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Biology Test 3


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What are the pigments involved in photosynthesis in plants?

What color light do they absorb? 

Chlorophyll a, b

they absorb red and blue light 

What happens to the pyruvate generated from glycolysis?

Where does this happen? 

It is oxidized to Acetyl CoA

At the inner membrane of the mitochondria 

What is the input molecule for glycolysis?

What is the end product? 

Glucose = input molecule

4 ATP = output molecules   **net yield of 2 ATP because 2 ATP are invested at the beginning of glycolysis 

What products of the light reactions are necessary to drive the Calvin cycle occur?


When NADH+H(+) interacts with oxygen what are the two products?

Is energy released or is an energy input required?

NAD(+) and water

Energy is released 

During fermentation in muscle cells, what molecule is pyruvate converted to and what else is produced during the reaction?
Lactic acid is produced and NADH+H(+) is oxidized
How do enzymes cause a lowering of the energy of activation?

They orient the substrates (reactants, so they can interact together easily.  *The enzymes concentrate the substrates at the active site.  *Active site provides a chemical environment due to the r-groups of amino acids, that allows the reacti

How does ATP get made during oxidative phosphorylation?
After the proton motive force builds up ATP is able to flow back to the matrix from the inter-membrane space through ATP synthase and as it flows through ADP and inorganic phosphate are fitted together to make ATP.
How does energy flow through biological systems?
Light energy (sun) ->chemical energy (photosynthetic organisms) -> chemical energy (consumers of photosynthetic organisms) -> thermal energy (heat)
How many reactions make up the glycolytic pathway?
10 reactions
How much ATP is generated per reduced NAD molecule during oxidative phosphorylation?  FAD?

2.5 ATP per reduced NAD

1.5 per reduced FAD 

If muscle cells are low on oxygen they perform fermentation, what is the purpose of this reaction?
To regenerate NAD+ and this can't be done by the ETS if oxygen levels are low
In terms of carbon molecules, what are the input and output of glycolysis?

C[6] = input

2C[3] = output

** []= subscript 

In terms of carbon molecules, what are the input and output of Krebs cycle?

Acetyl CoA (2 carbon molecule) = input

2 Carbon dioxide (2 one carbon molecules) = output

In terms of carbon molecules, what are the input and output of pyruvate oxidation?

C[3] = input (x2 per glucose)

Acetyl CoA (two carbon molecule) + Carbon dioxide (one carbon molecule) = output (x2 per glucose)

Is glucose oxidized or reduced during its breakdown in the cell?
Is the oxidation of glucose by oxygen to carbon dioxide and water exergonic or endergonic?
NAD can exist in what two forms?



** ()=superscript
Overall what occurs during oxidative phosphorylation?
FAD & NAD are recycled and a proton gradient is set.
Please be able to name all the electron carriers present in the inner mitochondrial membrane.
NADH-Q Reductase, Q, Cyt C Reductase, Cyt C, Cyt C Oxidase
What are the end products of the Krebs Cycle?

2 CO[2], 3 NADH+H(+), 1 FADH[2], 1 ATP

** x2 per glucose 

What are the four overall reactions of the Krebs cycle?
  1. C[2]+C[4] -> C[6]
  2. C[6] -> C[5]+CO[2]
  3. C[5] -> C[4]+CO[2]
  4. modification of C[4] back to oxaloacetate (C[4])
What are the roles of the C3 compounds generated during the Calvin cycle?
  • regenerate C[5] to keep Calvin cycle going
  • synthesis of starch in chloroplasts
  • synthesis of sucrose in cytoplasm
What are the two main components of photosynthesis and what do they yield?

Light reactions - ATP & NADPH[2]

Calvin Cycle - CO[2], H[2]O, ATP, NADPH[2] 

What are the two main steps of glucose breakdown?  Which require oxygen to function?

Glycolysis - does not require oxygen

Cellular Respiration (Krebs cycle & oxidative phosphorylation) - Do require oxygen 

what are the two properties associated with light?

wave - has a defined wavelength

particle - photons & they have a set amount of energy 

What effect do enzymes have on the energy of activation of a reaction?
They lower the energy of activation and make it more likely for the reaction to occur.
What energy carries are produced during glycolysis?
2 NADA+H(+) per glucose
What energy carries are produced during pyruvate oxidation?
2NADH+H(+) per glucose
What energy carries are produced during the Krebs cycle?

