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Chapter 8: Energy and Metabolism
1. What is the source of all energy on earth?
2. What is oxidation? What is reduction?
Why do redox reactions always occur together?
3. What does a reduced organic compound look like? (it generally has a number of hydrogens because
electrons often travel with protons)
4. Are the carbons reduced or oxidized when glucose is converted to carbon dioxide? How about in
photosynthesis when carbon dioxide is converted to glucose?
5. What are the generalized formulas for aerobic respiration (C6H12O6 + 6 O2 ---> 6 CO2 + 6 H2O + energy)
and for photosynthesis ( CO2 + 12 H2O + energy ---> C6H12O6 + 6 H2O + 6 O2)
6. Electrons moving to lower energy levels release or require energy? How about electrons moving to
higher energy levels?
7. What is the first law of thermodynamics?
8. What is the second law of thermodynamics? What is an exergonic reaction and what is an
endergonic reaction? Which occurs spontaneously and which requires an input of energy?
What is an exothermic reaction and what is an endothermic reaction?
9. What is entropy? Which has more energy-order or disorder?
10. What is activation energy? How do catalysts affect the activation energy of a reaction?
11. What is an enzyme? What is its effect on the activation energy?
Would metabolic reactions occur without enzymes?
12. What is an active site? Is it specific for a substrate? How is it made specific for a substrate?
(charges and hydrophobicity)
13. What are multienzyme complexes?
14. Are enzymes permanently altered by a reaction? How do they catalyze reactions (often bring
substrates into proper orientation)
15. What factors affect enzyme activity?
16. What are inhibitors and activators? In what way do they change the rate of a reaction?
17. What are coenzymes? What do they do? Which is the oxidized form of NAD+/NADH?
Which is the reduced form?
18. What is metabolism? Why are there metabolic pathways with lots of steps?
19. What role does ATP play in your cells?
What does ATP consist of (ribose + adenine + 3 phosphates)?
20. Know: ATP ----> ADP + Pi + energy and ADP + Pi + energy ---> ATP
What do these 2 equations mean?
21. What is a biochemical pathway? Why does metabolism typically occur using metabolic pathways instead of a single
reaction? Be able to model a biochemical/metabolic pathway using the generic terms: substrate, intermediate 1, intermediate
2…, enzyme 1, enzyme 2… and end product.
Chapter 9: How Cells Harvest Energy
1. Oxidation is the loss of electrons. In biological systems, when electrons are lost they are often accompanied by
protons:
2H+ + 2e- ----> H2
2. For glycolysis, know that it is a series of 9 steps, each catalyzed by a different enzyme.
Know the role of NADH.
3. Know that for glycolysis:
You start with 1 6-carbon glucose and end with:
2 3-carbon pyruvic acids/pyruvate
2 ATP
2 NADH
4. Know that it took energy to harness energy-really 4 ATP were made because to start glycolysis it took 2 ATP, leaving
a net gain of 2 ATP.
5. When oxygen is available the organisms will follow glycolysis by oxidizing pyruvate (pyruvic acid) to acetyl which
has 2 carbons-thus:
2 pyruvate --->2 acetyl + 2 CO2 + 2 NADH
6. Krebs cycle:
Coenzyme A picks up the acetyl group formed by the oxidation of the pyruvate and is now called acetyl CoA. This product
enters the Krebs cycle, coenzyme A leaves the acetyl group and is ready to be used to shuttle a new acetyl group into Krebs.
For each Krebs cycle:
2 CO2 are released
3 NAD+ are reduced to NADH
1 FAD+ is reduced to FADH2 (this is a new coenzyme)
1 ATP is formed
BUT REMEMBER-THERE WERE 2 ACETYL GROUPS FORMED FOR EACH GLUCOSE THAT STARTED THROUGH GLYCOLYSIS-SO DOUBLE THIS NUMBER
FOR TOTAL FOR GLUCOSE.
7. Electron transport chain:
How many ATP have been generated up till now? (2 ATP in glycolysis and 2 ATP in Krebs)
Where will the other 34 ATP be generated? (electron transport by oxidative phosphorylation)
Know that most of the energy from the oxidation of glucose is still in the electrons associated
with the coenzymes.
Know that NADH and FADH2 shuttle the electrons to the electron transport chain. As the electrons go down the chain,
a little energy is released at each step. This energy is used to pump electrons across the inner mitochindrion membrane (cristae).
This makes a proton gradient-which is an electrochemical gradient(+ charges on outside, - charges on inside). The protons
re-enter the inner matrix of the mitochondrion by diffusing down a channel established by the ATP synthetase complex. As
they pass through ATP is made from ADP + Pi.
