Biology paper 1

• Prokaryotic


  Cells that do not have a nucleus.
• Eukaryotic


  Cell with a nucleus.
• Mitochondria


  Site of respiration.
• Cell wall


  Supports the cell to keep it rigid.
• Cell membrane


  Acell structure that controls which substances can enter or leave the cell.
• Ribosomes


  Makes proteins.
• Nucleus


  Contains genetic material and controls cell.
• Chloroplasts


  Site of photosynthesis.
• Cyptoplasm


  Gel like, organelles float in it.
• Vacuole


  Stores cell sap.
• Things that are in a plant cell but not an animal cell (3)


  -Chloroplasts-Cell wall-Vacuole
• Plasmids


  Small circular DNA loops separate from the main DNA found in bacteria.
• Equation for image size

  Image size = actual size x magnification
• Total magnification


  Magnification = magnification of eyepiece x magnification of objective lens
• Adaptations of sperm cell (3)


  -Long tail and streamlined head to help swim to egg- Manymitochondria in cell to provide energy needed-Enzymes in head to digest egg cell membrane
• Adaptation of muscle cell (2)


  - Manymitochondria for energy release (contract etc)-Layers of protein filaments so they can slide over each other
• Adaptations of nerve cell (2)


  -Branched endings-Myelin sheath insulates the axon for fast transmission
• Adaptations of root hair cell (2)


  -Large surface area to absorb more water-Lots of mitochondria for more respiration for active transport of mineral ions
• Mitosis


  Cell division where 2 identical daughter cells are made.
• Meiosis


  Cell division that produces 4 genetically different daughter cells (gametes.)
• What happens in mitosis?


  Chromosomes line up in the middle of the cell and are then pulled to each end. New membranes are formed and this is called cytokinesis.
• Stem cell


  Unspecialized cell that can give rise to one or more types of specialized cells.
• Adult bone marrow stem cells


  -Can form many types of human cells e.g. blood cells-Cannot make every type of cell
• Embryonic stem cells


  An undifferentiated cell, taken from an embryo that has potential to give rise to most other cell or tissue types.
• Meristem


  Undifferentiated plant tissue from which many types of cells can be made from.
• Diffusion


  Movement of molecules from an area of higher concentration to an area of lower concentration. Process ispassive (without energy)
• Active transport


  Themovement of molecules across a cell membrane from an area of lower concentration to an area of higher concentration requiring energy input.
• Osmosis


  Movement of water through a selectively permeable membrane from a dilute solution to a concentrated solution.
• Adaptations of the small intestine (4)


  -Villi and microvilli increase surface area for faster absorption-Rich blood supply helps carry absorbed molecules away to maintain a steep diffusion gradient-Thin wall means short diffusion distance-Mitochondria to release energy for active transport of glucose when glucose concentrations are low in the gut
• Adaptations of lungs (4)


  -Many alveoli- increases surface area to increase rate of gas exchange-Walls 1 cell thick - short diffusion distance-Well ventilated- maintains a concentration gradient-Rich blood supply- maintains a concentration gradient-Moist lining to dissolve gasses for quicker diffusion
• Tissue


  Agroup of similar cells that perform the same function.
• Organ


  Acollection of tissues that carry out a specialized function of the body.
• Organ system


  Agroup of organs that work together to perform a major function.
• Lock and key theory


  Theory of enzyme action stating that the active site's shape is an exact fit for the substrate.
• Where is amylase found?


  In the mouth (salivary glands) and small intestine.
• Where is lipase found?


  Small intestine.
• Where is protease found?

  Stomach.
• What does amylase breakdown starch into?


  Glucose (sugars)
• What does lipase breakdown lipids into?

  Glycerol and fatty acids.
• What does protease breakdown proteins into?

  Amino acids.