Ch 6 HW

The central metabolic pathway that generates reducing power in the form of NADPH is the

The pentose phosphate pathway

Hydrogen sulfide is produced as a result of certain types of anaerobic respiration. Some chemolithotrophs can then use this as a/an ______.

energy source

competitive inhibition

Inhibitor binds to the active site of the enzyme, blocking access of the substrate

What happens to an organism if it lacks one or more enzymes in a given biosynthetic pathway?

It must have the end product provided from an external source.

If the theoretical maximum an ATP yield in prokaryotes from oxidative phosphorylation is 34 ATP for a single glucose molecule, what is the total ATP gain when substrate level phosphorylation is included?

38 ATP

Although the pentose phosphate pathway is used by cells to break down glucose it is particularly important because of its contribution to

Biosynthesis

Metabolic pathways can be linear,—- or ——?

Branched or cyclical (cycle)

Proteins are hydrolyzed by proteases, enzymes that break the peptide bonds between ____ _____ subunits.

amino acid

In photosynthesis, what do the light reactions, or light-dependent reactions, accomplish?

They capture radiant energy and convert it to chemical energy in the form of ATP.

Consider the three key central metabolic pathways (glycolysis, pentose phosphate pathway, and The TCA cycle) What three beneficial products of this pathways?

Reducing power ATP Precursor metabolites

The critical site of an enzyme to which a substrate binds by weak forces is called the ___ ___.

active site

The light-independent reactions of photosynthesis occur _______ the light-dependent reactions, and function to _______.

after; synthesize organic compounds from CO2

Nucleotide subunits of DNA and RNA are composed of three units: a 5-carbon sugar, a phosphate group, and a nucleobase. They are initially synthesized ______.

as ribonucleotides that can be converted to deoxyribonucleotides by replacing the 2' hydroxyl group with a hydrogen atom

Consider the effect of temperature on enzyme activity. If the temperature is too high, proteins will __ And no longer function.

denature

in addition to glucose, which of the following organic compounds can serve as energy sources for microbes?

fatty acids monosaccharides proteins polysaccharides disaccharides lipids

Glucose catabolism encompasses two key processes: (1) Oxidizing glucose molecules to generate ATP, reducing power and precursor metabolites and (2) transferring the electrons Carried by NADH and FADH2 to the terminal electron acceptor: The second process ,transfer of electrons, is accomplished as part of which of the following?

fermentation and cellular respiration

Calvin Cycle ___

incorporates carbon dioxide into organic compounds

What is the active site of an enzyme?

The critical site to which a substrate binds by weak forces

The primary pathway used by many organisms to convert glucose to pyruvate is:

glycolysis

Purines and pyrimidines are synthesized ______.

in distinctly different manners

The reactions that capture radiant energy and convert it into chemical energy in the form of ATP are called the ______

light-dependent reactions

After a deamination reaction removes the amino group from amino acids, the remaining carbon skeletons are converted into the appropriate ______ metabolites for entry into central metabolic pathways.

precursor

Certain intermediates of catabolic pathways, called precursor metabolites, are important because ______.

they serve as carbon skeletons from which subunits of macromolecules can be made

although the actual procedure is much more involved, the basic metabolism of wine-making involves inoculating grape juice with a special strain of the yeast Saccharomyces cerevisiae. S. cerevisiae will preferentially perform aerobic respiration on sugars in the juice but can also ferment those sugars to yield CO2 and alcohol, an important component of wine. Assume you inoculate a completely full container of juice and then close the lid. What will the yeast do?

they will grow aerobically, consume the O2 dissolved in the juice, and then switch to fermenting sugars to yield alcohol.

Microorganisms that can grow on polysaccharides and disaccharides first break these down to glucose or precursor metabolites that can then enter into the pathway of ____ to be oxidized.

glycolysis

When a cell processes glucose or other organic molecules through its central metabolic pathway, it does so to generate what three critical things?

•ATP •reducing power •precursor metabolites

What are the two mains forms of energy?

•Potential •Kinetic

TCA cycle completes the _______ of glucose

oxidation

All of the following accurately describe enzymes EXCEPT? • enzymes are very specific, usually acting on only one or a few substrates • enzymes provide energy to have reactions proceed more rapidly • enzymes are biological catalyst • The name of an enzyme typically reflects its function and ends in -ase • Enzymes are not used up in the process of catalyzing reactions

Enzymes provide energy to have reactions proceed more rapidly

Energy is the ability to do work and can exist as .... Energy (stored energy) and ..... energy (energy of motion)

Potential (Stored energy) Kinetic (Kinetic energy)

Some members of which of the following groups can use inorganic chemicals such as hydrogen sulfide and ammonia for energy?

Prokaryotes only

Which of the following are reasons an organism might use fermentation?

-They lack an electron transport chain. -A suitable inorganic terminal electron acceptor is not available. (fermentation is used by an organism that cannot respire)

In addition to yielding energy, catabolic pathways generate carbon intermediates that can be used in anabolic pathways for the biosynthesis of macromolecules. These carbon skeletons are called

precursor metabolites

Which of the following combinations of molecules is produced during the light-dependent reactions of photosynthesis and used in the light-independent reactions?

