NCERT - CELL - UNIT OF LIFE - 24-25
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Questions and Answers

What percentage of protein is approximately found in the membrane of human erythrocytes?

  • 60%
  • 40%
  • 30%
  • 52% (correct)

    • Cholesterol is absent in the cell membrane composition.

    False

    What are the two main classes of membrane proteins?

    Integral and peripheral proteins

    The fluid mosaic model was proposed by _______ and _______.

    <p>Singer, Nicolson</p> Signup and view all the answers

    Which of the following is NOT a function of the plasma membrane?

    <p>Nutrient preparation</p> Signup and view all the answers

    Match the following components of the cell membrane with their characteristics:

    <p>Phospholipids = Form the bilayer structure Integral proteins = Partially or totally buried in the membrane Peripheral proteins = Lie on the surface of the membrane Cholesterol = Stabilizes the membrane fluidity</p> Signup and view all the answers

    Passive transport requires energy to move molecules across the cell membrane.

    <p>False</p> Signup and view all the answers

    What enables the lateral movement of proteins within the cell membrane?

    <p>Quasi-fluid nature of lipids</p> Signup and view all the answers

    What is the function of radial spokes in the cilia and flagella structure?

    <p>To connect the central sheath to peripheral doublets</p> Signup and view all the answers

    Centrioles are arranged parallel to each other within the centrosome.

    <p>False</p> Signup and view all the answers

    Who first described the nucleus as a cell organelle?

    <p>Robert Brown</p> Signup and view all the answers

    Each peripheral fibril of the centriole is made up of ______ triplets.

    <p>nine</p> Signup and view all the answers

    Match the following parts of the nucleus with their descriptions:

    <p>Chromatin = The material that makes up the nucleus and stains with basic dyes Nuclear Matrix = The framework providing structure to the nucleus Nucleolus = Spherical bodies within the nucleus involved in ribosome production Nucleoplasm = The viscous fluid within the nucleus</p> Signup and view all the answers

    What is the composition of the centrioles in a centrosome?

    <p>Nine triplets of peripheral fibrils</p> Signup and view all the answers

    The hub of the centriole is solely made of tubulin protein.

    <p>False</p> Signup and view all the answers

    What is one primary function of the centrioles during cell division?

    <p>To form spindle fibers</p> Signup and view all the answers

    What is the primary characteristic of the genetic material in typical bacteria?

    <p>Genomic DNA is circular and naked</p> Signup and view all the answers

    Eukaryotic cells have a well-defined nucleus and organelles, while prokaryotic cells do not.

    <p>True</p> Signup and view all the answers

    What are plasmids and what unique characteristic do they confer to bacteria?

    <p>Plasmids are small circular DNA outside the genomic DNA that can confer antibiotic resistance.</p> Signup and view all the answers

    Bacterial cells have a chemically complex cell ______ that includes the glycocalyx, cell wall, and plasma membrane.

    <p>envelope</p> Signup and view all the answers

    Match the following structures with their functions:

    <p>Glycocalyx = Protective outer layer Cell wall = Provides shape and rigidity Plasma membrane = Regulates entry and exit of materials Mesosome = Infolding of cell membrane involved in cellular processes</p> Signup and view all the answers

    Which of the following is a defining feature of prokaryotic cells?

    <p>Absence of a well-defined nucleus</p> Signup and view all the answers

    Prokaryotic cells contain organelles like ribosomes.

    <p>True</p> Signup and view all the answers

    What is the function of mesosomes in prokaryotic cells?

    <p>Mesosomes are involved in cellular processes and are infoldings of the cell membrane.</p> Signup and view all the answers

    What is the primary function of the rough endoplasmic reticulum (RER)?

    <p>Protein synthesis and secretion</p> Signup and view all the answers

    The smooth endoplasmic reticulum (SER) has ribosomes attached to its surface.

    <p>False</p> Signup and view all the answers

    Who first observed the structures now known as the Golgi apparatus?

    <p>Camillo Golgi</p> Signup and view all the answers

    The Golgi apparatus has a distinct _______ face for packaging materials.

    <p>cis</p> Signup and view all the answers

    Match the following components with their main functions:

    <p>Endoplasmic Reticulum = Protein and lipid synthesis Golgi Apparatus = Packaging and transporting materials Rough Endoplasmic Reticulum = Synthesis of steroids Smooth Endoplasmic Reticulum = Detoxification</p> Signup and view all the answers

    Which type of endoplasmic reticulum is involved in lipid synthesis?

    <p>Smooth Endoplasmic Reticulum</p> Signup and view all the answers

    The rough endoplasmic reticulum connects to the outer membrane of the nucleus.

    <p>True</p> Signup and view all the answers

    What are the shapes of the structures found in the Golgi apparatus?

    <p>Flat, disc-shaped sacs or cisternae</p> Signup and view all the answers

    What structure holds two chromatids of a chromosome?

