Cycle 5: Integrated Metabolism

Question 1

How are mitochondria isolated from chlamy cells?

Answer 1

1. grind liters of chlamy cells
2. purify intact mito
3. wash mito
4. incubate mito in butter )so that mito don’t shrink or grow)

** measure O2 to see respiration level

Question 2

Change in respiration rate (oxygen consumption) in isolated mitochondria by addition of NADH?

Answer 2

NADH drives electron transport in OxPhos of CR
- oxygen is consumed in OxPhos to produce water

Question 3

Change in respiration rate (oxygen consumption) in isolated mitochondria by addition of ADP + Pi?

Answer 3

• ATP availability = ETC increases which consumes O2

Question 4

Change in respiration rate (oxygen consumption) in isolated mitochondria by addition of uncoupler?

Answer 4

uncoupler doesn’t allow for chemiosmosis so it causes the fasters rate of ETC so highest O2 consumption rate

Question 5

What is respiration control mechanisms?

Answer 5

availability of ADP and Pi controls rate of ETC and O2 consumption

Question 6

What is the link between chloroplast and CR?

Answer 6

G3P made in Calvin cycle, leaves chloroplast, makes pyruvate in cytosol

Question 7

What are the two roles of G3P that is exported form the chloroplast into the cytosol?

Answer 7

energy source - Calvin cycle and carbon source - pyruvate oxidation.

Question 8

Can Chlamy grow in the dark?

Answer 8

Yes – heterotrophic growth with acetate channel bc it allows acetyl CoA in for Citric acid cycle

Question 9

Why acetate and not glucose for Chlamy?

Answer 9

no glucose transporter bc glucose not abundant

Question 10

What is mixotrophic metabolism?

Answer 10

acetate and light = heterotrophic and autotrophic growth - fastest growth rate

TAP has acetate!

Question 11

How to measure photosynthesis using gas exchange?

Answer 11

CO2 analyzer detect reduction of CO2 because CO2 fixation occurs

Question 12

What are units of carbon fixation?

Answer 12

mol CO2 considered/min/cell

Question 13

What is the light response curve shape? What are the two distinct shapes? Why?

Answer 13

CO2 fixation(photosynthesis) vs light intensity/wavelength

Linear portion (light-limited region)
– more ADP and NADPH available so Calvin cycle turns faster since CO2 fixation is dependent on light reactions

Plateau (light-saturated region)
- Calvin cycle has speed limit

Question 14

Determine the rate of cellular respiration?

Answer 14

y -int (negative CO2 fixation)

Question 15

What is the Light Compensation Point?

Answer 15

light intensity needed for the rate of photosynthesis = rate of CR

0 net CO2 fixation

carbon gain = carbon loss

Question 16

What is the shape of the Rate of Reaction vs Enzyme concentration curve?

Answer 16

linear, directly proportional

Question 17

Why is one adaptation to low temperature is to increase enzyme concentration?

Answer 17

hexokinase works slowly at low temp so increase number of enzyme produced

Question 18

What is the shape of the Rate of Reaction vs Substrate Concentration curve?

Answer 18

exponential and plateau

plateau because there is a max enzyme catalysis rate no mater how much substrate

Question 19

What is Vmax? What is Km?

Answer 19

maximum reaction rate (at the plateau)

affinity between enzyme and substrate
(stringer affinity = faster reaction rate = reaches Vmax faster)

Question 20

What is a competitive inhibitor?

Answer 20

competes with substrate to bind with enzyme active site bc it has the same shape as substrate

can be overcome by high substrate concentration

Question 21

What does competitive inhibitor do to Km, Vmax? Why?

Answer 21

slower to get to Vmax

lower Km

need more substrate to get to max reaction rate and increase affinity

Question 22

What type of inhibition is competitive?

Answer 22

reversible (unlike penicillin)

Question 23

What does rate of reaction vs substrate conc curve look like with competitive inhibitor? without competitive inhibitor?

Answer 23

without - reaches plateau faster

Question 24

What is Non-competitive (allosteric) regulation of enzyme activity?

Answer 24

inhibitor (dec Km)or activator (inc Km) binds elsewhere on enzyme to induce or repress reaction rate

called allosteric site

Question 25

Advantage to regulating enzyme activity at the level of enzyme activity versus transcription/translation?

Answer 25

much faster