bioenergetics Flashcards
how is glucose used (in plants) for making amino acids?
it is combined with nitrate ions (absorbed from the soil) to make amino acids which are then made into proteins
why is glucose turned into oils and fats in plants?
for storing in seeds
how/why is glucose stored as starch in plants?
glucose is turned into starch and stored in roots stems and leaves ready for use when photosynthesis is not happening ( eg winter)
starch is insoluble which makes it better for storing than glucose - a cell with lots of glucose would draw lots of water in and swell up
what 3 factors affect photosynthesis?
light, co2 concentration and temperature
at night what is the limiting factor in photosynthesis?
light
when it’s winter what is often the limiting factor in photosynthesis?
temperature
when it’s warm and bright what is normally the limiting factor for photosynthesis?
Co2 concentration
what part of a plant could be a limiting factor in photosynthesis?
chlorophyll
what can affect the amount of chlorophyll in a plant?
- disease
- environmental stress (eg lack of nutrients)
describe how light intensity effects the rate of photosynthesis
as the light level increases, the rate of photosynthesis increases steadily until a certain point
beyond that point the level of light won’t make a difference because either CO2 or temperature will become the limiting factor
how can you increase light intensity in a lab?
move the lamp closer or further away
when investigating light intensity’s effect on photosynthesis, in order to get a graph that shows a consistent incline and then levels of, what equipment should you use?
a light meter to measure light intensity
describe how co2 concentration affects the rate of photosynthesis?
amount of co2 will only increase the rate of photosynthesis up until a point , and then the rate no longer increases showing co2 is no longer w limiting factor
usually if the limiting factor in photosynthesis is temperature it’s because it’s too low - why?
what happens if it gets too hot?
- enzymes needed for photosynthesis work slower at colder temperatures
- enzymes needed for photosynthesis are damaged
at what temperature does the enzymes of a plant denature at?
45 degrees
what does the inverse square law mean
if you halve the distance the light intensity will be 4 times greater, and if you third the distance the light intensity will be nine times. greater
light intensity =
1/d^2
why are greenhouses the most common way to create the ideal environment for plants to grow in?
- greenhouses help trap the suns heat, and make sure the temperature doesn’t become the limiting factor
- in the winter a farmer may use a heater as well to keep the temperature level ideal
- in summer them may use shades and ventilation to cool things down
- commercial farmers often supply artificial blight after the sun goes down
how may a farmer increase the concentration of co2 in a greenhouse?
by a paraffin heater used to heat the greenhouse, as paraffin burns it makes carbon dioxide as a by-product
what can farmers add to the soil in his greenhouse to provide all the minerals needed for healthy growth?
fertiliser
define respiration
the process of transferring energy from glucose, which goes on in every cell
what kind of reaction is respiration?
exothermic
what are 3 examples of how organisms use their energy transferred by respiration?
1) to build up larger molecules from smaller ones ( eg proteins from amino acids)
2) to allow muscles to contact, so animal can move about
3) in mammals and birds it’s used to maintain a constant body temperature in colder surroundings
what is metabolism?
the sun of all the chemical reactions happening in an organism
give 3 examples of metabolic reactions when large molecules are made from smaller molecules e
1) small glucose molecules are joined together in reactions to form: starch, glycogen and cellulose
2) 1 molecule of glycerol and 3 molecules of fatty acids form lipids
3) glucose combined with nitrate ions to make amino acids, which are then made into proteins
give 2 example of metabolic reactions when large molecules are broken down into smaller ones
1) glucose is broken down in respiration
2) excess protein is broken down in a reaction to produce urea
what is aerobic respiration?
- respiration using oxygen
where does most of aerobic respiration happen? ( part of cell)
mitochondria
what is the word equation for aerobic respiration?
glucose + oxygen -> carbon dioxide + water
what is anaerobic respiration?
respiration without oxygen, an incomplete breakdown of glucose creating lactic acid
when does your body start to do anaerobic respiration as well as aerobic?
when you do vigorous exercise and your body can’t supply enough oxygen to your muscles
why is anaerobic respiration only useful in emergencies?
because it doesn’t transfer as much energy as aerobic respiration because the glucose isn’t full oxidised
what is the word equation of anaerobic respiration in plants and yeast cells?
glucose -> ethanol + carbon dioxide
anaerobic respiration in yeast cells is called what?
fermentation
how is fermentation used in the food and rinks industry?
to make bread and alcoholic drinks
bread making: co2 makes bread rise
alcohol: fermentation process that produces the alcohol
why do you need more energy when you exercise?
because your muscles contract more frequently than normal
what changes happen in your body when you exercise?
- breathing rate and volume increases to get more oxygen in the blood
- heart rate increases to get the oxygenated blood around your body faster, removing co2 quickly at the same time
why is lactic acid not ideal?
when it builds up it’s painful
what can long periods of exercise lead to?
muscle fatigue - they muscles get tired and stop contacting efficiently
what is an oxygen debt?
the amount of extra oxygen your body needs to react with the build up of lactic acid and remove it from the cells, oxygen reacts with the glucose to form harmless co2 and water
why do you keep brushing hard for a while after you stop exercising?
to get more oxygen to your blood which is transported to your muscle cells
how is the liver involved with dealing with lactic acid?
the blood that enters your muscles transports the acid to the liver, where it is then converted back to glucose