    <p>Centromere</p> Signup and view all the answers

    Kinetochore structures are present on the sides of the centromere of each chromosome.

    <p>True</p> Signup and view all the answers

    What type of chromosome has its centromere at the end?

    <p>Telocentric chromosome</p> Signup and view all the answers

    Cells that contain a membrane-bound nucleus are classified as ______.

    <p>eukaryotic</p> Signup and view all the answers

    Match the types of chromosomes with their descriptions:

    <p>Metacentric = Centromere in the middle creating equal arms Sub-metacentric = Centromere slightly off-center Acrocentric = Centromere near one end creating a long and a short arm Telocentric = Centromere at the end of the chromosome</p> Signup and view all the answers

    Which of the following is NOT a component of eukaryotic cells?

    <p>Bacterial flagella</p> Signup and view all the answers

    Microbodies are present only in plant cells.

    <p>False</p> Signup and view all the answers

    What is the primary function of the centrosome?

    <p>To form the spindle apparatus during cell division</p> Signup and view all the answers

    Which organelle is primarily responsible for protein synthesis?

    <p>Ribosome</p> Signup and view all the answers

    Chloroplasts are responsible for oxidative phosphorylation.

    <p>False</p> Signup and view all the answers

    What is the role of the Golgi body in the cell?

    <p>Packing and transporting secretions from the cell.</p> Signup and view all the answers

    The ______ contains pigments like chlorophyll and is involved in photosynthesis.

    <p>chloroplast</p> Signup and view all the answers

    What is the function of lysosomes?

    <p>Digestion of macromolecules</p> Signup and view all the answers

    Match the following organelles with their functions:

    <p>Mitochondria = Energy production through oxidative phosphorylation Ribosomes = Sites for protein synthesis Chloroplasts = Photosynthesis in plant cells Golgi body = Packaging and transporting cell secretions</p> Signup and view all the answers

    The endoplasmic reticulum is composed solely of smooth tubules.

    <p>False</p> Signup and view all the answers

    What surrounds the nucleus of a cell?

    <p>Nuclear envelope</p> Signup and view all the answers

    What is the function of plasmids in bacteria?

    <p>They confer antibiotic resistance.</p> Signup and view all the answers

    Eukaryotic cells lack a well-defined nucleus.

    <p>False</p> Signup and view all the answers

    What is the primary structural feature of prokaryotic cells?

    <p>Lack of a well-defined nucleus.</p> Signup and view all the answers

    The cytoplasm is the fluid matrix filling the ______.

    <p>cell</p> Signup and view all the answers

    Match the following components of the prokaryotic cell with their characteristics:

    <p>Plasmids = Small circular DNA outside the genomic DNA Mesosomes = Infoldings of the cell membrane Glycocalyx = Outermost layer of the cell envelope Ribosomes = Sites of protein synthesis</p> Signup and view all the answers

    Which organelle is primarily responsible for energy production in cells?

    <p>Mitochondrion</p> Signup and view all the answers

    The cell wall is present in animal cells.

    <p>False</p> Signup and view all the answers

    Which component is NOT found in prokaryotic cells?

    <p>Nuclear membrane</p> Signup and view all the answers

    The cell envelope of most prokaryotic cells is a single-layered structure.

    <p>False</p> Signup and view all the answers

    What is the function of the Golgi apparatus?

    <p>Modifying, sorting, and packaging proteins and lipids for secretion.</p> Signup and view all the answers

    What is the significance of the cell wall in prokaryotic cells?

    <p>Provides structure and protection.</p> Signup and view all the answers

    In plant cells, _____ are used for communication between neighboring cells.

    <p>plasmodesmata</p> Signup and view all the answers

    Match the following organelles with their primary functions:

    <p>Lysosome = Digestion of waste materials Chloroplast = Photosynthesis Ribosome = Protein synthesis Nucleus = Genetic material storage</p> Signup and view all the answers

    Which structure is involved in the protein synthesis of a cell?

    <p>Ribosome</p> Signup and view all the answers

    The endoplasmic reticulum is strictly involved in lipid synthesis.

    <p>False</p> Signup and view all the answers

    What protects the nucleus in a eukaryotic cell?

    <p>Nuclear envelope</p> Signup and view all the answers

    What is the term for the movement of water across a membrane from higher to lower concentration?

    <p>Osmosis</p> Signup and view all the answers

    Active transport requires energy to move molecules against their concentration gradient.

    <p>True</p> Signup and view all the answers

    What is the primary function of the cytoskeleton?

    <p>Mechanical support and shape maintenance</p> Signup and view all the answers

    What structure forms an outer covering for the plasma membrane in fungi and plants?

    <p>Cell wall</p> Signup and view all the answers

    Cilia and flagella are the same in structure and function.

    <p>False</p> Signup and view all the answers

    The primary wall of a young plant cell is capable of __________ as the cell matures.

