2.8: Cell Respiration

Terms in this set (23)

Define "cell respiration."



Understanding: Cell respiration is the controlled release of energy from organic compounds to produce ATP.
Cellular respiration is a series of metabolic reactions that convert biochemical energy from organic molecules into adenosine triphosphate (ATP), and then release waste products.
State the reaction for cellular respiration.



Understanding: Cell respiration is the controlled release of energy from organic compounds to produce ATP.
Cellular respiration is the chemical reaction in which glucose and oxygen are turned into water, carbon dioxide, and ATP energy. In the reaction, glucose and oxygen are reactants, while water, carbon dioxide, and energy (ATP) are products.
State the types of organic compounds used in cellular respiration by animals and plants.



Understanding: Cell respiration is the controlled release of energy from organic compounds to produce ATP.
The main organic compound used for cellular respiration is the carbohydrate glucose, although lipids and proteins can also be used if glucose is not readily available to the cell.
State three example uses of ATP in the cell.



Understanding: ATP from cell respiration is immediately available as a source of energy in the cell.
ATP is an energy-rich molecule that can be used throughout the cell to *power active transport, synthesize polymers , and move structures within the cell. In addition, many enzymes require ATP to catalyze reactions within the cell that would otherwise proceed very slowly.
Outline energy transfer in the formation and use of ATP.



Understanding: ATP from cell respiration is immediately available as a source of energy in the cell.
Energy is released when a phosphate group is removed from ATP in a hydrolysis reaction.

The reverse reaction (which is what happens in cellular respiration) regenerates ATP and requires energy input.
Outline the role of NADH in cellular respiration.



Understanding: ATP from cell respiration is immediately available as a source of energy in the cell.
The NADH molecule is an electron carrier. In cellular respiration, electrons are removed from glucose and transferred to other molecules.
State reasons why cellular respiration must be continuously performed by all cells.
1. ATP can not be stored for later use.

2. ATP can not be transferred from cell to cell.

3. When ATP is used in cells heat energy is released. This heat energy can not be reused and will be lost to the environment.
Outline how the structure of ATP relates to its function.



Understanding: ATP from cell respiration is immediately available as a source of energy in the cell.
ATP is an RNA nucleotide with three phosphates. Ribose is attached to the nitrogenous base adenine and to the chain of three phosphates.

ATP is made unstable by the three adjacent negative charges in the phosphates, which "want" to get away from each other. Energy is released when one of these bonds is broken in a hydrolysis reaction.
Define "anaerobic respiration."



Understanding: Anaerobic cell respiration gives a small yield of ATP from glucose.
Anaerobic respiration is a type of cellular respiration that does not use oxygen.
List situations in which anaerobic respiration is useful.



Understanding: Anaerobic cell respiration gives a small yield of ATP from glucose.
Anaerobic respiration can act as a backup when cellular oxygen is depleted. For example, when muscle cells use up oxygen faster than it can be replenished, the cells start to perform anaerobic respiration in order to keep muscles moving.

Anaerobic respiration is used when ATP is needed quick, because anaerobic respiration is more rapid than aerobic respiration.

Anaerobic metabolism allows microbes to inhabit low-oxygen or oxygen-free environments which allows them to exploit an otherwise empty habitat.
Outline the anaerobic respiration reaction performed by yeasts.



Understanding: Anaerobic cell respiration gives a small yield of ATP from glucose.
First, in glycolysis, glucose is broken down to pyruvate and NADH and ATP are created.

Then, in alcohol fermentation, pyruvate is converted to ethanol. Carbon dioxide is released and NADH is recycled into NAD+.

The reaction nets two molecules of ATP.
Outline the anaerobic respiration reaction performed by humans.



Understanding: Anaerobic cell respiration gives a small yield of ATP from glucose.
First, in glycolysis, glucose is broken down to pyruvate and NADH and ATP are created.

Then, in lactic acid fermentation, pyruvate is converted to lactic acid. NADH is recycled into NAD+.

