Medical Biology Lecture 8 : Cell Structures and Function

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31 Questions

What type of protein makes up microfilaments?


Which cellular appendages are composed of specialized microtubules and covered by a specialized extension of the cellular membrane?

Cilia and flagella

What is the main function of actin filaments?

Projecting from certain cells and shortening or extending

What is the name of the protein that makes up microtubules?


Which structure is composed of 9 microtubules arranged in a very particular pattern?


What is the function of microtubules in cell division?

Forming spindle fibers to assist in the movement of chromosomes

What is the core of the structure termed in cilia and flagella?


Which type of cells contain a special organelle called a centriole?

Eukaryotic cells

What is the name for the arrangement where nine doublets oriented about two additional microtubules form cilia and flagella?

(9+2) arrangement

What is attached to a cell at a structure termed the basal body in eukaryotic cilia and flagella?

(Plasma membrane)

What are eukaryotic cilia and flagella composed of?


What plays a very important role in organizing the microtubules that position the chromosomes in the correct location during cell division?


Which organelle has a relatively simple phospholipid bilayer and contains protein structures called porins?


What is the primary function of the inter-membrane space in the mitochondria?

Oxidative phosphorylation

Which organelle is responsible for modifying proteins received from the rough endoplasmic reticulum (RER)?

Golgi apparatus

Which organelle is involved in autophagy and the storage of nutrients such as lipids, proteins, and carbohydrates?


In which organelle are membranous sacs filled with enzymes produced by the Golgi apparatus found?


What is the main function of peroxisomes?

Energy metabolism

Which cellular organelle packages and sorts proteins and other molecules before sending them to their final destination?

Golgi apparatus

What is the role of the cytoskeleton in a cell?

Cell structure and support

What does the inner membrane of mitochondria contain that aids in the production of ATP?

Cristae that increase the surface area for ATP synthesis

What is the main function of lysosomes within a cell?

Digestion of complex molecules and recycling within the cell

What is the main function of the cytoplasm in a cell?

To hold together the organelles and provide a medium for metabolic reactions

What is the composition of the cytoplasm?

Cytosol, vesicles, inclusions, and organelles excluding the nucleus

In a eukaryotic cell, where is the cytoplasm located?

Between the cell membrane and the nuclear envelope

Which organelle is described as 'the powerhouse of the cell'?


What is the size range of mitochondria?

0.5 - 10μm

Which component of the cytoplasm provides a medium for metabolic reactions to occur?


What percentage of water does the cytoplasm consist of?

Up to 90%

What is the protoplasm composed of in a eukaryotic cell?

Cytoplasm and nucleus

What does the mitochondrion generate most of for the cell?

Adenosine triphosphate (ATP)

Study Notes

  • College of Medicine Lecturer: Zahraa Ch. Hameed
  • Lecture: Medical Biology/ Lecture: 4, 5
  • Topic: Cell Structures and Function, specifically cytoplasm and organelles
  • Learning Objectives:
    • Students will learn the composition of the cell
    • Define the cell cytoplasm
    • Explain the types of cell organelles
    • Explain the Cytoskeleton of the cell
  • The Cytoplasm*
  • Jelly-like substance in the cell
  • Composition: up to 90% water, cytosol, vesicles, cytoskeleton, inclusions, and organelles excluding the nucleus
  • Located between the cell membrane and the nuclear envelope
  • Primary functions: holds organelles together, nourishes the cell, and provides a medium for metabolic reactions
  • Cellular Organelles*
  • Mitochondrion*
  • Double membrane-bound organelle
  • Generates most of the cell's supply of ATP
  • Sizes: 0.5 -10μm
  • Shape: round to oval
  • Structure: outer membrane, inner membrane, inter-membrane space, and matrix
  • Inner membrane has cristae for increased surface area
  • Cytoplasmic organelle for oxidative phosphorylation
  • Endoplasmic Reticulum*
  • Series of interconnected membranous sacs and tubules
  • Synthesizes and modifies proteins, lipids, and carbohydrates
  • Double membranes: rough ER (RER) and smooth ER (SER)
  • RER: performs protein synthesis, calcium storage, and signaling
  • SER: synthesizes and metabolizes lipids and steroids, detoxifies compounds, and creates steroid hormones
  • Golgi Body*
  • Stacks of slightly curved sacs (cisternae)
  • Packages and sorts proteins and other molecules
  • Modifies proteins, transports lipids, and creates lysosomes
  • Types of molecules processed: glycoproteins, lipids, and glucosaminoglycans
  • Ribosomes*
  • Complex biological machines for protein synthesis
  • Consists of two major components: small ribosomal subunit and large ribosomal subunit
  • Each subunit is composed of one or more ribosomal RNA molecules and a variety of ribosomal proteins
  • Vacuole*
  • Membrane-bound organelle
  • Stores water, nutrients, and waste products
  • Separates metabolic processes within the cell
  • Waste removal: autophagy
  • Lysosomes*
  • Membranous sacs filled with digestive enzymes
  • Digest complex molecules, recycle them for other uses, and remove harmful foreign substances
  • Diseases caused by missing enzymes: Tay-Sachs disease
  • Peroxisomes*
  • Small, membrane-enclosed cellular organelles
  • Contains oxidative enzymes for various metabolic reactions
  • Detoxifying organs: liver and kidneys
  • Cytoskeleton*
  • Network of fibers throughout the cell's cytoplasm
  • Maintains cell shape and acts as tracks for organelle movement
  • Divided into three categories: microfilaments, intermediate filaments, and microtubules.

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