    <p>growth</p> Signup and view all the answers

    Match the cell wall components with their descriptions:

    <p>Cellulose = Main structural component in plant cell walls Hemicellulose = Polysaccharides that provide support Pectins = Gel-like substances that help bind cells Calcium carbonate = A mineral component found in algae</p> Signup and view all the answers

    What is the arrangement of microtubules in the axoneme of cilia and flagella referred to as?

    <p>9+2 array</p> Signup and view all the answers

    The core structure of cilia and flagella is called the __________.

    <p>axoneme</p> Signup and view all the answers

    Which of the following organelles is NOT part of the endomembrane system?

    <p>Mitochondria</p> Signup and view all the answers

    Match the components of cilia and flagella with their descriptions:

    <p>Cilia = Small, hair-like structures that move fluids Flagella = Longer structures responsible for cell movement Axoneme = Core structure supporting microtubules in cilia/flagella Microtubules = Cylindrical protein structures that provide support</p> Signup and view all the answers

    The middle lamella is mainly composed of calcium pectate and helps glue neighbouring cells together.

    <p>True</p> Signup and view all the answers

    What is the main function of the plasmodesmata in plant cells?

    <p>Connects the cytoplasm of neighboring cells</p> Signup and view all the answers

    Which of the following best describes the function of cilia?

    <p>Movement of the cell or surrounding fluid</p> Signup and view all the answers

    Eukaryotic flagella are structurally identical to prokaryotic flagella.

    <p>False</p> Signup and view all the answers

    What are the two types of structures that make up the cytoskeleton?

    <p>Microtubules and microfilaments</p> Signup and view all the answers

    What is the primary function of the centrioles in the centrosome?

    <p>Formation of spindle fibers during cell division</p> Signup and view all the answers

    The central part of the proximal region of the centriole is composed of tubulin protein.

    <p>False</p> Signup and view all the answers

    What structure emerges from the basal body of cilia or flagella?

    <p>Cilia or flagella</p> Signup and view all the answers

    The centrosome usually contains two cylindrical structures called ______.

    <p>centrioles</p> Signup and view all the answers

    Match the following components of centrioles with their features:

    <p>Peripheral fibrils = Made up of tubulin protein Radial spokes = Connect tubules of the peripheral triplets Hub = Proteinaceous central region Triplets = Arranged in groups of three</p> Signup and view all the answers

    Which feature describes the arrangement of the centrioles within a centrosome?

    <p>Perpendicular to each other</p> Signup and view all the answers

    The chromatin in the interphase nucleus is highly condensed.

    <p>False</p> Signup and view all the answers

    Who first described the structure of the nucleus?

    <p>Robert Brown</p> Signup and view all the answers

    What structure is responsible for holding two chromatids of a chromosome together?

    <p>Centromere</p> Signup and view all the answers

    Metacentric chromosomes have a centromere located at one end.

    <p>False</p> Signup and view all the answers

    What term describes the small fragment appearance caused by non-staining secondary constrictions?

    <p>Satellite</p> Signup and view all the answers

    Chromatin consists of DNA and proteins known as ______.

    <p>histones</p> Signup and view all the answers

    Match each type of chromosome with its description:

    <p>Metacentric = Centromere in the middle Sub-metacentric = Centromere slightly off center Acrocentric = Centromere close to one end Telocentric = Centromere at the end</p> Signup and view all the answers

    What is the approximate length of DNA in a single human cell?

    <p>Two meters</p> Signup and view all the answers

    Kinetochore structures are located on the sides of the chromosomes during cell division.

    <p>True</p> Signup and view all the answers

    Eukaryotic cells have a nucleus that is ______ bound by a membrane.

    <p>membrane</p> Signup and view all the answers

    Which of the following statements accurately describes Gram positive bacteria?

    <p>They have a thick cell wall.</p> Signup and view all the answers

    The glycocalyx is always present as a thick capsule in all bacterial species.

    <p>False</p> Signup and view all the answers

    What are the three main parts of a bacterial flagellum?

    <p>Filament, hook, and basal body</p> Signup and view all the answers

    The outer protective layer of bacteria that provides structural support and determines cell shape is called the ______.

    <p>cell wall</p> Signup and view all the answers

    Match the bacterial structures with their functions:

    <p>Flagella = Provides motility to bacteria Pili = Facilitates attachment to surfaces Fimbriae = Helps in adherence to host tissues Mesosomes = Involved in cell wall formation and DNA replication</p> Signup and view all the answers

    Which structure in prokaryotes helps increase the surface area of the plasma membrane?

    <p>Mesosome</p> Signup and view all the answers

    Both pili and fimbriae assist in bacterial motility.

    <p>False</p> Signup and view all the answers

    What role do chromatophores play in cyanobacteria?

