Ch.10-11 Microbiology

Which of the following statements is true about the first law of thermodynamics?

a. Energy is created during spontaneous processes.

b. Energy is neither created nor destroyed.

c. Entropy decreases during spontaneous processes.

d. The universe tends to become more ordered.

b. Energy is neither created nor destroyed.

What is the major form of energy currency used by cells?

a. Heat

b. Glucose

c. ATP d. Entropy

c. ATP

Which type of reaction has a negative ΔG°′ and an equilibrium constant greater than one?

a. Endergonic reaction

b. Exergonic reaction

c. Spontaneous reaction

d. Non-spontaneous reaction

b. Exergonic reaction

What is the capacity to do work in a biological system called?

a. Thermodynamics

b. Entropy

c. Kinetics

d. Energy

d. Energy

What field of science analyzes energy changes in systems, including cells?

a. Chemistry

b. Biology

c. Thermodynamics

d. Biochemistry

c. Thermodynamics

Which of the following types of work involves the movement of molecules across a cell membrane?

a. Chemical work

b. Transport work

c. Mechanical work

d. Enzymatic work

b. Transport work

Which law of thermodynamics states that the randomness or disorder of the universe increases during spontaneous processes?

a. First law of thermodynamics

b. Second law of thermodynamics

c. Third law of thermodynamics

d. Zeroth law of thermodynamics

b. Second law of thermodynamics

What equation is used to calculate the change in free energy (ΔG) for a chemical reaction?

a. E = mc^2

b. ΔG = ΔH - T · ΔS

c. F = ma

d. E = PT

b. ΔG = ΔH - T · ΔS

Which common feature of metabolism involves the organization of chemical reactions into interconnected sequences?

a. Catalysis by enzymes

b. Redox reactions

c. Biochemical pathways

d. ATP as an energy currency

c. Biochemical pathways

What is the standard free energy change (ΔG°′) for a chemical reaction directly related to?

a. The rate of the reaction

b. The activation energy

c. The equilibrium constant

d. The entropy change

c. The equilibrium constant

What is ATP, and why is it important in cells?

a) ATP is a waste product of cellular metabolism.

b) ATP is a storage molecule for excess nutrients.

c) ATP is a high-energy molecule that carries energy within cells and powers various cellular processes.

d) ATP is a structural component of cell membranes.

c) ATP is a high-energy molecule that carries energy within cells and powers various cellular processes.

How is ATP synthesized from ADP and Pi (inorganic phosphate)?

a) By absorbing energy from exergonic reactions.

b) By breaking down glucose.

c) By consuming oxygen.

d) By a passive diffusion process.

a) By absorbing energy from exergonic reactions.

What is the term for the process of converting ATP back into ADP and Pi, releasing stored energy?

a) ATP synthesis

b) Hydrolysis

c) Dehydration synthesis

d) Oxidation

b) Hydrolysis

What is the role of ATP in cellular energy metabolism?

a) ATP stores excess energy for later use.

b) ATP provides structural support to the cell membrane.

c) ATP carries energy in a usable form and powers endergonic reactions.

d) ATP facilitates passive transport of molecules across cell membranes.

c) ATP carries energy in a usable form and powers endergonic reactions.

What is the cycling of ATP with ADP and Pi called within the cell?

a) ATP recycling

b) Cellular respiration

c) Energy generation

d) The cell's energy cycle

d) The cell's energy cycle

Which of the following statements is true regarding ATP and ADP?

a) ATP is formed from ADP and Pi during exergonic reactions.

b) ATP is converted into ADP and Pi during endergonic reactions.

c) ATP and ADP are identical molecules with the same energy content.

d) ADP is a product of ATP hydrolysis.

a) ATP is formed from ADP and Pi during exergonic reactions.

In which cellular process is ATP most directly involved?

a) DNA replication

b) Photosynthesis

c) Active transport

d) Cell division

c) Active transport

What is the result of the hydrolysis of ATP into ADP and Pi?

a) Energy is consumed.

b) Energy is released.

c) ADP and Pi are converted into glucose.

d) Oxygen is produced.

b) Energy is released.

