Cellular Structure and Function Quiz

Cellular Structure and Function

• Cells are the basic structural and functional units of all living organisms.
• They are formed by the division of existing cells.
• Cells contain genetic information (DNA) passed to daughter cells during division.
• All cells share the same fundamental chemical components.
• All life processes occur within cells.

Cell Types

• Two main types: prokaryotic and eukaryotic.
• Eukaryotic cells contain membrane-bound organelles and can be single-celled (protozoa, some algae and fungi) or multicellular (plants, animals, and some fungi).
• Prokaryotic cells are simpler, lacking membrane-bound organelles and are always single-celled (bacteria, archaea).

Eukaryotic Cell Components

• Cytoplasm: The jelly-like substance filling the cell.
• Cytoskeleton: Network of protein fibers supporting cell structure and movement.
• Nucleus: Contains the cell's DNA.
• Endoplasmic reticulum (ER): Involved in protein and lipid synthesis.
• Mitochondria: "Powerhouses" of the cell, responsible for cellular respiration and energy production.
• Golgi apparatus: Processes and packages proteins.
• Lysosomes: Contain digestive enzymes.
• Peroxisomes: Involved in detoxification.

Prokaryotic Cell Components

• Cell membrane: Separates the cell from its surroundings.
• Cell wall: Provides structural support (in bacteria).
• Capsule (mucus): Protective layer (in bacteria).
• Flagella (cilia): Structures for movement (in bacteria).
• Cytosol: The fluid component in the cytoplasm of prokaryotic cells
• Nucleoid: Region where DNA is located.
• Plasmids: Small, circular DNA molecules.
• Ribosomes: Sites of protein synthesis.

Chemical Composition of Cells

• Organic molecules: Contain carbon-hydrogen bonds.
  • Are larger and more complex.
  • Found in living organisms.
  • Form biological macromolecules (carbohydrates, proteins, lipids, nucleic acids).
    • Carbohydrates: Provide energy (e.g., glucose).
    • Proteins: Perform various functions (e.g., enzymes).
    • Lipids: Store energy and form cell membranes (e.g., fats, oils).
    • Nucleic acids: Carry genetic information (e.g., DNA, RNA).
• Inorganic molecules: Do not typically contain carbon-hydrogen bonds.
  • Are smaller and simpler.
  • Found in both living and non-living things.
  • Play vital roles in physiological processes (e.g., water, salts, minerals, gases).

Water

• Water is the major component of living organisms (70-80% of cells).
• Essential for life processes.
• Excellent solvent.
• Can be a substrate or product in many reactions.
• Its properties (dipolar nature, hydrogen bonding) are crucial for life.

Carbon

• Carbon is a fundamental element in organic molecules.
• Forms strong covalent bonds with other carbon atoms and other elements.
• Can form chains, branched structures, and rings.

Organic Compounds (containing carbon and hydrogen)

• Four major families:
  • Carbohydrates (saccharides): Contain carbon, hydrogen, and oxygen. Function in energy storage (e.g., glycogen, starch) and structural roles (e.g., cellulose, chitin).
  • Fatty acids: Have a hydrocarbon chain with a carboxyl group. Saturated vs. unsaturated. Important components of lipids.
  • Amino acids: Building blocks of proteins.
  • Nucleotides: Building blocks of nucleic acids (DNA, RNA)

Lipids

• Insoluble in water.
• Esters of fatty acids bonded to alcohols (e.g., glycerol, sphingosine).
• Components of cell membranes.
• Forms of energy storage.
• Types of lipids include fats, oils, waxes, phospholipids, and glycolipids.

Cell Membranes

• Separate internal and external environments.
• Composed of lipids, proteins, and carbohydrates.
• Regulates the transport of materials into and out of the cell.
• Protects cells from external factors.

Cell Components

• Organelles: Membrane-bound structures in eukaryotic cells performing specific functions.
• Cytoplasm: Area within the cell membrane, excluding the nucleus and organelle