Cell Processes

Cell Processes

Diffusion
1. Passive transport
  1. No energy required
2. semi-permeable membrane
  1. Stucture
    1. Hydrophilic head
    2. Hydropholic tail
    3. Phospholipid Layer
3. movement from area of high concentration to area of low concentration
  1. down the concentration gradient
4. Example: Carbon dioxide for photosynethesis
5. Factors that effect diffusion
  1. Concentration Gradient
    1. Diffusion rates will be higher when there is a greater difference in concentration between the two regions
  2. Diffusion Difference
    1. Diffusion over shorter distances occurs at a greater rate than larger distances
  3. Surface Area
    1. The rate of diffusion is greater when there is a large surface area across where diffusion occurs
  4. Physical Barriers
    1. Thick barriers slow the rate of diffusion
    2. Pores in a barrier enhance the diffusion
Facilitated Diffusion
1. Semi-permeable membrane
2. Passive transport
  1. No energy required
3. Same as diffusion but assisted by carrier protein
4. Example: Glucose
5. Movement from an area of high concentration to an area of low concentration
  1. Down the concentration gradient
Osmosis
1. Movement of water from area of high concentration to an area of low concentration
  1. Down concentration gradient
2. Passive transport
  1. no energy required
3. Example: water in the soil will move into the cell
4. Osmoregulation
  1. Isotonic Solutions: no net loss or gain
  2. Hypertonic Solutions: net loss
    1. Animal: shrivel up
    2. Plant: plasmolysed and flaccid
  3. Hypotonic Solutions: net gain
    1. Animal: Expand and burst
    2. Plant: turgid (tugor pressure)
Active Transport
1. semi-permeable membrane
2. Movement from an area of low concentration to an area of high concentration
  1. Against concentration gradient
3. Energy is required
4. Transport or carrier proteins are needed
5. Types
  1. Sodium-potassium pump
  2. Proton pumps
  3. Cytosis
6. Example: use ATP energy to move h+ ions in respiration
Enzymes
1. Biological catalyst that speeds up specific chemical reactions
  1. Lower energy barrier - activation energy
2. The lock and key model
3. Induced fit
4. Factors that effect enzyme reaction rate
  1. Temperature
    1. Increases until optimum temperature then decreases as the enzymes denature
      1. Denature is when the weak hydrogen bonds of the active site break
  2. pH value
    1. optimum temperature then denature
  3. Enzyme concentration
    1. increases
  4. Substrate concentration
    1. Increases then reaches saturation point
5. Proteins
6. Poisons when in wrong part of body
Respiration
1. The process of breaking down food and using oxygen to produce energy in the form of ATP
2. Aerobic respiration
  1. Glucose + Oxygen = carbon dioxide + water + lots of ATP
  2. Efficient
3. Anaerobic respiration
  1. Glucose = Carbon dioxide + lactic acid + water +little ATP
  2. Lactic acid build up in muscle and causes cramp
  3. Less efficient
4. Mitochondria
  1. The organelle where respiration occurs
  2. Outer membrane
    1. semi-permeable
  3. Cristae, folded inner membrane
    1. increase in surface area which allows respiration to be efficient and faster as number of reactions have increased
  4. Matrix, fluid
    1. High concentration of enzymes
      1. increase in reactions
5. Factors
  1. Temperature
    1. optimum temperature
  2. Body's enrgy demand
    1. rate of respiration will increase to maximum as the demand increases
6. Stages
  1. Glycolysis
  2. Krebs cycle
  3. Electron transfer chain
Photosynthesis
1. Equation: water + carbon dioxide + sunlight+ chlorophyll= glucose and oxygen
2. Factors
  1. Temperature
    1. increases to optimum then denature
  2. Light intensity
    1. increases rate to max. then no affect
  3. CO2 concentration
    1. increases to max. then no affect
3. Chloroplast
  1. stroma, fluid
    1. clear, doesnt block sunlight
      1. maxmising penetration light
  2. Grana
    1. stack of thylakoids
      1. thin, disc shape, short diffusion distance
    2. increase surface area
  3. outer and inner membrane
    1. transparent to allow max sunlight
4. Stages
  1. light independent stage
  2. light dependent stage

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	Created by georgia_rae over 8 years ago