-
What is the primary source of energy of cell
metabolism?
The sun
-
What do the terms oxidation and reduction refer
to?
- Oxidation is the loss of electrons. Reduction is
- the gain of electrons
-
What kind of reactions are responsible for
metabolism? What catalyzes these reactions? What happens to the electrons
involved?
- Metabolism is a series of exergonic, redox
- reactions catalyzed by enzymes. High energy electrons are transferred to
- low-energy states
-
Describe the process of a redox reaction.
- A high electron donor (reducing agent) is
- oxidized when it transfers electrons to an electron acceptor (oxidizing agent)
-
What are the electron donors involved in cell
respiration? What are they oxidized to? For photosynthesis?
- Organic molecules are oxidized to CO2 in
- respiration. In photosynthesis, H20 is oxidized to O2
-
What are the electron acceptors involved in cell
respiration? What are they reduced to? For photosynthesis?
- O2 is reduced to H2O in respiration. In photosynthesis,
- CO2 is reduced to macromolecules
-
What is the organelle responsible for
photosynthesis? What is the primary product of photosynthesis? What is the
byproduct of this process?
Chloroplasts; ATP; Oxygen
-
What organelle is responsible for respiration?What is the primary product of respiration? What is the byproduct?
Mitochondria; ATP; H2O
-
What is the electron carrier of photosynthesis?
Respiration?
NADPH (think of P for plants); NADH
-
What in metabolism drives ATP synthesis? What sets this up?
- H+ gradient; electron transport chain sets up
- the H+ gradient
-
Photosynthesis and respiration are similar in
that both use an ___________
(exergonic/endergonic) step-wise energy release from ________ (high/low)
energy electrons to drive synthesis.
Exergonic, endergonic
-
What is the primary source of energy in
photosynthesis? In respiration?
Light energy; chemical energy
-
What is broken down by respiration? What is
released?
Organic molecules; ATP and Heat
-
What is the electron receptor in aerobic
respiration?
Oxygen
-
What is the difference between aerobic
respiration and anaerobic respiration?
- Aerobic respiration uses oxygen and anaerobic
- respiration does not use oxygen
-
What is a predominant source of chemical energy?
- Molecules with lots carbon and hydrogen (organic
- molecules)
-
What happens when electrons are transferred?
- Energy is released which is used to do work and
- make ATP
-
What kinds of organisms make use of aerobic respiration?
- Both prokaryotes and eukaryotes, most large
- organisms, humans
-
Why aren’t electrons directly released to reduce
oxygen? How are they released?
- The direct combination would be explosive.
- Instead, electrons are passed down an electron transport chain from NADH to
- oxygen in a stepwise function. Potential energy is lost along the way.
-
How many molecules of ATP are produced from one
glucose molecule in aerobic respiration?
30-38 ATP
-
What are the four different steps of aerobic
respiration? What is the basic function of
- Glycolysis – 6 carbon glucose molecule is broken
- down into two 3-carbon molecules; pyruvate oxidation – 3-carbon molecule
- oxidized to 2-carbon molecule and CO2 is exhaled; citric acid cycle – 2-carbon
- molecule made into CO2; electron transport chain – electrons from previous 3
- steps used to drive ATP synthesis, O2 accepts final electron to form H2O
-
Where do the different steps of aerobic
respiration take place?
- Glycolysis happens in the cytosol, the others
- take place within the mitochondria
-
What sources of chemical energy are used as
electron receptors in respiration?
NAD+/NAHD, FAD/FADH2, ADP/ATP
-
What do the energy molecules NADH and FADH2
stand for?
- Nicotinamide adenine dinucleotide; flavin
- adenine dinucleotide
-
What happens in the investment stage of
glycolysis?
- A glucose molecule is phosphorylated twice by
- ATP and becomes fructose biphosphate. The fructose biphosphate is then split
- into two phosphorylated 3-carbon molecules
-
What are the products from the investment phase
of glycolysis? Which one is used further? What happens with the other one?
- Dihydroxyacetone phosphate and Glyceraldehyde
- 3-phosphate (G3P). G3P is used further; Isomerase can convert dihydroxyacetone
- phosphate into G3P as the equilibrium shifts
-
What happens in the energy payoff phase of
glycolysis?
