Chapter 7 Quiz

Fermentaion allows for hte production of ATP without using either ______ or __________________-----------

oxygen or ETC

For anerobic respiration to continue, the cell msut be suppllied with oxygen--the ultimate electron aceptor. What is the electron acceptor in fermentaion.

pyruvate

Alchol fermentation starts with GLucose and yeilds ethanol. Explain this process, and be sure to describe the NAD+ is recycled.

(releases carbons and then is reduced by NAdH, regentated NAD+, and then pyruvate becomes ethanol

The ten individual steps of glycolysis can be divided into two stages: energy investement and energy payoff. These steps are shown in Figure 7.9, which details the enzymes and reactions at each of the ten steps. While you are not expected to memorize these setps and enzymes, you should study the figure carefully. The next few questions will help you focus your study. a.what are the two specific steps where ATP is used? ____and _____ b.The second step in glycolysis is the energy payoff phase. Note that it provides both ATP and NADH. 1. What are the two stpes where ATP is formed?___ and ____ 2. What is the one step where NADH is formed?_______

1 and 3 ten and 7 step 6

using firgure 7.15, summarize the production of NADH and FADH2. How is ATP formed, and for each step indicate whether it is by substrate level or oxidative phosphorylation? Use the text to be suere you understand how each subtotal on the bar below the figure is released.

2 NADH Glycolysis, 1 during Pruvate oxidaiton, 6 during citric acid cycle, 2FADH2 during glycolosis.

Explain what has happened to each of the six carbons found in the original glucose molecule.

2 of those are released and the other four stay together

Use figure 7.11 to help you answer the following summary questions about the citric acid cycle: A: How many NADHs are formed B: How many total carbons are lost as pyruvate is oxidized C The carbons have been lost in the molecule D How many FADH2s have been formed E How many ATPs are formed F How many times does the citric acid cycle occur for each molecule of glucose

A 3 B 2 C CO2 D 1 E 1 F Twice

Explain how AMP simulates cellular respiration while citrate and ATP inhibit it.

As ATP is used up, AMP accumalates which signals more ATP to be made. The more ATP there is, the slower glycolysis is.

Give the formula for the catabolic degradation of glucose by cellular respiration.

C6H12O6 + 6O2= 6CO2+6H2O+ATP+heat

What are three organic macromolecules are often utilized to make ATP by cellular respiration?

Carbs give glucose, Fats give fatty acids and glycerol, and pritens give amino acids

Explain the difference in energy usage between the catabolic reactions of cellular respiration and anabolic pathways of biosynthesis.

Cellular respiration produces ATP, and biosynthesis comsumes ATP.

The correct answer to question 6 is NAD+. It is a coenzyme. What are coenzymes?

Coenzymes are non-protein molecules that help with lowering the activation energy.

Explain the difference between fermentation and cellular respiration

Fermentation makes a limited amount of ATP form glucose, and uses little oxygen, and cellular respiration occurs with oxygen

Describe what happens when NAD+ is reduced. What enzyme is involved.

Dehydrogenases remove a pair of hydrogen atoms from the substrate, oxidizing it. It delivers the electrons along with 1 proton to NAD+, forming NADH.

Why is the total ATP count reduced from 38 to 36?

Depends on if the NADH shuttle goes there, or the FADH shuttle arrives first.

The second form of phosphorylation is substrate level. Explain the direct transfer a phosphate from an organic substrate to ADP to form ATP.

Enzyme transfers a phosphate group from substrate to molecule to ADP.

The two electron carrier molecules that feed electrons into the electron transport system are....

FADH2 and NADH

Lactic Acid Fermentation starts with Glucose and yeilds Lactate. Explain this process and be sure to descrive how NAD+ is recycled.

Glycolysis follwed by the reduction of Pyruvate to lactate regenerates NAD+ with no oxygen, co2 released

What is the meaning of glycolosis? What occurs in this step of ceullular respiration?

Glycolysis means "sugar splitting", splits it into 2 3-carbon molecules.

Oxygen stabilizes the electons by combining with two hydrogen ions to form what compound?

