Cells A

• Function of the cell membrane: controls substances moving in and out of cells
• Function of ribosomes

  where protein synthesis takes place
• Fucntion of cell wall: strengthens the cell and gives it support

  made of cellulose
• Function of permanent vacuole: filled with cell sap to keep the cell rigid
• Specialised cells: Cells made to carry out a particular function
• Eukaryotic cells: Cell membrane surrounded by cell wall in plants and funghi

  DNA found in nucleus- plasmids found in few simple eukaryotic organisms
• Muscle cells: Smooth or striped, can be found in gut

  Many mitochondria

  special protein- contract & relax
• Nerve cells: Carry electrical impulses

  Allows rapid communication

  Endings adapted to pass impulses through chemical transmitters

  Many mitochondria to make chemicals
• Sperm cells: Long tail and many mitochondria to move to egg

  Acrosome digestive enzymes break down outside of egg

  Large nucleus to carry genetic info
• Photosynthetic cells: many chloroplasts

  large permanent vacuole

  positioned in continuous layers to absorb light well
• Xylem: carries water and minerals and helps support plant

  alive when first formed, chemical builds up in spirals, then dies making it hollow
• Stem cells

  undifferentiated cells
• Positives of stem cells: Embryonic stem cells are easy to extract and can produce any types of cell to replace faulty ones
• Negatives of stem cells: Mutations can behave like cancer

  contaminated cells with viruses would be transferred to a patient

  embryos viewed as a commodity

  adult stem cells are difficult to find and extract
• Binary fission: A form of asexual reproduction in which one cell divides to form two identical cells.
• Binary fission / mitosis equation: starting population x 2 ^ number of divisions
• Function of the nucleus: controls cell activities; contains the genetic material - DNA
• A) Cyctoplasm

  B) Nucleus

  C) Cell membrane

  D) cell wall

  E) Mitochondria

  F) Permanent vacuole

  G) Chloroplast