Respiration and Food Production

Question 1

Why do living organisms respire?

Answer 1

To produce energy(ATP)

Question 2

Where does aerobic respiration happen?

Answer 2

Mitochondria

Question 3

Where does anaerobic respiration occur?

Answer 3

Cytoplasm

Question 4

What are the different types of respiration?

Answer 4

Anaerobic and aerobic

Question 5

What is the word equation for aerobic respiration in animals?

Answer 5

glucose + oxygen -> carbon dioxide and water(+energy(ATP))

Question 6

What is the chemical/symbol equation for aerobic respiration?

Answer 6

C6H12O6 + 6O2 -> 6CO2 + 6H2O

Question 7

How are the reactants for aerobic respiration obtained?

Answer 7

glucose via digestion
oxygen via breathing

Question 8

Why would there be more mitochondria in a muscle cell than in a cheek cell?

Answer 8

A muscle cell needs to work more which means in needs to contract more which requires more energy which requires more respiration which requires more mitochondria

Question 9

Why does breathing rate increase when humans exercise?

Answer 9

Humans exercise more
more muscle contraction
more energy needed
more aerobic respiration
more oxygen needed

Question 10

what is the word equation for anaerobic respiration in animals

Answer 10

glucose -> lactic acid

Question 11

How is lactic acid broken down and what is the word equation

Answer 11

Lactic acid is broken down with oxygen
lactic acid + oxygen -> carbon dioxide + water

Question 12

Why is lactic acid toxic

Answer 12

• Due to low pH which lowers pH in cells which denatures enzymes
• Causes muscle cramp and fatigue

Question 13

where is excess lactic acid taken?

Answer 13

To the liver to process the toxic lactic acid

Question 14

Why do you breathe heavily after excercising?

Answer 14

Because of the oxygen debt which is built up in you muscles which need to be repaid

Question 15

What does oxygen do to lactic acid?

Answer 15

oxidise it into carbon dioxide and water

Question 16

What is the anaerobic respiration in plants and fungi?

Answer 16

glucose -> ethanol + carbon dioxide (+energy (ATP))

Question 17

How do plants obtain carbon dioxide and oxygen?

Answer 17

diffusion through stomata controlled by guard cells

Question 18

Why do more stomata mean that there are more gas exchanges?

Answer 18

Greater SA:V ratio

Question 19

What are examples of yeast products

Answer 19

bread, wine, beer, quorn

Question 20

What are the parts in a yeast cell?

Answer 20

budding, nucleus, cytoplasm, cell wall, cell membrane, vacuole and food storage granules

Question 21

What are the factors affecting the rate of respiration?

Answer 21

Temperature, pH, ethanol concentration(or lactic acid), glucose concentration

Question 22

Why does temperature affect the rate of respiraton

Answer 22

Higher temperature leads to more kinetic energy and more collisions to form more enzyme substrate complexes. If too high temperature, enzymes denature

Question 23

Why does pH affect the rate of respiration?

Answer 23

If not optimum pH, enzymes denature

Question 24

Why does ethanol (or lactic acid) concentration affect the rate of respiration?

Answer 24

Ethanol or lactic acid is a toxic waste product produced in anaerobic respiration which eventually kills cells

Question 25

Why does the concentration of glucose affect the rate of respiration?

Answer 25

Glucose is a substrate needed for respiration which increases the number of enzyme substrate complexes, which increase the rate of respiration till the limiting factor is the concentration of enzymes

Question 26

Why is ethanol toxic?

Answer 26

Ethanol is toxic because it dissolves most bacteria's, viruses' and fungi's cell walls and denatures the proteins

Question 27

Why does bread need to be heated

Answer 27

* fungi or bacteria will start respiring anaerobically and will eventually die due to the ethanol concentration there will be and high temperatures which will denature enzymes * This will make carbon dioxide which will rise the bread * The ethanol will be burnt so that the bread is not alcoholic

Question 28

Why does bread rise?

Answer 28

Because fermentation produces carbon dioxide which is trapped in air bubbles causing the bread to rise

Question 29

What are fermenters?

Answer 29

Fermenters are machines used to grow fungi and other micro-organisms

Question 30

What different parts are there in a fermenter?

Answer 30

A nutrient input, a water jacket, an air inlet, a motor, a temperature and pH probe, a stirring paddle and a harvest line

Question 31

What is the use of a nutrient input

Answer 31

to provide glucose and nitrates and amino acids

Question 32

what does a water jacket do?

Answer 32

Keep the temperature at optimum

Question 33

What does the air inlet do?

Answer 33

* prevents contamination * provides oxygen

Question 34

What does the motor do?

Answer 34

turns stirring paddles

Question 35

What does temperature and pH probes do?

Answer 35

measure the temperature and the pH

Question 36

what do stirring paddles do?

Answer 36

mix the contents to make sure that all microorganisms have equal nutrients

Question 37

What is the harvest line

Answer 37

Where the produces of fermentation are released

Question 38

What is penicillin?

Answer 38

an anti-biotic fungi produced by penicillium which can be found naturally or grown in a fermenter

Question 39

What happens to the fermenter before use

Answer 39

fermenters are sterilised with steam before use to that unwanted organisms are killed and removes competition and contamination

Question 40

What are the steps in making yogurt

Answer 40

Milk is pasteurised at 85-95 degrees for 15 minutes milk is homogenised milk is cooled to 40 degrees and lactobacillus is added mixture is incubated where fermentation occurs yogurt is stirred and cooled to 5 degrees Flavouring and colorant can be added

Question 41

What is pasteurising

Answer 41

when heating kills any other microorganism as high temperatures denature enzymes

Question 42

what is homogenised?

Answer 42

when fat globules are dispersed evenly

Question 43

why is milk cooled to 40 degrees and lactobacillus is added?

Answer 43

lactobacillus: lactose + water -> lactic acid lowers pH of the milk milk proteins coagulate as they denature coagulation of milk proteins makes the yogurt thicken

Question 44

Why is thick milk cooled to 5 degrees

Answer 44

so that microbial growth is slowed down.