
(c) Amyloplasts.
(d) Chromoplasts.
Answer: (c) Amyloplasts.
Question 58: Elaioplasts are responsible for storing:
(a) Proteins.
(b) Starch.
(c) Oils and fats.
(d) Pigments.
Answer: (c) Oils and fats.
Question 59: The space limited by the inner membrane of the chloroplast is called the:
(a) Matrix.
(b) Stroma.
(c) Lumen.
(d) Perimitochondrial space.
Answer: (b) Stroma.
Question 60: Flat membranous sacs present in the stroma of chloroplasts are called:
(a) Cristae.
(b) Thylakoids.
(c) Cisternae.
(d) Mesosomes.
Answer: (b) Thylakoids.
Question 61: The stroma of the chloroplast contains enzymes required for the synthesis of:
(a) DNA only.
(b) Carbohydrates and proteins.
(c) Lipids only.
(d) ATP only.
Answer: (b) Carbohydrates and proteins.
Question 62: Ribosomes were first observed under the electron microscope as dense particles by:
(a) Camillo Golgi.
(b) George Palade.
(c) Robert Brown.
(d) Christian de Duve.
Answer: (b) George Palade.
Question 63: Eukaryotic ribosomes are ______ while prokaryotic ribosomes are ______ type.
(a) 70S, 80S.
(b) 80S, 70S.
(c) 60S, 40S.
(d) 50S, 30S.
Answer: (b) 80S, 70S.
Question 64: In the 80S ribosome, 'S' stands for Svedberg’s unit, which is a measure of:
(a) Size and density.
(b) Shape and size.
(c) Density and mass.
(d) Velocity only.
Answer: (a) Size and density.
Question 65: The cytoskeleton in a cell is involved in functions such as:
(a) Mechanical support.
(b) Motility.
(c) Maintenance of the shape of the cell.
(d) All of the above.
Answer: (d) All of the above.
Question 66: The core of cilia and flagella is called the:
(a) Axoneme.
(b) Basal body.
(c) Centriole.
(d) Microfilament.
Answer: (a) Axoneme.
Question 67: The axoneme of eukaryotic cilia and flagella usually has a ______ arrangement of microtubules.
(a) 9 + 0.
(b) 9 + 2.
(c) 7 + 2.
(d) 4 + 4.
Answer: (b) 9 + 2.
Question 68: Centrosome is an organelle usually containing two cylindrical structures called:
(a) Cilia.
(b) Centrioles.
(c) Chromatids.
(d) Centromeres.
Answer: (b) Centrioles.
Question 69: The organization of the centriole is like a:
(a) Star shape.
(b) Cartwheel.
(c) Hexagonal ring.
(d) Spiral staircase.
Answer: (b) Cartwheel.
Question 70: Centrioles are made up of nine evenly spaced peripheral triplets of ______ protein.
(a) Actin.
(b) Tubulin.
(c) Myosin.
(d) Keratin.
Answer: (b) Tubulin.
Question 71: The central part of the proximal region of the centriole is proteinaceous and called the:
(a) Radial spoke.
(b) Hub.
(c) Bridge.
(d) Axoneme.
Answer: (b) Hub.
Question 72: The centrioles form the basal body of cilia or flagella, and ______ that give rise to spindle apparatus.
(a) Asters.
(b) Spindle fibers.
(c) Kinetochores.
(d) Nucleolus.
Answer: (b) Spindle fibers.
Question 73: The nucleus was first described by Robert Brown in the year:
(a) 1831.
(b) 1838.
(c) 1855.
(d) 1898.
Answer: (a) 1831.
Question 74: The material of the nucleus stained by the basic dyes was given the name chromatin by:
(a) Robert Brown.
(b) Flemming.
(c) Schleiden.
(d) Schwann.
Answer: (b) Flemming.
Question 75: Which of the following cells lack a nucleus at maturity?
(a) Mature erythrocytes of many mammals.
(b) Sieve tube cells of vascular plants.
(c) Both (a) and (b).
(d) Companion cells.
Answer: (c) Both (a) and (b).
Question 76: The space between the two parallel membranes of the nuclear envelope is called:
(a) Perinuclear space.
(b) Perimitochondrial space.
(c) Intermembrane space.
(d) Nucleoplasm.
Answer: (a) Perinuclear space.
Question 77: The nuclear pores are the passages through which movement of ______ and ______ molecules takes place.
(a) DNA and RNA.
(b) RNA and protein.
(c) DNA and protein.
(d) Lipid and carbohydrate.
Answer: (b) RNA and protein.
Question 78: The nucleolus is a site for active synthesis of:
(a) mRNA.
(b) tRNA.
(c) rRNA.
(d) DNA.
Answer: (c) rRNA.
Question 79: A single human cell has approximately ______ meter long thread of DNA distributed among its 46 chromosomes.
(a) 1.
(b) 2.
(c) 3.
(d) 4.
Answer: (b) 2.
Question 80: Every chromosome essentially has a primary constriction called the:
(a) Kinetochore.