    <p>They contain pigments involved in photosynthesis.</p> Signup and view all the answers

    Which component of mitochondria is primarily responsible for producing ATP?

    <p>Cristae</p> Signup and view all the answers

    Plastids are only found in plant cells.

    <p>False</p> Signup and view all the answers

    What are the three types of plastids based on the pigments they contain?

    <p>Chloroplasts, chromoplasts, and leucoplasts.</p> Signup and view all the answers

    The mitochondria divide by ______.

    <p>fission</p> Signup and view all the answers

    Match the following types of plastids with their functions:

    <p>Chloroplasts = Photosynthesis Chromoplasts = Pigment storage Leucoplasts = Nutrient storage</p> Signup and view all the answers

    What is the primary role of chloroplasts in plant cells?

    <p>Photosynthesis</p> Signup and view all the answers

    Mitochondria have a single circular DNA molecule within their matrix.

    <p>True</p> Signup and view all the answers

    What pigments are responsible for the yellow, orange, or red color found in chromoplasts?

    <p>Carotenoid pigments.</p> Signup and view all the answers

    Which of the following organelles is responsible for packaging materials in the cell?

    <p>Golgi apparatus</p> Signup and view all the answers

    The smooth endoplasmic reticulum is responsible for protein synthesis.

    <p>False</p> Signup and view all the answers

    What is the primary function of lysosomes?

    <p>Digestion of macromolecules and cellular waste</p> Signup and view all the answers

    Which structure is selectively permeable, allowing certain substances to pass while blocking others?

    <p>Plasma membrane</p> Signup and view all the answers

    The nucleolus is involved in the synthesis of ribosomal RNA.

    <p>True</p> Signup and view all the answers

    Name one key characteristic that distinguishes eukaryotic cells from prokaryotic cells.

    <p>Eukaryotic cells have a well-defined nucleus.</p> Signup and view all the answers

    The smooth endoplasmic reticulum (SER) is where steroid hormones are synthesized.

    <p>True</p> Signup and view all the answers

    What are the two distinct compartments formed by the endoplasmic reticulum?

    <p>Luminal and extra luminal</p> Signup and view all the answers

    The Golgi apparatus primarily functions in _______ materials for cellular targeting or secretion.

    <p>packaging</p> Signup and view all the answers

    Which of the following best describes the structure of the Golgi apparatus?

    <p>Several stacked flat sacs called cisternae</p> Signup and view all the answers

    The cis face of the Golgi apparatus is where materials are delivered to be packaged.

    <p>True</p> Signup and view all the answers

    Match the following structures with their respective functions:

    <p>Rough Endoplasmic Reticulum = Site for protein synthesis Smooth Endoplasmic Reticulum = Site for lipid synthesis Golgi Apparatus = Packaging of cellular materials Cisternae = Flat sacs in Golgi</p> Signup and view all the answers

    What is the main role of the nucleus within a cell?

    <p>Control of organelle activities and role in heredity</p> Signup and view all the answers

    Lysosomes are responsible for protein synthesis.

    <p>False</p> Signup and view all the answers

    What are the infoldings in mitochondria called?

    <p>Cristae</p> Signup and view all the answers

    The ___ contains flattened membranous sacs involved in packing secretions.

    <p>Golgi body</p> Signup and view all the answers

    Which type of endoplasmic reticulum is associated with ribosomes?

    <p>Rough endoplasmic reticulum</p> Signup and view all the answers

    Chloroplasts are found in both plant and animal cells.

    <p>False</p> Signup and view all the answers

    What structure surrounds and encloses the nucleus?

    <p>Nuclear envelope</p> Signup and view all the answers

    How many radial spokes are present in the structure of cilia and flagella?

    <p>9</p> Signup and view all the answers

    The centrosome typically contains three centrioles.

    <p>False</p> Signup and view all the answers

    What are the two structures that make up the centrosome?

    <p>Centrioles</p> Signup and view all the answers

    The central part of the proximal region of the centriole is called the ______.

    <p>hub</p> Signup and view all the answers

    Match the following components of the centrosome with their descriptions:

    <p>Centrioles = Cylindrical structures organized like a cartwheel Pericentriolar material = Surrounds the centrioles Radial spokes = Connects hub to peripheral triplets Basal body = Forms the base of cilia or flagella</p> Signup and view all the answers

    What type of fibers is chromatin composed of?

    <p>Nucleoprotein fibers</p> Signup and view all the answers

    Each peripheral fibril in the centriole is composed of doublet structures.

    <p>False</p> Signup and view all the answers

    Who first coined the term 'chromatin' for the nucleus material?

    <p>Flemming</p> Signup and view all the answers

    What is the primary site of protein synthesis in prokaryotic cells?

    <p>Ribosomes</p> Signup and view all the answers

    All eukaryotic cells have a well-defined nucleus.

    <p>True</p> Signup and view all the answers

    What type of structures store reserve material in prokaryotic cells?

