Cell Biology Quiz: Cell Walls and Organelles

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Questions and Answers

What is the main structural difference between plant cell walls, prokaryote cell walls and fungal cell walls?

Plant cell walls have peptidoglycan, prokaryotes have cellulose, and fungi have chitin.

Plant cell walls have cellulose, prokaryotes have peptidoglycan, and fungi have chitin. (correct)

Plant cell walls have pectin, prokaryotes have cellulose, and fungi have peptidoglycan.

Plant cell walls have chitin, prokaryotes have cellulose, and fungi have peptidoglycan.

Which layer of the plant cell wall is secreted first and is present during cell division?

Cell membrane

Middle lamella

Secondary cell wall

Primary cell wall (correct)

What is the primary role of the crisscross arrangement of cellulose microfibrils in the primary cell wall?

To facilitate the transport of water and dissolved materials.

To provide the cell wall with great strength and flexibility. (correct)

To allow the cell wall to stretch and grow elastically.

To regulate the synthesis of pectin.

Which of the following best describes the permeability of the plant cell wall?

Permeable , allowing free passage of water and dissolved materials. (A) Signup and view all the answers

Which component of the plant cell wall is soluble in hot water and a major constituent of both the primary wall and middle lamella?

Pectin (D) Signup and view all the answers

Which structure is NOT present in an animal cell?

Cell Wall (A) Signup and view all the answers

What is the significance of the primary cell wall stretching plastically?

It allows irreversible expansion of the cell during growth. (D) Signup and view all the answers

What property of pectic acids allows them to form insoluble gels with Calcium and Magnesium?

They are hydrophilic. (B) Signup and view all the answers

Which term describes the less viscous portion of the cytoplasm near the nucleus?

Cytosol (A) Signup and view all the answers

What is the primary function of the cyclosis movement within the cytoplasm?

Distribution of cell contents (C) Signup and view all the answers

In eukaryotic cells, where are the 80S ribosomes primarily located?

Attached to the RER or dispersed in cytoplasm (C) Signup and view all the answers

Which organelle is primarily involved in modifying and packaging proteins for secretion?

Golgi complex (C) Signup and view all the answers

Which function is associated with the smooth endoplasmic reticulum (SER)?

Lipid synthesis and detoxification (D) Signup and view all the answers

What is the structural composition of ribosomes?

RNA and protein (A) Signup and view all the answers

What distinguishes rough endoplasmic reticulum (RER) from smooth endoplasmic reticulum (SER)?

RER has ribosomes attached on its surface (A) Signup and view all the answers

What is the term for a chain of multiple ribosomes translating a single mRNA molecule?

Polysome or polyribosomes (C) Signup and view all the answers

What is a key function of the cytosol?

Site of metabolic pathways such as glycolysis (A) Signup and view all the answers

Which of the following is NOT a function of the Golgi complex?

Formation of ribosomes (D) Signup and view all the answers

Which organelle is essentially extended from the nuclear membrane throughout the cytoplasm?

Endoplasmic reticulum (C) Signup and view all the answers

What do the terms 'cis face' and 'trans face' refer to, specifically?

The different ends of the Golgi complex (A) Signup and view all the answers

Where are ribosomes formed within a cell?

Nucleolus (D) Signup and view all the answers

What is the role of magnesium ions ($Mg^{2+}$) in ribosome structure?

Attachment of ribosomal subunits (A) Signup and view all the answers

What is the primary function of the cytogel?

Storage of useful and waste compounds (A) Signup and view all the answers

Which of the following best describes the primary function of the middle lamella?

Holding adjacent plant cells together. (A) Signup and view all the answers

The rigidity of the secondary cell wall is mainly attributed to the presence of which component?

Lignin (B) Signup and view all the answers

What is the typical arrangement of cellulose microfibrils in the secondary cell wall?

Crisscross arrangement (C) Signup and view all the answers

Which type of cell predominantly has a secondary cell wall?

