TOPIC B4 BIOENERGETICS Flashcards
what does photosynthesis do
-uses energy to change carbon dioxide and water into glucose and oxygen
where does photosynthesis take place
-in chloroplasts in green plant cells
-contain pigments like chlorophyll which absorb light
is photosynthesis exo or endothermic, what does this outcome mean
-endothermic
-means energys transferred from the environment in a process
word equation for photosynthesis
carbon dioxide + water—(light)—— glucose +oxygen
6CO2 + 6H2O __LIGHT) C6H12O6 + 6O2
state why plants use glucose
-for respiration
-making cellulose
-making amino acids
what factors affect the rate of photosynthesis
-intensity of light
-concentration of CO2 and temperature
e.g
-at night, light is the limiting factor
-in winter, temperature
-warm and bright enough, amount of CO2 is usually limiting
state the affect of the amount of chlorophyll
in a plant it is affected by disease or environmental stress, such as a lack of nutrients
-these factors cause chloroplasts to become damaged
state why not enough light slows down the rate of photosynthesis
-light provides energy needed for photosynthesis
-as light level raises, photosynthesis increases steadily
-as light goes up, the rate no longer increases
explain the affect low carbon dioxide concentration has on the rate of photosynthesis
-raw material for photosynthesis
-after the graph flattens out, the rate no longer increases
why does temperature have to be just right for photosynthesis
-if too low, enzymes needed work more slowly
-if too hot, enzymes will be damaged
-happens at 45degrees
how to show the effect of limiting factors
by using a graph to show
state the inverse square law
light intensity= 1
DIVIDED BY
distance (d)squared
what does light intensity and distance increase for the inverse square law link
as distance increases, light intensity decreases
theyre inversley proportional to each other
state the most common environment to grow plants and why
a greenhouse
-as they trap the sun’s heat and make sure temperature doesn’t become limiting
-in winter they use a heater
-in summer they use shades
-supply artifical light
-enclosed keeps them away from pests
respiration definiton
is it exo or endothermic
the process of breaking down glucose to transfer energy which occurs in every cell
exothermic
state 3reasons why respiration transfers energy
- to build larger molecules from smaller ones e.g (proteins from amino acids)
- in animals, is used to allow muscles to contract
- in mammals is used to keep body temperature steady
2types of respiration
-aerobic
-anaerobic
what is aerobic respiration
-uses oxygen
-goes on all the time in plants and animals
-happen inside mitochondria
word equation and symbol for aerobic respiration
glucose + oxygen —– carbon dioxide + water
C6 H12 O6 + 6O2 — 6CO2 + 6H2 O
when is anerboic respiration used
-when there isn’t enough oxygen
-doesn’t transfer as much energy as the glucose hasn’t fully oxidised
word equation for anaerobic respiration
glucose ———— lactic acid
state how anaerobic respiration in plants and yeast is different
-they can respire without oxygen but produce ethanol and carbon dioxide
-ANAERBOIC RESPIRATION IN YEAST CELLS IS FERMENTATION
how does excersise affect the body
-muscles need energy from respiration to contract
-increase in respiration in cells means you need more oxygen into them
-breathing and volume increase to get more oxygen into the blood and heart rate increases
word equation for anaerboic respiration in plants and yeast cells
glucose —— ethanol + carbon dioxide
what does anaerboic respiration lead to
oxygen debt
-the amount of extra oxygen your body needs to react with the build up of lactic acid
what organ is lactic acid coverted back to glucose
in the liver
-the blood that enters the muscles transports the lactic acid to the liver
how would you measure a persons breathing rate
watch their chest and count how many times it rises and falls in 1 minute
how would you measure a persons heart rate
feel their pulse and count how many beats there are in 1minute
