Cell biology

• Name 2 types off cell and give examples

  Eukaryotic (plant and animal)

  Prokaryotic (bacteria)
• Define chromosome, how many are there in a human cell?

  A structure made of DNA carrying a large number of genes / 46 (23 pairs)
• Which cells are unique to plant cells?

  Semi-permanent vacuole, chloroplasts, cell wall
• Sequence the process of mitosis

  Sub-cellular structures replicate, cell grows, DNA replicates

  Chromosomes are pulled to each end of cell and nucleus divides

  Cytoplasm and cell membrane divide
• Give an example of a specialised cell and state how it is adapted to carry out its function

  Sperm cell- Tail for swimming

  Nerve cell- Long to carry information
• What is meant by cell differentiation

  When a cell becomes specialised to carry out a particular function
• List 3 sources of stem cells

  Bone marrow, Embryos, Meristem tissue
• State 2 conditions that stem cells may be able to treat

  Diabetes and paralysis
• Give 2 uses of cloning plants

  Increasing the population of rare species to protect from extinction, Producing large numbers of disease resistant crops
• Define diffusion

  Movement of particles from an area of high concentration to an area of low concentration
• List the substances that are transported in and out of cells by diffusion

  Oxygen, Carbon dioxide, Urea
• What is the role of an enzyme?

  Speed up biological reactions
• State 3 factors that affect the rate of diffusion

  Concentration gradient, Surface area, temperature
• Describe how lungs, gills, intestines and roots are adapted for diffusion

  Large surface area, Thin membrane (Short diffusion pathway), Efficient blood supply (Maintain concentration gradient), Good ventilation
• Define osmosis

  The movement of water across a partially permeable membrane from a dilute solution to a concentrated solution
• Define active transport

  The movement of substances from a low to high concentration using energy from respiration