CH. 7 Sapling HW

When a person is sprinting, the person's muscle cells will begin using anaerobic respiration in addition to keeping the mitochondria respiring aerobically as much as the oxygen supple will allow. What benefits do muscle cells gain from anaerobic respiration in this situation?

- adding electrons from NADH to pyruvate regenerates NAD+, so that glycolysis can continue, and produces lactic acis, a waste product that can diffuse out of the cell - without using oxygen, the cell generates two ATP molecules that can keep the muscles moving for every glucose molecule that enters glycolysis

Gylcolysis is a step in the breakdown of glucose. Which of the following statements describe gylcolysis?

- it is common to aerobic and anaerobic respiration - it breaks down glucose to two pyruvate molecules

The pyruvic acid from glycolysis can be converted to acetic acid, which can enter the citric acid cycle. Because this process is a cycle, the atoms entering the cycle must balance the atoms that leave. Consider carbon balance in the citric acid cycle. How many CO2 molecules leave the cycle for each acetic acid molecule that enters? For this question, assume that carbon only enters as acetic acid and exits as CO2. Note that acetic acid has two carbon atoms. You can determine the number of carbon atoms in carbon dioxide from its formula, CO2.

2 CO2 atoms

During glycolysis, glucose is broken down into two molecules of pyruvic acid. How many carbon atoms are in each pyruvic acid molecule?

3 carbon atoms

Using the above answer, how many molecules of CO2 are directly generated by the citric acid cycle from 2 molecules of acetic acid? Again, in this question assume that carbon only enters as acetic acid and exits as CO2.

4 CO2 atoms

A product that can be used directly for energy

ATP

The direct energy source for glycolysis

ATP

Which molecule is used as the primary source of chemical energy for tasks within a cell?

ATP

Cellular respiration is carried out in the presence of oxygen (aerobic conditions) or the absence of oxygen (anaerobic conditions). Determine whether each of the following occur under aerobic conditions, anaerobic conditions, or both aerobic and anaerobic conditions

Aerobic Conditions: - citric acid cycle (Krebs cycle) - electron transport chain Anaerobic Conditions: - fermentation Both: - glycolysis

Identify compounds that are required for the electron transport chain and compounds that are produced by the electron transport chain.

Compounds that enter the electron transport chain: - NADH - FADH2 - O2 - ADP Compounds produced by the electron transport chain: - NAD+ - FAD - H2O - ATP

What disrupts cellular respiration by destroying the proton gradient in the mitochondrion?

DNP (diet pill)

Compare and contrast lactic acid fermentation and ethanol fermentation (alcohol fermentation).

Ethanol Fermentation: - used by yeast cells - generates ethanol Lactic Acid Fermentation: - used by animal cells - produces lactic acid (lactate) Both: - occurs under anaerobic conditions - regenerates NAD+ that can be used in glycolysis

T/F An ATP molecule contains the nitrogenous base guanine

False

T/F An ATP molecule contains three AMP molecules

False

T/F High-energy phosphate bonds in ATP link the phosphate groups and the base adenine

False

Place the steps of glycolysis in the order that they occur

First Step - glucose is converted to glucose-6-phosphate by hexokinase - phosphoenolpyruvate is converted to pyruvate - fructose-6-phosphate is phosphorylated by phosphofructokinase - 3-phosphoglycerate is formed -glyceraldehyde-3-phosphate is converted to 1, 3 bisphosphoglycerate - aldolase cleaves the six-carbon sugar into two three-carbon sugars Last Step

A product that donates electrons to the electron transport chain

NADH

T/F ATP contains ribose, a five-carbon sugar

True

T/F ATP has three phosphate groups

True

T/F ATP is a nucleotide containing a base, a sugar, and phosphate groups

True

Identify the oxidized substance, the reduced substance, the oxidizing agent, and the reducing agent in the following redox reaction: Fe(s) + Cu2+(aq) --> Fe2+(aq) + Cu(s)

Which substrate gets oxidized - Fe Which substrate gets reduced - Cu2+ What is the oxidizing agent - Cu2+ What is the reducing agent - Fe

In general, what happens during an oxidation-reduction reaction between two molecules?

an atom in the reduced molecule attracts an electron that an atom in the oxidized molecule donates

What disrupts cellular respiration by stalling the conversion of pyruvate to acetyl-CoA?

arsenic

Breakdown of glucose to pyruvate

cytosol

Anaerobic respiration allows a cell to break down carbohydrates in the absence of oxygen. Identify how NAD+ is used by animal cells during anaerobic respiration.

during fermentation, NAD+ is generated from NADH and is used to continue glycolysis

Amino acids can be used as fuel during cellular respiration once the nitrogen-containing amine groups have been removed from them. When do amino acids that have had their amine groups removed enter the pathways of cellular respiration?

during the Krebs cycle or during glycolysis

Cytochromes are critical participants in the electron transport chains used in photosynthesis and cellular respiration. How do cytochromes donate and accept electrons?

each cytochrome has an iron-containing heme group that accepts electrons and then donates the electrons to a more electronegative substance

The electron transport chain uses the transfer or __________ between protein complexes to set up a proton gradient.

electrons

A proton gradient is formed in the mitochondria such that the concentration of protons (H+) is higher on one side of the inner mitochondrial membrane than on the other side. What is the purpose of this proton gradient?

generates ATP in the electron transport chain

A carbohydrate that enters glycolysis directly

glucose

Which of the following describes the effect of cyanide on cellular respiration?

inhibits the function of cytochrome c oxidase in the electron transport chain

What is the function of the proton gradient in the mitochondria?

it is potential energy that the cell uses to generate ATP

What disrupts cellular respiration by stalling the electron transport chain?

low oxygen

Citric acid cycle

mitochondrial matrix

Conversion of pyruvate to acetyl-CoA

mitochondrial matrix

The majority of ATP is generated

mitochondrial membrane

Cellular respiration cnsumes glucose during glycolysis. What product of glycolysis can be subsequently modified to enter the citric acid cycle under aerobic conditions?

pyruvate

An end product that is modified to enter the citric acid cycle

pyruvic acid

Pyruvate is a product of glycolysis and is subsequently converted to acetyl-CoA. Acetyl-CoA is a substrate for the citric acid cycle (CAC). Exactly how many molecules of glucose must be oxidized in glycolysis to provide the input for tour turns of the CAC?

two

Although the path of one glucose molecule through glycolysis generates a total of four ATP molecules, there is a net gain of only two ATP for each glucose molecule that enters the pathway. Why does the passage of one glucose molecule through glycolysis have a payoff of only two ATP molecules?

two ATP molecules are used in the initial phase of glycolysis, reducing the net gain of two ATP