3-Bioenergetics

Created by

isa

Cards (26)

the word equation for photosynthesis
carbon dioxide + water = glucose + oxygen
the symbol equation for photosynthesis
6CO2 + 6H2O = C6H12O6 + 6O2
process of photosynthesis
6CO₂ diffuses into the leaves through the stomata
6H₂O is taken up by the roots by osmosis
6H₂O is transported to the leaves through xylem
light energy is taken in from the sun which makes it an endothermic reaction
6O₂ produced is released from the leaves or used for respiration
C₆H₁₂O₆(glucose) produced is used as energy store and respiration
usage of glucose produced by plants
for cellular respiration
to make cellulose
to make starch
making amino acids
making oils and fats
explained uses of glucose in plants
cellular respiration- breaks down glucose to release energy
make cellulose- complex carbohydrate to strengthen cell walls
make starch- complex carbohydrate used for glucose as long term storage: compact, insoluble. Used when photosynthesis isn't happening
make amino acids- used to make proteins by combining glucose with nitrate ions from soil
make lipids- store energy for later in the seeds
factors affecting the rate of photosynthesis
temperature
light intensity
concentration of carbon dioxide
amount of chlorophyll
how chlorophyll affects the rate photosynthesis
lack of chlorophyll can be caused by disease (TMV), lack of nutrients, environmental stress
these factors damage chloroplasts which causes them to not make as much chlorophyll which is what absorbs light energy for photosynthesis
limiting factors are light intensity, carbon dioxide and temperature
light intensity and carbon dioxide graphs become plateaued after a while due to other limiting factors
temperature graphs start to rise initially but then drop as enzymes can work more quickly but then begin to denature
ways farmers artificially create conditions for plant growth
greenhouses to trap heat and prevent pests and pathogens from damaging their crops
artificial light so plants can photosynthesise continually
paraffin heater to release CO2 and heat
fertilisers to ensure they have enough minerals
pesticides to kill any unwanted bugs
how carbon dioxide affects the rate of photosynthesis
it's one of the reactants for photosynthesis
if the concentration of CO2 is increased then the rate of photosynthesis will increase
how light intensity affects the rate of photosynthesis
it is the energy needed for photosynthesis to happen
if there isn't much light then photosynthesis will not happen quickly
how temperature affects the rate of photosynthesis
the chemical reactions that combine carbon dioxide and water to make glucose are controlled by enzymes
rate initially increases with temperature- gives particles energy to move faster and react more
rate is highest- once optimum temperature for the enzymes is reached
rate drops- once temperature rises above optimum as enzymes start to break down
rate falls to zero- when enzymes are denatured
different types of respiration
aerobic- with oxygen
anaerobic- without oxygen
cellular respiration is an exothermic reaction which transfers energy from glucose to be released and is continually happening in living cells
how cells use their energy from respiration
to build up larger molecules from smaller molecules
break down larger molecules into smaller molecules
muscular contraction
maintaining body temperature
move substances around the cell
metabolism is the combination of all chemical reactions in an organism to maintain life
aerobic respiration
glucose + oxygen = carbon dioxide + water
C6H12O6 + 6O2= 6CO2 + 6H2O
takes place whenever there is enough oxygen
takes place continuously in the mitochondria
anaerobic respiration
glucose = lactic acid
takes place without oxygen
takes place only when needed- can't get enough oxygen to keep up with aerobic respiration
not often used: there's incomplete breakdown of glucose molecule(no oxygen to oxidise it) it means not all of the energy is unlocked from glucose, lactic acid build-up which can damage cells and can lead to an oxygen debt
anaerobic respiration in plants and yeast
glucose = ethanol + carbon dioxide
called fermentation for yeast
exercise:
requires muscles to contract and relax more
contraction requires energy- cellular respiration
most efficient is aerobic respiration- needs oxygen
oxygen needs to be pumped faster around body
results in increased heart and breathing rate
it may produce enough oxygen but may not meet demands, anaerobic respiration will be carried out
after exercise if anaerobic respiration was carried out:
build up of lactic acid in tissues- burning sensation
to get rid of lactic acid- needs to react with oxygen
called oxygen debt
blood carries lactic acid from the muscles to the liver to react with oxygen and convert to glucose
investigating the effects of exercise on the body
breathing rate- count how many times chest rises and falls in one minute
heart rate- measure pulse with two fingers on the artery in your wrist or neck
defence systems from pathogens- physical barriers
skin- doesn't allow pathogens through, secretes oils and antimicrobial substances to kill them
nose- lots of little hairs and mucus to trap pathogens so they can't enter
trachea- covered in layer of mucus to trap pathogens, lined with cilia to prevent build-up as they slowly move mucus to back of throat
defence systems from pathogens- chemical barriers
stomach- produces hydrochloric acid which kills almost all pathogens due to it's strong pH of 2
immune system- white blood cells
phagocytosis: they track the pathogen, bind to them, engulf them and can be destroyed
antitoxins: bind and neutralise the harmful toxins that pathogens release to damage our cells
antibodies: bind to antigens and act as signals so that white blood cells can destroy them, they are specific and will recognise a previous pathogen- makes us immune
photosynthesis takes place in the leaves in the palisade and spongy mesophyll cells in chloroplasts which contain chlorophyll