Cell Biology

• What are the two main types of cells in biology?

  Prokaryotic and eukaryotic cells
• What is a key difference between prokaryotic and eukaryotic cells?

  Prokaryotic cells do not have a nucleus
• What is the function of ribosomes?

  Site of protein synthesis
• What is the role of mitochondria in cells?

  Site of respiration
• What does the nucleus contain?

  DNA
• What is the function of chloroplasts?

  Absorbs light for photosynthesis
• What is the function of the cell wall?

  Provides strength to the cell
• What is the function of the cell membrane?

  Controls what can enter and leave a cell
• What is the function of a vacuole in plant cells?

  Contains cell sap
• What is the function of flagella?

  Allows a cell to move
• What are plasmids?

  Small rings of DNA found in the cytoplasm of bacterial cells
• What are the main differences between prokaryotic and eukaryotic cells?

  • Prokaryotic cells are smaller than eukaryotic cells.
  • Prokaryotic cells do not have mitochondria.
  • Prokaryotic cells have no nucleus; DNA is free in the cytoplasm.
  • Prokaryotic cells have a single loop of genetic material.
  • Prokaryotic cells have plasmids, whereas eukaryotic cells do not.
• What are the functions of the main cell structures?

  • Ribosomes: Site of protein synthesis.
  • Mitochondria: Site of respiration.
  • Nucleus: Contains DNA and controls cell activities.
  • Chloroplasts: Absorbs light for photosynthesis.
  • Cytoplasm: Site of chemical reactions.
  • Cell wall: Provides strength.
  • Cell membrane: Controls entry and exit of substances.
  • Vacuole: Contains cell sap.
  • Flagella: Allows movement.
  • Plasmids: Small rings of DNA in bacteria.
• What is the first step in preparing a plant cell slice for observation?

  Take a piece of onion and peel a thin layer
• What should you do if the onion layer is white when preparing a slide?

  Put a drop of iodine on top before placing the cover slip
• What is the purpose of using a coarse adjustment knob when using a microscope?

  To move the stage up to just below the objective lens
• What is the purpose of the fine adjustment knob?

  To get a clear image of what’s on the slide
• What are the steps for biological drawings under a microscope?

  1. Draw with a sharp pencil.
  2. Take up as much space as possible.
  3. No shading or coloring.
  4. Draw cellular structures in proportion.
  5. Include a title and magnification.
  6. Label important features with straight lines.
• What is cell differentiation?

  Cells acquire different structures to perform specific functions
• What is the function of a sperm cell?

  To pass on paternal genetic material
• What is the structure of a sperm cell?

  It has a head, acrosome, mitochondria, mid-piece, and tail
• What is the function of a nerve cell?

  Conduction of impulses
• What is the structure of a nerve cell?

  It has extensions called dendrites and a long axon
• What is the function of a muscle cell?

  Contraction for movement
• What is the structure of a muscle cell?

  It has layers of protein filaments that slide over one another
• What is the function of root hair cells?

  Absorption of water and minerals from soil
• What is the structure of root hair cells?

  Protrusions increase surface area for absorption
• What is the function of xylem cells?

  Transport water and ions through a plant
• What is the structure of xylem cells?

  They have no cell contents and thickened walls with lignin
• What is the function of phloem cells?

  Transport sugars through a plant
• What is the structure of phloem cells?

  They have sieve plates that allow dissolved sugars to move freely
• What are the parts of a light microscope and their functions?

  • Eyepiece lens: Magnifies the specimen.
  • Arm: Used to carry the microscope.
  • Coarse adjustment knob: Focuses the image under low magnification.
  • Fine adjustment knob: Focuses the image under high magnification.
  • Rotating nosepiece: Switches between objective lenses.
  • Stage clips: Holds the slide in place.
  • Stage: Where the slide is placed.
  • Diaphragm: Controls light passing through the slide.
  • Light source: Provides light for viewing.
  • Base: Supports the microscope.
• What is the advantage of using an electron microscope compared to a light microscope?

  Higher magnification and resolution
• What is standard form and its purpose?

  • Standard form is written as \( A \times 10^n \) where \( 1 \leq A < 10 \) and \( n \) is an integer.
  • It allows easy comparison of very large or small numbers.
• What is the aseptic technique in culturing microorganisms?

  • Sterilize Petri dishes and culture medium to kill unwanted microorganisms.
  • Sterilize inoculating loops before use.
  • Lightly tape the lid of the Petri dish after transferring bacteria.
  • Store Petri dishes upside down to prevent condensation.
• What is the purpose of using a control in antibiotic testing?

  To ensure any difference in bacterial growth is due to the antibiotic
• What is the role of chromosomes in a cell?

  DNA is arranged in bundles called chromosomes
• What is a gene?

  A small section of DNA on a chromosome that codes for a protein
• What is a karyotype?

  A complete set of chromosomes in an individual's cell
• What happens during the longest stage of the cell cycle?

  Cells carry out normal activities and DNA is replicated