B4 Flashcards
(48 cards)
what do animals/plants use oxygen for?
oxidise food during aerobic respiration which
transfers energy organism needs to perform their functions
what happens during vigorous exercise?
anaerobic resp.
human body cant supply cells with sufficient oxygen switches to anaerobic respiration
it supplies energy but causes the build-up of lactic acid in muscles -> causes muscle fatigue
photosynthesis equation
CO2 + water ->(light) glucose + oxygen
glucose formula
C6 H12 O6
why is photosynthesis endothermic?
energy is transferred from the environment to the
chloroplasts by light (light energy)
photosynthesis symbol equation
6CO2 + 6H2O -> C6H12O6 + 6O2
how do plants use glucose?
respiration -> transfer energy from glucose to convert it into other substances
making cellulose -> to make strong plant cell walls
make amino acids -> combined with nitrate ions to make AAs then proteins
stored as fats/oils -> turned to lipids, stored in seeds
stored as starch -> stored in roots, stems + leaves, to be used when no photosynthesis is happening e.g. winter
why is starch better for storage in plants than glucose?
it’s insoluble
a cell with lots of glucose in it would draw up loads of water and swell up
what’s a limiting factor of photosynthesis?
stops photosynthesis of happening faster
how can chlorophyll be a limiting factor?
amount of chlorophyll can be affected due to disease
e.g. TMV or lack of nutrients (magnesium deficiency)
less light will be absorbed
how does light affect the rate?
provides energy needed for photosynthesis
as light levels increase, ROR increases steadily up to a certain point
after that point it wont make a diff. as another factor e.g. CO2 would be the limiting factor
how does CO2 affect the rate?
raw material needed for photosynthesis
as CO2 levels increase, ROR increases steadily up to a certain point
after that point CO2 is no longer the limiting factor
describe CO2 + LIGHT ROR graphs
line increases steadily up until a certain point before plateauing
how does temp. affect the rate?
enzymes needed for photosynthesis work slower at lower temps.
optimum temp -> high KE -> move faster etc.
if temp. is too hot, enzymes denature
denature at 45°C
at what temp. do the enzymes denature?
45°C
oxygen bubble PAG
READ CGP + PAG BOOKLET
what do plants use to make proteins?
nitrate ions absorbed by active transport by root hair cells in the roots from soil
explain inverse square law in relation to light intensity and dist.
as dist. between pond weed and light source increases, light intensity decreases (inverse proportion)
state the light intensity equation
light intensity ∝ 1 / dist.²
explain the inverse square law if you 1/2 or 1/3 the dist.
1/2 the dist -> light intensity is 4x greater
1/3 the dist. light intensity us 9x greater
heat + greenhouses
trap sun’s heat -> for max. plant growth
ensures temp. doesn’t become a limiting factor
winter -> use a heater to keep ideal levels
summer -> shade/ventilation to keep plants cool
light + greenhouses
artificial light -> enhances natural sunlight quality
especially overnight/on cloudy days
gives more time for quality photosynthesis
CO2 + greenhouses
CO2 gas can be pumped into the air
paraffin heaters -> as they burn CO2 produced as by-product
issue with greenhouses
getting optimum conditions can be expensive