    <p>Inclusion bodies</p> Signup and view all the answers

    Eukaryotic cells have a variety of complex __________ structures.

    <p>cytoskeletal</p> Signup and view all the answers

    Match the following components of eukaryotic and prokaryotic cells with their characteristics:

    <p>Ribosomes = Site of protein synthesis Inclusion bodies = Reserve material storage Nucleus = Organized genetic material Centrioles = Cell division in animal cells</p> Signup and view all the answers

    What is the smallest type of cell mentioned?

    <p>Mycoplasma</p> Signup and view all the answers

    Prokaryotic cells are larger than eukaryotic cells.

    <p>False</p> Signup and view all the answers

    Name one non-membrane bound organelle found in all cells.

    <p>Ribosomes</p> Signup and view all the answers

    The four basic shapes of bacteria are bacillus, coccus, vibrio, and ______.

    <p>spirillum</p> Signup and view all the answers

    Match the following types of cells with their descriptions:

    <p>Mycoplasmas = Smallest cells Red blood cells = Biconcave and round Nerve cells = Branched and long Mesophyll cells = Round and oval</p> Signup and view all the answers

    Which of the following is a feature of prokaryotic cells?

    <p>Cell wall surrounding the cell membrane</p> Signup and view all the answers

    Animal cells contain organelles that are not found in prokaryotic cells.

    <p>True</p> Signup and view all the answers

    Cells vary greatly in size, shape, and ______.

    <p>activities</p> Signup and view all the answers

    What is the name of the space limited by the inner membrane of the chloroplast?

    <p>Stroma</p> Signup and view all the answers

    The ribosomes in chloroplasts are larger than those found in the cytoplasm.

    <p>False</p> Signup and view all the answers

    What are the organized, flattened membranous sacs within the stroma of chloroplasts called?

    <p>Thylakoids</p> Signup and view all the answers

    What term describes the movement of water across a membrane from higher to lower concentration?

    <p>Osmosis</p> Signup and view all the answers

    Chlorophyll pigments are present in the __________ of the chloroplast.

    <p>thylakoids</p> Signup and view all the answers

    The cell wall is a living structure that provides support to plant cells.

    <p>False</p> Signup and view all the answers

    Match the following structures with their corresponding descriptions:

    <p>Thylakoids = Stacks arranged like piles of coins Grana = Site of photosynthesis Stroma = Liquid-filled space in chloroplast Lumen = Contains enzymes for carbohydrate synthesis</p> Signup and view all the answers

    What type of transport moves ions or molecules against their concentration gradient using energy?

    <p>Active transport</p> Signup and view all the answers

    Which of the following is true regarding ribosomes?

    <p>80S ribosomes consist of 60S and 40S subunits.</p> Signup and view all the answers

    The main function of stroma in chloroplasts is to provide a site for light-dependent reactions.

    <p>False</p> Signup and view all the answers

    Match the following components of the endomembrane system with their functions:

    <p>Endoplasmic Reticulum = Protein and lipid synthesis Golgi complex = Modification and packaging of proteins Lysosomes = Digestion of macromolecules Vacuoles = Storage of substances</p> Signup and view all the answers

    Which of the following substances are found in the cell wall of algae?

    <p>Calcium carbonate</p> Signup and view all the answers

    What are the two subunits of prokaryotic ribosomes?

    <p>50S and 30S</p> Signup and view all the answers

    Plasmodesmata are structures that connect the cytoplasm of neighboring cells.

    <p>True</p> Signup and view all the answers

    What is the primary role of the middle lamella in plant cells?

    <p>To hold neighboring cells together</p> Signup and view all the answers

    How many radial spokes connect the central sheath to the peripheral doublets in cilia and flagella?

    <p>9</p> Signup and view all the answers

    The centrioles in a centrosome are arranged parallel to each other.

    <p>False</p> Signup and view all the answers

    What protein is primarily used to form the triplets in the peripheral fibrils of centrioles?

    <p>tubulin</p> Signup and view all the answers

    A centrosome contains two cylindrical structures known as __________.

    <p>centrioles</p> Signup and view all the answers

    Match the following components of centrioles with their descriptions:

    <p>Hub = Proteinaceous central part connecting to triplets Triplets = Nine peripheral fibrils of tubulin Radial spokes = Connects hub to peripheral triplets Amorphous pericentriolar materials = Surrounds the centrioles</p> Signup and view all the answers

    What is the primary role of the centrioles?

    <p>Spindle fiber formation during cell division</p> Signup and view all the answers

    Chromatin is the material in the nucleus that is stained by basic dyes.

    <p>True</p> Signup and view all the answers

    Which structure is responsible for trapping light energy essential for photosynthesis in plant cells?

    <p>Chloroplasts</p> Signup and view all the answers

    Ribosomes are involved in the breakdown of macromolecules within lysosomes.

