Microbiology metabolic pathways study I

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 dioxyribonucletides by replacing the 2 hydroxyl group with a hydrogen atom

In electron transport chans, quinones, cytochromes, and flavoproteins are all _______.

- electron carriers

Use the following four words to correctly complete thesentence: endergonic, exergonic, anaboism, catabolism. "Cells constantly produce ATP during ____ reactions of _____ and then use it to power ______ reactions of ___________.

- exergonic - catabolism - endergonic - anabolism

Most lipids are synthesized from _____ and ______.

- fatty acids - glycerol

Glutamate synthesis is especially important for bacteria, because it provides a mechanism for the incorporation of _______ into organic material.

- nitrogen

The terminal electron acceptor in aerobic respiration is:

- oxygen

The central metabolic pathway that breaks down glucose but whose primary role is the production of compounds used in biosynthesis, including reducing power in the form of NADPH as well as two precursor metabolites, is called the _______ pathway.

- pentose pathway

The central metabolic pathway that breaks down glucose but whose primary role is the production of compounds used in biosynthesis, including reducing power in the form of NADPH as well as two precursor metabolites, is called the ______ pathway.

- pentose phosphate

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

- pentose phosphate

Proteins are hydrolyzed by ______, enzymes that break ____ bonds between amino acid subunits.

- proteases - peptide

Place the following steps in the correct order to show the spatial arrangementof electron carriers in a bacterial electron transport chain helps explain how protons are shuttled from one side of the membrane to the other.

- 1 An electron carrier donates electrons to a hydrogen carrier - 2 The hydrogen carrier must pick up protons from inside the cell - 3 the hydrogen carrier passes electrons to a carrier that only accepts electrons - 4 Because the electron carrier only accepts electrons, the protons, are released to the outside of the cell - 5 A proton motive force is setup as protons are moved from the inside of the cell to the outside

Consider the pathway that converts the amino acid threonine to the amino acid isoleucine. Isoleucine is an allosteric inhibitor of the first enzyme of the pathway. This is an example of the mechanism called ______.

- feedback inhibition

Fats, the most common simple lipids, are a combination of fatty acids and ______; they are hydrolyzed by enzymes called _______.

- glycerol - lipases

Microorganisms that can grow on polysaccharides and disaccharides first break these down to glucose or precursor metabolites that can then be entered into the appropriate part of a central metabolic pathway to be oxidized. This central metabolic pathway is called ____.

- glycolysis

Microorganisms that can grown on polysaccharides and disaccharide first break these down to glucose or precursor metabolites that can then be entered into the appropriate part of a central metabolic pathway to be oxidized. This central metabolic pathway is called _____.

- glycolysis

In competitive inhibition such as what occurs with sulfa drugs, as the concentration of the _____ increases relative to the ______, the more likely the active site of the enzyme will be occupied, thereby blocking the regular function of the enzyme.

- inhibitor - substrate

Why is glutamate synthesis especially important for bacteria ?

- it provides a mechanism for incorporating nitrogen into organic material

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

The ability of organisms such as E. coli to ferment via the mixed acids pathway can be tested by the _____ test, which detects the low pH resulting from the acidic end products.

- methyl red

The ability of organisms such as E. coli to ferment via the mixed acids pathway can be tested by the ______ test, which detects the low pH resulting from the acidic end products.

- methyl red

Starch and cellulose are both polymers of _______, which means that, following hydrolysis, the component monosaccharides can enter directly into the central metabolic pathway of ______ to be oxidized.

- glucose - glycolysis

In the synthesis of the aromatic amino acids tryptophan, tyrosine, and phenylalanine, the first step is the formation of a 7-carbon compound, shown. How is this first step regulated in E. coli?

- 3 different enzymes can catalyze this step; each has a different allosteric site inhibited by one of the the 3 amino acids.

In photosynthesis, the protein complexes locatedwithin photosynthic membranes that contain pigments and are responsible for capturing radiant energy are called _______.

- photosystems

Purple bacteria and green bacteria have only a single photosytem and cannot use water as an electron donor for reducing power. Therefor, they are ________ photosynthetic bacteria.

- anoxygenic

Which of the following correctly describe the transition step and the tricarboxylic acid (TCA) cycle?

