Biology test Review

Plant Cells vs. Animal Cells

  • Plant Cells:

    • Contain chloroplasts for photosynthesis
    • Have a cell wall for structure and support
    • Large central vacuole for storage and maintaining shape

  • Animal Cells:

    • No cell wall
    • Smaller vacuoles

Cell Functions

  • Cell Wall:

    • Strengthens and maintains cell shape

  • Cell Membrane:

    • Controls exchange of materials in and out of cell

  • Cytoplasm:

    • Site for biochemical functions

  • Nucleus:

    • Stores genetic information
    • Controls cellular activities

  • Mitochondria:

    • Powerhouse of the cell
    • Produces ATP through cellular respiration

  • Chloroplasts:

    • Site of photosynthesis
    • Converts CO₂ and H₂O into glucose

  • Endoplasmic Reticulum (ER):

    • Rough ER:
    • Packages proteins made by ribosomes
    • Smooth ER:
    • Synthesizes lipids and metabolizes carbohydrates

  • Golgi Apparatus:

    • Modifies, processes, and packages proteins for transport

Cell Division

  • Mitosis Stages:
    • Interphase:
    • Cell grows, replicates chromosomes
    • Prophase:
    • Chromosomes condense, spindle fibers form
    • Nuclear membrane breaks down
    • Metaphase:
    • Chromosomes align at cell center
    • Anaphase:
    • Sister chromatids separate to opposite ends
    • Telophase:
    • New nuclear membranes form, chromosomes de-condense
    • Cytokinesis:
    • Cell membrane pinches to form two daughter cells

Microorganisms & Food Spoilage

  • Causes of Spoilage:

    • Mainly caused by bacteria, yeasts, molds
    • Pathogens can lead to foodborne illnesses

  • Hygienic Practices:

    • Important in food industry to prevent contamination
    • Includes proper handling, cooking, and storage

Forms of Food Preservation

  • Heat Sterilization:
    • Kills bacteria through boiling/steaming
  • Refrigeration:
    • Slows bacterial growth at ~5°C
  • Frozing:
    • Reduces water availability for microbes
  • Drying:
    • Removes moisture, killing pathogens
  • Chemical Preservatives:
    • Acids, sugars, and salts that hinder microbial growth

Living vs Non-living Things

  • Living things are made of one or more cells and carry out life processes (MRS GREN)
  • Cell theory:
    • All living organisms consist of cells
    • Cells come from pre-existing cells

Cell Types

  • Prokaryotic:
    • Unicellular, lack a nucleus, e.g., bacteria
  • Eukaryotic:
    • Have a nucleus and organelles, e.g., plants, animals, fungi

Transport Mechanisms

  • Passive Transport:
    • Movement from high to low concentration (e.g., osmosis, diffusion)
  • Active Transport:
    • Movement from low to high concentration, requires energy

Importance of Microorganisms

  • Role in nutrient cycling, fermentation, disease prevention
  • Used in biotechnology for insulin production, vaccines, and more

Gene Cloning and Biotechnology

  • Alters genetic material for medical and agricultural applications
  • Techniques such as recombinant DNA technology to produce necessary proteins