Ch 6 Cellular Respiration

Question 1

cellular respiration

Answer 1

The process by which cells create usable energy in the form of ATP from a series of biochemical reactions, involving the breakdown of glucose.

Question 2

glucose

Answer 2

A simple 6-carbon sugar molecule with the formula C6H12O6.

Question 3

ATP

Answer 3

Adenosine triphosphate, a high energy molecule that, when broken down, provides energy for cellular processes.

Question 4

aerobic cellular respiration

Answer 4

Cellular respiration that occurs in the presence of oxygen. Involves three stages, during which glucose and O2 are converted into ATP, CO2, and water.

Question 5

anaerobic fermentation

Answer 5

A metabolic pathway that occurs in the absence of oxygen. Involves glycolysis, followed by further reactions that convert pyruvate into lactic acid in animals, or ethanol and CO2 in yeast.

Question 6

Krebs cycle

Answer 6

The second stage of aerobic cellular respiration, where multiple reactions occur to create ATP, NADH, FADH2, and the waste product CO2. Also known as the citric acid cycle or TCA cycle.

Question 6

glycolysis

Answer 6

The first stage of aerobic cellular respiration in which glucose is converted to two pyruvate molecules.

Question 7

electron transport chain

Answer 7

The third stage of aerobic cellular respiration, in which a series of protein complexes embedded
in the inner membrane of a mitochondrion harness the stored energy in NADH and FADH2 to generate large amounts of ATP.

Question 7

mitochondrion (pl. mitochondria)

Answer 7

A double-membrane-bound organelle that is the site of the second and third stages of aerobic cellular respiration.

Question 8

cytosol

Answer 8

The aqueous fluid that surrounds a cell’s organelles inside the plasma membrane.

Question 9

crista (pl. cristae)

Answer 9

The folds of the inner membrane of a mitochondrion. The site of the electron transport chain.

Question 10

mitochondrial matrix

Answer 10

The space inside the inner membrane of a mitochondrion. The site of the Krebs cycle.

Question 11

pyruvate

Answer 11

A three-carbon molecule that can be formed from the breakdown of glucose via glycolysis.

Question 12

nicotinamide adenine dinucleotide (NAD)

Answer 12

A coenzyme that acts as a proton (H+) and electron carrier in cellular respiration. NAD can cycle between its NAD+ and NADH forms, depending on the reaction it takes part in.

Question 13

flavin adenine dinucleotide (FAD)

Answer 13

A coenzyme that acts as a
proton (H+) and electron carrier
in cellular respiration. FAD can cycle between its FAD and FADH2 forms, depending on the reaction it takes part in.

Question 13

coenzyme A

Answer 13

A large organic non- protein molecule that plays a key role in the modification of pyruvate to allow it to enter the Krebs cycle. Also known as CoA.

Question 14

ATP synthase

Answer 14

An enzyme in the inner mitochondrial membrane that uses the concentration gradient of H+ to synthesise ATP from ADP and Pi.

Question 14

acetyl-CoA

Answer 14

The product of the link reaction where pyruvate is conjugated to coenzyme A, creating the primary input into the Krebs cycle.

Question 15

catalyse

Answer 15

To increase the rate of a reaction.

Question 16

yeast

Answer 16

Unicellular eukaryotic organisms from the kingdom Fungi.

Question 16

anaerobic fermentation

Answer 16

A metabolic pathway that occurs in the absence of oxygen. Involves glycolysis, followed by further reactions that convert pyruvate into lactic acid in animals, or ethanol and CO2 in yeasts.

Question 17

lactic acid fermentation

Answer 17

The process of anaerobic fermentation in animals, where pyruvate produced via glycolysis is converted to lactic acid.

Question 18

lactic acid

Answer 18

A 3-carbon molecule that is the product of anaerobic fermentation in animals. Also known as lactate.

Question 19

ethanol

Answer 19

A 2-carbon alcohol molecule that is produced along with carbon dioxide during anaerobic fermentation in yeast, bacteria, and plants.

Question 20

ethanol fermentation

Answer 20

The process of anaerobic fermentation in yeasts, where pyruvate produced via glycolysis is converted to ethanol and carbon dioxide. Also known as alcohol fermentation.

Question 20

optimal

Answer 20

The point at which for a given condition (e.g. temperature), the maximum function of an enzyme occurs. Also known
as optimum.

Question 21

denature

Answer 21

The disruption of a molecule’s structure by an external factor such as heat.

Question 22

saturation point

Answer 22

The point at which a substance
(e.g. an enzyme) cannot receive more of another substance (e.g. a substrate).

Question 22

pH

Answer 22

A scale used to measure the acidity or basicity of an aqueous solution.

Question 23

enzyme inhibitor

Answer 23

A molecule that binds to and prevents an enzyme from functioning.

Question 23

competitive inhibitor

Answer 23

A molecule that hinders an enzyme by blocking the active site and preventing the substrate from binding.

Question 24

non-competitive inhibitor

Answer 24

A molecule that hinders an enzyme by binding to an allosteric site
and changing the shape of the active site to prevent the substrate from binding.

Question 25

allosteric site

Answer 25

A region on an enzyme that is not the active site.

Question 25

reversible inhibition

Answer 25

Enzyme inhibition that involves weaker bonds that can be overcome.

Question 26

irreversible inhibition

Answer 26

Enzyme inhibition that involves stronger bonds that cannot be broken.

Question 27

end-product inhibition

Answer 27

A form of inhibition where the final product in a series of reactions inhibits an enzyme in an earlier reaction in the sequence.

Question 28

fossil fuel

Answer 28

Fuel that formed over tens of millions of years from the remains of dead organic material. Fossil fuels are considered non- renewable.

Question 29

non-renewable

Answer 29

Refers to a resource that is replenished at a slower rate than it is being used, meaning that it will eventually run out.

Question 30

biofuel

Answer 30

Fuel created from organic material known as biomass.

Question 31

biomass

Answer 31

Organic material, including plants, animal by-products, and biological waste material. Biomass can be sourced from many industries,
including farming, forestry, and food manufacturing.

Question 31

renewable

Answer 31

Refers to a resource that can typically be replenished at the same (or faster) rate than it is being used, meaning it is unlikely to run out.

Question 31

carbon neutral

Answer 31

A state in which there is no net release of carbon dioxide into the atmosphere, meaning that there is a balance between the amount of CO2 that is emitted during combustion of a fuel and how much was originally absorbed during the formation process of that fuel.

Question 31

fermentation

Answer 31

The anaerobic chemical breakdown of high- energy organic molecules, typically via the action of enzymes. For many plants, fermentation involves the conversion of glucose to ethanol and carbon dioxide.

Question 32

bioethanol

Answer 32

A type of biofuel that is produced via the anaerobic fermentation of plants such as sugarcane or corn.

Question 33

hydrolysis

Answer 33

A chemical reaction in which water is used to break down the chemical bonds of a substance.

Question 34

food vs fuel debate

Answer 34

A central concern of large-scale biofuel manufacturing that questions the validity of using arable farmland to produce fuel, rather than food.

Question 35

first-generation biofuels

Answer 35

Biofuels produced from edible food crops such as corn or sugarcane. These compete directly with agricultural land.

Question 36

second-generation biofuels

Answer 36

Biofuels produced from non-edible crops such as agricultural and forestry residues and municipal waste. These typically compete less with agricultural land.