Biology Chapter: Cell Structure and Function
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Questions and Answers

What is the primary function of the cell membrane?

  • To produce metabolic wastes
  • To provide energy for cellular activities
  • To separate extracellular fluid from intracellular fluid (correct)
  • To facilitate the reproduction of cells

    • Which of the following statements about the composition of the cell membrane is correct?

  • It consists of 55% proteins, 40% lipids, and 5% carbohydrates. (correct)
  • It is composed of 55% carbohydrates.
  • Proteins make up 40% of the cell membrane.
  • Lipids constitute 5% of the cell membrane.

    • Which part of the cell contains the genetic material?

  • Extracellular fluid
  • Cytoplasm
  • Cell membrane
  • Nucleus (correct)

    • Which characteristic is NOT true about cells?

    <p>All cells can reproduce.</p> Signup and view all the answers

    What is the role of cytoplasm in a cell?

    <p>It surrounds the nucleus and provides a medium for metabolic activities.</p> Signup and view all the answers

    Which layer of the cell membrane is formed by lipid substances?

    <p>Central layer</p> Signup and view all the answers

    Which system in the human body is responsible for digestion?

    <p>Digestive system</p> Signup and view all the answers

    What is NOT a general characteristic of cells?

    <p>Cells produce carbon dioxide only.</p> Signup and view all the answers

    What is the primary function of the glycocalyx in the cell membrane?

    <p>Act as a barrier to negatively charged substances</p> Signup and view all the answers

    Which of the following accurately describes the protective function of the cell membrane?

    <p>It protects the cytoplasm and organelles from external damage</p> Signup and view all the answers

    What is the key characteristic of rough endoplasmic reticulum (RER)?

    <p>It has a bumpy or granular appearance due to ribosomes</p> Signup and view all the answers

    How does the cell membrane contribute to maintenance of cell shape?

    <p>By controlling the structural integrity of the cell</p> Signup and view all the answers

    Which of the following substances are NOT expelled through the cell membrane's excretory function?

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

    What is the primary function of the Rough Endoplasmic Reticulum (RER)?

    <p>Degradation of worn-out organelles</p> Signup and view all the answers

    What role does the endoplasmic reticulum play within the cell?

    <p>It connects the cell membrane to the nuclear membrane</p> Signup and view all the answers

    Which of the following substances is primarily synthesized by the Smooth Endoplasmic Reticulum (SER)?

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

    Which type of endoplasmic reticulum is characterized by the presence of ribosomes on its surface?

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

    What role does the SER play in muscle tissue?

    <p>Storage and release of calcium</p> Signup and view all the answers

    Which of the following is a function of carbohydrates in the cell membrane?

    <p>They enable tight fixation of neighboring cells</p> Signup and view all the answers

    What is the primary function of the Golgi apparatus?

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

    From which cellular structure are lysosomes formed?

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

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

    <p>5 to 8 flattened membranous sacs</p> Signup and view all the answers

    Which face of the Golgi apparatus is associated with receiving vesicles from the endoplasmic reticulum?

    <p>Cis face</p> Signup and view all the answers

    What type of substances do lysosomes primarily degrade?

    <p>Cellular waste</p> Signup and view all the answers

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

    <p>It is a fluid structure.</p> Signup and view all the answers

    Which part of the phospholipid molecule is hydrophilic?

    <p>Outer part</p> Signup and view all the answers

    What role do channel proteins play in the cell membrane?

    <p>They assist in diffusion of water-soluble substances.</p> Signup and view all the answers

    What is the function of carrier proteins in the cell membrane?

    <p>To transport substances across the cell membrane.</p> Signup and view all the answers

    Which substances are able to pass through the lipid layer of the cell membrane?

    <p>Oxygen and carbon dioxide</p> Signup and view all the answers

    What do glycoproteins and glycolipids have in common?

    <p>They are formed by attaching carbohydrates to proteins or lipids.</p> Signup and view all the answers

    Which of the following is a function of receptor proteins in the cell membrane?

    <p>Binding hormones and neurotransmitters.</p> Signup and view all the answers

    How do integral proteins contribute to cell adhesion?

    <p>They attach cells to their neighbors or basal lamina.</p> Signup and view all the answers

    Which type of lysosome is inactive despite containing hydrolytic enzymes?

    <p>Primary lysosome</p> Signup and view all the answers

    What is the primary function of lysosomes in the cell?

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

    How are secondary lysosomes formed?

    <p>By the fusion of a primary lysosome with a phagosome or endosome</p> Signup and view all the answers

    Which enzyme group in lysosomes hydrolyzes nucleic acids?