Sclerenchyma cells (B) Signup and view all the answers

The fluid mosaic model describes the plasma membrane as primarily composed of:

A phospholipid bilayer with embedded proteins. (D) Signup and view all the answers

What is the approximate thickness of the plasma membrane?

7 nm (B) Signup and view all the answers

What role do cholesterol molecules play in the plasma membrane?

They decrease the membrane's fluidity and stabilise it. (C) Signup and view all the answers

Which of the following is a function of plasma membrane proteins?

Regulating the movement of molecules across the membrane. (A) Signup and view all the answers

What is primarily conferred on the plasma membrane by the presence of unsaturated fatty acids?

Enhanced fluidity (B) Signup and view all the answers

How does a receptor protein in the plasma membrane typically function?

By binding a molecule and triggering an intracellular response. (A) Signup and view all the answers

What is the main function of Glycolipids and glycoproteins on the cell surface?

Serve as cell surface markers for cell recognition. (C) Signup and view all the answers

Which best describes the cytoplasm?

The region between the nuclear membrane and the plasma membrane. (B) Signup and view all the answers

What is the primary component of the cytoplasm?

Water (B) Signup and view all the answers

What is a key difference between the cytoplasm of prokaryotic and eukaryotic cells?

The presence or absence of membrane-bound organelles. (D) Signup and view all the answers

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

To distribute genetic material. (C) Signup and view all the answers

What structure is formed by the fusion of Golgi vesicles during plant cell cytokinesis?

Phragmoplast (B) Signup and view all the answers

Which organelle is responsible for synthesizing the enzymes found within lysosomes?

Rough Endoplasmic Reticulum (RER) (B) Signup and view all the answers

What is the term for a lysosome that is actively digesting the cell's own organelles?

Autophagosome (D) Signup and view all the answers

Which process involves the programmed cell death where lysosomes release enzymes throughout the cytoplasm?

Autolysis (D) Signup and view all the answers

What are the diseases called that occur due to the absence of certain lysosomal enzymes?

Lysosomal storage diseases (B) Signup and view all the answers

Which enzyme is responsible for breaking down hydrogen peroxide into water and oxygen in peroxisomes?

Catalase (B) Signup and view all the answers

In plant cells, where are glyoxysomes primarily found?

Seedlings of oil seed plants (B) Signup and view all the answers

The function of converting stored fatty acids to carbohydrates is performed by which organelle?

Glyoxysomes (A) Signup and view all the answers

What is the primary role of peroxisomes in liver cells?

Detoxification of alcohol (B) Signup and view all the answers

What type of enzymes do lysosomes possess?

Hydrolytic enzymes (B) Signup and view all the answers

Which of these is NOT considered a pathway from which vesicles fuse with lysosomes?

Exocytosis (D) Signup and view all the answers

What is the term for the cell structure that digests a food vacuole?

Secondary lysosome (C) Signup and view all the answers

Which of these molecules are recycled within the cell after breakdown by lysosomes?

Amino acids, monosaccharides, nucleotides, fatty acids (A) Signup and view all the answers

Which of these best describes the function of vacuoles?

Perform a variety of functions in different types of cells (A) Signup and view all the answers

What is the main function of glycolic acid oxidase in plant peroxisomes?

Conversion of glycolate to glycine (A) Signup and view all the answers

What is the main function of contractile vacuoles in freshwater protists?

To pump excess water out of the cell. (C) Signup and view all the answers

What is the function of the tonoplast in plant cells?

It separates a vacuole from the cytoplasm. (C) Signup and view all the answers

Which cell type possesses a large central vacuole?

Mature plant cells (A) Signup and view all the answers

What type of molecules are transported through porins in the mitochondrial outer membrane?

A variety of molecules. (A) Signup and view all the answers

What is the role of cristae in mitochondria?

To increase the surface area of the inner membrane. (D) Signup and view all the answers

What is the composition of the mitochondrial matrix?

A jelly-like material containing small circular DNA, RNA, ribosomes and enzymes. (B) Signup and view all the answers

What are F0-F1 particles, as found in mitochondria, responsible for?

