Photosynthesis/ Cell Respiration Flashcards
Which of the following statements about exergonic reactions is FLASE?
- ) They release energy
- ) glucose metabolism is an example
- ) their products have more energy than the reactants
- ) some energy is converted to less biologically useful forms
3.) Their products have more energy than the reactants.
Compare light reactions with the Calvin Cycle of Photo in plants.
A. Light reactions alone
B. The Calvin cycle alone
C. Both the light reactions and the Calvin cycle
D. Neither the light reactions nor the Calvin cycle
E. Occurs in the chloroplast but is not part of photosynthesis
Produces NADH: D
Produces molecular oxygen: A
Produces three-carbon sugars: B
Requires ATP: B
During which phase of aerobic respiration is ATP produced directly by substrate-level phosphorylation?
Glycolysis and The Krebs Cycle
What is true for photosynthetic pathways?
They consume energy to build up polymers from monomers.
The final hydrogen acceptor in the noncyclic pathway of ATP formation is…
NADP+
Molecules that can potentially be converted to intermediates of glycolysis and/or the citric acid cycle include…
Amino acids & proteins
Glycerol and fatty acids
Starch and glycogen
For glycolysis to begin,
There must be an input of energy from ATP
The final hydrogen acceptor in the noncyclic pathway of ATP formation is…
NADP+
Molecules that can potentially be converted to intermediates of glycolysis and/or the citric acid cycle include…
Amino acids & proteins
Glycerol and fatty acids
Starch and glycogen
For glycolysis to begin,
There must be an input of energy from ATP
Compare light reactions with the Calvin Cycle of Photo in plants.
A. Light reactions alone
B. The Calvin cycle alone
C. Both the light reactions and the Calvin cycle
D. Neither the light reactions nor the Calvin cycle
E. Occurs in the chloroplast but is not part of photosynthesis
Produces NADH: D
Produces molecular oxygen: A
Produces three-carbon sugars: B
Requires ATP: B
During which phase of aerobic respiration is ATP produced directly by substrate-level phosphorylation?
Glycolysis and The Krebs Cycle
What is true for photosynthetic pathways?
They consume energy to build up polymers from monomers.
What best describes the relationships between photosynthesis and respiration?
Photosynthesis stores energy in complex organic molecule, while respiration releases it
During the noncyclic pathway of photosynthesis,
Hydrogen ions are pumped into the thylakoid compartment
During the noncyclic pathway of photosynthesis,
Hydrogen ions are pumped into the thylakoid compartment
During glycolysis, when glucose is catabolized to pyruvate, most of the energy of glucose is,
Retained in the pyruvate
Inside an active mitochondrion, most electrons follow which pathway?
Citric acid cycle–> NADH–> electron transport chain—> oxygen
What’s not true of photosystem 1?
Electrons from PS 1 return to PS2 when it runs as a cyclic pathway
The highly toxic cyanide poison binds to the last molecule in the electron transfer chain, halting additional electron transfer. What’s the consequence?
Oxygen can’t pick up elections.
No more water will be formed.
No more ATP will be formed.
How many molecules of CO2 would be released from the complete aerobic respiration of a molecule of sucrose (C12H22O11), a disaccharide?
12
What’s not produced in the synthesis (light independent) reactions?
NADPH
In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle, First, though, the pyruvate,
1.) losses a carbon, given off a molecule of Co2
2.) is oxidized to form a two-carbon compound called acetate
3.) is bonded to coenzyme A
These three steps result in the formation of….
Acetyl CoA, NADH, and CO2
(Look at notecard with Citric Acid cycle)
How many molecules of CO2 would be produced by five turns of the CAC?
Starting with one molecule of isocitrate and ending with fumarate, what is the maximum number of ATP molecules that could be produced through substrate-level phosphorylation?
10
1
What is true about NADPH?
It is produced in the light-dependent reactions of photosynthesis.
As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin Cycle in one hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. Where did the extra ATP molecules come from?
Cyclic electron flow
A. Photosynthesis
B. Respiration
C. Both photosynthesis & resp
D. Neither
- )Reduction of NADP+
- )Generation of proton gradients across membranes
- )Synthesis of ATP by the chemiosmotic mechanism
- ) A
- ) C
- ) C
The carbon dioxide acceptor in the Calvin-Benson cycle is….
RuBP
Which statement is false?
