Biology Cell Introduction
15 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What did Robert Hooke contribute to the cell theory?

  • First person to use chambers in the structure of cork as cells (correct)
  • Proposed the theory of biogenesis
  • Concluded that all animal tissues are composed of cells
  • Concluded that plant tissues are composed of cells

    • What is the function of the Golgi apparatus?

    Modifies, packages, and sorts materials that arrive from the endoplasmic reticulum in transport vesicles.

    Mitosis is the division of cells in prokaryotes.

    False

    Diffusion is the movement of a substance from an area of its higher concentration to an area of its lower concentration. __________ transports small solutes across the cell membrane.

    <p>Simple diffusion</p> Signup and view all the answers

    Match the following parts of the eukaryotic cell with their descriptions:

    <p>Nucleus = Enclosed within a double membrane called the nuclear envelope; contains nucleolus. Mitochondria = Responsible for the building up of energy in the form of ATP. Lysosome = Spherical shaped membrane-bound organelle that digests microbes or materials by the cell. Endoplasmic Reticulum = Responsible for cellular processes and can be rough or smooth.</p> Signup and view all the answers

    What percentage of the cell weight is accounted for by water?

    <p>70-75%</p> Signup and view all the answers

    What is the main component of the plasma membrane?

    <p>Phospholipid bilayer</p> Signup and view all the answers

    What is the function of the plasma membrane?

    <p>To act as a physical barrier to enclose cell contents</p> Signup and view all the answers

    What is the basic unit of life?

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

    What determines the function of the cell?

    <p>Its structure (anatomy)</p> Signup and view all the answers

    What is the percentage of the cell weight accounted for by organic compounds?

    <p>25-30%</p> Signup and view all the answers

    What is the theory that states cells only arise from pre-existing cells?

    <p>Theory of biogenesis</p> Signup and view all the answers

    Who concluded that all animal tissues are composed of cells?

    <p>Theodor Schwann</p> Signup and view all the answers

    What is the term that describes the division of cells?

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

    What is the composition of the remaining cell weight?

    <p>Inorganic compounds</p> Signup and view all the answers

    Study Notes

    The Cell

    • All living organisms, including humans, are made up of cells.
    • 70-75% of the cell's weight is composed of water, while organic compounds account for 25-30% of the cell's weight.
    • Inorganic compounds make up the rest of the cell's weight.

    History/Background

    • Robert Hooke was the first person to use the term "cell" to describe the small empty chambers in the structure of cork.
    • Matthias Schleiden concluded that all plant tissues are composed of cells.
    • Theodor Schwann concluded that all animal tissues are composed of cells.
    • Rudolf Virchow proposed the theory of biogenesis, stating that cells can only arise from pre-existing cells.

    Cell Theory

    • The cell is the basic unit of life.
    • The activities of the cell depend on the collective activities of its cells.
    • The structure of the cell determines its function.

    Parts of a Eukaryotic Cell

    • Plasma Membrane

      • A phospholipid bilayer containing cholesterol, proteins, and some carbohydrates.
      • Forms a selectively permeable boundary of the cell.
      • Regulates material movement into and out of the cell.
      • Enables cell communication.

    • Nucleus

      • Contains DNA that serves as the genetic material for directing protein synthesis.
      • Enclosed within a double membrane called the nuclear envelope.
      • Nucleolus consists of RNA and proteins that function in ribosomal assembly.

    • Cytoplasm

      • Can be seen between the plasma membrane and the nucleus.
      • Organelles are membrane-bound structures that carry out specific metabolic activities of the cell.
      • Cytosol provides support for organelles and serves as the viscous fluid medium.

    • Mitochondria

      • Double membrane-bound organelles containing a circular strand of DNA.
      • Responsible for building up energy in the form of ATP.

    • Endoplasmic Reticulum (ER)

      • Rough ER: has ribosomes attached on the cytoplasmic surfaces.
      • Smooth ER: has no ribosomes and produces lipids, cholesterol, and hormones.

    • Golgi Apparatus

      • Modifies, packages, and sorts materials from the ER in transport vesicles.
      • Vesicles transport cellular material.

    • Peroxisomes

      • Smaller, spherical membrane-bound organelles that detoxify specific harmful substances.

