1 bioenergetics 3

Question 1

What is aerobic respiration?

Answer 1

It’s the chemical reaction that takes place in all cells to release energy from our food. It requires oxygen.

Question 2

What’s the word and symbol equation for aerobic respiration?

Answer 2

Glucose + Oxygen ——> carbon dioxide + water + (energy) C_6 H_12 O_6 + 6O_2 —> 6CO_2 + 6H_2O

Question 3

How do you prove the presence of carbon dioxide in our expired air?

Answer 3

• by blowing through a solution of lime water

- it should turn cloudy, indicates the presence of CO_2

Question 4

Why do animals and plants need respiration?

Answer 4

1. Cells use energy to build (synthesise) large molecules from smaller building blocks for growth or break down (digest) large molecules into smaller ones
2. Warm-blooded animals generate heat through respiration (Exothermic) to keep there bodies at a constant temperature
3. Animals needed energy to contract muscles for movement
4. Plants use energy to absorb minerals from nitrates from the soil by active transport into the root Hair cells

Question 5

Define respiration

Answer 5

The process of Transferring Energy from glucose which goes in every cell

Question 6

Give 4 examples of how organisms use the energy transferred by respiration?

Answer 6

• to build large molecules from smaller ones (for growth) or break down large molecules into smaller ones
• warm-blooded animals generate lots of heat through respiration (Exothermic)
• animals use energy to contract muscles for movement
• plants use energy to absorb minerals from soil by active transport into the root hair cells

Question 7

Where does aerobic respiration take place?

Answer 7

• Inside the mitochondria in every cell, where they have folded inner membrane covered in enzymes
• more active cells with have more mitochondria to release more energy for processes such as movement

Question 8

Name 3 cells that have more mitochondria

Answer 8

• ciliated cells
• sperm cells
• muscle cells

Question 9

Explain why during exercise more blood must be supplied to the muscle cells

Answer 9

• your muscles contract harder and faster when exercising
• so they need more energy for the protein fibres in each cell to move
• for more energy, respiration must increase
• more glucose and oxygen must be supplied to the muscles
• and carbon dioxide must be removed
• so more blood must be supplied to the muscle cells

Question 10

What’s an accurate way to measure someone’s breathing?

Answer 10

A spirometer

Question 11

Explain how a spirometer works

Answer 11

• when you breath out, the floating drum lifts, making the line go up
• as you breath in, the drum drops and the line falls

Question 12

What’s the response to exercise?

Answer 12

• Heart rate goes up, as does the force of the heart’s contractions. This increases the amount of blood leaving the heart every minute, called the cardiac output.
• The arteries supplying the muscles dilate (widen) allowing more blood to reach them. These two increase the amount of glucose and oxygen reaching the respiring cells, and removes the excess carbon dioxide
• Breathing rate and depth increases to absorb more oxygen and remove more carbon dioxide from the blood
• Glycogen stored within the muscle cells is broken down to provide additional glucose

Question 13

How can you tell if someone is fit?

Answer 13

• there heart and lungs become larger and develop more efficient blood supply
• the heart rate slows, as its now capable of expelling more blood with each contraction

Question 14

Explain why having a slow heart rate is good?

Answer 14

• the heart can still speed up if necessary
• it means the fit person can exercise more
• as they can deliver more blood to respiring muscles to provide more oxygen and glucose

Question 15

If exercise is too intense, what happens?

Answer 15

• insufficient oxygen is supplied to the working muscles for all of the energy to be provided by aerobic respiration
• Instead, anaerobic respiration takes place, which is the release of energy in the absence of oxygen
• It’s less efficient than aerobic as it only releases a small amount of additional energy, as the glucose is not broken down completely

Question 16

What happens to the Lactic acid in anaerobic respiration?

Answer 16

• The blood attempts to remove the lactic acid from the muscle cells, but prolonged muscle use causes it to build up
• This stops the muscle fibres from contracting efficiently, leading to muscle fatigue

Question 17

What’s the formula for anaerobic respiration?

Answer 17

Glucose ——–> Lactic acid (+energy)

Question 18

What’s the formula for the built up Lactic acid after exercise?

Answer 18

Lactic acid + oxygen —> carbon dioxide + water

Question 19

Why does your heart rate and breathing rate remain high after you’ve finished exercising?

Answer 19

• when you stop exercising after resorting to anaerobic respiration you still need to remove the lactic acid in your body:
• lactic acid + oxygen —–> carbon dioxide and water
• so more oxygen needs to be provided to the muscle and liver cells and carbon dioxide removed
• which is why your heart rate and breathing rate remain high after you’ve finished exercising
• the oxygen needed to break down the Lactic acid is called oxygen debt

Question 20

Why do you recover more quickly from exercise if you’re fitter?

Answer 20

Because the Lactic acid built up in exercise is less due to there increase in aerobic capacity the resort to anaerobic respiration later

Question 21

Define metabolism

Answer 21

The metabolism is the sum of all the chemical reaction that take in a cell or in the whole body

Question 22

List 6 common metabolic reactions:

Answer 22

• reactions of respiration
• reactions of photosynthesis
• The conversion of glucose to starch, cellulose (plants) or glycogen (animals)
• The production of lipid (fat) molecules from 1 molecule of glycerol and 3 molecules of fatty acid
• The breakdown of excess proteins in the liver to form urea for excretion
• the use of glucose and nitrate ions to form amino acids which in turn are used to synthesise proteins

Question 23

What 5 functions does the liver have?

Answer 23

• It produces bile to aid fat digestion
• It breaks down excess proteins into urea
• Converting lactic acid from anaerobic respiration back into glucose
• Detoxifying the blood by breaking down poisonous substances such as ethanol
• Breaking down old, worn out red blood cells and storing the iron for future blood cells

Question 24

Explain the metabolic reaction of photosynthesis

Answer 24

1. CO2 and H2O go in to the plant forms glucose
2. glucose is used to build cellulose for cell walls
3. glucose is used in respiration fro energy
4. glucose is used for fats and oils, which build cell membrane and store energy
5. glucose, nitrate ions and other minerals (from the soil/ water) are converted into amino acids, to form proteins
6. glucose is joined together to form starch for storage

Question 25

What are the functions of the liver in the body?

Answer 25

1. Produces bile to aid fat digestion (emulsification)
2. It breaks down excess proteins into urea
3. Converts Lactic acid from anaerobic respiration back into glucose
4. Detoxifying the blood by breaking down poisonous substances such as ethanol (alcohol)
5. Breaking down old, worn out red blood cells and storing the iron for future blood cells

Question 26

Explain anaerobic respiration in yeast

Answer 26

-Yeast (a single-called fungi) can also break down glucose in the presence or absence of oxygen
-it has different enzymes to animals so the products are different:
Glucose—

Question 27

Apart from in yeast where else does fermentation occur?

Answer 27

-in plants, when the soil becomes saturated with water and the roots cannot receive oxygen

Question 28

What can fermentation be used for?

Answer 28

• the release of carbon dioxide is useful in making bread rise
• the ethanol released is used to make alcoholic drinks, like beer and wine. Alcohol is toxic to yeast, so above 15% strength it kills the cells and beer/wine cannot become any stronger