- the TCA cycle oxidizes a 2-carbon acetyl group to release two molecules of CO2 -They produce 3 precursor metabolites and ATP - Together they generate the most reducing power of all the central metabolic pathways - The transition step converts the pyruvate from glycolysis into acetyl-CoA

In a biosynthetic pathway, **feedback-inhibition** refers to:

- the end product acting as an allosteric inhibitor of the pathway

Cells prefer to use carbohydrates as energy sources because:

- they contain the greatest amount of energy per unit

Glycolysis is the central metabolic pathway that involves the breakdown of :

- glucose

Match up the correct descriptions with the numbers shown, to complete the visual analogy of electrons flowing through an electron transport chain

- 1. - Electrons from the energy source - 2. - Energy released is used to generate a proton motive force - 3. - Electrons donated to the terminal electron acceptor - 4. - High energy - 5. - Low energy

The energy released during the reactions of glycolysis is used to burn:

- adenosine triphosphate

Match the pathway A. Lactic acid fermenation B. Ethanol fermenation C. Butyric acid fermentation D. Propionic acid fermetation E. Mixed acids fermention F. 2,3,-Butanediol fermentation

- A. Lactic acid fermentation - Streptococcus Lactobacillus - B. Ethanol fermentation - Saccheromyces - C. Butyrate acid fermentation - Clostridium - D. Propionic acid fermentation - Propionibacterium - E. Mixed acids fermentation - 2,3,-Butanediol fermentation - Enterobacter

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

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

- ATP synthase

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

Match the organism with the correct locton of the photosystems.

- Cyanobacteria - Embedded in the membranes of the thylakoids located within the cells - Plants and algae - In thylakoids located. In the stroma of the chloroplast - Purple bacteria - In extensive invagination a of the cytoplasmic membrane - Green bacteria - In chlorosomes attached to the inner surface of the cytoplasmic membrane

Testing for the ability of organisms to produce mixed acids via fermentation can be clinically important because it can differentiate members of the family _____.

- Enterobacteriaceae

Testing for the ability of organisms to produce mixed acids via fermentation can be clinically important because it can differentiate members of the family ______.

- Enterobacteriaceae

Testing for the ability of organisms to produce mixed via fermentation can be clinically important because it can differentiate members of the family ______.

- Enterobacteriaceae

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

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

Compounds such as ATP ADP reflect a cell's relative energy supply and often serve as allosteric regulators of catabolic pathways. Which of the following best explains the relationship between levels of ATP and ADP and allosteric regulation of such catabolic pathways?

- High levels of ATP inhibit,ad high levels of ADP stimulate, the catabolic pathways

The transition step occurs twice for every molecule of glucose that enters glycolysis, oxidizing pyruvate to form acetyl-CoA. Together, these generate:

- NADH and 1 precursor metabolite (2 molecules of acetyl-CoA)

A genus of bacteria that uses fermentation to produce propionic acid and is used as a part of Swiss cheese production is ________.

- Propionibacterium

A genus of bacteria that uses fermentation to produceacid and is used as par of Swiss cheese production is __________.

- Propionibacterium

Consideer the three major groups of electron carriers found in electron transport chains. Match. Each description with the correct name. Quinones Cytochromes Flavoprotines

- Quinones - Lipid-soluble organic molecules that move freely in the membrane; include one the serves as a source of vit. K for humans and other mammals - Cytochromes - Proteins that contain heme, a molecule that holds an iron atom in its center. - Flavoproteins - Proteins that are synthesized from the vit. Riboflavin.

Propionibacterium species use a multistep fermentation pathway that first adds CO2 to pyruvate to generate a compound that serves as a terminal electron acceptor. After reduction by NADH, it is further modified to form propionate. Humans take advantage of this process to make what product?

- Swiss cheese

Instead of fulfilling both their energy and carbon needs form organic compounds the way chemoheterotrophs do, why do chemolithotrophs incorporate CO2 into an organic form to fulfill their carbon needs?

- They fulfill their energy needs from inorganic compounds such as H2S and NH3 that lack carbon, so they need to obtain their carbon elsewhere.

Pigments that increase the efficiency of light capture by absorbing wavelengths not absorbed by other pigments are called ________.

- accessory pigments

You are growing E. coli in a medium that includes nitrate. If the bacteria run out of O2 you might expect them to continue growing using _____ respiration, using _____ as a terminal electron acceptor.

- anaerobic - nitrate

You are growing E. coli in a medium that includes nitrate. If the bacteria run out of O2 you might expect them to continue growing using ______ respiration, using _____ as a terminal electron acceptor.

- anaerobic - nitrate

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

- biosynthesis

Unlike organisms that use organic molecules to fill both their energy and carbon needs, chemolithotrophs must use a process called ____ to produce organic carbon compounds t fulfill their carbon needs.

- carbon fixation

The synthesis of aromatic amino acids begins with the formation of a 7-carbon compound. This is made from a 4-carbon and a 3-carbon compound that originate, respectively, from what two central metabolic pathways?

- carbon from the pentose phosphate pathway - 3-carbon from glucose

In prokaryotes, the electron transport chain is located in the _____ membrane, whereas in eukaryotic cells it is in the ______ member of ________.

- cytoplasmic - inner - mitochondria

Starch and cellulose are both polymers of ______, which means that, following hydrolysis, the component monosaccharides can enter directly into the central metabolic pathway of ______ to be oxidized.

- glucose - glycolysis

The central metabolic pathway that breaks down glucose but whose primary role is the production of compounds used in biosynthesis, including reducing power in the form of NADPH as well as two precursor metabolites, is called the _________ pathway.

- pentose phosphate