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Photosynthesis converts light energy into chemical energy through a series of reactions known as
What is the beginning of the light reactions of photosynthesis?
The absorption of light by chlorophyll a and accessory pigments in the thylakoids.
In the light reactions, excited electrons that leave chlorophyll a travel along...
...two electron transport chains.
In the light reactions, the excited electrons leave chlorophyll a and travel along two electron transport chains, resulting the the production of...
In the light reactions, the electrons are replaced when water is split into electrons, protons, and oxygen in the...
(In the light reactions) As electrons travel along the electron transport chains, protons move into the thylakoid and build up a...
(In the light reactions) The movement of protons down the concentration gradient of protons and through ATP synthase results in the...
...synthesis of ATP through chemiosmosis.
What drives the second stage of photosynthesis (the Calvin cycle)?
The ATP and NADPH produced in the light reactions
In the Calvin cycle, CO2 is incorporated into organic compounds, a process called...
Some G3P molecules are used to make other organic compounds, including:
amino acids, lipids, and carbohydrates.
Plants that evolved in hot, dry climates fix carbon through what alternative pathways?
the C4 and CAM pathways
Plants that use the C4 and CAM pathways to fix carbon carry out carbon fixation and the Calvin cycle either...
...in different cells or at different times.
What happens in the light reactions stage of photosynthesis?
Energy is absorbed from sunlight and converted into chemical energy.
What happens during the Calvin cycle (stage of photosynthesis)?
Carbon dioxide and chemical energy are used to form organic compounds.
The rate of photosynthesis increases as then reaches a plateau as...
...light intensity of CO2 increases.
What is cellular respiration?
The process by which cells break down organic compounds to produce ATP.
What happens during glocolysis?
One glucose molecule is oxidized to form two pyruvic acid molecules.
If oxygen is not present, glycolysis may lead to anaerobic pathways. What happens in the anaerobic pathways?
Pyruvic acid is converted into other organic molecules in the cytosol.
Through glycolysis, what percent of the energy available from the oxidation of glucose is captured as ATP?
Only about 2 percent.
What happens in the mitochondrial matrix during aerobic respiration?
Pyruvic acid produced in glycolysis is converted into acetyl CoA.
In aerobic respiration, what happens after the pyruvic aside is converted into acetyl CoA?
Then, acetyl CoA enters the Krebs cycle.
What do the NADH and FADH2 do in aerobic respiration?
They donate electrons to the electron transport chain in the inner mitochondrial membrane. (These electrons are passed from molecule to molecule in the transport chain).
In aerobic respiration, what happens as electrons pass along the electron transport chain?
Protons donated by NADH and FADH2 are pumped into the space between the inner and outer mitochondrial membranes.
In aerobic respiration, what does the pumping of protons between the inner and outer mitochondrial membranes create?
A concentration gradient of protons and a charge gradient across the inner mitochondrial membrane.
In aerobic respiration, what happens as protons move through ATP synthase, down their concentration and charge gradients and back into the mitochondrial matrix?
ATP is produced.
During aerobic respiration, oxygen accepts both protons and electrons from the electron transport chain. What happens as a result of this?
Oxygen is converted to water.
About how many ATP molecules can cellular respiration produced from the oxidation of the single molecule of glucose?
Up to 38 ATP molecules
About what percent of the energy released by the oxidation of glucose can be transferred to ATP?
Up to 39% percent
Most eukaryotic cells produce about how many ATP molecules per molecule of glucose?
About 36 ATP molecules
What processes does cellular respiration use to obtain energy from organic compounds?
The processes of glycolysis and aerobic respiration
Name 3 life processes that use energy.
photosynthesis, anaerobic respiration and aerobic respiration
What happens to a chlorophyll molecule that absorbs light energy?
Some of the electrons move to a higher level.
In cellular respiration, the most ATP is generated during the...
...aerobic respiration (electron transport chain)
What happens during photosynthesis?
Light is converted into chemical energy, which is stored in the glucose molecule.
What happens during cellular respiration?
The energy stored in glucose is released, and the cell produces the energy molecule known as ATP.
The formation of glucose during photosynthesis takes place in 2 major steps known as:
The light and dark reactions
In the light reactions, hydrogen atoms combine with molecules of the coenzyme NADP to form...
...NADPH + H+ (which is needed in the dark reactions).
