Bio Topic 6 Flashcards
What is biomass?
Material in an organism
What part of the plant traps sunlight for photosynthesis?
Chloroplasts containing chlorophyll
What type of reaction is photosynthesis and why?
Endothermic because it takes in energy from the surroundings.
Explain how glucose made in photosyntesis goes to sucrose
Glucose molecules link together to form a polymer called starch which gets broken down in the cytoplasm to make sucrose
4adaptations of leaves
Large surface area for maximum light absorbtion
Palisade cells allow lots of sunlight to be absorbed
Waxy top layer to protect from water loss and disease
Thin leaves so carbon dioxide does not have to diffuse as far
What do stomata do?
Contain guard cells which open and close to control gas exchange and water loss
3 limiting factors for photosynthesis?
Carbon dioxide concentration
Temperature (enzymes that catalyse photosynthesis work better in warmer temperatures)
Light intensity
2 adaptations of root hair cells?
Large surface area so water and mineral ions can be quickly absorbed
Hairs have thin cell walls so flow of water into cells is not slowed down
What is osmosis
Water moving from a high to low concentration through a semi permable membrane
What is diffusion
A substance moving from a high to low concentration
What is active transport
A substance going against the concentration gradient that requires energy
What is transpiration?
Evapouration of water at the surface of the leaves which helps cool the leaves down
Factors that affect the rate of transpiration?
Wind- moves water away from stomata
Low humidity
Higher temperature- particles move faster so diffuse quicker
Greater light intensity- makes stomata wider so water can pass out
What does the phloem do?
Contains pores which enable the movement of cell sap which contain sugars the plant needs to bring up or down for energy or to be stored. REMEMBER IT CAN TRANSPORT BOTH DIRECTIONS.
What are xylem cells?
Tubes made up of dead xylem cells which are strengthend by lignin that transport water and mineral ions from the routes to the leaves so water can be used for photosynthesis.