3 NADH + H(+), 1 FADH[2], 1 ATP 

(x2 per glucose) 

What energy input (ATP/glucose) is required during the first 5 reactions of glycolysis?
Glucose & 2 ATP
What energy output occurs during the reactions after the first 5 (ATP & NAD+h(+)) in glycolysis per glucose molecule?

Output = 4 ATP & 2NADH+H(+) per glucose

**There is a net yield of only 2ATP because 2 are invested at the beginning of glycolysis 

What is a catalyst?
speeds up a chemical reaction without being used up
What is a pigment?
something that absorbs light
What is an ATP synthase?
an enzyme that synthesizes ATP
What is an enzyme?
Protein catalyst that is highly specific
What is oxidative phosphorylation?
use of proton motive force to take ADP & inorganic phosphate to make ATP.  It also regenerates NAD(+) & FAD(+).
What is photophosphorylation?
energy of light used to make ATP from ADP and inorganic phosphate
What is substrate level phosphorylation?
Enzyme-catalyzed transfer of phosphate groups from donor molecules to ADP molecules to form ATP
What is the definition of photosynthesis?
energy of the sun that powers processes on earth through light energy capture that is converted to chemical energy
What is the end product of fermentation in yeast and what industry does this product support?
Ethanol, the alcohol industry
What is the energy of activation of a reaction?
It is an energy barrier that reactants must overcome
What is the energy yield of pyruvate oxidation?
What is the final electron acceptor in the light reactions?
What is the final electron acceptor of the ETS in the mitochondria?
What is the fuel for most living cells?
What is the gain of electrons by a substance called?  How about the loss of electrons?

Gain of electrons = Reduction

Loss of electrons = oxidation 

What is the input molecule for glycolysis?  What is the net end product?


2 ATP 

What is the name of the enzyme that catalyzes the first step in the Calvin cycle?
What is the name of the site on the enzyme where the substrates bind?
Active Site
What is the net yield of glycolysis?
  • 2 ATP
  • 2 NADH+H(+)
  • 2 pyruvate
  • *per glucose
What is the overall yield in ATP for the complete oxidation of glucose?

30 ATP

glycolysis = 2, Krebs Cycle = 2, ETS = 28, -2 invested at the beginning of glycolysis 

What is the source of energy?
The sun
What is the source of oxygen produced during photosynthesis?
Oxygen is a produce of splitting water at photosystem II
What is the starting point of the Krebs cycle?

 Carbon fixation - the Acetyl CoA is attached to a 4 carbon molecule to make a 6 carbon molecule


What is the ultimate fate of energy?
To be released as heat
What organisms first capture this energy?
Photosynthetic organisms
What specific energy carriers are used by cells during oxidation-reduction (redox) reactions?
What specific energy carriers are used during redox reactions?
What three factors discussed in class can regulate enzyme activity?
Temperature & pH optimum & inhibitors
Where do the light reactions in photosynthesis occur?
thylakoid membranes in cholorplasts
Where does oxidatie phosphorylation occur?
inner membrane of the mitochondria
Where does the Calvin cycle occur?
stroma of cholorplasts
Where does the Krebs Cycle occur?
Matrix of the mitochondria
Where within the cell does glycolysis occur?
Where within the cell does oxidative phosphorylation occur?
Inner membrane of the mitochondria
Where within the cell does the Krebs cycle occur?
In the matrix of the mitochondria
Which wavelength of light has more energy: blue or red?
Why are enzymes highly specific?
Because the reactants (substrates) bind to the active site on an enzyme.  The active site is a crevice on the surface of the 3D folded shape of the protein.
why are plants green?
They absorb red and blue light.  They reflect/transmit the other colors.
Why can a hydrogen ion gradient be used to make ATP?
e(-) are donated to carriers in the inner mem., as e (-) flow from one carrier to the next H(+) are moved across the inner mem. to the intermem. space, flow back of H(+) through ATP synthase is used like water behind a dam.
Why do yeast cells perform fermentation?
to regenerate NAD and keep glycolysis going when oxygen leves are low
Why must reduced NAD & FAD be regenerated & what happens if they were not?
They have to be regenerated to keep the Krebs cycle running and in turn keep oxidative phosphorylation running.  If they are not glycolysis is the only process that can run (fermentation).

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