(b) Centromere.
(c) Satellite.
(d) Telomere.
Answer: (b) Centromere.
Question 81: Disc-shaped structures present on the sides of the centromere are called:
(a) Satellites.
(b) Kinetochores.
(c) Chromatids.
(d) Centrioles.
Answer: (b) Kinetochores.
Question 82: A chromosome with the centromere in the middle, giving two equal arms, is called:
(a) Sub-metacentric.
(b) Acrocentric.
(c) Metacentric.
(d) Telocentric.
Answer: (c) Metacentric.
Question 83: In which type of chromosome is the centromere situated close to its end, forming one extremely short and one very long arm?
(a) Metacentric.
(b) Sub-metacentric.
(c) Acrocentric.
(d) Telocentric.
Answer: (c) Acrocentric.
Question 84: A telocentric chromosome has the centromere at the:
(a) Middle.
(b) Slightly away from middle.
(c) Terminal end.
(d) Sub-terminal end.
Answer: (c) Terminal end.
Question 85: Some chromosomes have non-staining secondary constrictions at a constant location, giving the appearance of a small fragment called the:
(a) Kinetochore.
(b) Satellite.
(c) Centromere.
(d) Telomere.
Answer: (b) Satellite.
Question 86: Microbodies are membrane-bound minute vesicles that contain various ______ and are present in both plant and animal cells.
(a) Hormones.
(b) Enzymes.
(c) Pigments.
(d) Lipids.
Answer: (b) Enzymes.
Question 87: Which organelle is responsible for the synthesis of steroidal hormones in animal cells?
(a) Rough ER.
(b) Smooth ER.
(c) Golgi complex.
(d) Lysosomes.
Answer: (b) Smooth ER.
Question 88: The osmotic expansion of a cell kept in water is chiefly regulated by:
(a) Mitochondria.
(b) Vacuoles.
(c) Plastids.
(d) Ribosomes.
Answer: (b) Vacuoles.
Question 89: Which of the following is correct regarding the fluid mosaic model?
(a) Lipids are arranged in a monolayer.
(b) Proteins are embedded in the lipid bilayer.
(c) The membrane is rigid and static.
(d) Carbohydrates are the most abundant component.
Answer: (b) Proteins are embedded in the lipid bilayer.
Question 90: Peptide bond formation during protein synthesis in a cell happens in:
(a) Nucleus.
(b) Ribosomes.
(c) Golgi body.
(d) Lysosomes.
Answer: (b) Ribosomes.
Question 91: Which of the following is NOT a feature of the prokaryotic cell?
(a) Absence of nuclear membrane.
(b) Presence of 70S ribosomes.
(c) Absence of membrane-bound organelles.
(d) Presence of mitochondria.
Answer: (d) Presence of mitochondria.
Question 92: The primary wall of plant cells gradually ______ as the cell matures.
(a) Increases.
(b) Diminishes.
(c) Hardens.
(d) Remains constant.
Answer: (b) Diminishes.
Question 93: Select the mismatched pair:
(a) Amyloplast — Stores starch.
(b) Elaioplast — Stores proteins.
(c) Aleuroplast — Stores proteins.
(d) Chromoplast — Contains carotenoids.
Answer: (b) Elaioplast — Stores proteins.
Question 94: The hydrolytic enzymes of lysosomes are active at pH:
(a) 5.
(b) 7.
(c) 8.
(d) 10.
Answer: (a) 5.
Question 95: The stroma-lamellae in chloroplasts connect:
(a) Two grana.
(b) Two thylakoids of different grana.
(c) Inner and outer membrane.
(d) Stroma and matrix.
Answer: (b) Two thylakoids of different grana.
Question 96: What is the main function of the nucleolus?
(a) DNA replication.
(b) Lipid synthesis.
(c) Ribosomal RNA synthesis.
(d) Protein packaging.
Answer: (c) Ribosomal RNA synthesis.
Question 97: Chromatin contains DNA and some basic proteins called:
(a) Non-histones.
(b) Histones.
(c) Albumin.
(d) Globulin.
Answer: (b) Histones.
Question 98: A sub-metacentric chromosome has:
(a) Centromere in the exact middle.
(b) Centromere slightly away from the middle.
(c) Centromere at the very tip.
(d) No centromere.
Answer: (b) Centromere slightly away from the middle.
Question 99: Which organelle is referred to as the "Shipping Center" of the cell?
(a) ER.
(b) Golgi apparatus.
(c) Lysosome.
(d) Vacuole.
Answer: (b) Golgi apparatus.
Question 100: According to the endomembrane system, the pathway of a secreted protein is:
(a) RER -> Golgi -> Secretory Vesicle -> Plasma membrane.
(b) SER -> Golgi -> Lysosome.
(c) Nucleus -> RER -> Mitochondria.
(d) Golgi -> RER -> Plasma membrane.
Answer: (a) RER -> Golgi -> Secretory Vesicle -> Plasma membrane.
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