What type of reaction is ATP hydrolysis (the breakdown of ATP into ADP and Pi)?

a) An endergonic reaction

b) A spontaneous reaction

c) An exergonic reaction

d) A redox reaction

c) An exergonic reaction

Why is ATP often referred to as the "energy currency" of the cell?

a) Because it can be easily converted into DNA.

b) Because it is used to build cell membranes.

c) Because it carries and transfers energy within the cell for various metabolic processes.

d) Because it is a structural component of ribosomes.

c) Because it carries and transfers energy within the cell for various metabolic processes.

What is the central concept of oxidation-reduction (redox) reactions?

a. Proton transfer

b. Electron transfer

c. Heat transfer

d. Mass transfer

b. Electron transfer

In a redox reaction, how do electrons move?

a. From an electron donor to an electron acceptor

b. From an electron acceptor to an electron donor

c. Within the same molecule d. In a random fashion

a. From an electron donor to an electron acceptor

What are the two half reactions that make up a redox reaction?

a. Acidic half reaction and basic half reaction

b. Electronegative half reaction and electropositive half reaction

c. Electron-donating half reaction and electron-accepting half reaction

d. Exothermic half reaction and endothermic half reaction

c. Electron-donating half reaction and electron-accepting half reaction

What are the molecules that participate in a half reaction called?

a. Catalysts

b. Reactants

c. Conjugate redox pairs

d. Enzymes

c. Conjugate redox pairs

What does the standard reduction potential measure in a redox reaction?

a. The concentration of reactants

b. The tendency of the acceptor of a conjugate redox pair to gain electrons

c. The speed of the reaction

d. The pH of the solution

b. The tendency of the acceptor of a conjugate redox pair to gain electrons

In a redox reaction, which conjugate redox pairs donate electrons to those with more positive reduction potentials?

a. Conjugate redox pairs with more negative reduction potentials

b. Conjugate redox pairs with more positive reduction potentials

c. Conjugate redox pairs with neutral reduction potentials

d. Conjugate redox pairs with acidic reduction potentials

a. Conjugate redox pairs with more negative reduction potentials

What is made available during the transfer of electrons in redox reactions?

a. Heat energy

b. Light energy

c. Chemical energy

d. Kinetic energy

c. Chemical energy

What is the purpose of an electron transport chain (ETC) in metabolic processes?

a. To synthesize ATP

b. To transport electrons from the primary electron acceptor to the primary electron donor

c. To transport electrons from the primary electron donor to the final electron acceptor

d. To produce glucose

c. To transport electrons from the primary electron donor to the final electron acceptor

Which of the following is NOT an electron carrier commonly found in cells?

a. NAD+

b. FAD

c. ATP

d. Coenzyme Q

c. ATP

What is the role of NAD+ in cellular respiration?

a. It acts as a final electron acceptor in the ETC.

b. It transfers electrons to the ETC.

c. It is an energy carrier molecule.

d. It stores excess glucose.

b. It transfers electrons to the ETC.

Which of the following is a characteristic of electron carriers within an ETC?

a. They always accept and transfer the same number of electrons and protons.

b. They differ in how many electrons and protons they accept and transfer.

c. They are found in the nucleus of the cell.

d. They are not involved in redox reactions.

b. They differ in how many electrons and protons they accept and transfer.

True or False: Electron carriers in ETCs are typically associated with cellular membranes

True

Which molecule is a component of the mitochondrial electron transport chain and plays a central role in oxidative phosphorylation?

a. NADP+

b. Cytochrome

c. ATP d. Ribosome

b. Cytochrome

What is the function of coenzyme Q in the ETC?

a. To produce glucose

b. To transfer electrons between complexes in the ETC

c. To store excess energy

d. To act as a final electron acceptor

b. To transfer electrons between complexes in the ETC

Which of the following electron carriers is involved in photosynthesis?

a. NAD+

b. Cytochrome

c. FAD

d. FMN

d. FMN

In cellular respiration, what is the final electron acceptor in the ETC?

