Cell respiration Details

Question 1

Components of nucleotides

Answer 1

-a nitrogen-containing base
-a five-carbon sugar
-one or more phosphate groups

Question 2

Components of ATP(adenosine triphosphate)

Answer 2

-Adenine(as the base)
-Ribose(as the sugar)
-Three phosphate groups(all of them are in a chain and are negatively charged)

Question 3

Purpose of ATP

Answer 3

-Temporary storage of energy
-Energy transfer between processes and different parts of the cell(hence why it’s called the energy currency of the cell)

Question 4

Properties of ATP that make it ideal as the cellular energy currency

Answer 4

-Chemically stable at neutral pH levels typical of cells(do ATP doesn’t break down and prematurely release energy)
-Soluble in water(so ATP can diffuse freely in the cytoplasm)
-Unable to diffuse through the phospholipid bilayers of membranes(so ATP’s movement within cells can be controlled and there is no leakage outside of cells)

Question 5

Why would the third phosphate group of ATP being able to easily be removed and reattached by hydrolysis and condensation reactions make ATP ideal as the cellular energy currency?

Answer 5

Breaking the bond between the third and second phosphate group in ATP(hence creating ADP) releases a lot of energy which can be used by the cell for metabolic reactions, protein synthesis, etc.

Question 6

Formula for the conversion of ATP to ADP and vice versa

Answer 6

Question 7

What happens to the excess energy produced by hydrolysing ATP to form ADP?

Answer 7

It gets converted into heat energy

Question 8

Examples of life processes within cells that ATP supplies with energy

Answer 8

-Synthesizing macromolecules(anabolic reactions are endothermic and hence require ATP for energy)
-Active transport(the energy needed is used to cause reversible changes in the conformation/shape of the pump protein)
-Movement(both of cell components and the entire cell)

Question 9

What does ADP stand for?

Answer 9

Adenosine Diphosphate

Question 10

ATP and ADP are endlessly interconvertible(T/F)

Answer 10

True

Question 11

Energy is released when ATP is converted to ADP(so ATP has more chemical potential energy)(T/F)

Answer 11

True

Question 12

Energy has to be invested to convert ADP to ATP(T/F)

Answer 12

True

Question 13

The energy needed to convert ADP and a phosphate group back to ATP can come from…

Answer 13

-Cell respiration
-Photosynthesis
-Chemosynthesis

Question 14

Conversion of ADP to ATP is a phosphorylation reaction(T/F)

Answer 14

True

Question 15

There is a continual regeneration of ATP from ADP and phosphate(T/F)

Answer 15

True

Question 16

Energy transfers during interconversions between ATP and ADP are not 100% efficient(T/F)

Answer 16

True(and so some energy is lost to heat)

Question 17

What happens in respiration?

Answer 17

Carbon compounds are oxidised to release energy in the form of ATP

Question 18

Principal substrates used in respiration

Answer 18

Glucose and fatty acids(although other carbon compounds can also be used, like amino acids)

Question 19

How is cell respiration and gas exchange interdependent?

Answer 19

-Without gas exchange, cell respiration could not continue because there would soon be a lack of oxygen and a harmful excess of carbon dioxide inside the cell
-Without cell respiration, gas exchange could not continue because the use of oxygen and the production of carbon dioxide in respiration create the concentration gradietns which cause the gases to diffuse

Question 20

Types of cell respiration

Answer 20

-Aerobic respiration
-Anaerobic respiration

Question 21

Word equation for aerobic respiration

Answer 21

Glucose + Oxygen → Carbon dioxide + Water (+Energy)

Question 22

Chemical equation for aerobic respiration

Answer 22

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Question 23

Word equation for anaerobic respiration

Answer 23

Glucose → Lactate

Question 24

Chemical equation for anaerobic respiration

Answer 24

C₆H₁₂O₆ → 2C₃H₆O₃

Question 25

Word equation for anaerobic respiration in yeast(and some fungi)

Answer 25

Glucose → Ethanol + Carbon dioxide

Question 26

Chemical equation for anaerobic respiration in yeast(and some fungi)

Answer 26

C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂

Question 27

In all types of cell respiration, ADP is converted to ATP(T/F)

Answer 27

True

Question 28

Features of aerobic cell respiration

Answer 28

-Oxygen is used as an electron acceptor -Carbon dioxide and water are waste products -Aerobic respiration has a higher yield of ATP(i.e. releases more energy) -Aerobic respiration occurs slowly -The initial reactions are in the cytoplasm, but more occur in the mitochondria

Question 29

Features of anaerobic cell respiration

Answer 29

-Oxygen is not used at all -Carbon dioxide and lactate/ethanol are the waste products -Anaerobic respiration has a lower yield of ATP -Anaerobic respiration occurs quickly -All reactions are in the cytoplasm

Question 30

Anaerobic cell respiration is used when we need to maximise the power of muscle contractions(T/F)

Answer 30

True

Question 31

What restricts how much anaerobic respiration can be done?

Answer 31

The amount of lactate(lactic acid) in the body limits the amount of anaerobic respiration(there is a limit to how much lactate the body can tolerate)

Question 32

Why can the power of muscle contractions be maximized only for a short time period?

Answer 32

The body can only tolerate a limited amount of lactate acid that is produced as a waste product in anaerobic respiration

Question 33

What happens to lactate after anaerobic respiration?

Answer 33

It is broken down by oxygen

Question 34

Factors which affect the rate of cell respiration

Answer 34

-Oxygen uptake -Carbon dioxide production -Consumption of glucose(or other respiratory substrates)

Question 35

Components of a respirometer

Answer 35

-A sealed glass or plastic container(in which the organism or tissue is placed with enough air for it to remain healthy) -A base(alkali) such as potassium hydroxide to absorb carbon dioxide produced during respiration -A capillar tube containing fluid connected to the container to measure changes in the volume of air inside the respirometer

Question 36

How a respirometer works

Answer 36

-A sample is put into the apparatus, from which it can absorb oxygen and secrete CO₂ into the air around it -An alkali(e.g. potassium hydroxide) absorbs all of the CO₂ excreted, so changes in the air pressure or volume inside the respirometer are due to oxygen consumption

Question 37

How a respirometer looks like

Answer 37

Question 38

How can O₂ uptake and CO₂ release be calculated using a respirometer?

Answer 38

-O₂ uptake can be calculated from the decrease in air pressure -CO₂ release can be calculated from the decrease in pH of the potassium hydroxide solution

Question 39

What is the respiration rate?

Answer 39

O₂ uptake or CO₂ release per unit time

Question 40

Why is it important to keep temperature constant when using a respirometer, and how can this be done?

Answer 40

-Temperature changes affect air pressure -Temperature can be kept constant using a thermostatically controlled water bath