Cell Biology

• What process allows substances to be absorbed against a concentration gradient?

  Active transport
• How does active transport differ from diffusion?

  Active transport moves substances against the gradient
• What is the energy source required for active transport?

  Energy from respiration
• What is a concentration gradient?

  A difference in concentration across a space
• If a cell needs to bring in a molecule at high concentration inside, what process does it use?

  Active transport
• Why can't sugars diffuse into the cell from the lumen?

  Because their concentration is lower in the lumen
• What role do mitochondria play in active transport?

  They provide energy needed for active transport
• What ions do root hair cells transport into plants?

  Magnesium ions
• Why do plants need magnesium ions?

  To make chlorophyll in the leaves
• How do root hair cells use active transport?

  To move ions from soil into the cell
• What happens to ions after they are absorbed by root hair cells?

  They are transported to the xylem vessels
• What are the key differences between active transport and diffusion?

  • Active transport moves substances against the gradient
  • Diffusion moves substances down the gradient
  • Active transport requires energy from respiration
  • Diffusion does not require energy
• What are the two main types of cells?

  Eukaryotes and prokaryotes
• What types of cells are eukaryotes?

  Animal and plant cells
• Where is DNA located in eukaryotic cells?

  In a nucleus
• What do eukaryotic cells contain besides DNA?

  Cell membrane and cytoplasm
• What type of cell is a prokaryote?

  Bacteria cell
• Where is DNA located in prokaryotic cells?

  Not inside a nucleus
• How do prokaryotic cells compare in size to eukaryotic cells?

  Prokaryotic cells are smaller
• What form does DNA take in prokaryotes?

  A loop of DNA
• What additional genetic material do prokaryotes have?

  Plasmids
• What structures do prokaryotic cells have?

  Cell membrane and cell wall
• How many micrometres are in a metre?

  1,000,000 micrometres
• What is the typical size range of a human cell?

  10-20 µm
• How many nanometres are in one metre?

  1x10^-9 (1,000,000,000)
• What does 10x represent in terms of orders of magnitude?

  1 order of magnitude
• What does 100x represent in terms of orders of magnitude?

  2 orders of magnitude
• What does 1000x represent in terms of orders of magnitude?

  3 orders of magnitude
• What are the main components of animal cells?

  • Nucleus
  • Cytoplasm
  • Cell membrane
• What are the main components of plant cells?

  • Cell wall (provides shape)
  • Chloroplasts (site of photosynthesis)
  • Nucleus (controls cell activities)
  • Cytoplasm (site of chemical reactions)
  • Mitochondria (site of aerobic respiration)
• How do plant cells differ in shape compared to animal cells?

  Plant cells have a regular shape
• What is the process called when cells become specialized?

  Differentiation
• What is the primary function of a sperm cell?

  To join with an egg cell
• What happens during fertilization?

  Genetic information combines from sperm and ovum
• What does a sperm cell carry in its nucleus?

  Genetic information
• How much genetic information does a sperm cell contain?

  Half of a normal adult cell
• What adaptation helps sperm cells swim to the egg?

  A long tail
• What do sperm cells contain to help them penetrate the ovum?

  Enzymes
• What is the primary function of a nerve cell?

  To send electrical impulses
• What does the axon of a nerve cell do?

  Carries electrical impulses