Which of the following statements regarding photosynthesis and cellular respiration is true?
Photosynthesis occurs in chloroplasts, and cellular respiration occurs in mitochondria.
How do cells capture the energy released by cellular respiration?
They produce ATP.
The processes of photosynthesis and cellular respiration are complementary. During these energy conversions, some energy is
lost in the form of heat.
Which of the following are products of cellular respiration?
energy to make ATP and carbon dioxide
C) oxygen and glucose
The overall equation for the cellular respiration of glucose is
C6H12O6 + 6 O2 ? 6 CO2 + 6 H2O + energy.
During cellular respiration, the energy in glucose
is carried by electrons.
During redox reactions,
electrons are lost from one substance and added to another substance.
In biological systems, an important enzyme involved in the regulation of redox reactions is
dehydrogenase.
During cellular respiration, NADH
delivers its electron load to the first electron carrier molecule.
Which of the following options lists the stages in cellular respiration in the correct order?
glycolysis, the citric acid cycle, and oxidative phosphorylation
During which of the following phases of cellular respiration does substrate-level phosphorylation take place?
glycolysis and the citric acid cycle
Which of the following metabolic pathways is common in aerobic and anaerobic metabolism?
glycolysis
As a result of glycolysis there is a net gain of ________ ATPs.
2
After glycolysis but before the citric acid cycle,
pyruvate is oxidized.
The enzymes of the citric acid cycle are located in the
matrix and inner mitochondrial membrane.
The end products of the citric acid cycle include all of the following except
pyruvate.
At the end of the citric acid cycle, most of the energy remaining from the original glucose is stored in
NADH.
During chemiosmosis,
ATP is synthesized when H+ ions move through a channel in ATP synthase.
In the electron transport chain, the final electron acceptor is
an oxygen atom.
Which of the following processes produces the most ATP per molecule of glucose oxidized?
aerobic respiration
Which of the following statements regarding cellular respiration is false?
Cellular respiration is a single chemical reaction with just one step.
The overall equation for the cellular respiration of glucose is
C6H12O6+6O2--->6CO2+6H2O+energy
Oxidation is the ________, and reduction is the ________.
loss of electrons....gain of electrons
During cellular respiration, the energy in glucose
is carried by electrons
During redox reactions,
electrons are lost from one substance and added to another substance.
During cellular respiration, NADH
carries electrons to the electron transport chain in mitochondria.
How many molecules of NADH are produced during glycolysis?
2
Which of the following is a result of glycolysis?
conversion of glucose to two three-carbon compounds
At the end of the citric acid cycle, most of the energy remaining from the original glucose is stored in
NADH
During chemiosmosis,
ATP is synthesized when H+ ions move through a protein port provided by ATP synthase.
In eukaryotes, cellular respiration
harvests energy from food, yields large amounts of ATP, and Uses ATP to drive cellular work.
In photosynthesis
some of the energy in sunlight is captured by chloroplasts, atoms of carbon dioxide and water are rearranged, and glucose and oxygen are produced.
In cellular respiration
glucose is broken down to carbon dioxide and water and the cell captures some of the released energy to make ATP.
Cellular respiration takes place in the
mitochondria of eukaryotic cells.
Respiration, as it relates to breathing, and cellular respiration are not the same
Respiration, in the breathing sense, refers to an exchange of gases. Usually an organism brings in oxygen from the environment and releases waste CO2. Cellular respiration is the aerobic (oxygen requiring) harvesting of energy from food molecules by cells
Cellular respiration is an
exergonic process that transfers energy from the bonds in glucose to form ATP.
Cellular respiration
produces up to 32 ATP molecules from each glucose molecule and captures only about 34% of the energy originally stored in glucose.
The energy necessary for life is contained in
the arrangement of electrons in chemical bonds in organic molecules.
When the carbon-hydrogen bonds of glucose are broken, electrons are transferred to oxygen.
Oxygen has a strong tendency to attract electrons.
An electron loses potential energy when it "falls" to oxygen.
Energy can be released from
glucose by simply burning it. The energy is dissipated as heat and light and is not available to living organisms.
On the other hand, cellular respiration is the controlled
breakdown of organic molecules.
Energy is
gradually released in small amounts,
captured by a biological system, and
stored in ATP.
redox reaction
The movement of electrons from one molecule to another is an oxidation-reduction reaction
redox reaction 2
the loss of electrons from one substance is called oxidation, the addition of electrons to another substance is called reduction, a molecule is oxidized when it loses one or more electrons, and reduced when it gains one or more electrons.
A cellular respiration equation is helpful to
show the changes in hydrogen atom distribution.
Glucose
loses its hydrogen atoms and becomes oxidized to CO2.
Oxygen
gains hydrogen atoms and becomes reduced to H2O.
Enzymes are necessary to
oxidize glucose and other foods.
NAD+
is an important enzyme in oxidizing glucose, accepts electrons, and becomes reduced to NADH.