a. Oxygen

b. Carbon dioxide

c. Glucose

d. Water

a. Oxygen

What is the primary function of electron transport chains in cells?

a. To produce heat energy

b. To transport protons across the cell membrane

c. To generate a proton gradient for ATP synthesis

d. To break down carbohydrates

c. To generate a proton gradient for ATP synthes

What are the intermediates and products of biochemical pathways commonly called?

a. Biochemical substances

b. Reactants

c. Metabolites

d. Enzymes

c. Metabolites

How are metabolic pathways organized within cells?

a. In a random and disorganized manner

b. As isolated, independent processes

c. To form biochemical pathways

d. As separate organelles

c. To form biochemical pathways

Metabolic pathways can be interconnected. What does this mean?

a. They are isolated from each other.

b. The intermediates of one pathway are used exclusively in that pathway.

c. The intermediates and end products of one pathway can serve as starting molecules for others.

d. They share the same enzymes.

c. The intermediates and end products of one pathway can serve as starting molecules for others.

What is "metabolite flux" referring to in the context of biochemical pathways?

a. The rate of reactions in a single pathway

b. The concentration of enzymes in a cell

c. The turnover of metabolites as they are used in various biochemical pathways

d. The storage of metabolites in cellular vacuoles

c. The turnover of metabolites as they are used in various biochemical pathways

What are enzymes, and what is their primary function?

a) Enzymes are nucleic acids that store genetic information.

b) Enzymes are proteins that catalyze specific reactions.

c) Enzymes are lipids that provide energy storage.

d) Enzymes are carbohydrates that support cell structure.

b) Enzymes are proteins that catalyze specific reactions.

What are cofactors in the context of enzymes?

a) Cofactors are the substrates upon which enzymes act.

b) Cofactors are products generated by enzyme reactions.

c) Cofactors are metals or organic molecules that assist enzyme function.

d) Cofactors are the end products of metabolic pathways.

c) Cofactors are metals or organic molecules that assist enzyme function.

What is the role of coenzymes in enzyme-catalyzed reactions?

a) Coenzymes provide structural stability to enzymes.

b) Coenzymes serve as the primary building blocks of enzymes.

c) Coenzymes act as catalysts to accelerate reactions.

d) Coenzymes transport electrons during reactions.

d) Coenzymes transport electrons during reactions.

How do enzymes speed up chemical reactions?

a) By increasing substrate concentration.

b) By binding substrates at their active sites and lowering activation energy.

c) By releasing cofactors.

d) By inhibiting ribozymes.

b) By binding substrates at their active sites and lowering activation energy.

What is the Michaelis constant (Km) in enzyme kinetics?

a) The maximum velocity of an enzyme-catalyzed reaction.

b) The substrate concentration needed to achieve half-maximal velocity.

c) The pH optimum for enzyme activity.

d) The temperature at which enzymes denature.

b) The substrate concentration needed to achieve half-maximal velocity.

What happens to the rate of an enzyme-catalyzed reaction as substrate concentration increases?

a) It remains constant.

b) It decreases.

c) It reaches a plateau.

d) It becomes exponential.

c) It reaches a plateau.

How do changes in pH and temperature affect enzyme activity?

a) They have no effect on enzyme activity.

b) Enzymes work optimally at high pH and low temperature.

c) Enzymes have pH and temperature optima for activity.

d) Enzymes are only active in extreme pH conditions.

c) Enzymes have pH and temperature optima for activity.

What are competitive inhibitors in enzyme reactions?

a) Molecules that increase enzyme activity.

b) Substances that bind to the active site of an enzyme.

c) Cofactors required for enzyme function.

d) Enzymes that speed up reactions without inhibitors.

b) Substances that bind to the active site of an enzyme.

What is the function of ribozymes in cellular processes?

a) Ribozymes store genetic information.

b) Ribozymes act as structural components of cell membranes.

c) Ribozymes are involved in protein synthesis and RNA processing.

d) Ribozymes catalyze reactions in the mitochondria.

c) Ribozymes are involved in protein synthesis and RNA processing.

