Biology
Plants
Describe the use of carbohydrates in plants.
- Cellulose
- For cell walls
- Starch
- For energy / respiration
Describe the use of amino acids in plants.
- To make proteins
- For growth
Explain how roots are adapted to absorb ions.
- Root hair cells
- Large surface area for increased rate of absorption of water & mineral ions
Explain the effects of nitrate ion deficiency on plant growth.
- Needed to make amino acids isabelle
- Protein is needed for growth
What is the function of stomata?
- For gaseous exchange
- For photosynthesis / respiration / transpiration
Explain how auxins control the growth response.
- Auxins are made in the shoot tip
- Auxins are collected in the side away from light
- Auxins stimulate greater cell elongation
Plant transport
Explain how transpiration occurs in leaves.
- Water evaporates
- From the surface of mesophyll cells
- Water vapour diffuses
, - Through the stomata out of the leaf
Define diffusion.
- Net movement of particles from a region of high concentration to a region of
low concentration
- Down a concentration gradient
- As a result of their random movement
Define osmosis.
- Water particles moving from a region of high water potential to a region of
low water potential
- Through a partially permeable membrane
Explain how xylem is adapted for its functions.
- Elongated
- Hollow
- Has lignin
-
isabelle
Water impermeable - to prevent water loss
Xylem’s functions: transport water & mineral ions ; support the plant
Phloem’s functions: transport sucrose & amino acids
Pollination
State structural features of wind pollinated plants.
- Long filaments
- Anthers hang outside, easily exposed to the wind
- Stigma hangs outside
- Large / feathery stigma
- Small / light pollen
- No to little petals
State structural features of insect pollinated plants.
- Anther inside the flower
- Stigma inside the flower
, - Large stick & spiky pollen
- Large & brightly coloured petals
Name the part of the flower that develops into the seed.
Ovule
Name the part of the flower that develops into the fruit.
Ovary
Human
Describe the role of bile.
- Emulsification of fats
- To fatty acid & glycerol
- Neutralises stomach acid
- Increase surface area for enzyme action
Describe the role of hydrochloric acid in the stomach.
-
- isabelle
Provides an acidic pH for enzymes
Kills bacteria
What is meant by double circulation?
- Blood flows through the heart twice, for one complete circuit
- Pulmonary circulation, systemic circulation
What are the advantages of double circulation?
- Prevent mixing of oxygenated and deoxygenated blood
- Allows different blood pressure in each loop
- Ensure efficient supply of oxygen
Explain why vitamin D is important.
- For bones
- For teeth
- Prevent rickets
Explain why iron is important.
Plants
Describe the use of carbohydrates in plants.
- Cellulose
- For cell walls
- Starch
- For energy / respiration
Describe the use of amino acids in plants.
- To make proteins
- For growth
Explain how roots are adapted to absorb ions.
- Root hair cells
- Large surface area for increased rate of absorption of water & mineral ions
Explain the effects of nitrate ion deficiency on plant growth.
- Needed to make amino acids isabelle
- Protein is needed for growth
What is the function of stomata?
- For gaseous exchange
- For photosynthesis / respiration / transpiration
Explain how auxins control the growth response.
- Auxins are made in the shoot tip
- Auxins are collected in the side away from light
- Auxins stimulate greater cell elongation
Plant transport
Explain how transpiration occurs in leaves.
- Water evaporates
- From the surface of mesophyll cells
- Water vapour diffuses
, - Through the stomata out of the leaf
Define diffusion.
- Net movement of particles from a region of high concentration to a region of
low concentration
- Down a concentration gradient
- As a result of their random movement
Define osmosis.
- Water particles moving from a region of high water potential to a region of
low water potential
- Through a partially permeable membrane
Explain how xylem is adapted for its functions.
- Elongated
- Hollow
- Has lignin
-
isabelle
Water impermeable - to prevent water loss
Xylem’s functions: transport water & mineral ions ; support the plant
Phloem’s functions: transport sucrose & amino acids
Pollination
State structural features of wind pollinated plants.
- Long filaments
- Anthers hang outside, easily exposed to the wind
- Stigma hangs outside
- Large / feathery stigma
- Small / light pollen
- No to little petals
State structural features of insect pollinated plants.
- Anther inside the flower
- Stigma inside the flower
, - Large stick & spiky pollen
- Large & brightly coloured petals
Name the part of the flower that develops into the seed.
Ovule
Name the part of the flower that develops into the fruit.
Ovary
Human
Describe the role of bile.
- Emulsification of fats
- To fatty acid & glycerol
- Neutralises stomach acid
- Increase surface area for enzyme action
Describe the role of hydrochloric acid in the stomach.
-
- isabelle
Provides an acidic pH for enzymes
Kills bacteria
What is meant by double circulation?
- Blood flows through the heart twice, for one complete circuit
- Pulmonary circulation, systemic circulation
What are the advantages of double circulation?
- Prevent mixing of oxygenated and deoxygenated blood
- Allows different blood pressure in each loop
- Ensure efficient supply of oxygen
Explain why vitamin D is important.
- For bones
- For teeth
- Prevent rickets
Explain why iron is important.
