U3AOS2

Question 1

Enzyme/subsrate concentration

Answer 1

concentration increases, reaction rate increases. Eventually rate will plateau with saturation when all active sites are full or all substrates have enzymes.

Question 2

Glycolysis

Answer 2

In the cytosol, the breakdown of glucose.
C6H12O6 +2ATP +2ADP +2NAD+ —> 2pyruvate +4ATP +2NADH.
2ATP GAIN

Question 3

Cellular respiration equation

Answer 3

C6H12O6 +6O2 —> 6CO2 +6H2O (+26-28 ATP)

Question 4

Temperature (enzyme activity)

Answer 4

hotter=faster=better. If the optimum temperature is exceeded then enzymes denature and the reaction rate decreases rapidly. At lower temperatures, the reaction rate is decreased.

Question 5

Ethanol Fermentation

Answer 5

in plants/fungi
glucose is converted into pyruvate (this makes 2ATP and 2NADH). then pyruvate is converted into acetaldehyde (making CO2), and then it is converted into ethanol (converting the NADh back into NAD+)

Question 6

Inhibitors

Answer 6

A molecule that blocks the action of an enzyme.
Competitive: blocks the active site, with more enzyme concentration it can be flushed out.
Non-Competitive: binds to the allosteric site (doesn’t compete with substrate) so increased substrate concentration has no effect.
Both can be reversible or non-reversible

Question 7

Enzyme

Answer 7

Protein that lowers the activation energy for a specific reaction to occur. A biological catalyst

Question 8

Cofactors

Answer 8

are Inorganic. Bind to an enzyme to help the reaction to be catalysed.

Question 9

Lactic acid fermentation

Answer 9

Anaerobic fermentation (in the absence of oxygen) - Krebs cycle and E.T.C. stop
gl\ucose converted to pyruvate, making 2ATP and 2NADH, then pyruvate converted to lactic acid, converting NADH back to NAD+

Question 10

Endergonic

Answer 10

The energy of reactants<products

Question 11

repeatability

Answer 11

do the results agree, based on the sameness of the conditions in different trials? How close all factors are, e.g. gear, people, location

Question 12

Precision

Answer 12

How closely a set of measurements agree with each other. Gives no indication of closeness to true value.

Question 13

Reproducibility

Answer 13

Even if it’s conducted in a changed environment the results will be the same.

Question 14

Accuracy

Answer 14

How close measurements are to a hypothetical true value? More trials will increase the accuracy

Question 15

Light-dependant reaction

Answer 15

water and unloaded coenzymes (ADP and NADP+) converted with light energy into oxygen gas and loaded coenzymes (ATP and NADPH)
In the thylakoid membrane or grana.

Question 16

Chlorophyll

Answer 16

is a light-absorbing pigment that is located in the chloroplasts.

Question 17

Active site

Answer 17

The specific location on an enzyme where a substrate binds.

Question 18

Coenzymes

Answer 18

bind to an enzyme/substrate complex in order for the reaction to be catalysed. They are organic and can be loaded (ready to give energy) or unloaded (ready to accept energy)

Question 19

Catalytic power

Answer 19

Enzymes aren’t part of reactions and hence they can catalyse many reactions. Reactions are often reversible

Question 20

Substrate

Answer 20

molecules that enzymes work on. most enzymes only work on one substrate

Question 21

C4 Photosynthesis

Answer 21

optimised for high temperatures.
Concentrates CO2 first to avoid photorespiration.
in the Mesophyll: CO2 is fixed with PEPcase into oxaloacetate (a 4-carbon molecule)
in the Bundle sheath: oxaloacetate is converted back into CO2, in this highly concentrated and high-pressure low-oxygen environment the Calvin cycle occurs, but with less photorespiration.

Question 22

Light availability (photosynthesis)

Answer 22

reaction rate increases and then plateaus as chlorophyll can only absorb so much light.

Question 23

Calvin cycle

Answer 23

Rubisco fixes CO2 into the Calvin cycle, energy from ATP and NADPH are required, and the end product is glucose.

Question 24

Light-independent reaction

Answer 24

ATP +NADPH +CO2 —> C6H12O6 (+ unloaded coenzymes)
in the stroma (fluid-filled) part of the chloroplast.
THE CALVIN CYCLE.

Question 25

Validity

Answer 25

is the experiment doing what it was set up to do? Is it testing the hypothesis?

Question 26

True Value

Answer 26

hypothetical perfect measurement

Question 27

CAM Photosynthesis

Answer 27

if it is too dry.
At Night: stomata are open, and CO2 is fixed into organic malic acid, which is stored in the vacuoloes.
DAY: Stomata are closed to preserve water. CO2 is converted back to CO2, Calvin cycle.

Question 28

Electron transport chain

Answer 28

In the Cristae (inner membrane) of the mitochondria.
NADH +FADH2 push H+ ions into the intermembrane space against the concentration gradient. The movement of the H+ ions back powers ATP synthase to make ATP.
Oxygen is used to take the electrons off the end of the ETC, it then bonds with the H+ ions to make water.
NADH +FADH2 + 6O2—> 26-28 ATP + H2O (+ unloaded coenzymes)

Question 29

carbon dioxide concentration (photosynthesis)

Answer 29

there is relatively stable atmospheric CO2. also increases then plateaus when saturation is reached.

Question 30

Temperature (photosynthesis)

Answer 30

• too hot will denature but otherwise hotter=faster=more photosynthesis.

Question 31

Krebs Cycle

Answer 31

In the matrix of the mitochondria, The link reaction converts pyruvate to acetyl-CoA.
Krebs cycle is pyruvate + unloaded coenzymes (NAD+FADH+ADP) —> 6CO2 + loaded coenzymes
(2ATP)

Question 32

Biochemical pathways

Answer 32

Series of reactions where the products of one reaction are the reactants of the next. Each step is controlled by a specific enzyme

Question 33

C3 Photosynthesis

Answer 33

norma. Really good in cool/wet conditions. if it is too hot then Rubisco will bind to oxygen instead and do photorespiration, which is very inefficient. if too dry then the plant will die from water loss.

Question 34

Photosynthesis equation

Answer 34

6O2 + 12H2O —> C6H12O6 +6O2 +6H2O

Question 35

pH (enzyme activity)

Answer 35

how acidic/basic the environment is. if too far off the optimum the enzyme will denature

Question 36

Exergonic

Answer 36

the energy of reactants>products

Question 37

Lock and Key vs. induced fit

Answer 37

lock and key: active site has a fixed shape for the substrate
induced fit: active site changes shape upon binding to the substrate