The reaction nets two molecules of ATP.
State the location of anaerobic respiration in the cell.



Understanding: Anaerobic cell respiration gives a small yield of ATP from glucose.
Anaerobic respiration occurs in the cell cytoplasm.
Compare the total amount of ATP made from anaerobic and aerobic respiration.



Understanding: Aerobic cell respiration requires oxygen and gives a large yield of ATP from glucose.
Anaerobic respiration produces a net of 2 ATPs per molecule of glucose.

Aerobic respiration produces up to 38 ATPs per molecule of glucose.
State the location of aerobic respiration in the cell.



Understanding: Aerobic cell respiration requires oxygen and gives a large yield of ATP from glucose.
Aerobic respiration occurs in the cell mitochondria.
Outline how anaerobic respiration in yeast is used in baking and brewing.



Application: Use of anaerobic cell respiration in yeasts to produce ethanol and carbon dioxide in baking.​
Anaerobic respiration in yeast is used during brewing and bread-making:

glucose → ethanol + carbon dioxide

Ethanol is the alcohol found in alcoholic drinks like beer and wine. In bread-making, bubbles of carbon dioxide gas expand the dough and help the bread rise.
Outline how anaerobic respiration in yeast is used to make ethanol bio-fuel.



Application: Use of anaerobic cell respiration in yeasts to produce ethanol and carbon dioxide in baking.​
Bioethanol is a fuel produced by yeast alcohol fermentation of sugarcane or corn in large scale fermentors.

Enzymes are used to break down starch and cellulose into glucose and then yeast carry out anaerobic respiration using the glucose; producing ethanol.
State the condition in which humans would perform anaerobic respiration.



Application: Lactate production in humans when anaerobic respiration is used to maximize the power of muscle contractions.
When exercising at high intensity, cell demand will exceed available supplies of O2. Muscle cells will start breaking down glucose anaerobically to supply ATP rapidly for a short period of time.

Red blood cells do not have mitochondria, so anaerobic respiration always happens.
​Outline production of lactate in humans during anaerobic respiration.



Application: Lactate production in humans when anaerobic respiration is used to maximize the power of muscle contractions.
In lactic acid fermentation NADH produced in glycolysis transfers its electrons directly to pyruvate, generating lactate as a byproduct.
Define "respirometer."



Skill: Analysis of results from experiments involving measurement of respiration rates in germinating seeds or invertebrates using a respirometer.
A respirometer is any measuring tool used to determine the cellular respiration rate of an organism by measuring the rate use of O2 or production of CO2.
Outline the use of a respirometer to measure cellular respiration rate.



Skill: Analysis of results from experiments involving measurement of respiration rates in germinating seeds or invertebrates using a respirometer.
The living specimen (i.e. germinating seeds or invertebrate) is enclosed in a sealed container.

Oxygen use or carbon dioxide production can be measured directly with a data logger.

Alternatively, changes in pressure can be measured. If KOH is included in the sealed container, the CO2 that is produced during cellular respiration will combine with it to form a solid precipitate (K2CO3), removing CO2 gas from the container. Since O2 is being used up and CO2 gas is precipitating, there is less gas in the system and the pressure will decrease. The change in pressure can be measured with a data logger or U-tube manometer.
*State how changes in CO2 and/or O2 levels can be measurements of cellular respiration."



Skill: Analysis of results from experiments involving measurement of respiration rates in germinating seeds or invertebrates using a respirometer.
Increasing carbon dioxide levels indicates an increase in respiration (CO2 is a product of aerobic respiration and alcohol fermentation).

Decreasing oxygen levels indicate an increase in respiration (O2 is a requirement for aerobic respiration).
List ethical questions that must be considered before using animals in experiments.
One of the important issues in scientific research is to consider ethics in animal experimentation. Regulations and guidelines govern the use of animals, including:.

1. The purpose of the experiment must have some benefit.

2. Overall use of animals should be minimized. Alternative methods should be used if available.

3. Pain and distress must be minimized.
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