8. Know: For each NADH - 3 ATP get made
For each FADH2 - 2 ATP get made through the electron transport chain
9. Know the structure of the mitochondrion (2 membranes-the inner membrane is arranged in folds and called the cristae,
inner most compartment is called the matrix).
10. Know that glycolysis occurs in the cytoplasm. Krebs and the electron transport chain occur in the mitochondria.
The electron transport chain is actually embedded in the cristae membrane.
11. Know the structure of the mitochondrion.
12. Write a summary of glycolysis, Krebs cycle and electron transport chain paying attention to:
a. carbon skeleton
b. NAD+ ---> NADH
c. ATP generated
(all of the information is in these objectives)
13. In the absence of oxygen, organisms undergo fermentation rather than going to Krebs cycle. The 2 major fermentation
products are ethanol and lactic acid (sore muscles). Fermentation only makes 2 ATP per glucose rather than 38 ATP per glucose
so fermentation is very inefficient. The purpose of fermentation is to re-oxidize the NADH to NAD+ which is needed for glycolysis.
Chapter 10: Photosynthesis
1. What form of energy does earth receive from the sun? Into what form of energy does photosynthesis convert it?
2. What are the two thoeries of light? What is the relationship between wavelength and energy in the light?
3. What is the electromagnetic spectrum? Which wavelengths are smaller than we can see (gamma, x-rays and uv)? Which
wavelengths are longer than we can see (infared, microwaves, radiowaves)
4. Chlorophyll and carotenoids are both pigments. What is a pigment? What is an absorbtion spectrum?
5. What happens to a pigments electron(s) when it absorbs light?
What are the three possible consequences of this electronic shift? and which consequence occurs in photosynthesis?
6. Photosynthesis occurs in two stages: the energy capturing reactions and the Calvin Cycle. What are the results of
each of these stages?
7. The energy capturing reactions: What are the two photosystems?
Which one is believed to capture energy first? What are the end results of each of these two photosystems? (Photosystem
I generates ATP through photophosphorylation and photosystem II reduces NADP+ to NADPH)
8. Photosystem II: At what wavelength does its chlorophyll a absorb energy? (remember, its called P680) What happens
to the energy that is absorbed? Where does the electron go? Where did the electron come from? How (Why) are oxygen and
2 protons generated?
9. Photosystem I: At what wavelength does its chlorophyll a absorb energy? (remember its called P700). What happens
to the energy that is absorbed? Where does the electron go? From where did the electron come?
10. Which photosystem is used in cyclic energy flow? What is generated in cyclic energy flow? What is not generated
(relative to photosynthesis using both photosystems)?
11. Photosynthetic phosphorylation: How is it similar to ATP generation by oxidative phosphorylation (in the mitochondria)?
12. How is photophosphorylation different from oxidative phosphorylation?
13. The Calvin Cycle: Each turn of the Calvin cycle reduces one CO2. The overall reaction is written as:
3CO2 + 9ATP + 6 NADPH--> 1 glyceraldehyde 3-phosphate + 9 ADP + 6NADP+
a. What sugar does it start with? (ribulose bisphosphate)
b. What is added to that sugar? (CO2)
c. What happens to the resulting 6 carbon compound? (it immediately splits into two 3-carbon compounds)
d. After several steps there are 2 molecules of glyceraldehyde 3-phosphate (3 carbon compounds)
One glyceraldehyde 3-phosphate leaves the cycle to be joined with another molecule forming glucose (several steps).
The other glyceraldehyde 3-phosphate stays in the cycle and is used to form a new ribulose bisphosphate for the next cycle.
Chapter 11: How Cells Divide
1. Why do single-celled organisms undergo cell division?
2. What are the purposes of cell division in multicellular organisms?
3. Outline cell division in prokaryotes.
4. Why is cell division more complex in eukaryotes than prokaryotes?
5. What does haploid, 1N, diploid and 2N mean? What does gamete, somatic cell and homologous mean? How many chromosomes
do human gametes have? How many chromosomes do human somatic cells have?
6. Know the phases of the eukaryotic cell cycle. What events are occurring during each phase?
7. What is the goal of mitosis?
8. What are the phases of mitosis? Know them by name, know what events are occurring during each phase. Be able to recognize
them in drawings and be able to draw them.
9. Know what the following structures are and their role in mitosis.
a. spindle
b. centrioles
c. centromere
d. kinetochores
e. chomatids
f. microtubules
g. aster
10. What is cytokinesis, when does it occur and how does it occur?
11. Explain what the cell plate is, how it forms and what the middle lamella is.
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