    • Lysosome

      • Spherical shaped membrane-bound organelles that digest microbes or materials by the cell.

    • Cytoskeleton

      • Organized network of protein filaments that maintains structural support and organization of the cell.
      • Microfilaments maintain cell shape, intermediate filaments give mechanical support to structures like the nucleus and plasma membrane, and microtubules provide structural support.

    Prokaryotic Cell

    • Lack a membrane-bound nucleus.
    • DNA is condensed within the cytosol to form a nucleoid.
    • Have no subcellular organelles, only infoldings of the plasma membrane called mesosomes.

    Cell Membrane Transport

    • Passive Transport Process

      • Diffusion: movement of a substance from an area of higher concentration to an area of lower concentration.
      • Facilitated diffusion: requires a channel or protein carrier.
      • Osmosis: diffusion of water across a selectively permeable membrane.

    • Active Transport Process

      • Uses energy (ATP) provided by the cell.

    Cell Life Cycle

    • Interphase

      • Longer phase of the cell cycle.
      • DNA replication occurs.

    • Mitosis

      • Prophase: two chromatids joined at the centromeres.
      • Metaphase: chromosomes aligned at the center.
      • Anaphase: chromatids separated at the centromeres to opposite poles.
      • Telophase: chromosomes uncoil, and nuclear envelope reforms.

    Cellular Structure and Function

    • Cells are the basic unit of life, and all living organisms, including humans, are made up of cells.
    • There are two major classes of cells: Eukaryotes and Prokaryotes.
    • Eukaryotes have DNA found in the nucleus of the cell, contain membrane-bound organelles, and undergo mitosis.
    • Prokaryotes lack membrane-bound organelles, do not have DNA enclosed within a membrane, and undergo binary fission.

    Mitochondria

    • Mitochondria are double membrane-bound organelles containing a circular strand of DNA.
    • The outer membrane is highly permeable due to the presence of a pore-forming protein called porin.
    • The intermembrane space contains many proteins that participate in oxidative phosphorylation.
    • The inner membrane has multiple folds projecting inwards, called cristae, where energy is built up in the form of ATP.

    Endoplasmic Reticulum (ER)

    • ER is a network of protein filaments responsible for modifying, packaging, and sorting materials.
    • There are two types of ER: Rough ER and Smooth ER.
    • Rough ER has ribosomes attached to its surface, responsible for protein synthesis.
    • Smooth ER lacks ribosomes, produces lipids, cholesterol, and hormones, and breaks down toxins.

    Golgi Apparatus

    • The Golgi Apparatus is a series of elongated, flattened sac-like membranous structures.
    • It modifies, transports, and packages materials, and stores proteins produced by attached ribosomes.

    Lysosomes

    • Lysosomes are spherical-shaped membrane-bound organelles formed from the Golgi apparatus.
    • They contain digestive enzymes and are responsible for digesting microbes or materials ingested by the cell.

    Cytoskeleton

    • The cytoskeleton is an organized network of protein filaments providing structural support and organization to the cell.
    • Microfilaments maintain cell shape, intermediate filaments provide mechanical support, and microtubules regulate material movement into and out of the cell.

    Nucleus

    • The nucleus is enclosed within a double membrane called the nuclear envelope.
    • It contains the DNA that serves as the genetic material for directing protein synthesis.
    • The nucleolus is a region within the nucleus where RNA and proteins are found, functioning in ribosomal assembly.

    Cytoplasm

    • Cytoplasm is the fluid medium between the plasma membrane and the nucleus where organelles are embedded.
    • It provides support for organelles and serves as the viscous fluid medium for cellular metabolic activities.

    Plasma Membrane

    • The plasma membrane is a phospholipid bilayer containing cholesterol, proteins, and some carbohydrates.
    • It forms a selectively permeable boundary of the cell and acts as a physical barrier to enclose cell contents.

    Peroxisomes

    • Peroxisomes are smaller, spherical membrane-bound organelles formed from the endoplasmic reticulum.
    • They detoxify specific harmful substances.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Test your knowledge of cell biology, including the composition of cells and cell division. Learn about the basics of cellular biology and molecular composition.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser