Bioenergetics Flashcards
what is photosynthesis?
Plants synthesis glucose using light energy from the sun. Light energy is converted into chemical energy
where does photosythsis take place?
In the cholorphyll of leaf mainly in the palisade cells
Word equation for photosythesis?
carbon dioxide + water = glucose+ oxygen
Is photo an endothermic or exothermic reaction?
Endothermic, energy from the sun enters the leaves.
(RQ) How can you have shown that the plant gives off oxygen during photosythesis?
Using a water plant like pond grass, and contain the bubbles created by photosythesis in the water. The gas will be able to relight a splint as it contains oxygen
Leaf adaptations for maximum photosynthesis is?
Broad leaves = larger surface area
thin leaves = shorter diffusion distance
lots of chlorophyll = ensure’s that the most light energy is trapped
Transport veins = pholem can quickly take the glucose produced away
Air spaces = allows Co2 and O 2 to leave the plant
Guard cells = control the stomata for gas exchange and control water loss
What affects the rate of photosynthesis?
Temperature, light intensity, carbon dioxide concentration and chlorophyll amount
How does temperature affect it?
Increasing the temperature increases the rate of photosythsis, as it increases the kinetic energy of particles. However the rate increasing past a certain temp will cause enzymes to be denatured
How does light affect the rate?
Light will increase the rate of photosythesis until another factor becomes limiting
What is a limiting factor?
An environmental factor that restricts the amount of photosythesis
How can you calculate the rate of photosythesis by measuring oxygen production? (RQ)
Set up a bubble potmeter apparatus pondweed in a sealed tube of water attached to a capillary tube and a gas syringe
Oxygen gas produced causes the bubble in the capillary tube to move the distance moved by the bubble is used to calculate the amount of oxygen
how can farmers use the limiting factors for maximum profit?
They can control temperature (greenhouse) light intensity (artifical lighting) and co2 concentration (paraffin heaters) leading to a greater yield.
5 uses of glucose in the plant
for respiration
stored as starch for storage
cellulose for strength
amino acids for protien sythensis
lipids for energy in seeds
What is aerobic respiration?
An exothermic reaction in which glucose reacts with oxygen to release energy
word equation for aerobic respiration?
Glucose + oxygen = carbon dioxide + water + (energy)
Where does aerobic respiration take place?
Mitrochondria
Why do organsims need the energy made by respiration?
To synthsis larger molecules
Muscle contraction
maintence of body temperature (homeostatsis)
Active transport
what is anerobic respiration?
An exothermic reaction in which glucose is broken down to release energy when oxygen is absent
word equation for anerobic
Glucose = lactic acid
Why is anerobic less efficent then aerobic?
Glucose is only broken down partially so not all energy is transferred
Why can anerobic lead to muscle fatigue?
Lactic acid will build up in muscles leading to fatigue as the muscles cannot efficently contract
what is fermentation?
A type of anaerobic respiration that occurs in yeast cells
word equation for fermentation?
Glucose = ethanol + carbon dioxide +(energy)
Why is fermentation used?
Necesarry in products like bread or wine
differences between aerobic and anaerobic
aerobic requires oxygen, anarobic does not
Aerobic transfers a greater amount of energy
Aerobic produces co2 and water; anaerobic will produce lactic acid or co2 and ethanol
How do muscles store glucose?
As glycogen
what happens to the body when the muscles are in use?
The heart rate increases and the arteries dialate ( get wider) to allow more blood to the muscles
breathing rate is increased to allow for more gas exchange
The glycogen stored is now converted back into glucose
How is lactic acid transported away from the muscles?
blood flow through the muscles transports lactic acid into the liver, where it is oxidised back into glucose
what is metabolism?
The sum of all reaction that take place in a cell or organsim
How do cells use the energy transferred by respiration?
by going through enzyme controlled proccess’s in the body e.g sythesis new molecules
Give examples of metabolic reactions?
Glucose into starch/glycogen/cellulose
glycerol and fatty acids into lipids
glucose and nitrate ions into amino acids
photosythsis
respiration