The Calvin cycle begins when 3 carbon dioxide molecules combine with 3 molecules of a 5-carbon compound (RDP), resulting in:
three 6-carbon compound molecules that are unstable and break to form six 3-carbon compound molecules called PGA.
In the Dark Reactions, hydrogen from the light reactions combines with PGA to form six new 3-carbon compounds called...
In the Dark reactions, three carbon dioxide molecules enter at the start of the cycle to be following by...
...an additional three molecules of carbon dioxide.
An easy way to understand the Calvin cycle is to..
....follow the number of carbon atoms around the cycle.
Molecules of PGAL can combine and reorganize to form additional RDP molecules, or two PGAL molecules can combine to form...
In photosynthesis, the coenzyme NADP transfers hydrogen and electrons from...
...light to dark reactions.
The breakdown of glucose during cell respiration requires two series of reactions, known as...
...anaerobic and aerobic respiration.
In anaerobic respiration, 2 molecules of ATP are used to break glucose (glycolysis) into 2 3-carbon compounds called...
In anaerobic respiration, how many molecules of ATP are produced by each pyruvate?
2 molecules of ATP are produced for each pyruvate (for a total of 4 ATP molecules).
During anaerobic respiration, how many ATP are gained?
2 ATP are gained (4 ATP produced minus the 2 ATP used to break glucose).
In anaerobic respiration, the hydrogen atoms lost by PGAL combine with molecules of the coenzyme NAD to form...
...NADH + H+ where they are needed for aerobic respiration).
What happens in fermentation?
Glucose is broken down to form 2 pyruvate molecules, each of which is further broken down into the alcohol ethanol.
How is fermentation important in industry?
The brewing industry uses ethanol for a variety of alcoholic beverages, and the baking industry uses CO2 to make dough rise.
In the Krebs cycle (aerobic respiration), each pyruvate loses a carbon atom to form...
...carbon dioxide and acetate (a 2-carbon compound) that combines with coenzyme A to form acetyl CoA.
As a result of going around the Krebs cycle twice (once for each acetyl CoA) and the accompanying electron transport system, how many ATP are produced?
34 ATP are produced.
In aerobic respiration, the hydrogen atoms from anaerobic respiration combine with oxygen, the final hydrogen acceptor to form...
In aerobic respiration, if oxygen is not available, pyruvate form...
...lactic acid (takes place in muscles and is reversible when oxygen becomes available).
In cellular respiration, glucose is broken down to produce...
...energy (ATP), carbon dioxide, and water.
In photosynthesis, glucose and oxygen are produced using...
...light energy, carbon dioxide, and water.
Why are 2 molecules of ATP needed to start the process of anaerobic respiration?
To break the glucose molecule and start the process of anaerobic respiration.
What is fermentation?
A form of anaerobic respiration performed by yeast. Glucose is broken down to yield ethanol, carbon dioxide, and ATP.
How can a yeast call survive with only a gain of 2 ATP from a anaerobic respiration?
Yeast cells are small microscopic organisms and do not require more than 2 ATP. Humans are large organisms and require the additional ATP that can be released from pyruvate by the addition of oxygen during aerobic respiration.
How much ATP is gained during anaerobic respiration?
2 ATP are gained during anaerobic respiration. (2 ATP are used to break glucose into pyruvate, producing 4 ATP).
How much ATP is gained during aerobic respiration?
34 ATP are gained during aerobic respiration. (2 ATP from Krebs cycle and 32 ATP from the electron transport system).
Which process is more efficient, anaerobic or aerobic respiration?
Aerobic respiration is more efficient than anaerobic respiration. Anaerobic respiration produces a gain of only 2 ATP. Aerobic respiration produces a gain of 34 ATP by completely breaking down pyruvate. If the ATP gained by the two processes is added, the total gain is 36 ATP for all cellular respiration.
How is cellular respiration different from photosynthesis?
In cellular respirtion, glucose is broken down into carbon dioxide and water to release the energy )ATP) that is stored in this molecule during its formation by photosynthesis. Cellular respiration takes place at and in the mitochondria in 2 steps, called anaerobic and aerobic respiration. All organisms perform respiration all the time. Photosynthesis takes place in green plants and green algae but only during light hours. Photosynthesis requires carbon dioxide, water, and light energy to be converted into glucose in 2 series of reactions called the light and dark reactions.
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