Where is an important ribozyme located, and what is its role?

a) In the cell nucleus, where it regulates DNA replication.

b) In the cytoplasm, where it aids in cellular respiration.

c) In the ribosome, where it links amino acids during protein synthesis.

d) In the endoplasmic reticulum, where it synthesizes lipids.

c) In the ribosome, where it links amino acids during protein synthesis.

What are the three major approaches to regulating metabolism mentioned in the text?

a) Metabolic channeling, feedback inhibition, and posttranslational regulation

b) Metabolic channeling, regulation of gene expression, and posttranslational regulation

c) Metabolic compartmentation, gene expression, and transcriptional regulation

b) Metabolic channeling, regulation of gene expression, and posttranslational regulation

What does metabolic channeling refer to?

a) The regulation of gene expression

b) Localizing metabolites and enzymes in different parts of the cell

c) Posttranslational modification of enzymes

b) Localizing metabolites and enzymes in different parts of the cell

Which type of regulation involves controlling the rate of transcription and translation?

a) Allosteric control

b) Regulation of gene expression

c) Covalent modification

b) Regulation of gene expression

In allosteric control, how does an allosteric effector influence enzyme activity?

a) It binds covalently to the enzyme's catalytic site.

b) It binds noncovalently to a separate regulatory site, causing a conformational change.

c) It induces the enzyme to degrade other molecules.

b) It binds noncovalently to a separate regulatory site, causing a conformational change.

What is covalent modification in the context of enzyme regulation?

a) Reversible attachment of a chemical group to the enzyme, altering its activity

b) Irreversible attachment of a chemical group to the enzyme, permanently inactivating it

c) Regulation of enzyme activity by changing its location within the cell

a) Reversible attachment of a chemical group to the enzyme, altering its activity

What is feedback inhibition, and which enzymes are often subject to it?

a) It's the activation of enzyme activity by end products; all enzymes are subject to it.

b) It's the inhibition of enzyme activity by end products; the first enzyme in a pathway and enzymes at branch points are often subject to it.

c) It's the activation of enzyme activity by end products; only enzymes in metabolic channeling are subject to it.

b) It's the inhibition of enzyme activity by end products; the first enzyme in a pathway and enzymes at branch points are often subject to it.

What is the result of excess end product in feedback inhibition?

a) It accelerates the synthesis of the end product.

b) It has no effect on the synthesis of the end product.

c) It slows down the synthesis of the end product.

c) It slows down the synthesis of the end product.

What are the three essential requirements for all organisms mentioned in the text?

a) Oxygen, light, and glucose

b) Carbon, energy, and electrons

c) Water, vitamins, and minerals

d) DNA, RNA, and proteins

b) Carbon, energy, and electrons

Heterotrophs primarily use _______ as their source of carbon.

a) CO2

b) Organic molecules

c) Light

d) Electrons

b) Organic molecules

Autotrophs utilize _______ as their primary carbon source.

a) Glucose

b) CO2

c) Oxygen

d) Proteins

b) CO2

What do phototrophs use as their source of energy?

a) Organic molecules

b) Light energy

c) Chemical compounds

d) Electrons

b) Light energy

Chemotrophs derive their energy from:

a) Photosynthesis

b) Oxidation of chemical compounds

c) Light energy

d) Organic molecules

b) Oxidation of chemical compounds

What type of organisms extract electrons from reduced inorganic substances?

a) Phototrophs

b) Chemotrophs

c) Autotrophs

d) Heterotrophs

b) Chemotrophs

Which of the following is NOT one of the five nutritional types mentioned in the text?

a) Photoorganoheterotroph

b) Chemolithoheterotroph

c) Chemoorganoheterotroph

d) Photochemolithoautotroph

d) Photochemolithoautotroph

In the term "chemolithoautotroph," what does "autotroph" indicate?

a) It uses light as an energy source.

b) It obtains electrons from reduced organic compounds.

c) It uses CO2 as its primary carbon source.

d) It oxidizes chemical compounds for energy.

c) It uses CO2 as its primary carbon source.