ATP synthesis. (C) Signup and view all the answers

Which process do mitochondria use to divide?

Binary Fission. (C) Signup and view all the answers

What is the primary function of mitochondria in cells?

Cellular respiration. (C) Signup and view all the answers

What is the theory of endosymbiosis for mitochondria and chloroplasts?

They were independent organisms engulfed by eukaryotic cells. (A) Signup and view all the answers

Which cell structure regulates the number of mitochondria?

Lysosomes. (C) Signup and view all the answers

Which statement is true about inheritance of mitochondria?

Mitochondria are inherited only from the mother. (A) Signup and view all the answers

What type of plastids store starch?

Amyloplasts. (A) Signup and view all the answers

Which of the following plastids is responsible for the bright colors seen in flower petals?

Chromoplasts. (A) Signup and view all the answers

Where are chloroplasts typically found within plants?

In green parts of the plant. (C) Signup and view all the answers

Which of the following is NOT a component of a chloroplast?

Cristae (D) Signup and view all the answers

What is the main function of the stroma within a chloroplast?

Facilitating the light-independent reactions of photosynthesis (B) Signup and view all the answers

What is the structural arrangement of microtubules in centrioles?

Nine triplets arranged in a ring with no central microtubules (B) Signup and view all the answers

What is the primary role of the mitotic apparatus during cell division?

Distributing chromosomes to daughter cells (C) Signup and view all the answers

How do microfilaments contribute to muscle function?

By facilitating muscle contraction and relaxation. (C) Signup and view all the answers

What is a characteristic feature of intermediate filaments?

They provide mechanical support to the nuclear envelope and plasma membrane. (C) Signup and view all the answers

Which organelle is considered the site of photosynthesis in plant cells?

Chloroplast (A) Signup and view all the answers

What is the structure within the chloroplast where the light dependent reactions of photosynthesis take place?

Grana (D) Signup and view all the answers

What is the composition of the axoneme in cilia and flagella?

Nine peripheral doublets with two central microtubules. (D) Signup and view all the answers

What distinguishes cilia and flagella in terms of their movement?

Flagella exhibit undulating motion; cilia beat metachronously or synchronously (A) Signup and view all the answers

Which term describes the movement of cilia where they beat one after the other in a row?

Metachronous (B) Signup and view all the answers

What is the main protein component of microtubules?

Tubulin (D) Signup and view all the answers

What is the general role of cytoskeleton?

Providing cell structure and movement (A) Signup and view all the answers

Which of the following describe the thylakoids?

Double membrane sac like structures containing chlorophyll (B) Signup and view all the answers

What is the role of porins in chloroplast outer membrane?

Allowing free passage for small molecules (B) Signup and view all the answers

During the effective stroke of a cilium, how many of the double fibrils contract?

Five (C) Signup and view all the answers

During the recovery stroke of a cilium, what is the state of the cilium?

Straight (C) Signup and view all the answers

What is a key characteristic of flagellar movement, as seen in human sperm cells?

Rapid, successive waves of bending from the base to the free end (D) Signup and view all the answers

Which of the following is NOT a constituent of a typical eukaryotic nucleus?

Chromoplast (A) Signup and view all the answers

What space separates the two membranes of the nuclear envelope?

Perinuclear space (D) Signup and view all the answers

What specific transport protein is used in nuclear pores for material exchange?

Nucleoporin (A) Signup and view all the answers

Which of the following moves from the nucleus to the cytoplasm via the nuclear pore?

RNA and ribosomal proteins (A) Signup and view all the answers

What is a key difference between nucleoplasm and cytoplasm?

Nucleoplasm contains histone and non-histone protein, while cytoplasm does not (D) Signup and view all the answers

Which structure within the nucleus is responsible for ribosome construction?

Nucleolus (A) Signup and view all the answers

During cell division, what happens to the chromatin fibers?

They condense and coil up into chromosomes (B) Signup and view all the answers

What is the function of the centromere?

To attach and move chromatids (A) Signup and view all the answers

What kind of protein complex is present on the opposite sides of the centromere?