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

    What structure within the mitochondrion is responsible for ATP synthesis?

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

    What is the primary role of mitochondria in cellular functions?

    <p>Production of energy</p> Signup and view all the answers

    What percentage of the total cell volume does the nucleus occupy?

    <p>10%</p> Signup and view all the answers

    What is the defining characteristic of eukaryotic cells?

    <p>They contain a nucleus.</p> Signup and view all the answers

    What is the primary function of the nucleus in a cell?

    <p>Regulating cell metabolism and reproduction</p> Signup and view all the answers

    What constitutes the major components of the nucleus?

    <p>Nucleoplasm, chromatin, and nucleolus</p> Signup and view all the answers

    What is the role of the nucleolus within the nucleus?

    <p>It synthesizes RNA and forms ribosome subunits.</p> Signup and view all the answers

    How many pairs of chromosomes are typically found in dividing non-reproductive human cells?

    <p>23 pairs</p> Signup and view all the answers

    What is chromatin primarily composed of?

    <p>Coiled DNA and histone proteins</p> Signup and view all the answers

    What structure regulates communication between the nucleoplasm and the cytoplasm?

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

    Which function of the nucleus involves the transmission of genetic information?

    <p>Sending genetic instructions through mRNA</p> Signup and view all the answers

    What is the composition of the nucleoplasm?

    <p>Nucleotides and enzymes</p> Signup and view all the answers

    Study Notes

    Introduction

    • Cells are the fundamental structural and functional units of living organisms.
    • Cells group together to form tissues, which then combine to form organs and systems.
    • The body's systems work together to maintain homeostasis and overall health.
    • Cells need nutrients, oxygen, and energy for survival and growth.
    • Cells produce energy, eliminate waste products, and respond to internal and external stimuli.
    • Reproduction, through cell division, ensures continuation of life.

    General Cell Characteristics

    • All cells require nutrients and oxygen.
    • Each cell produces energy for its functions.
    • Cells eliminate metabolic waste products.
    • Cells maintain a stable internal environment to support processes.
    • Cells respond to invaders.
    • Cells multiply through division (except some like neurons).

    Cell Structure

    • A cell comprises a cell body and a surrounding cell membrane.
    • The cell body contains a nucleus and cytoplasm.
    • Three main components are studied: cell membrane, cytoplasm, and nucleus.

    Cell Membrane

    • A protective layer, also known as the plasma or plasmalemma.
    • Separates intracellular fluid (inside the cell) from extracellular fluid (outside the cell).
    • A semipermeable membrane.
    • Consists of lipids (phospholipids and cholesterol) and proteins.

    Cytoplasm

    • Gel-like material filling the cell body.
    • Contains various organelles with specific functions.
    • Cytoplasm includes cytosol, organelles, and various other particles.

    Nucleus

    • The control center of the cell.
    • Contains the cell's genetic material (DNA).
    • A membrane-bound organelle.
    • Contains nucleoplasm and nucleoli.
    • Important for cell division and protein synthesis.

    Other Organelles (Page 4-5)

    • Endoplasmic Reticulum (ER): A network of tubules; rough ER is studded with ribosomes (involved in protein synthesis), while smooth ER lacks ribosomes (involved in lipid synthesis and detoxification).
    • Golgi Apparatus: Processes and packages proteins and other molecules.
    • Lysosomes: Contain enzymes for breaking down cellular waste and debris.
    • Mitochondria: "Powerhouses" where energy is produced (ATP).
    • Ribosomes: Involved in protein synthesis.
    • Vacuoles/Vesicles: Membrane-bound sacs for storage and transport.

    Membrane Carbohydrates

    • Some membrane carbohydrates are attached to proteins (glycoproteins) or lipids (glycolipids).
    • Carbohydrate molecules form a layer called glycocalyx.

    Functions of Cell Membrane

    • Protective barrier
    • Selective permeability (controlling what enters and exits)
    • Absorption and excretion
    • Gas exchange
    • Maintaining cell shape and size

    Functions of Nucleus

    • Controlling all cell activities.
    • Synthesizing RNA.
    • Forming ribosome subunits.
    • Directing protein synthesis.
    • Controlling cell division.
    • Storing genetic information.

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    UNIT 1. Cell - Structure and Function PDF

    Description

    Test your knowledge on cell membranes, organelles, and their functions with this comprehensive quiz. From the role of the cell membrane to the importance of the rough endoplasmic reticulum, each question delves into the essential characteristics of cells and their components. Challenge yourself and enhance your understanding of cellular biology!

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