What is the initial step in aerobic respiration of glucose?

a) Tricarboxylic acid cycle

b) Pentose phosphate pathway

c) Glycolysis

d) Entner-Doudoroff pathway

c) Glycolysis

Which pathway produces two NADH and two ATP, as well as precursor metabolites, during glucose catabolism?

a) Glycolysis

b) Entner-Doudoroff pathway

c) Pentose phosphate pathway

d) Tricarboxylic acid cycle

a) Glycolysis

The Entner-Doudoroff pathway produces which of the following important molecules that can be used in other metabolic pathways?

a) Pyruvate

b) ATP

c) NADH

d) Glyceraldehyde 3-phosphate

d) Glyceraldehyde 3-phosphate

Which pathway is a significant source of NADPH and plays a role in anabolism?

a) Glycolysis

b) Tricarboxylic acid cycle

c) Pentose phosphate pathway

d) Entner-Doudoroff pathway

c) Pentose phosphate pathway

The Embden-Meyerhof and pentose phosphate pathways are considered amphibolic because they:

a) Function only in catabolism

b) Function only in anabolism

c) Function in both catabolism and anabolism

d) Are not involved in metabolic processes

c) Function in both catabolism and anabolism

What is the primary product formed when pyruvate is fed into the tricarboxylic acid cycle?

a) ATP

b) Acetyl-CoA

c) NADPH

d) FADH2

b) Acetyl-CoA

How many NADH molecules are produced per acetyl-CoA during the tricarboxylic acid cycle?

a) None

b) One

c) Two

d) Three

b) Three

Which metabolic pathway oxidizes acetyl-CoA to produce CO2 and precursor metabolites?

a) Glycolysis

b) Entner-Doudoroff pathway

c) Pentose phosphate pathway

d) Tricarboxylic acid cycle

d) Tricarboxylic acid cycle

What is the primary role of the electron transport chain (ETC) in cellular respiration?

a. Synthesizing ATP directly

b. Oxidizing NADH and FADH2

c. Producing glucose molecules

d. Facilitating glycolysis

b. Oxidizing NADH and FADH2

During electron transport in the ETC, electrons flow from carriers with __________ reduction potentials to those with __________ reduction potentials.

a. positive; positive

b. positive; negative

c. negative; positive

d. negative; negative

c. negative; positive

What is the main function of the proton motive force (PMF) generated during electron transport?

a. Oxidizing organic molecules

b. Regulating glycolysis

c. Generating ATP by oxidative phosphorylation

d. Promoting cell division

c. Generating ATP by oxidative phosphorylation

In eukaryotic cells, where is ATP synthase located?

a. On the outer mitochondrial membrane

b. In the cytoplasm

c. On the inner mitochondrial membrane

d. In the nucleus

c. On the inner mitochondrial membrane

What is the role of ATP synthase in oxidative phosphorylation?

a. It transports electrons in the ETC.

b. It catalyzes the synthesis of ATP using PMF.

c. It converts glucose into pyruvate.

d. It stores energy in the form of NADH.

b. It catalyzes the synthesis of ATP using PMF.

What is the P/O ratio for NADH in eukaryotes?

a. 1.0

b. 2.5

c. 32

d. 11.4

b. 2.5

What is the maximum number of ATP molecules that can be theoretically generated through aerobic respiration in eukaryotes?

a. 2 ATP

b. 12 ATP

c. 32 ATP

d. 64 ATP

c. 32 ATP

What is the main difference between anaerobic and aerobic respiration?

a) Anaerobic respiration uses oxygen as the terminal electron acceptor.

b) Anaerobic respiration uses an exogenous molecule other than O2 as the terminal electron acceptor.

c) Anaerobic respiration produces more energy than aerobic respiration.

d) Anaerobic respiration has a longer electron transport chain (ETC).

b) Anaerobic respiration uses an exogenous molecule other than O2 as the terminal electron acceptor.