- Glyceraldehyde 3-phosphate dehydrogenase (GAPDH)
- catalyzes the removal of electrons to form NADH from NAD+ and phosphorylate
- G3P. Phosphoglycerate kinase then catalyzes the transfer of a phosphate group
- to ADP to form ATP. Pyruvate kinase then transfers the second phosphate group
- to another ADP to form another ATP molecule
-
What is the final product from the energy payoff
phase of glycolysis? What is it’s chemical composition? How many ATP molecules
are produced from the process?
Pyruvate; a carboxyl, , and hydrocarbon; 2
-
Is glycolysis a net endergonic or exergonic
process?
Exergonic, although parts of it are endergonic
-
What happens in the pyruvate oxidation phase?
- It enters the mitochondria. The carboxyl group
- is removed to form CO2 and electrons are removed to form NADH. The acetyl group
- then attaches to the sulfur atom of coenzyme A
-
Citrate acid is formed when what two molecules
come together?
- Acetyl (after shedding COA) and 4-carbon
- oxaloacetate
-
What happens to the carbon molecules of citrate
acid as it moves through the citric acid/krebs cycle?
- 2 carbons are removed as CO2 and 4-carbon
- oxaloacetate is reformed
-
What happens to electrons of the citrate acid
molecule as it passed through the citric acid/Krebs cycle?
- They are removed to form 3 NADH molecules and 1
- FADH2 molecule
-
CoA is removed at the beginning of the citric
acid/Krebs cycle but reappears later in the cycle. What does it attach to and
why does it reappear?
- It attached to 4-carbon succinyl to aid in
- phosphorylation and help form ATP or GTP
-
What products and how many of each are produced
in the citric acid/Krebs cycle?
3 NADH, 1 FADH2, 1 ATP or GTP, 2 CO2
-
How are fats transformed into energy?
- 2 carbons are removed from the fatty acid which
- are then turned into an acetyl group in a process that also yields NADH and
- FADH2. The acetyl group then attaches to CoA and enters the citric acid/Krebs
- cycle.
-
Why do fats have high caloric content?
- They contain lots of carbon and can make lots of
- acetyl groups which then go on to be processed and create energy in the citric
- acid/Krebs cycle
-
What is the net change in free energy from the
respiration of one glucose molecule? Order steps from most energy to least
energy used
- About -700; Citric acid cycle, pyruvate
- oxidation, glycolysis
-
Where do the different phases of respiration
take place?
- Glycolysis takes place in the cytosol, pyruvate
- oxidation and citric acid/Krebs cycle take place in the matrix of the
- mitochondria, electron transport chain takes place in the cristae of the
- mitochondria
-
What is the electron transport chain in
respiration made from and where is it located?
- It is a chain of proteins located on the inner
- mitochondrial membrane (cristae)
-
What molecules donate electrons to the electron
transport train in respiration? Where are they delivered to? What happens to
them?
- NADH and FADH2; membrane proteins; they are
- energized to perform active transport a proton against the gradient
-
Where does a high proton concentration
accumulate during cellular respiration?
In the intermembrane space of the mitochondria
-
What membrane proteins are mostly responsible
for the transport of electrons in respiration?
Cytochromes and others that contain iron
-
What acts as the final electron acceptor in
cellular respiration and what does it form once it accepts the electrons?
O2->H2O
-
What is the process of chemiosmosis and what
does it do in respiration? What aids in this process and what is this made
from?
- Chemiosmosis is the facilitated diffusion of
- protons back into the mitochondrial matrix and results in ATP production. ATP,
- made from about 10 proteins, synthase is what helps the proton diffuse.
-
What are the byproducts of each of the steps in
cellular respiration?
- Glycolysis = 1 ATP and 1 NADH, Pyruvate
- oxidation = 1 NADH and 1 CO2, Citric Acid Cycle = 3 NADH, 1 FADH2, 1 ATP, 2
- CO2, Oxidative Phosphorylation = 15 ATP
-
Where does ATP synthase occur in PROKARYOTES?
On the Cell membrane using an ion gradient
-
What is anaerobic respiration? Where does it
occur? How is it similar/different than aerobic respiration?
- Respiration without O2; prokaryotes; similar to
- aerobic respiration but just with a different final electron acceptor
-
What is fermentation?
- It is a process to make ATP that includes only
- glycolysis and sometimes pyruvate oxidation. It makes much less ATP than respiration
- because it only includes substrate level phosphorylation
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