    <p>False</p> Signup and view all the answers

    What type of endoplasmic reticulum is associated with the synthesis of proteins?

    <p>Rough endoplasmic reticulum</p> Signup and view all the answers

    The ______ is a membranous organelle composed of flattened sacs that packs and transports cell secretions.

    <p>Golgi body</p> Signup and view all the answers

    What is the function of the chromatin network within the nucleus?

    <p>Genetic information storage</p> Signup and view all the answers

    Plastids are present in both plant and animal cells.

    <p>False</p> Signup and view all the answers

    What structure surrounds the nucleus and contains nuclear pores?

    <p>Nuclear envelope</p> Signup and view all the answers

    Who proposed that all living organisms are composed of cells and that all cells arise from pre-existing cells?

    <p>Rudolf Virchow</p> Signup and view all the answers

    Eukaryotic cells lack membrane-bound organelles.

    <p>False</p> Signup and view all the answers

    What is the outer boundary of a typical plant cell called?

    <p>cell wall</p> Signup and view all the answers

    The ______ is the membrane-bound structure that contains the genetic material in eukaryotic cells.

    <p>nucleus</p> Signup and view all the answers

    Match the following scientists with their contributions to cell theory:

    <p>Matthias Schleiden = Observed plant cells and contributed to cell theory Theodore Schwann = Studied animal cells and proposed the plasma membrane concept Rudolf Virchow = Proposed that all cells arise from pre-existing cells</p> Signup and view all the answers

    Which of the following statements correctly describes prokaryotic cells?

    <p>They lack a membrane-bound nucleus.</p> Signup and view all the answers

    The cytoplasm is the site for most chemical reactions in both plant and animal cells.

    <p>True</p> Signup and view all the answers

    What term is used to describe cells that have a membrane-bound nucleus?

    <p>eukaryotic</p> Signup and view all the answers

    What is the primary characteristic of the lipid bilayer in the plasma membrane?

    <p>The hydrophilic heads face outward and hydrophobic tails face inward</p> Signup and view all the answers

    Integral proteins are only found on the surface of the plasma membrane.

    <p>False</p> Signup and view all the answers

    Name one important function of the plasma membrane.

    <p>Transport of molecules</p> Signup and view all the answers

    The plasma membrane is primarily composed of ______ and proteins.

    <p>lipids</p> Signup and view all the answers

    Match the following components of the plasma membrane with their roles:

    <p>Phospholipids = Form the bilayer structure Cholesterol = Stabilizes membrane fluidity Integral proteins = Facilitate transport across the membrane Peripheral proteins = Serve as enzymes or signaling molecules</p> Signup and view all the answers

    Which type of transport does not require energy to move molecules across the plasma membrane?

    <p>Passive transport</p> Signup and view all the answers

    The fluid mosaic model describes a rigid structure of the cell membrane.

    <p>False</p> Signup and view all the answers

    What is the role of cholesterol in the plasma membrane?

    <p>To stabilize the fluidity of the membrane</p> Signup and view all the answers

    The tonoplast is responsible for anchoring the vacuole to the cell membrane.

    <p>False</p> Signup and view all the answers

    What structures are formed by ribosomes on the endoplasmic reticulum and modified in the Golgi apparatus?

    <p>proteins</p> Signup and view all the answers

    Mitochondria are often referred to as the ______ of the cell.

    <p>powerhouse</p> Signup and view all the answers

    Which statement about vacuoles is correct?

    <p>Plant cells have vacuoles that can occupy up to 90% of their volume.</p> Signup and view all the answers

    Mitochondria have a single membrane structure.

    <p>False</p> Signup and view all the answers

    The hydrolytic enzymes in lysosomes are most active at an ________ pH.

    <p>acidic</p> Signup and view all the answers

    Which structure is referred to as the space limited by the inner membrane of the chloroplast?

    <p>Stroma</p> Signup and view all the answers

    Thylakoids are arranged in stacks known as grana within the stroma of chloroplasts.

    <p>True</p> Signup and view all the answers

    What type of pigments are present in the thylakoids?

    <p>Chlorophyll</p> Signup and view all the answers

    The ribosomes of chloroplasts are smaller and classified as ______ ribosomes.

    <p>70S</p> Signup and view all the answers

    Match the following ribosome types with their corresponding characteristics:

    <p>70S = Found in prokaryotic cells 80S = Found in eukaryotic cells 60S and 40S = Subunits of 80S ribosomes 50S and 30S = Subunits of 70S ribosomes</p> Signup and view all the answers

    What connects the thylakoids of different grana?

    <p>Stroma lamellae</p> Signup and view all the answers

    Who first observed ribosomes under the electron microscope?

    <p>George Palade</p> Signup and view all the answers

    Both chloroplasts and prokaryotic ribosomes contain membrane-bound structures.

    <p>False</p> Signup and view all the answers

    Flagella and cilia are both involved in cell movement.

