T4 bioenergetics Flashcards
why is photosynthesis endothermic?
it takes in energy from its surroundings
what is the equation for photosynthesis?
carbon + water –> glucose + oxygen
what are the 4 limiting factors of photosynthesis?
amount of chlorophyll
concentration of carbon dioxide
light intensity
temperature
if we increase the light intensity what happens
the rate of photosynthesis increases
if we increase temperature what happens
reaction will work faster and in the optimum point it reaches it will denature and the rate of photosynthesis will decrease
name 5 ways glucose is used in a plant from photosynthesis
- release energy from mitochondria for respiration
2.produce insoluble starch
3.coverts to fats and oils for energy storage - produce amino acids to protein synthesise which plants need to absorb nitrate ions from soil
5.cellulose made from glucose
pondweed practical for photosynthesis
- start by boiling a tube and placing it 10cm away from an LED light source
- led is used so it doesn’t release much heat
- if you don’t have LED place s beaker of water in between light and tube as it will absorb heat - fill boiling tube with sodium hydrogen carbonate solution
- this is used as it releases carbon dioxide which is needed for photosynthesis - put pondweed inside tube with the cut end faced on the top
- leave for 5 minutes
- oxygen gas bubbles will form
- get stop watch and record the number of gas bubbles in one minute
- repeat experiment but with the distance of light being 10cm 20cm 30cm and 40cm away and calculate the mean
what are the disadvantages of photosynthesis pondweed practical
too many gas bubbles formed to count
bubbles not always the same size
what can you do to fix the problem of pondweed photosynthesis practical
use a measuring cylinder, place on top of the ends of pondweed and measure volume of oxygen gas produced
what happens when you double the distance of light to pondweed
the light intensity falls by 4 times
why is respiration an exothermic reaction
it releases energy
when muscle cells respire and are in shortage of oxygen how do they respire?
anaerobically
when muscle cells respire anaerobically what is the equation?
glucose—>lactic acid
why does anaerobic respiration release less energy than aerobic respiration
the oxidation of glucose is incomplete
what is the equation for anaerobic respiration in yeast cells and plants
glucose—> carbon dioxide + ethonal
what is anaerobic respiration in yeast cells called
fermentation
what increases during exercise in order for more oxygen in body cells
breathing rate and breathing volume increase
what chemical builds up when the muscles do not receive enough supply of oxygen
lactic acid
what does lactic acid cause the muscle to feel
fatigued
what happens when the body tries to get rid of the lactic acid
oxygen debt
how is the lactic acid transported by out of
the blood
where is the lactic acid put back and converted into
the liver and converted to glucose in a series of chemical reactions