NADPH and ATP

In the case of plants, algae, and cyanobacteria, the two major products of photosynthesis are ______.

glucose and oxygen

The enzymes of that tricarboxylic acid Cycle are found in the ___ matrix in eukaryotes and in the ____ prokaryotes

• Mitochondrial matrix • Cytoplasm

In terms of their metabolism, prokaryotes are _______ with respect to compounds they use for energy and _______ in their biosynthetic processes.

highly diverse; remarkably similar

Some enzymes act with the assistance of a non-protein component. This component is called a ___? If that component is an organic molecule is it can be called a?

Non-protein component : Cofactor Organic molecule : Coenzyme

The mechanism by which cellular respiration uses reducing power generated in glycolysis, the transition step, and the TCA cycle to synthesize ATP is ________.

Oxidative Phosphorylation

Autotrophs use carbon dioxide (CO2) to synthesize organic compounds. Which of the following descriptions of this process are true?

-It is called carbon fixation. -It often involves the Calvin cycle. -In photosynthetic organisms, the process is called the light-independent reactions.

oxidative phosphorylation, The mechanism by which cellular respiration uses the NADH and FADH2 generated in glycolysis, the transition step, and the TCA cycle to synthesize ATP, involves what two steps

-The electron transport chain generates a proton motive force -ATP synthase uses the energy of the proton motive force to drive the synthesis of ATP

Proteins are composed of various combinations of usually how many different amino acids?

20

Enzymes are biological ___ that are typically ___?

Catalyst; protein

In respiring bacteria, how does ATP synthase generate ATP?

It uses the energy released from allowing protons to flow back into the cell to add a phosphate group to ADP

metabolic pathway

The series of sequential chemical reactions in a cell that converts a starting compound to an end product is called

The figure illustrates a type of regulation used by cells to rapidly control certain key in size the arrow label "1" point to the ___ and the arrow labeled "2" to the __

(1) allosteric site (2) active site

Which of the following are true statements about what happens to glucose inside the cell?

•Some glucose might be oxidized to CO2, generating the maximum amount of ATP • glucose can be used in catabolism to yield energy, or the precursor metabolites generated from its breakdown can be used in anabolism • some glucose might enter glycolysis, only to be siphoned off as a precursor metabolite for Biosynthesis

Metabolism

The sum total of all Chemical reactions in a cell

As part of cellular respiration, a membrane-bound enzyme called _____ uses energy from a proton-motive force to add a phosphate group to ADP.

ATP Synthase

Cells can quickly alter the activity of certain key enzymes, using the molecules other that bind reversibly and distort them. This control enzyme is called?

Allosteric Regulation

Considering the general equation that describes photosynthesis, the rate of the process would be most influenced by the availability of _______ in the atmosphere.

CO2

The process by which chemolithoautotrophs and photoautotrophs incorporate CO2 into organic compounds is called

Carbon Fixation

The energy released by —- is captured by the cells to make ATP; this ATP can then be used for biosynthesis, or ——-?

Catabolism ; anabolism

In order to form lipids, how are fatty acids and glycerol synthesized?

Fatty acid chains are assembled from 2-carbon acetyl groups from the transition step; the precursor to glycerol comes from glycolysis.

Starch and cellulose are both polymers made up of the monosaccharide _____ which means that hydrolysis of the polymers releases subunits that can enter directly into the central metabolic pathway of _____ to be oxidized.

Glucose , Glycolysis

Lipid synthesis generally requires the components __ and __acids.

Glycerol and fatty acids

The series of sequential chemical reactions in a cell that converts a starting compound to an end product is called

Metabolic pathway

Noncompetitive inhibition by enzymes poisons

Inhibitor permanently changes the shape of the enzyme, making the enzyme non-functional

Non-competitive inhibition by regulatory molecules

Inhibitor reversibly changes the shape of the enzyme so that the substrate can no longer bind to the active site

Until the optimal temperature is reached, raising the temperature has what effect on the speed of enzymatic reactions?

It increases their rate.

The electron transport chain is a cluster of membrane-embedded electron carriers that accept electrons from the coenzymes _______and _______ and then pass these electrons along the chain.

NADH and FADH2

Which side is catabolic and which side is anabolism

The left side (light blue) shows catabolism and the right side shows anabolism

For each six carbon molecule of glucose that enters glycolysis how many molecules of pyruvate are made in a how many carbon atoms does each pyruvate have?

Two molecules of pyruvate, each with three carbon atoms.

With respect to their synthesis, how are amino acids typically grouped?

By structurally related families that share common biosynthesis pathways

Fats are hydrolyzed by lipases. The glycerol component is then converted to a precursor metabolite, and the fatty acids are degraded using a series of reactions called β-oxidation that remove successive 2-carbon units. Where do these components enter the central metabolic pathways for further oxidation?

The precursor metabolites from glycerol enter glycolysis; the 2-carbon units from fatty acids are added to coenzyme A and enter the TCA cycle.

Microorganisms can grow on a variety of organic compounds other than glucose, including polysaccharides, proteins, and lipids. How do they accomplish this?

They break these macromolecules down into appropriate precursor metabolites that are then introduced into central metabolism or used in biosynthesis.

Fats, the most common simple lipids, are broken down by lipases into their component ______.

glycerol and fatty acids

Identify each of the following by the most precise descriptive term as either a cofactor or coenzyme: magnesium: ____; NADP+: ____; zinc: ____

Magnesium : Cofactor NADP+ : Coenzyme Zinc : Cofactor

True or false: The Calvin cycle is a two-step linear pathway that photosynthetic organisms use to fix carbon dioxide

false