    <p>True</p> Signup and view all the answers

    Match the following structures with their descriptions:

    <p>Cilia = Short hair-like structures that cause fluid movement Flagella = Longer structures responsible for cell movement Microtubules = Components of the axoneme that support movement Cytoskeleton = Network providing mechanical support and shape</p> Signup and view all the answers

    Which of the following statements about prokaryotic and eukaryotic flagella is true?

    <p>Eukaryotic flagella have a 9+2 arrangement of microtubules.</p> Signup and view all the answers

    Cilia work like ______ to move the cell or surrounding fluid.

    <p>oars</p> Signup and view all the answers

    The axoneme of cilia and flagella contains a combination of microfilaments and intermediate filaments.

    <p>False</p> Signup and view all the answers

    Which type of chromosome has a centromere located in the middle, resulting in two equal arms?

    <p>Metacentric chromosome</p> Signup and view all the answers

    The kinetochore is found at the ends of chromosomes.

    <p>False</p> Signup and view all the answers

    What is the primary function of the centrosome during cell division?

    <p>To form the spindle apparatus</p> Signup and view all the answers

    The __________ are specialized structures formed by the centrioles that aid in cell division.

    <p>spindle apparatus</p> Signup and view all the answers

    Match the following types of chromosomes with their descriptions:

    <p>Metacentric = Centromere in the middle Sub-metacentric = Centromere slightly off the middle Acrocentric = Centromere close to one end Telocentric = Centromere at the terminal end</p> Signup and view all the answers

    Which of the following statements about chromatin is correct?

    <p>Chromatin contains DNA, RNA, and proteins.</p> Signup and view all the answers

    All human cells have the same length of DNA distributed among their chromosomes.

    <p>True</p> Signup and view all the answers

    What feature characterizes a satellite in some chromosomes?

    <p>A small fragment appearing due to non-staining secondary constrictions</p> Signup and view all the answers

    Which structure is responsible for cell division in animal cells?

    <p>Centrosome</p> Signup and view all the answers

    All prokaryotic cells have a membrane-bound nucleus.

    <p>False</p> Signup and view all the answers

    What is the smallest known type of cell?

    <p>Mycoplasmas</p> Signup and view all the answers

    Which of the following statements is true regarding ribosomes?

    <p>Ribosomes are non-membrane bound organelles.</p> Signup and view all the answers

    Match the following cell types with their primary shapes:

    <p>Red blood cells = Disc-like Nerve cells = Branched and long Columnar epithelial cells = Long and narrow Mycoplasmas = Rod-like</p> Signup and view all the answers

    Prokaryotic cells are generally larger than eukaryotic cells.

    <p>False</p> Signup and view all the answers

    How do the shapes of cells vary?

    <p>Cells can be disc-like, polygonal, columnar, cuboid, thread-like, or irregular.</p> Signup and view all the answers

    What is the main characteristic of the phospholipid bilayer in the cell membrane?

    <p>The hydrophilic heads face outward.</p> Signup and view all the answers

    Integral proteins are fully embedded within the cell membrane.

    <p>True</p> Signup and view all the answers

    What is the primary function of the plasma membrane?

    <p>Transport of molecules across it</p> Signup and view all the answers

    The __________ model describes the structure of the plasma membrane as a fluid mosaic.

    <p>fluid mosaic</p> Signup and view all the answers

    Match the following components of the cell membrane with their main roles:

    <p>Phospholipids = Form the bilayer Cholesterol = Stabilize membrane fluidity Integral Proteins = Transport and signaling Peripheral Proteins = Enzymatic functions</p> Signup and view all the answers

    Which type of transport allows molecules to move across the membrane without the use of energy?

    <p>Passive transport</p> Signup and view all the answers

    The cell membrane restricts the movement of all types of molecules equally.

    <p>False</p> Signup and view all the answers

    What is the primary role of the centrioles in a centrosome?

    <p>Spindle formation during cell division</p> Signup and view all the answers

    The radial spokes in cilia and flagella only serve aesthetic functions.

    <p>False</p> Signup and view all the answers

    What are the structures called that link adjacent triplets in centrioles?

    <p>links</p> Signup and view all the answers

    The middle lamella is a layer made mainly of calcium pectate that helps glue neighboring cells together.

    <p>True</p> Signup and view all the answers

    What process requires energy and moves ions or molecules against their concentration gradient?

    <p>Active transport</p> Signup and view all the answers

    The central part of the proximal region of the centriole is known as the ______.

    <p>hub</p> Signup and view all the answers

    Algae have a cell wall made of __________, galactans, mannans, and minerals.

    <p>cellulose</p> Signup and view all the answers

    Match the components of the centrosome with their descriptions:

    <p>Centrioles = Perpendicular cylindrical structures Pericentriolar material = Surrounds centrioles Radial spokes = Connects triplets to the hub Tubulin protein = Builds the fibrils of centrioles</p> Signup and view all the answers

    How are the centrioles in a centrosome arranged?

