Biology CSF Chapter 7 HW

Electron carrier molecules transfer electrons between metabolic pathways. Choose the electron carriers that transfer electrons from glycolysis to the electron transport chain and from the citric acid cycle to the electron transport chain. One of the molecules will be place more than once and one answer box will have two molecules.

(a) NADH (b) FADH2 NADH

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

- NADH - ATP - Phospholipids - Sucrose

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

- lactic acid - NADH - ADP - acetyl-CoA - pyruvate

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

An iron-containing heme group located on each cytoshrome accepts electrons and then donates the electrons to a more electronegative neighbor.

An ATP molecule contains one ADP molecule and one AMP molecule. T/F

False

Which of the following is true based on the phylogenetic trees depicted?

Only tree 4 shows a different evolutionary pattern

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

True

ATP has three phosphate groups. T/F

True

Carbon dioxide (CO2) is one of the products of the citric acid cycle, or Krebs cycle. Click on an arrow in the diagram below that coincides with a step at which CO2 is produced. Use the cellular respiration lab to help you answer the question.

a-ketoglutarate ----> Succinyl

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: -Electron transport chain -Citric Acid Cycle (Krebs cycle) Both: - Glycolysis Anaerobic Conditions: - Fermentation

Use the cellular respiration lab to answer the following questions. Why does disruption of oxidative phosphorylation also disrupt other cellular processes? (a) Why does arsenic and limited oxygen result in fermentation? (b)

(a) Oxidative phosphorylation generates ATP, which is required for many cellular processes. (b) Arsenic prevents acetyl-CoA formation, whereas limited oxygen disables the electron transport chain.

Glycolysis is a step in the breakdown of glucose. Which of the following statements describe glycolysis?

- It occurs only when an animal is breathing - It produces a net gain of two ATP and two NADH - It is common to aerobic and anaerobic respiration - It occurs in a cell's mitochondria

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. (a) Using the above answer, how many molecules of CO2 are directly generated by the citric acid cycle from 3 molecules of acetic acid? Again, in this question assume that carbon only enters as acetic acid and exits as CO2. (b)

(a) 2 CO2 (b) 6 CO2

Identify compounds that are required for the electron transport chain compounds that are produced by the electron transport chain. Not all the potential reactants or products are given. Place all the compounds.

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

Compare and contrast lactic acid fermentation and ethanol fermentation (alcohol fermentation). Move each phrase to the appropriate category. If a phrase describes both types of fermentation, classify it as both.

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

AN ATP molecule contains the nitrogenous base guanine. T/F

False

Use the cellular respiration lab to help you answer the following questions. Which cellular respiration disruptors were given to Leif the action figure in the three images below? (a) (b) (c) Use Drop-up menus to complere the following sentences. (d) ______ disrupts cellular respiration by destroying the proton gradient in the mitochondria (e) ______ disrupts cellular respiration by stalling the conversion of pyruvate to acetyl CoA (f) ______ disrupts respiration by stalling the electron transport chain

(a) low oxygen (b) arsenic (c) DNP -diet pill (d) DNP disrupts cellular respiration by destroying the proton gradient in the mitochondria (e) Arsenic disrupts cellular respiration by stalling the conversion of pyruvate to acetyl CoA (f) Low oxygen disrupts respiration by stalling the electron transport chain

Glycolysis is a series of chemical reactions that convert glucose to pyruvic acid. Glycolysis also uses and generates chemical energy. Several compounds are necessary for glycolysis. These compounds are also components of other metabolic pathways in the cell. Match the compounds in the drop-down menus on the right with the descriptions on the left. You will not select all the compounds. You may select any compound more than once.

- A carbohydrate that enters a glycolysis directly (Glucose) - The direct energy source for glycolysis (ATP) - the end product that is modified to enter the citric acid cycle (Pyruvic Acid) - a product that donates electrons to the electron transport chain (NADH) - A product that can be used directly for energy (ATP)

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 supply will allow. What benefits do muscle cells gain from anaerobic respiration in this situation?

- The mitochondria can use the oxygen generated as a waste product during lactic acid fermentation to increase their output of ATP. - Adding electrons from NADH to pyruvate regenerates NAD , so that glycolysis can continue, and produces lactic acid, a waste product that can diffuse out of the cell. - For every glucose molecule that enters glycolysis, the cell generates, without oxygen, two ATP molecules that can keep the muscles moving. - When pyruvate is transformed into lactic acid, four more ATP molecules are produced that can power muscle movement while NAD is regenerated.

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 pyruvate in glycolysis - generates ATP in the electron transport chain - generates NADH in the electron transport chain - generates ATP in the citric acid cycle

Use the cellular respiration lab to help you complete the passages below. 2,4-dinitrophenol (DNP) was a popular ingredient in diet pills in the 1930s before it was discovered that moderate doses of the compound cause exceptionally high body temperature and even death. Complete the following passages detailing how DNP\'s mechanism of action explains why it causes both high body temperature and weight loss. 2,4-dinitrophenol (DNP) causes ________ to pass directly across the inner mitochondrial membrane instead of returning to the mitochondrial matrix through ________ proteins. Because of DNP's effect on the mitochondrion, less energy is captured in the form of ________ and more energy is instead wasted as heat.

2,4-dinitrophenol (DNP) causes Protons to pass directly across the inner mitochondrial membrane instead of returning to the mitochondrial matrix through ATP synthase proteins. Because of DNP's effect on the mitochondrion, less energy is captured in the form of ATP and more energy is instead wasted as heat.

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

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

False

Use the cellular respiration lab to help you answer this question. Which steps of cellular respiration generate NADH or FADH2 as products, and which steps receive those molecules as inputs?

Generates NADH or FADH2 - Glycolysis - Acetyl CoA Production - Citric Acid Cycle Receives NADH or FADH2 - Oxidative Phosphorylation

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?

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

The electron transport chain consists of protein complexes embedded in the inner mitochondrial membrane, where it generates a proton gradient by a series of oxidation-reduction, or redox, reactions. Although all the stages of cellular respiration (glycolysis, the citric acid cycle, and the electron transport chain) are necessary for life, the electron transport chain is sometimes called the most important stage. First complete the sentence, then answer the question below. The electron transport chain uses the transfer of (_____) between protein complexes to set up a proton gradient. What is the fuction of the proton gradient in the mitochondria?

The electron transport chain uses the transfer of ELECTRONS between protein complexes to set up a proton gradient. --- - It is kinetic energy that inter-converts NAD+ and NADH - It is chemical energy that directly drives the synthesis of proteins - It is potential energy that the cell uses to generate ATP - It is potential energy that can oxidize )2 forming H2O

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

True

Below are events that occur during cellular respiration. Idnetify where each of the events occur within a eukaryotic cell. Each cellular location may be used one, more than once, or not at all.

conversion of pyruvate to acetyl-CoA: mitochondrial matrix electron transport chain: mitochondrial membrane breakdown of glucose to pyruvate: cytosol citric acid cycle: mitochondrial matrix

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

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