What happens during cellular respiration?

Question 1

What is cellular respiration?

Answer 1

all organisms respire to release energy to fuel their living processes

respiration can be aerobic - where it uses glucose and oxygen
OR
anaerobic - where it uses only glucose

respiration must happen all the time so that an organism can survive

Question 2

What kind of process is respiration releasing energy?

exorthermic or endothermic?

Answer 2

exothermic

energy is stored in molecules of ATP

ATP can be broken down in other processes in cells to release the stored energy

Question 3

Why do organisms need energy in the form of ATP?

Answer 3

to increase the chemical reactions needed to keep organisms alive - these reactions build complex carbohydrates, proteins and lipids from the products of photosynthesis in plants that require energy

movement in animals requires ATP for muscles to contract

Question 4

What is ATP required for?

Answer 4

cell division

transmission of nerve impulses

Question 5

What do consumers gain?

Answer 5

consumers gain biomass from other organisms when they eat them. some of the biomass is converted into molecules of glucose, the fuel for cellular respiration

Question 6

What does cellular respiration involve?

Answer 6

many chemical reactions and makes molecules of ATP.

this occurs in the cytoplasm and mitochondria of animal and plant cells.

ATP is required for processes that are essential for life, including breakdown of molecules, active transport and muscle contraction.

Question 7

What does aerobic respiration do?

Answer 7

breaks down glucose and combines the breakdown products of oxygen, making water and carbon dioxide a waste product

Question 8

When does anaerobic respiration occur?

Answer 8

in conditions of low or no oxygen at all

there is a partial (sort of) breakdown of glucose so fewer molecules of ATP are produced.

Question 9

What is the equation for aerobic respiraiton?

Answer 9

glucose + oxygen -> carbon dioxide + water

Question 10

What is the rate of respiration in yeast?

Answer 10

yeast can be used to see how the rate of respiration changes when different carbohydrate substrates are used.

e.g. yeast can use glucose in respiration

Question 11

How can the rate of a reaction be calculated?

Answer 11

by measuring how much product is made in a specific amount of time

carbon dioxide will be produced when yeast respires

carbon dioxide can be collected using the equipment

Question 12

How do you investigate the rate of respiration? (PRACTICAL)

Answer 12

1. set up the measuring cylinder in a water bath so that the cylinder is full of water and clamped into position
2. add 20cm^3 of water to 1g yeast and 0.5g glucose and stir. add this mixture to the round-bottomed flask
3. place a bung with a tube into the neck of the flask and place the flask in a waater bath at 40 degees.
4. wait 5 minutes for the yeast to begin respiring at a constant rate.
5. bubbles should emerge from the end of the tube..
   place the end of the tube under the open end of the measuring cylinder and start the timer.
6. record the volume of gas produced after 3 mins
7. repeat steps 1 to 6 twice more.
8. repeat steps 1 to 7 using the other carboydrate mixtures.