Kinetochore Protein (A) Signup and view all the answers

What is the primary difference between eukaryotic and prokaryotic cells regarding their genetic material?

Eukaryotes have their DNA enclosed in a nucleus, while prokaryotes have dispersed DNA (D) Signup and view all the answers

What type of ribosomes are found in eukaryotic cells?

80S ribosomes (B) Signup and view all the answers

Which process do both prokaryotic and eukaryotic cells use for division respectively?

Binary fission and mitosis/meiosis (B) Signup and view all the answers

Study Notes

Cell Wall and Plasma Membrane

Plasma membrane: Outer boundary of the cell, separating the cell's interior from the environment
Cell wall: Extracellular component found in plant cells, prokaryotes, and fungi; absent in animal cells. It's permeable, allowing free passage of water and dissolved materials.
Plant cell wall composition: Primarily cellulose, with layers including the primary cell wall, middle lamella, and (optionally) secondary cell wall
Primary cell wall: Forms during cell growth, composed of cellulose microfibrils in a crisscross arrangement for strength. It can stretch to allow growth.
Middle lamella: Gel-like layer between primary walls of adjacent cells, holding them together and made of pectin and calcium/magnesium salts.
Secondary cell wall: Forms only in some cells (e.g., sclerenchyma cells) after reaching maximum size. It's thicker and rigid, made of lignin, cellulose, hemicellulose and other materials, providing mechanical support.

Plasma Membrane Details

Plasma membrane composition: Primarily proteins (60-80%), lipids (20-40%) and carbohydrates, arranged in a fluid mosaic model.
Fluid mosaic model: Phospholipid bilayer with embedded proteins; proteins can be partially or completely embedded, with varying patterns across different membranes and surfaces. Membrane thickness is roughly 7nm.
Membrane fluidity: Dependent on lipids (phospholipids, glycolipids, and cholesterol). Unsaturated fatty acids increase fluidity; cholesterol stabilizes.
Membrane proteins: Perform diverse functions, including transport (channels and carriers), enzymatic activity (e.g., adenylate cyclase), signal reception (receptors), and cell recognition (antigens).
Roles of glycolipids and glycoproteins: Involved in cell-to-cell recognition and interactions.
Membrane transport: Regulates the movement of materials in and out of the cell for nutrient uptake, excretion of waste, secretion of useful substances, generating ionic gradients, and maintaining internal pH/ion concentration.

Cytoplasm and Organelles

Cytoplasm: Region between the plasma membrane and nuclear envelope, containing cytosol (less viscous internal portion) and cytogel (more viscous outer portion). Cyclosis is the circular streaming movement in the cytoplasm, for distribution of materials.
Cytoplasm's roles: Site of metabolic processes (e.g., protein synthesis, glycolysis) and storage of cellular materials (useful compounds and waste).
Cell Organelles: Membrane-bound structures in eukaryotic cytoplasm, performing specific functions. Examples include endoplasmic reticulum, ribosomes, Golgi complex, lysosomes, peroxisomes, glyoxysomes, vacuoles, mitochondria, and chloroplasts.

Endoplasmic Reticulum (ER)

Endoplasmic reticulum (ER): Interconnected network of cisternae (sacs) extending throughout the cytoplasm.
Rough ER (RER): Contains ribosomes, involved in protein synthesis and providing structural support.
Smooth ER (SER): Lacks ribosomes, involved in lipid synthesis, detoxification (especially in the liver), calcium storage, and transport of cellular products.

Ribosomes

Ribosomes: Non-membrane-bound organelles found in all cells (prokaryotic and eukaryotic).
Eukaryotic ribosomes (80S): Larger, composed of 60S and 40S subunits. Involved in protein synthesis, and can be attached to RER or free in the cytoplasm.
Prokaryotic ribosomes (70S): Smaller, found in mitochondria and chloroplasts.
Polysomes (polyribosomes): Multiple ribosomes attached to a single mRNA molecule for rapid protein synthesis.