- ) The thylakoid membranes contain the photosynthetic pigments
- ) the O2 released during photosynthesis comes from water
- ) RuBP is produced during cyclic electron flow in the light reactions of photosynthesis
- ) the light reactions of photo provide the energy for the Calvin cycle
3.)
In the thylakoid membranes, what is the main role of the antenna pigment molecules?
Harvest photons and transfer light energy to the reaction-center-chlorophyll.
What’s not true in the process of phosphorylation?
It produces ADP from ATP
The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation is….
The difference in H+ concentration on opposite sides of the inner mitochondrial membrane
What’s true about the light reactions of photosynthesis?
The splitting of water molecules provides a source of e-
Chlorophyll absorbs light energy, excites e-
ATP is generated by photophosphorylation
A young relative of yours has never had much energy. He goes to a doctor for help and is sent to the hospital for some tests. There they discover his mitochondrion can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. What’s the explanation of his condition?
His mitochondrion lack the transport protein that moves pyruvate across the outer mitochondrial membrane
Some photosynthetic organisms contain chloroplasts that lack PS2, yet are able to survive. The best way to detect the lack of PS2 would be…
To test for liberation of O2 in the light
The primary role of oxygen in cellular respiration is to….
Act as an acceptor for e- and H+ forming water
Cellular respiration
Is a mechanism of tapping the energy found in the bonds between atoms in organic compounds.
The primary function of the mitochondrion is the production of ATP. To carry out this function, the mitochondrion mustn’t have….
Enzymes for glycolysis
If anaerobic pathways follows glycolysis,
The two NADH molecules produced as pyruvate is converted to lactate
Which kind of metabolic poison would most directly interfere with glycolysis?
An agent that closely mimics the structure of glucose but is not metabolized
What’s the relationships between the light reactions and the Calvin Cycle?
The light reactions provide ATP and NADPH to the Calvin Cycle, and the Calvin cycle returns ADP, Pi, and NADP+ to the light reactions
Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which process?
The synthesis of ATP
What describes an Electron transfer chain?
It transfers energy, stepwise, from one compound to another
What doesn’t match the starting materials?
Formation of acetyl CoA:
Citric acid, CO2, NADH
When individuals have mitochondrial disorders, why are the skeletal and heart muscles and the brain most often affected? They….
Have the highest energy need
Substrate-level phosphorylation
Occurs during glycolysis
What best describes the results of this reaction?
C6H12O2—>6O2+6H2O+ energy
C6H12O6 is oxidized, and O2 is reduced
A high concentration of
H+ in the thylakoid compartment provides energy for the _____ by _____.
Production of ATP; ATP synthesis
Co2 is released during which of the following stages of cellular respiration?
Oxidation of pyruvate to acetyl CoA and the citric acid cycle
Trace the path of a single electron through the noncyclic electron pathway by putting the following in order:
- ) the e- is excited in PS1
- ) the e- is passed to the plastiquinone pool
- ) the e- is excited into PS2
- ) the e- is released from water and added to the PS
- ) a proton gradient is generated by the cytochrome complex as the e- arrives and then departs
- ) the e- is transferred to NADP+
4,3,2,5,1,6
There are eight total steps in the CAC, and pyruvate is completely oxidized in steps three and four. What is the purpose of the last four steps?
To regenerate oxaloacerate to attach another acetate molecule.
We study cellular respiration b/c it is one of the most important pathways in biology. In fact, nearly all carbohydrates at some point in their catabolism are directed through cellular respiration. Why is it NOT necessary to have multiple independent pathways to break down different molecules?
The molecules that are degraded are all structurally similar and relatively easily interconverted.
Oxygen is able to allow e- of a very low energy level to combine with it at the end of cellular respiration and ultimately make water. How are the specific properties of oxygen beneficial to the organism that uses it as a final e- acceptor?
Oxygen is strongly electronegative and helps pull the e- through the electron transport China
You have a friend who lost 7kg(about 15 lb) of fat on a “low carb” diet. How did the fat leave her body?
It was released as CO2 and H2O
Why does NADH produce more energy that FADH+?
NADH donates electrons to a higher energy acceptor in the electron transfer chain.
Plants that fix CO2 into organic acids at night when the stomata are open and carry out the Calvin Cycle during the day when the stomata are closed are called….
CAM plants
