respiration

What is aerobic respiration?

An exothermic reaction in which glucose

reacts with oxygen to release energy

which can be used by cells.

What are the equations for aerobic

respiration? (word and symbol)

Glucose + oxygen → carbon dioxide + water (+energy)

C6H12O2 + 6O2 → 6CO2 + 6H2O (+energy)

Where does aerobic respiration take place?

In the mitochondria

Why do organisms require the energy

released by respiration?

● Synthesis of larger molecules

● Muscle contraction

● Maintenance of body temperature

● Active transport

What is anaerobic respiration?

An exothermic reaction in which glucose

is broken down to release energy in the

absence of oxygen.

What is the equation for anaerobic respiration?

Glucose → lactic acid (+energy)

Why is anaerobic respiration less

efficient than aerobic respiration?

Glucose is not completely broken down,

so less energy is transferred.

Why can anaerobic respiration lead to muscle

fatigue?

Lactic acid (product of anaerobic respiration)

builds up in muscles, preventing efficient

contraction.

What is an oxygen debt?

The amount of oxygen needed to convert

lactic acid into back into glucose after

anaerobic respiration.

What is fermentation?

A type of anaerobic respiration that

occurs in yeast cells.

What is the equation for fermentation?

Glucose → ethanol + carbon dioxide (+energy)

Why is the fermentation reaction important?

It is used in the production of bread and

alcoholic drinks.

What are the differences between

aerobic and anaerobic respiration?

● Aerobic requires oxygen; anaerobic does not.

● Aerobic produces CO2 and water; anaerobic

produces lactic acid or ethanol + CO2.

● Aerobic transfers a greater amount of energy.

How do muscles store glucose?

As glycogen

What changes take place when muscular

activity increases in the body?

● Heart rate increases and arteries dilate - increases

flow of oxygenated blood to muscles.

● Breathing rate increases and breathing is deeper -

increases the rate of gaseous exchange.

● Stored glycogen is converted back into glucose.

How is lactic acid transported away from

the muscles?

(higher)

Blood flow through the muscles transports

lactic acid to the liver, where it is oxidised

back to glucose.

What is metabolism?

The sum of all the reactions that take

place in a cell or an organism.

How do cells use the energy transferred by

respiration?

To continuously carry out enzyme-controlled

processes which lead to the synthesis of 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

● Photosynthesis

● Respiration

● Breakdown of excess proteins into urea