Respiration

Question 1

Why do we take oxygen and food into our body?

Answer 1

We take oxygen and food into our body so we can release energy.

Question 2

As a result of our body releasing energy what waste gas is produced?

Answer 2

As a result of this, our body produces a waste gas called carbon dioxide, which we can breath out. So we breath and eat food so we can release energy,

Question 3

What do we need energy for?

Answer 3

Making new cells by cell division
Making substances e.g proteins such as enzymes and antibodies.
Making our muscles work( contract )
Sending electrical impulses along neurons.

Question 4

What type of energy does food contain?

Answer 4

Food contains chemical energy.

Question 5

How do our cells make energy?

Answer 5

Our cells break down food molecules to release energy SLOWLY in a series of enzyme controlled chemical reactions called RESPIRATION.

Question 6

What is the definition of respiration?

Answer 6

Respiration is therefore a series of enzyme controlled reactions so that chemical energy in the glucose is gradually released to produce the energy transfer molecule ATP.

Question 7

Explain aerobic respiration (respiration with oxygen)?

Answer 7

When there is a good supply of oxygen then cells can use this oxygen to help break down food molecules (e.g. glucose) completely so that lots of energy is released. This type of respiration is called aerobic respiration.

Question 8

What are the waste products in aerobic respiration?

Answer 8

There are two waste products made: water and carbon dioxide.

Question 9

What is the word equation for the aerobic respiration reaction taking place in your cells?

Answer 9

Glucose+oxygen->energy+carbon dioxide+water.

Question 10

What does ATP stand for?

Answer 10

Adenosine triphosphate.

Question 11

What is adenosine triphosphate (ATP) made from?

Answer 11

ATP is made up from a molecule of adenosine and three inorganic phosphate groups (Pi).

Question 12

What is adenosine triphosphate (ATP)?

Answer 12

Adenosine triphosphate (ATP) is an energy transfer molecule which transfers energy from energy-releasing reactions (e.g. respiration) in a cell to the energy consuming reactions (e.g. protein synthesis) in the cell. It makes energy transfer in the cell very efficient.

Question 13

What is the first stage in respiration?

Answer 13

Breakdown of glucose into pyruvate. Splitting one molecule into two molecules of pyruvate.

Question 14

Where does the first stage of respiration occur?

Answer 14

The first stage of respiration occurs in the cytoplasm of a cell.

Question 15

Does the first stage of respiration need oxygen?

Answer 15

The first stage of respiration does not need oxygen. (i.e. is an anaerobic stage)

Question 16

Does the first stage of respiration need oxygen?

Answer 16

The first stage of respiration does not need oxygen. (i.e. is an anaerobic stage)

Question 17

During the first stage of respiration how many ATP molecules are produced?

Answer 17

During this reaction, enough energy is released to produce (yield) 2 ATP molecules.

Question 18

What is the second stage in respiration?

Answer 18

Breakdown of pyruvate into carbon dioxide and water.

Question 19

Does the second stage of respiration require oxygen?

Answer 19

The second stage does require oxygen and is known as the aerobic stage of respiration.

Question 20

Describe what happens in the aerobic stage of respiration.

Answer 20

The pyruvate molecules formed during the first stage of respiration still contain energy. If oxygen is present in the cell, then pyruvate molecules diffuse into a mitochondrion so that pyruvate can then be completely broken down into carbon dioxide during the second, aerobic stage of respiration.

Question 21

During the aerobic stage of respiration how how many ATP molecules are produced?

Answer 21

During this reaction, enough energy is released to produce (yield) 36 ATP molecules.

Question 22

Where is the mitochondrion found?

Answer 22

The mitochondrion is an organelle found in the cytoplasm.

Question 23

What is the function of the mitochondrion?

Answer 23

The mitochondrion is the site of aerobic respiration.

Question 24

Describe the mitochondrion’s membrane?

Answer 24

It has a double membrane. The inner membrane is folded giving a large surface area for the production of ATP. Cells that need a lot of energy have a large number of mitochondrion.

Question 25

Name cells that need lots of energy.

Answer 25

Cells that need a lot of energy have a large number of mitochondria, e.g. sperm, liver, muscle, neurons, companion cells.

Question 26

What is fermentation?

Answer 26

When there is a lack of oxygen, organisms do a type of respiration called fermentation.

Question 27

What happens to the glucose during fermentation?

Answer 27

During fermentation glucose is only partly broken down.

Question 28

What are the products made during fermentation?

Answer 28

The products made are different depending on whether the organism is an animal, plant or fungus.

Question 29

Where does fermentation occur?

Answer 29

Fermentation occurs in the cytoplasm of a cell.

Question 30

When does fermentation occur in animal cells?

Answer 30

In animal cells, the fermentation pathway occurs when no oxygen is available or when the oxygen supply runs out e.g. in humans this occurs during vigorous exercise.

Question 31

What happens to the pyruvate during fermentation in animal cells?

Answer 31

The pyruvate is converted into lactate.

Question 32

What does lactate cause?

Answer 32

When pyruvate is converted into lactate this causes muscle fatigue.

Question 33

What is the word equation for fermentation in animal cells?

Answer 33

Glucose-> pyruvate-> lactate

Question 34

How many ATP molecules are made during fermentation in animal cells?

Answer 34

The breakdown of one glucose molecule to pyruvate and then to lactate would only produce a small quantity of energy (2 ATP) from the breakdown of glucose to pyruvate.

Question 35

When does fermentation in plant or fungal cells take place?

Answer 35

In plant and yeast cells, the fermentation pathway occurs when no oxygen is available e.g. when root hair cells become water logged or when yeast cells are deprived of oxygen during wine making.

Question 36

What happens to the pyruvate during fermentation in plant and fungal cells?

Answer 36

The pyruvate is broken down to ethanol (alcohol) and carbon dioxide.

Question 37

What is the word equation which shows the fermentation reaction taking place in plant/yeast cells?

Answer 37

Glucose->pyruvate->ethanol+carbon dioxide+energy

Question 38

How many ATP molecules are made during fermentation in plant and fungal cells?

Answer 38

The breakdown of one glucose molecule to pyruvate then to ethanol and carbon dioxide would therefore only produce a small quantity of energy (2ATP) from the breakdown of glucose to pyruvate.

Question 39

Is fermentation in plant and fungal cells reversible?

Answer 39

The carbon dioxide diffuses out the cell. Since the carbon dioxide gas has been lost from the cell, the ethanol cannot be converted back into pyruvate i.e the reaction is not reversible.

Question 40

What happens if fermentation in plant and fungal cells goes on for too long?

Answer 40

If fermentation goes on too long the build up of ethanol will kill the plant/ yeast cells.

Question 41

What is a respirometer?

Answer 41

A respirometer is a piece of apparatus which is used to measure the rate of respiration.

Question 42

What does a respirometer measure?

Answer 42

A respirometer can measure the consumption of oxygen and some can also measure the production of carbon dioxide.This provides information about the respiration rate of the organism being studied.