Topics 3d, 3e, 3f

Question 1

Potential energy is…?

Answer 1

stored energy

• energy of position
• chemical energy

Question 2

Kinetic energy is…?

Answer 2

energy of motion

• light (photons)
• heat (molecules)
• electricity (electrons)
• movement of large objects

Question 3

1st law of thermodynamics?

Answer 3

conservation of energy (energy cannot be created or destroyed)

Question 4

2nd law of thermodynamics?

Answer 4

entropy is always increasing (closed system tend towards disorder)

Question 5

If energy is liberated by a chemical reaction, it is said to be what? Give example.

Answer 5

exergonic/exothermic

glucose + O2 = CO2 + H2O + energy

Question 6

If energy is required by a chemical reaction, it is said to be what? Give example.

Answer 6

endergonic/endothermic

CO2 + H2O + energy = glucose + O2

Question 7

What is an energy carrier molecule? Eg…

Answer 7

molecules that carry energy in cells in the form of high-energy chemical bonds
eg. ATP

Question 8

High energy molecules…

Answer 8

ATP
glucose
protein

Question 9

low energy molecules…

Answer 9

ADP + P
CO2 + H2O
animo acids

Question 10

Endergonic & exergonic reactions are coupled by …? What happens to this product?

Answer 10

ATP which gets ‘recycled’ and reused

Question 11

What do catalysts do to activation energy?

Answer 11

lower it (interact with reactants to make chemical interactions energetically more favourable)

Question 12

T or F - catalysts can participate in reactions repeatedly

Answer 12

true

Question 13

T of F - catalysts get changed during a reaction

Answer 13

false

Question 14

A bit about enzymes…

Answer 14

biological catalysts
made up of proteins (mainly)
generally very specific activity
end in …ase

Question 15

Metabolism is defined as …?

Answer 15

…the sum of all biochemical reactions

Question 16

Which factors regulate reactions?

Answer 16

enzyme concentration (more enzymes => faster reaction)
enzyme activity (certain conditions eg pH) competitive/noncompetitive inhibition

Question 17

Competitive inhibition occurs how?

Answer 17

competitive inhibitor binds to active site preventing entry of substrate

Question 18

Noncompetitive inhibition occurs how?

Answer 18

noncompetitive inhibitor binds to substrate (away from active site) changing the shape of the molecule so substrate does not ‘fit’

Question 19

Give example of allosteric regulation

Answer 19

+ve & -ve feedback loops

Question 20

Major environmental variables that influence enzyme function?

Answer 20

temp
pH
[salt}

Question 21

What is protein denaturation?

Answer 21

change in 3D shape of a protein
amino acid sequence remains UNCHANGED
is sometime reversible

Question 22

For most cellular enzymes (human), max activity occurs at what pH/temp?

Answer 22

pH: ~7.4
temp: 37 degrees c

Question 23

The breakdown of glucose to pyruvate costs/yields how many ATP molecules? Net ATP?

Answer 23

costs 2ATP (for activation energy)
total yields 4 ATP
net = 2 ATP

Question 24

Compound losing an electron is …?

Answer 24

oxidised

Question 25

Compound gaining an electron is…?

Answer 25

reduced

Question 26

where does glycolysis occur?

Answer 26

cytosol

Question 27

T or F - glycolysis requires O2

Answer 27

false

Question 28

T or F - glycolysis has efficient energy recovery

Answer 28

fale - inefficient 2%

Question 29

Other products of glycolysis that can recover energy?

Answer 29

pyruvate

NADH

Question 30

Net products yielded from 1 glucose molecule in glycolysis…?

Answer 30

2 ATP
2NADH
2 pyruvate

Question 31

What is the role of O2 in the electron transport chain?

Answer 31

ultimate electron acceptor (the main reason we need to breath, and to expel CO2)

Question 32

Celular resp occurs in which organisms? Where?

Answer 32

Only in eukaryotes - mitochondria

Question 33

2 key parts of cellular respiration?

Answer 33

Krebs cycle

electron transport chain

Question 34

Krebs cycle inputs…?

Answer 34

input: 2-carbon molecules (acetyl Co-A); NAD+/FAD; ADP

Question 35

Krebs cycle outputs…?

Answer 35

coenzyme A
CO2
NADH/FADH2
ATP

Question 36

What are NADH & FADH2?

Answer 36

reduced electron carriers that transport e’s to ETC for ‘work’

Question 37

Total products yielded from Krebs cycle alone…?

Answer 37

3 NADH
1 FADH2
1 ATP

Question 38

Define the chemiosmotic theory

Answer 38

proton gradient created during transit of e’s thru ETC is utilised by ATP synthase in the phosphorylation of ADP -> ATP

Question 39

3 requirements for chemiosmosis…?

Answer 39

chemical gradient (H+ gradient)
isolated location (inter membrane space of mitochondria)
enzyme (ATP synthase)

Question 40

Total yield from glucose thru cellular respiration…?

Answer 40

36-38 ATP (32 or 34 ATP NET)
6H2O
6CO2

Question 41

Total molecules yielded from glucose -> ETC…?

Answer 41

36-38 ATP
10 NADH
2 FADH2

Question 42

Light reaction inputs…?

Answer 42

H2O
light
ADP
NADP+

Question 43

Light reaction outputs…?

Answer 43

ATP
NADPH
O2

Question 44

Where does the light-dependent reaction take place?

Answer 44

thylakoid membrane inside chloroplasts

Question 45

What happens in light-independent reactions?

Answer 45

Energy from ATP & NADPH -> Calvin cycle -> 6 molecules of G3P -> 1 G3P leaves cycle (5 stay) -> 1 G3P + 1 G3P = 1 glucose molecule

Question 46

Light-independent reaction inputs…?

Answer 46

ATP
NADPH
CO2

Question 47

Light-independent reaction outputs…?

Answer 47

glusose
ADP
NADP+