Golgi Complex

Golgi complex: Stacked, flattened sacs (cisternae) and vesicles, processing cell secretions (mainly proteins) received from RER. Modifies proteins, packages them, and exports them.
Golgi function in plants: Involved in cell wall synthesis during cytokinesis

Lysosomes

Lysosomes: Single-membrane vesicles containing hydrolytic enzymes for intracellular digestion.
Lysosome function: Digest cellular wastes and macromolecules, participate in autophagy (self-eating), and autolysis (programmed cell death).
Lysosomal storage diseases: Inherited disorders due to a missing lysosomal enzyme, resulting in harmful substance accumulation.

Peroxisomes and Glyoxysomes

Peroxisomes: Contain oxidative enzymes (catalase, peroxidases) that break down hydrogen peroxide; Involved in detoxification (e.g., alcohol metabolism).
Glyoxysomes: Specialized peroxisomes found only in germinating seeds; catalyze the conversion of fatty acids to carbohydrates via the glyoxylate cycle.

Vacuoles

Vacuoles: Large vesicles originating from ER and Golgi; perform various functions.
Plant vacuoles: Food vacuoles, contractile vacuoles, central vacuole (maintains turgor pressure, storage of compounds).

Mitochondria

Mitochondria: Double-membrane organelles in eukaryotic cells, involved in cellular respiration and ATP production. Contain their own DNA and ribosomes (70S).
Mitochondrial structure: Outer membrane (porous), inner membrane (folded into cristae), intermembrane space, and matrix (contains enzymes for metabolic cycles).

Plastids (Chloroplasts & others)

Plastids: Organelles found in plants and algae; essential for photosynthesis and storage.
Proplastids: Immature plastids that develop into other types.
Leucoplasts: Colourless plastids for storage (starch, lipids, proteins).
Chromoplasts: Synthesize pigments other than chlorophyll.
Chloroplasts: Site of photosynthesis; double membrane envelope, stroma, and thylakoids (granal thylakoids and intergranal thylakoids).

Centrioles

Centrioles: Non-membranous organelles in animal cells (and some protists); composed of microtubule triplets; involved in spindle fibre formation during cell division.

Cytoskeleton

Cytoskeleton: Network of fibrous proteins in eukaryotic cells (e.g. microfilaments, microtubules, intermediate filaments) providing structural support and involved in cellular movement.
Microfilaments (actin): Thin, contractile fibres important for cyclosis (cytoplasmic streaming) and muscle contraction.
Microtubules: Hollow cylinders involved in cell division (spindle fibres), formation of centrioles, cilia, and flagella.
Intermediate filaments: Intermediate sized, composed of vimentin, provide mechanical support to nuclear envelope and plasma membrane.

Cilia and Flagella

Cilia and flagella: Hair-like projections for cell movement.
Structure: Composed of microtubules arranged in a 9+2 pattern.
Movement: Generated by sliding of microtubules and bending movements.

Nucleus

Nucleus: Largest organelle in eukaryotic cells, containing genetic material (DNA). Divided into nuclear envelope, nucleoplasm, nucleolus, and chromatin.
Nuclear envelope: Double membrane with pores for nucleo-cytoplasmic exchange.
Nucleoplasm: Semi-fluid substance within the nucleus, containing proteins, enzymes, and nucleic acids.
Nucleolus: Non-membrane-bound structure involved in ribosome production.
Chromatin: Network of DNA and proteins; condenses to form chromosomes during cell division.
Chromosomes: Structures composed of chromatids held together by a centromere (kinetochores).

Prokaryotic vs. Eukaryotic Cells

Prokaryotic cells: Lack membrane-bound nucleus and other organelles; DNA is dispersed in the cytoplasm; simpler cell division (binary fission).
Eukaryotic cells: Possess a nucleus and membrane-bound organelles; more complex cell division (mitosis/meiosis).

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Description

Test your knowledge on the structural differences between plant, prokaryote, and fungal cell walls. This quiz also explores the functions of ribosomes, cytoplasm properties, and other cellular components. Prepare to dive into the fascinating world of cell biology!