biology topic 1

• What are the main components of plant and animal cells?

  Cell membrane, cytoplasm, and genetic material in a nucleus
• How do bacterial cells differ from eukaryotic cells?

  Bacterial cells are smaller, have no nucleus, and contain a single DNA loop
• What is the genetic material in bacterial cells called?

  A single DNA loop and plasmids
• What should students be able to demonstrate regarding cell size?

  Understanding of the scale and size of cells and order of magnitude calculations
• What are the main sub-cellular structures in animal and plant cells?

  Animal cells typically have:

  • Nucleus
  • Cytoplasm
  • Cell membrane
  • Mitochondria
  • Ribosomes

  
  

  Plant cells also have:

  • Chloroplasts
  • Permanent vacuole filled with cell sap
  • Cell wall made of cellulose
• What is the function of chloroplasts in plant cells?

  Chloroplasts are involved in photosynthesis
• What is the role of the cell wall in plant cells?

  The cell wall strengthens the cell
• How do bacteria multiply?

  By binary fission
• What conditions allow bacteria to multiply rapidly?

  Enough nutrients and a suitable temperature
• What is required for investigating the action of disinfectants and antibiotics?

  Uncontaminated cultures of microorganisms
• Why must Petri dishes and culture media be sterilised before use?

  To prevent contamination
• What is the purpose of securing the lid of the Petri dish with adhesive tape?

  To prevent contamination
• At what temperature should cultures generally be incubated in school laboratories?

  25°C
• What is the function of chromosomes in the nucleus?

  They carry genes made of DNA molecules
• What happens during the cell cycle?

  The genetic material is doubled and then divided into two identical cells
• What is the importance of mitosis in multicellular organisms?

  It is important for growth and development
• What is a stem cell?

  An undifferentiated cell capable of giving rise to many more cells
• How can stem cells from human embryos be used?

  They can be cloned and differentiated into various human cell types
• What is the role of stem cells in adult animals?

  They can form many types of cells, including blood cells
• What is the significance of meristem tissue in plants?

  It can differentiate into any type of plant cell throughout the plant's life
• What is therapeutic cloning?

  Producing an embryo with the same genes as the patient for stem cell treatment
• What are some potential risks of using stem cells?

  Transfer of viral infection and ethical objections
• How does diffusion occur across cell membranes?

  Particles move from an area of higher concentration to an area of lower concentration
• What factors affect the rate of diffusion?

  Concentration gradient, temperature, and surface area of the membrane
• Why do single-celled organisms have a large surface area to volume ratio?

  To allow sufficient transport of molecules into and out of the cell
• What is osmosis?

  The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
• What is the purpose of active transport?

  To move substances against a concentration gradient, requiring energy
• How do plants absorb mineral ions?

  Through active transport from very dilute solutions in the soil
• How are sugar molecules absorbed in the gut?

  By active transport from lower concentrations into the blood
• What is the first step in the scientific method?

  Come up with a hypothesis
• What happens if all evidence supports a hypothesis?

  It becomes an accepted theory
• What is a hypothesis?

  A possible explanation for an observation
• What is peer review?

  When other scientists check results
• How can accepted theories change over time?

  As new evidence is found
• What determines characteristics in inheritance?

  Hereditary units called genes
• What do representational models do?

  They simplify descriptions of real systems
• What is the lock and key model an example of?

  A representational model of enzyme action
• What do computational models use to simulate processes?

  Computers
• What are the four issues created by scientific developments?

  1. Economic issues (cost of technology)
  2. Environmental issues (impact on nature)
  3. Social issues (effects on society)
  4. Personal issues (individual preferences)
• What is a hazard?

  Something that could potentially cause harm