Which of the following is NOT a common alternate electron acceptor used in anaerobic respiration?

a) Nitrate

b) Sulfate

c) Oxygen

d) Carbon Dioxide (CO2)

c) Oxygen

Why does anaerobic respiration provide less energy compared to aerobic respiration?

a) Anaerobic respiration has a longer electron transport chain.

b) Anaerobic respiration uses more oxygen.

c) The alternate electron acceptors in anaerobic respiration have lower reduction potentials than oxygen.

d) Anaerobic respiration produces more protons.

c) The alternate electron acceptors in anaerobic respiration have lower reduction potentials than oxygen.

What is the primary role of fermentation in cellular metabolism?

a) To produce ATP through oxidative phosphorylation

b) To generate NADH through the catabolism of glucose

c) To reoxidize NADH and produce ATP through substrate-level phosphorylation

d) To transport electrons along the electron transport chain

c) To reoxidize NADH and produce ATP through substrate-level phosphorylation.

During fermentation, what is used to reoxidize NADH generated during glucose catabolism?

a) An exogenous electron acceptor

b) An endogenous electron acceptor

c) An electron transport chain

d) Oxygen molecules

b) An endogenous electron acceptor.

True or False: Flow of electrons from the electron donor to the electron acceptor during fermentation involves an Electron Transport Chain (ETC).

False.

How is ATP primarily synthesized during fermentation?

a) By oxidative phosphorylation

b) By chemiosmosis

c) By substrate-level phosphorylation

d) By photophosphorylation

c) By substrate-level phosphorylation.

What is the outcome of the different fermentation pathways in most organisms?

a) Production of oxygen

b) Production of carbon dioxide

c) Production of lactate or ethanol

d) Production of glucose

c) Production of lactate or ethanol.

Why are fermentation pathways of practical importance in clinical and industrial settings?

a) Because they involve the electron transport chain

b) Because they produce oxygen

c) Because they generate large amounts of ATP

d) Because they produce valuable products and have medical applications

d) Because they produce valuable products and have medical applications.

What is the primary source of energy for microorganisms during catabolism?

a) Polysaccharides

b) Monosaccharides

c) Disaccharides

d) Proteins

b) Monosaccharides

How are monosaccharides taken in and prepared for catabolism by microorganisms?

a) Phosphorylation

b) Oxidation

c) Hydrolysis

d) Fermentation

a) Phosphorylation

What process converts intracellular glycogen and starch into glucose 1-phosphate?

a) Hydrolysis

b) Phosphorolysis

c) Oxidation

d) Deamination

b) Phosphorolysis

Which enzyme is responsible for hydrolyzing triglycerides into glycerol and fatty acids?

a) Protease

b) Lipase

c) Amylase

d) Ribonuclease

b) Lipase

What is the usual fate of fatty acids following their hydrolysis?

a) Conversion to glucose

b) Oxidation to acetyl-CoA

c) Fermentation to lactic acid

d) Phosphorylation to form ATP

b) Oxidation to acetyl-CoA

How are proteins broken down during catabolism?

a) Deamination

b) Phosphorylation

c) Glycosylation

d) Oxidation

a) Deamination

What can be done with the carbon skeletons produced by deamination of amino acids?

a) Fermentation

b) Conversion to triglycerides

c) Conversion to nucleotides

d) Incorporation into cell walls

a) Fermentation

What is the primary purpose of oxygenic photosynthesis in eukaryotes and cyanobacteria?

a) To produce glucose

b) To generate ATP only

c) To trap light energy and produce ATP and NADPH

d) To convert CO2 into oxygen

c) To trap light energy and produce ATP and NADPH

Which two photosystems are involved in noncyclic photophosphorylation?

a) Photosystem I and Photosystem III

b) Photosystem I and Photosystem II

c) Photosystem II and Photosystem III

d) Photosystem II and Photosystem IV

b) Photosystem I and Photosystem II

In cyclic photophosphorylation, which of the following is generated?

a) ATP only

b) NADPH only

c) Both ATP and NADPH

d) Oxygen

a) ATP only