Topic 1- cells

• Mitochondria - an organelle that converts the energy stored in glucose for use in cell (respiration).
• Large vacuole - water filled space that stores chemicals that exerts pressure against the walls.
• Cell wall - composed of cellulose this provides both protection and structure.
• Nucleus - controls many functions of the cell and contains the DNA.
• Ribosomes - an organelle responsible for making proteins.
• Chloroplast - an organelle in which photosynthesis takes place. Contains chlorophyll.
• Cell membrane - a thin partially-permeable membrane that surrounds that cytoplasm (controls entry and exit).
• Cytoplasm - stores chemicals and maintains the shape of the cell.
• Plant cell contains:

  • Nucleus
  • Mitochondria
  • Large vacuole
  • Cell wall
  • Ribosomes
  • Chloroplast
  • Cell membrane
  • Cytoplasm
• Animal cell contains:

  • Mitochondria
  • Ribosomes
  • Nucleus
  • Cell membrane
• Chromosomal DNA - carries genes that specify the proteins that make up the organism.
• Flagella - allow the cell to move.
• Plasmid DNA - non-essential small circles of DNA containing between 5 and 100 genes.
• Bacteria cell:

  • Chromosomal DNA
  • Flagella
  • Plasmid DNA
  • Ribosomes
• Sperm cell:

  • Tail
  • Mitochondria
  • Haploid nucleus
  • Acrosome
• Egg cell:

  • Cell membrane (that changes after fertilisation).
  • Haploid nucleus.
  • Cytoplasm (nutrients).
• Ciliated epithelial cells:

  • Cilia (little hairs).
• Actual size= Image size x Magnification.
• Enzymes are biological catalysts that speed up chemical reactions in the body. Can be denatured, therefore a change in the active site, no longer works effectively.
• Factors affecting the rate of a reaction:

  • Temperature
  • Pressure
  • Catalysts
• Lipase digests lipids (fats) to fatty acids and glycerol.
• Proteases, including pepsin, digest proteins to amino acids.
• Carbohydrases, including amylase, which digest carbohydrates (starch) to simple sugars.
• Diffusion - the random net movement of particles from a high to low concentration until balanced.
• Osmosis - the net movement of water from a high to low concentration down a concentration gradient, across a semi-permeable membrane.
• Active Transport - a process required to move particles against a concentration gradient, using energy for protein pumps.