There are other electron "carrier" molecules that function like NAD+
They form a staircase where the electrons pass from one to the next down the staircase. These electron carriers collectively are called the electron transport chain. As electrons are transported down the chain, ATP is generated.
Stage 1: Glycolysis
occurs in the cytoplasm, begins cellular respiration, and
breaks down glucose into two molecules of a three-carbon compound called pyruvate.
Stage 2: The citric acid cycle
takes place in mitochondria, oxidizes pyruvate to a two-carbon compound, and supplies the third stage with electrons.
Stage 3: Oxidative phosphorylation
involves electrons carried by NADH and FADH2,
shuttles these electrons to the electron transport chain embedded in the inner mitochondrial membrane,
involves chemiosmosis, and generates ATP through oxidative phosphorylation associated with chemiosmosis.
In glycolysis,
a single molecule of glucose is enzymatically cut in half through a series of steps, two molecules of pyruvate are produced, two molecules of NAD+ are reduced to two molecules of NADH, and a net of two molecules of ATP is produced.
ATP is formed
in glycolysis by substrate-level phosphorylation during which an enzyme transfers a phosphate group from a substrate molecule to ADP and ATP is formed.
The pyruvate formed in glycolysis is
transported from the cytoplasm into a mitochondrion where the citric acid cycle and oxidative phosphorylation will occur.
Two molecules of pyruvate are produced for
each molecule of glucose that enters glycolysis.
Pyruvate does not
enter the citric acid cycle, but undergoes some chemical grooming in which a carboxyl group is removed and given off as CO2, the two-carbon compound remaining is oxidized while a molecule of NAD+ is reduced to NADH, coenzyme A joins with the two-carbon gr
The citric acid cycle
is also called the Krebs cycle (after the German-British researcher Hans Krebs, who worked out much of this pathway in the 1930s), completes the oxidation of organic molecules, and generates many NADH and FADH2 molecules.
During the citric acid cycle
the two-carbon group of acetyl CoA is added to a four-carbon compound, forming citrate, citrate is degraded back to the four-carbon compound, two CO2 are released, and 1 ATP, 3 NADH, and 1 FADH2 are produced.
Remember that the citric acid cycle processes
two molecules of acetyl CoA for each initial glucose.
Thus, after two turns of the citric acid cycle,
the overall yield per glucose molecule is 2 ATP,
6 NADH, and 2 FADH2.
Oxidative phosphorylation
involves electron transport and chemiosmosis and
requires an adequate supply of oxygen.
Oxidative phosphorylation 2
Electrons from NADH and FADH2 travel down the electron transport chain to O2. Oxygen picks up H+ to form water.Energy released by these redox reactions is used to pump H+ from the mitochondrial matrix into the intermembrane space.In chemiosmosis, the H+ d
Three categories of cellular poisons obstruct the process of oxidative phosphorylation. These poisons
block the electron transport chain (for example, rotenone, cyanide, and carbon monoxide),
inhibit ATP synthase (for example, the antibiotic oligomycin), or make the membrane leaky to hydrogen ions (called uncouplers, examples include dinitrophenol).
Recall that the energy payoff of cellular respiration involves
glycolysis, alteration of pyruvate, the citric acid cycle, and oxidative phosphorylation.
Lactate
carried by the blood to the liver, where it is converted back to pyruvate and oxidized in the mitochondria of liver cells.
The dairy industry uses lactic acid fermentation
by bacteria to make cheese and yogurt.
Other types of microbial fermentation turn
soybeans into soy sauce and cabbage into sauerkraut.
alcohol fermentation
In this process yeasts (single-celled fungi) oxidize NADH back to NAD+ and convert pyruvate to CO2 and ethanol. The total yield is about 32 ATP molecules per glucose molecule. This is about 34% of the potential energy of a glucose molecule.In addition, wa
Fermentation
a way of harvesting chemical energy that does not require oxygen. Takes advantage of glycolysis,
produces two ATP molecules per glucose, and
reduces NAD+ to NADH. The trick of fermentation is to provide an anaerobic path for recycling NADH back to NAD+.
Your muscle cells and certain bacteria can oxidize NADH
through lactic acid fermentation, in which NADH is oxidized to NAD+ and pyruvate is reduced to lactate.
Obligate anaerobes
are poisoned by oxygen, requiring anaerobic conditions, and live in stagnant ponds and deep soils.
Facultative anaerobes
include yeasts and many bacteria, and can make ATP by fermentation or oxidative phosphorylation.
Although glucose is considered to be the primary source of sugar for respiration and fermentation, ATP is generated using
carbohydrates, fats, and proteins.
Fats make excellent cellular fuel because they
contain many hydrogen atoms and thus many energy-rich electrons and yield more than twice as much ATP per gram than a gram of carbohydrate or protein.
Cells use
intermediates from cellular respiration for the biosynthesis of other organic molecules.
Metabolic pathways are often regulated by
feedback inhibition in which an accumulation of product suppresses the process that produces the product.