Micro 301 chapter 6 pt 2

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

By structurally related families that share common biosynthesis pathways

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 Calvin cycle is a two-step linear pathway that photosynthetic organisms use to fix carbon dioxide

False, the pathway is complex and cyclic

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.

Other than generating some ATP via the substrate-level phosphorylation steps of glycolysis, what critical role do the additional steps of fermentation accomplish? Multiple choice question.

They consume excess reducing power in order to regenerate NAD+ so that it can accept electrons to keep glycolysis going.

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.

The electron transport chain of mitochondria has ______ different protein complexes.

four

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

glucose and oxygen

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

glycerol and fatty acids

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

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

oxidative

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

polysaccharides lipids disaccharides fatty acids proteins monosaccharides

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

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

synthase

This picture of a set of stairs best exemplifies the electron _________ _________

transport chain

With respect to the location of the electron transport chain, the inner membrane of mitochondria is analogous to the cytoplasmic membrane of bacterial cells.

true

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.

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.

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

highly diverse; remarkably similar

Purines and pyrimidines are synthesized ______.

in distinctly different manners

The Calvin cycle ______.

incorporates carbon dioxide into organic compounds

The reactions that capture radiant energy and convert it into chemical energy in the form of ATP are called the ________ - _________ reactions.

light-dependent

he electron transport chain consists of large protein-complexes embedded in a membrane. These pass electrons from one to the next, while simultaneously pumping ________across the membrane,

protons

Menaquinone is a quinone used in the electron transport chain of some prokaryotes. It plays an important role for humans and other mammals because it ______.

serves as a source of vitamin K, providing much of the host's requirement via absorption in the intestinal tract

The ATP generated by fermentation comes from ______.

substrate-level phosphorylation during glycolysis

Which of the following correctly describe cytochromes found in an electron transport chain?

- Cytochromes are proteins that contain heme, a molecule that holds an iron atom in its center. - Several different cytochromes exist.

In prokaryotes, the electron transport chain is located in the _______________membrane, whereas in eukaryotic cells it is in the____________ membrane of mitochondria.

- Cytoplasmic - Inner

In an electron transport chain, electron carriers are found in what two general locations?

- Grouped into large protein complexes that function as proton pumps. - Freely moving in the membrane where they can shuttle electrons between protein complexes.

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

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

The three main types of electron carriers in a typical electron transport chain are __________,________ , and flavoproteins.

- Quinones - Cytochromes

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.

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.

E. coli will preferentially use __________ respiration in the presence of O2, but when O2 is not available, it can switch to _________ respiration if a suitable electron acceptor such as nitrate is present.

- aerobic - anaerobic

In addition to four protein complexes, the mitochondrial electron transport chain has two freely-moving ______, ubiquinone and cytochrome c, that serve to ______.

- electron carriers; - shuttle electrons between the complexes

A general group of electron carriers found in electron transport chains is quinones, that ______

- exist as several types, including ubiquinone and menaquinone - are lipid-soluble organic molecules that move freely in the membrane, transferring electrons between different protein complexes

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 - fatty acid

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

-Oxidative

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

20

If the theoretical maximum 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

All of the following are essential for an electron transport chain to function EXCEPT ______.

ATP

In respiring bacteria, how does ATP synthase generate ATP?

In respiring bacteria, how does ATP synthase generate ATP?

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.

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 FADH

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

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

Prokaryotes only

In prokaryotes, how does the energy yield of aerobic respiration compare to anaerobic respiration?

The energy yield of aerobic respiration is greater than anaerobic respiration.

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.

Why does anaerobic respiration yield less energy than aerobic respiration?

The terminal electron acceptors used in anaerobic respiration have lower electron affinities than O2

With respect to prokaryotic species such as E. coli, each individual cell will have an electron transport chain made up of the same components.

false, a single. species can have several alternative carriers

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 ______. Multiple choice question.

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

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

carbon fixation

Examples of electron carriers are proteins that contain heme, a molecule that holds an iron in its center. These are called _______.

cytochromes

In oxidative phosphorylation, quinones, cytochromes, and flavoproteins are all _______ carriers.

electron

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

energy source

Proteins are hydrolyzed by proteases, enzymes that break the _________ bonds between amino acid subunits.

peptide or covalent