H2O

Oxygenthree types of phosphorylation are covered in the text, and two of these occur in cellular respiration. Explain how the electron transport chain utilized in oxidative phosphorylation.

It powers the oxidative phosphorylation, and also increases entropy.

Explain why pyruvate is a key juncture in metabolism.

It repersents a fork in the catabolic pathwasy of cellular respiration

What is the function of the electron transport chain in cellular respiration?

Makes reactions less explosive, it is a sequence of electron carrier moleules that shuttle electrons down a series of redox reactions that release energy used to make ATP.

It is essential for you to understand the concept of oxidation/reduction and energy transfer. For the following pair, which molecule is the oxidized form, and which is reduced? Which molecule holds higher potential energy? Which is lower in potential energy?

NAD+ is oxidzed higher potential energy NADH is lower potential energy

In cellular respiration, electrons are not transferred directly from glucose to oxygen. Following the movement of hydrogens allows you to follow the flow of electrons. The hydrogens are held in the cell temporarily by what electron carrier? What electron carrier is hydrogen transferred to first?

Nad+

Both cellular respiration and photosynthesis are redox reactions. In redox, reactoins pay attention to the flow of electrons. What is the difference between oxidation and reduction.

Oxidation is the loss of an electron, and reduction is the gain of an electron

What strongly electronegative atom, pulling electrons down the electron transport chain, is the final electron acceptor.

Oxygen

Oxygen is the ulitmate electron acceptor. Why is this?

Oxygen is very electronegative, which is why oxygen binds to the electrons.

To enter the citric acid cycle, pyruvate must enter the mitochondria by active transport. Three things are necessary to convert pyruvate to acetyl CoA. Explain the three steps in the conversion process. a. b. c.

Redox Reactions: Pyruvate is oxidized, NAD+ reduced, 4 carbon molecule oxidized, releases/oxidizes NAD+ CO2 release:Exits in steps 3 and 4 ATP formation: GTP gived ADP 1 phosphate

Using figure 7.13, explain the overall concpet of how ATP syntahse uses the flow of hydrogen ions to produce ATP

The hydrogen acts somewhat like a stream rushing to and spinning like a waterfall

Two key terms are chemiosmosis and proton-motive force. Relate both of these terms to these processes of oxidative phosphorylation.

The protein motor force is potential energy stored in the form of an electrochemical gradient. Oxidative phosphorylation creates that gradient. Chemiosmosis is an energy coupling mechanims that uses energy stored in th form of a hydrogen ion, gradient and oxidative phosphorylation is the reason for the H+ gradient.

What is the role of teh ETC in forming the hydrogen ion gradient across the inner mitochondrial membane?

Uses the exxergonic flow of electrons from NADH, FADH2, gets drowned into the mitochondrial matrix

The following is a generalized formula for a redox reaction. Draw an arrow showing which component (X or Y) is oxidized and which is reduced. Xe- + Y --> X + Ye-

X is the reducing agent in this reaction, and Y is the oxidizing agent.

The step that converts pyruvate to acetyl CoA at the top of the diagram occurs twice per glucose. This oxidation of pyruvate accounts for two additional reduced ________ molecules and two molecules of CO2.

citrate

Notice that glycolysis occurs in the cytoplasm of the cell. Is oxygen required

no

oxidative phosphorylation involves two components: the ETC and ATP synthesis. Refering to figure 7.12 notice that each member of the etc is lower in free _________ than the preceding member of the chain, but higher in ______________. The molecule at 0 free energy, which is _______, is lowest of all the molecules in free energy and highest in electronegativity

energy....electronegativity.......oxygen

Electorn transport involves a series of electron carriers. a. where are these found in eukaryotic cells> b. where are these found in prokaryotic cells

eukaryotic cells in inner membrane of the mitochondria, and in prokaryotic cells is the plasma membrane.

When compounds lose electrons, they ________________ energy; when compounds gain electrons, they _______________ energy.

gain....lose

The starting product of glycolysis is the six-carbon sugar ________, and the ending products are two ________-carbon molecules of ____________.

glucose...3....sugars