2019 Paper 2 Flashcards
What is a plants response to gravity called
Geotropism
Why is too much fertiliser in a pond bad for plants in pond
Rapid growth of algae on surface blocks light causing plants to decay and die as less sunlight reaches them so less photosynthesis
Plan an investigation to show effect of light from one direction on growth of plant seedlings
Use several pots of seedlings that will be given the same volume of water, temperature and soil
Have one pot of seedlings in one area where light is all around - acts as a control
Have other pots with lids and a hole in one side with lamp light shining through
Measure seeding height at beginning of experiments by straightening them out against ruler. Calculate average height per pot
Calculate mean height increase for each pot
Use a protractor to measure angle of bending and compare with direction of light entry
Describe how the eye focuses near objects
Ciliary muscles contract causing a smaller diameter
Suspensory ligaments slacken
Lens becomes thicker and more curved
So more light refracted onto retina
Explain why a long sighted person has difficulty seeing near objects
Eyeball is too short so light focuses behind retina
Describe how glasses help long sightedness
Convex lens used so light rays refract inwards so light refracts on retina
Describe why when a clone is produced it is the same as original parent
Clones produced by mitosis and without fusion of gametes so they are use genetically identical
Why are nutrients added to agar jelly when making clones
Makes protein
Why are hormones added to agar jelly when making clones
Allows differentiation
Explain how a man walking through dessert body reduces water lost
Blood is more concentrated ( lower water potential in blood) causes more ADH to be released which increases permeability of tubules so increased water reabsorption into body
Explain why on a graph there is a peak
More bacteria so more divisions
Why is it good for crops of weeds die
Less competition for light so more photosynthesis and higher yield
Explain how body deals with high glucose levels
Blood glucose levels increase causing pancrease to secrete insulin. Insulin causes glucose to enter muscle cells
Excess glucose converted into glycogen. Blood glucose levels deacrease so glucagon is secreted causing glycogen to be converted into glucose
2 Benefits of kidney transplant per dialysis
Changes in concentration of urea minimised so less damage to body cells
Not repeatedly puncturing skin so less chance of infection