    <p>Perpendicular to each other</p> Signup and view all the answers

    The substance that makes up the nucleoli is mainly _____.

    <p>RNA</p> Signup and view all the answers

    Which of the following structures is NOT part of the endomembrane system?

    <p>Chloroplast</p> Signup and view all the answers

    Plasmodesmata allow for direct connection of the cytoplasm between neighboring plant cells.

    <p>True</p> Signup and view all the answers

    The chromatin in the interphase nucleus is compact and inactive.

    <p>False</p> Signup and view all the answers

    What is the rigid outer covering of fungal and plant cells called?

    <p>Cell wall</p> Signup and view all the answers

    What did Matthias Schleiden contribute to the cell theory?

    <p>He observed that all plants are composed of cells.</p> Signup and view all the answers

    The plasma membrane is unique to plant cells.

    <p>False</p> Signup and view all the answers

    Who first explained that new cells are formed from pre-existing cells?

    <p>Rudolf Virchow</p> Signup and view all the answers

    Cells that lack a membrane-bound nucleus are referred to as ______.

    <p>prokaryotic</p> Signup and view all the answers

    Match the following structures to their characteristics:

    <p>Cell Wall = Present in plant cells Plasma Membrane = Surrounds all cell types Nucleus = Contains genetic material Cytoplasm = Site of cellular activities</p> Signup and view all the answers

    Which component is not a characteristic of eukaryotic cells?

    <p>Cell wall made of peptidoglycan</p> Signup and view all the answers

    The nucleus contains mitochondria.

    <p>False</p> Signup and view all the answers

    What structure is responsible for cellular respiration in eukaryotic cells?

    <p>Mitochondria</p> Signup and view all the answers

    Which type of chromosome has the centromere located in the middle?

    <p>Metacentric</p> Signup and view all the answers

    Chromatin consists only of DNA and histones.

    <p>False</p> Signup and view all the answers

    The __________ is a small fragment that appears due to non-staining secondary constrictions on some chromosomes.

    <p>satellite</p> Signup and view all the answers

    Which chromosome type is formed when the centromere is located close to one end?

    <p>Telocentric</p> Signup and view all the answers

    Identify the types of microbodies found in both plant and animal cells.

    <p>Peroxisomes and Glyoxysomes</p> Signup and view all the answers

    Eukaryotic cells have a well-defined nucleus and organelles.

    <p>True</p> Signup and view all the answers

    Study Notes

    Cell Theory

    • All living organisms are composed of cells and products of cells.
    • All cells arise from pre-existing cells.

    Cell Structure

    • Cells are the basic units of life.
    • Unicellular organisms consist of a single cell.
    • Multicellular organisms have many cells.
    • A typical eukaryotic cell has a cell membrane, nucleus, and cytoplasm.
    • Plant cells have a cell wall outside the cell membrane.
    • The cell membrane is selectively permeable, facilitating transport.
    • The endomembrane system includes the endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles.
    • The nucleus contains nucleoli and chromatin.

    Cell Organelles

    • Mitochondria: Double membrane-bound, sites of aerobic respiration, producing ATP ("powerhouses").
    • Plastids: Found in plant cells, containing pigments (chloroplasts for photosynthesis, chromoplasts for color, leucoplasts for storage).
    • Ribosomes: Involved in protein synthesis, found free in the cytoplasm or attached to the endoplasmic reticulum.
    • Endoplasmic Reticulum (ER): Network of membranes, rough ER with ribosomes for protein synthesis, smooth ER for lipid synthesis and detoxification.
    • Golgi apparatus: Modifies, sorts, and packages proteins and lipids.
    • Lysosomes: Contain enzymes for intracellular digestion.
    • Vacuoles: Membrane-bound sacs, storing water, waste products, and other substances. In plant cells, vacuoles take up most of the space.
    • Centrosomes and centrioles: Involved in cell division, part of the cytoskeleton.
    • Cilia and flagella: Motile appendages, for locomotion (similar in prokaryotes and eukaryotes).
    • Microbodies: Membrane-bound vesicles containing certain enzymes.

    Prokaryotic Cells

    • Lack a membrane-bound nucleus and other organelles.
    • Have a cell wall
    • Have a glycocalyx
    • Have a plasma membrane.
    • Possess ribosomes.
    • Have unique inclusions.

    Eukaryotic Cells

    • Eukaryotic cells have a membrane-bound nucleus and other organelles.
    • Often larger than prokaryotic cells.

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    G.N. Ramachandran (1922-2001) PDF

    Description

    Explore the fundamental concepts of cell theory, structure, and organelles in this quiz. Understand how cells function as the basic units of life and the differences between unicellular and multicellular organisms. Test your knowledge of essential cell components and their roles.

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