Microbiology Reveiew for Exam 3

Arrange the electron acceptors in the proper order in which they participate in electron transport 1=Cytochrome c 2=Oxygen 3=Cytochrome c Oxidase

(1)Cytochrome c --> (3)Cytochrome c Oxidase--> (2)Oxygen

Equation that correctly represents the mechanism of enzyme function

(Substrate=S, Product=P, Enzyme=E) E-S->E-S->E-P->E+P

A single turn of the Krebs cycle (not including the prior formation of acetyl-CoA from pyruvate) will yield

-1 ATP -3 NADH - 1 FADH2

The net yield of the TCA cycle for each acetyl-CoA molecule is

-2 CO2 -3 NADH -1 FADH2 - 1 ATP or GTP

The Entner-Doudorof pathway (E-DP) differs from the Embden-Meyerhof pathway (E-MP) in that

-The E-DP utilizes enzymes that produce 2-keto-3-deoxy-6-phosphogluconate as an intermediate whereas E-MP does not utilize those enzymes

Anoxygenic phototrophs have light-absorbing pigments called __1__; in some bacteria, these are located in membranous vesicles called __2__

1.) Bacteriochlorophylls 2.) Chlorosomes

According to the chemiosmotic hypothesis, mitochondrial ECT's are organized so that __1__ move across the inner membrane from the mitochondrial matrix to the intermembrane space as __2__ are transported down the chain

1.) Protons 2.) Electrons

The NET products from the oxidation of glucose to pyruvate in the Emden-Meyerhof pathway are

2 NADH and 2 ATP

Following the formation of acetyl-CoA, the initial reaction of the Krebs cycle involves the addition of a

2-carbon molecule to a 4-carbon molecule * 2-carbon acetyl-CoA enters the cycle and joins with 4-carbon oxaloacetate to form citrate, a 6-carbon molecule

Consider the biochemical pathway used to synthesize the amino acid proline. A high concentration of proline will most likely lead to

A decrease in proline production

In the ETC and Oxidative phosphorylation, When protons are pumped outside the cell membrane

A proton motive force is created

The end product of aerobic respiration

ATP

The Calvin Cycle uses ________, which are products of light reactions of photosynthesis

ATP & NADPH

During feedback inhibition, the inhibitor binds to the

Allosteric site of the enzyme being inhibited

In the ETC and Oxidative phosphorylation, protons received from NADH

Are pumped across the membrane

What does NOT apply to metabolic channeling

Bacterial cells, having no nucleus or organelles, are not capable of metabolic channeling -False -True; bacterial cells are capable of metabolic channeling; they use their perplasmic space and microcompartments to separate their metabolic processes

What is true about biochemical pathways

Biochemical pathways are very well organized and structured and they convert an initial substrate, via a series of steps, into an end product

The electrons that are transferred through the electron transport system initially belonged to

Both NADH and FADH2

In oxygenic phototrophs, the most important pigments are

Chlorophylls -Large planar molecules composed of four substituted pyrrole rings with magnesium atom coordinated to the four central nitrogen atoms

In the TCA cycle, ATP or GTP is generated by substrate-level phosphorylation when

CoA is cleaved from the succinyl-CoA -The hydrolysis of the thioester bond in succinyl-CoA is used to produce a large amount of energy, which is captured to form ATP or GTP by substrate-level phosphorylation

The incorporation of CO2 into organic material is an

Endergonic process

Anaplerotic reactions that generate intermediates in the TCA cycle are essential because

Energy to fuel biosynthetic reactions must also be generated by the reduced coenzymes produced in the TCA cycle

The Calvin Cycle functions to construct carbohydrates from carbon dioxide

False

Under aerobic conditions, the end product of glycolysis is further reduced to yield more ATP

False -aerobic respiration is the oxidation of glucose to produce energy in the form of ATP

In Glycolysis, glucose is phosphorylated at the expense of one ATP, producing

Glucose 6-phosphate -Glucose is phosphorylated to glucose-6-phosphate

Pathway that is a modified TCA cycle found in some bacteria, fungi, and protists that uses isocitrate lyase and malate synthase

Glyoxylate Cycle

How do enzymes hexokinase and glucose-6-phosphatase differ

Hexokinase transfers a phosphate from ATP to glucose to make glucose-6-phosphate, and glucose-6-phosphate catalyzes the reverse reaction

The movement of protons through ATP synthase in eukaryotes occurs from the

Intermembrane space to the matrix

After pyruvate is produced by the oxidation of glucose, it is oxidized and cleaved to form one CO2 and the 2-carbon molecule (acetyl-CoA) which then enters the tricarboxylic acid cycle also known as

Krebs Cycle

Consider the biochemical pathway A-E1->B-E2->C. If enzyme 2 is inactive, which compound will accumulate

Only Compound B will accumulate

The formation of ATP as a result of the activity of the electron transport system is termed

Oxidative phosphorylation

Many Microbes capture the energy in light and use it to synthesize ATP and reducing power (NADPH). When the ATP and reducing power are used to reduce and incorporate carbon dioxide, the process is called

Photosynthesis

Enzymes act as catalysts and are made up of

Proteins

In glycolysis, glucose is converted to

Pyruvate

The TCA cycle is linked to glycolysis through the intermediate molecule

Pyruvate

After the glycolytic pathway produces ________, the partially oxidized carbon is fed into the TCA cycle and oxidized completely to CO2 with the production of some GTP or ATP, NADH, and FADH2

Pyruvate -The first step involves the breakdown of glucose to form pyruvate

The Calvin Cycle begins by the attachment of CO2 to

RuBP

Enzymes speed up cellular reactions by providing an active site for reacting molecules that are known as

Substrates

It is feasible that a regulatory enzyme can be both allosteric and covalently modified. Having both levels of regulation allows for the allosteric effectors to exert varying effects depending on the nature and number of covalently bound chemical groups

TRUE

The Krebs Cycle occurs in the mitochondrion of eukaryotes and the Cytoplasm of bacteria & archaea

TRUE

Pyruvate is converted to carbon dioxide via three separate decarboxylation reactions during the TCA cycle

TRUE -Three-carbon pyruvate requires three separate decarboxylation reactions to form three CO2 molecules

Allosteric regulation involves

The binding of a positive or negative effector molecule to the regulatory site of an enzyme which changes the conformation of the active site. -By contrast, covalent modification involves the covalent binding of a particular chemical group to the enzyme

In feedback inhibition, the inhibiter of the biochemical pathway is typically

The final product of the biochemical pathway

In the ETC and Oxidative phosphorylation, Oxygen acts as

The terminal electron acceptor

During glycolysis, a 6-carbon sugar diphosphate molecule is split into TWO 3-carbon sugar phosphate molecules

True

Glyceraldehyde-3-phosphate and 3-phosphoglycerate are three-carbon molecules produced during the Calvin Cycle

True

The energy captured in the phosphorylation of ADP to ATP comes from the proton motive force created when energy is released following the oxidation of electron carriers

True

When oxygen accepts electrons, water is produced as a byproduct

True -Most ATP generated during respiration comes from the energy conserved when NADH & FADH2 are oxidized by an ETC. -When the terminal electron acceptor oxygen is reduced, water is formed as a byproduct

Before entering the Krebs Cycle, pyruvate is converted to

acetyl-CoA