bio paper 2

• photosynthesis


  6 CO2 + 6 H2O ➔ C6H12O6 + 6 O2
• plants get their energy from the sun
• the chloroplasts absorb the energy from the sun needed for photosynthesis
• photosynthesis is considered an endothermic reaction because it absorbs light energy from the environment
• glucose can be used for respiration, it can be converted to starch or cellulose or other molecules/fats/amino acids
• the rate of photosynthesis increases with light intensity

  above a certain light intensity/500 lux, the rate of photosynthesis increases at a much slower rate

  suggesting a limiting factor other than light intensity
• Active transport is the movement of molecules across a membrane, from a region of lower concentration to a region of higher concentration. This requires energy from respiration.
• the xylem transports water and saved mineral ions
• TSH - thryroid stimulating hormone
• the dependent variable is what is measured for every change in the independent variable.
• the independent variable is the variable that is changed or altered
• control variable is the variable kept the same throughout
• why does the rate of transpiration increase when light intensity increases?

  The stomata open wider to let more carbon dioxide into the leaf for photosynthesis.
• How does negative feedback work?

  Any change in a system causes an action that reverses the change
• How can oestrogen act as a contraceptive? 

  Inhibit FSH production, so that eggs can't mature
• eutrophication is caused by excess nutrients in waterways
• the body needs to maintain optimum conditions for optimum enzyme action and cell function
• A hormone can only stimulate a cell if the cell has the correct receptor for that hormone. 
• hormonal contraceptives can contain oestrogen and/or progesterone
• What makes starch a useful long term storage molecule?

  It is insoluble in water

  It can easily be broken down when needed 

  It is compact
• FSH - follicle stimulating hormone
• how rate of photosynthesis varies w temperarure:

  Rate initially increases with temperature...

  ...because particles have more energy and move faster, so react more frequently

  Highest rate is at optimum temperature for enzyme

  At higher temperatures the rate decreases as bonds holding the enzyme together begin to break, and so the enzyme changes shape

  Rate falls to zero as enzymes denature 
• the coordination centres in the body are the brain and the spinal cord
• Farmers in cooler climates often use greenhouses. These help trap the heat energy from sunlight, and so increase the temperature. They also keep out pests which could otherwise damage the plants. 
• smaller organisms have a larger surface area : volume ratio
• rate of transpiration increases if wind speed increases. The wind blows away water vapour as soon as it diffuses out of the leaf. This maintains a strong concentration gradient between the inside and outside of the leaf, which increases the rate at which water diffuses out.
• adrenaline is released from the adrenal gland
• Interdependence is when All organisms in an ecosystem depend upon one another, with countless complex relationships between them all. 
• the role of the mitochondria is to do: Aerobic respiration and Release energy for the cell to use
• the molecular form of glucose is C6H12O6
• the role of chlorophyll is to absorb light energy for photosynthesis
• the nucelus contains the cell's DNA and so controls its activities
• translocation is the movement of cell sap up and down a plant
• what are the risks of IVF?

  can cause abdominal pain and vomiting; doesn't always work; high chance of multiple births with associated compilations; can be stressfu and emotionally upsetting
• Oxygen passes down its concentration gradient from the alveoli, into the bloodstream
• providing fish-in-fish farms with high-proteing foods promotes rapid growth for human consumption
• root hair cells absorb water through the soil via osmosis
• in theosmosis experiment we use distilled water so we can compare the results with the salt or sugar solutions
• glucose water and amino acids are able to diffuse in and out of cells
• platelets clot the blood when a blood vessel breaks