Cell Organelles: Mitochondria and Ribosomes
30 Questions
4 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

Where are ribosomal subunits synthesized?

  • ER
  • Nucleus (correct)
  • Mitochondria
  • Cytoplasm

    • What is the main function of ribosomes?

  • Initiating apoptosis
  • Synthesizing lipids
  • Protein synthesis (correct)
  • Producing blood proteins

    • What organelle is referred to as the 'powerhouse' of the cell?

  • Nucleus
  • Mitochondria (correct)
  • Ribosomes
  • Endoplasmic Reticulum

    • Which organelle plays an important role in apoptosis by releasing cytochrome c?

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

    Where do ribosomal subunits pass to after being formed in the nucleus?

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

    Which organelle is an interconnected network of tubules, vesicles, and cisternae?

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

    What is the function of the plasma membrane in a cell?

    <p>Regulates what enters and exits a cell</p> Signup and view all the answers

    Which component makes up 45% of the cell membrane?

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

    What is the function of the nucleus in a cell?

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

    What is the composition of the cell membrane mainly made of?

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

    Which part of a phospholipid molecule is hydrophilic?

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

    What is the function of organelles in a cell?

    <p>Perform specific functions for the cell</p> Signup and view all the answers

    What is the function of lysosomes in a cell?

    <p>To digest bacteria and other large objects</p> Signup and view all the answers

    Which cell types are likely to have abundant lysosomes?

    <p>Macrophages and neutrophils</p> Signup and view all the answers

    During autophagy, what cellular components do lysosomes help break down?

    <p>Damaged mitochondria</p> Signup and view all the answers

    Which organelle is known as the 'digestive system of the cell'?

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

    What happens to cells during the process of atrophy?

    <p>Cells become smaller and more energy-efficient</p> Signup and view all the answers

    Why are lysosomes sometimes referred to as 'cellular garbage disposals'?

    <p>For their role in digesting unwanted cellular components</p> Signup and view all the answers

    What is the function of cholesterol in the plasma membrane?

    <p>Causes stiffening and strengthening of the membrane</p> Signup and view all the answers

    Which type of membrane proteins extend through the entire thickness of the membrane?

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

    What makes the tail of the membrane hydrophobic?

    <p>Insoluble in water but soluble in fat solvents</p> Signup and view all the answers

    Which function do membrane proteins NOT perform?

    <p>Act as hormones and chemical messengers</p> Signup and view all the answers

    How do peripheral proteins differ from integral proteins?

    <p>Associated with both intracellular and extracellular membrane surfaces</p> Signup and view all the answers

    What is the role of linker proteins in the cell membrane?

    <p>Binds to other proteins in the ECF and cytosol</p> Signup and view all the answers

    Which organelle is prominent in cells specialized for protein secretion?

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

    What is the function of smooth endoplasmic reticulum (SER) in liver cells?

    <p>Synthesis of lipid and steroid hormones</p> Signup and view all the answers

    What is the main function of the Golgi apparatus in secretory cells?

    <p>Protein and lipid modification</p> Signup and view all the answers

    Which organelle is rich in steroid hormone–producing cells of the adrenal cortex?

    <p>Smooth endoplasmic reticulum (SER)</p> Signup and view all the answers

    In muscle cells, which organelle is involved in the release and recapture of calcium ions for contraction and relaxation?

    <p>Smooth endoplasmic reticulum (SER)</p> Signup and view all the answers

    What distinguishes rough endoplasmic reticulum (RER) from smooth endoplasmic reticulum (SER) at a structural level?

    <p>Presence of ribosomes</p> Signup and view all the answers

    Study Notes

    Ribosomal Subunits and Ribosomes

    • Ribosomal subunits are synthesized in the nucleolus of the nucleus.
    • The main function of ribosomes is to facilitate protein synthesis by translating messenger RNA (mRNA) into polypeptide chains.

    Energy and Apoptosis

    • The mitochondrion is referred to as the 'powerhouse' of the cell due to its role in ATP production through cellular respiration.
    • Mitochondria play a key role in apoptosis by releasing cytochrome c, which activates the apoptotic pathway.

    Cellular Structures and Functions

    • Ribosomal subunits pass from the nucleus to the cytoplasm after being formed, where they assemble with mRNA and tRNA to synthesize proteins.
    • The endoplasmic reticulum (ER) is an interconnected network of tubules, vesicles, and cisternae involved in protein and lipid synthesis.
    • The plasma membrane functions as a protective barrier that regulates the movement of substances in and out of the cell.

    Cell Membrane Composition

    • Phospholipids make up approximately 45% of the cell membrane structure.
    • The cell membrane is primarily composed of a phospholipid bilayer, along with proteins, cholesterol, and carbohydrates.

    Phospholipids

    • The hydrophilic (water-attracting) part of a phospholipid molecule is the phosphate group.
    • The hydrophobic (water-repelling) tail of the membrane is made up of fatty acid chains.

    Organelle Functions

    • Organelles in a cell serve specific functions, including energy production, protein synthesis, and waste disposal.
    • Lysosomes function as the 'digestive system of the cell,' breaking down waste material and cellular debris.

    Lysosomes and Cellular Maintenance

    • Cells with high metabolic activity, such as macrophages and certain glandular cells, are likely to have abundant lysosomes.
    • During autophagy, lysosomes help break down damaged organelles, misfolded proteins, and other cellular components.
    • Lysosomes are sometimes referred to as 'cellular garbage disposals' because they digest and remove waste from the cell.

    Membrane Components and Proteins

    • Cholesterol maintains the fluidity and stability of the plasma membrane.
    • Integral membrane proteins extend through the entire thickness of the membrane, while peripheral proteins are attached to the surface.

    Membrane Structure and Function

    • The hydrophobic tail of membrane phospholipids prevents the free passage of water-soluble substances.
    • Membrane proteins do not directly perform energy production; their roles include transport, signaling, and structural support.
    • Peripheral proteins differ from integral proteins as they are not embedded within the lipid bilayer.

    Role of Linker Proteins

    • Linker proteins in the cell membrane connect cytoskeletal elements to membrane proteins, contributing to cell shape and structure.

    Specialized Cellular Structures

    • The rough endoplasmic reticulum (RER) is prominent in cells that specialize in protein secretion, characterized by ribosomes on its surface.
    • The smooth endoplasmic reticulum (SER) in liver cells functions in the detoxification of drugs and the metabolism of carbohydrates and lipids.
    • The Golgi apparatus is essential for modifying, sorting, and packaging proteins for secretion in secretory cells.

    Calcium Management in Muscle Cells

    • In muscle cells, the sarcoplasmic reticulum is responsible for the release and recapture of calcium ions, crucial for muscle contraction and relaxation.

    Structural Differences in ER

    • Rough endoplasmic reticulum (RER) has ribosomes attached to its cytoplasmic surface, making it appear 'rough' under a microscope, while smooth endoplasmic reticulum (SER) lacks these ribosomes and appears smooth.

    Studying That Suits You

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

    Quiz Team

    Description

    Learn about the vital functions of mitochondria as the 'powerhouses' of the cell and the role of ribosomes in protein synthesis. Understand how mitochondria play a key role in apoptosis, while ribosomes are essential for creating proteins.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser