Combo with "Biology Exam #2" and 1 other

fermentation

(1) Speaking specifically about energy metabolism, the anaerobic degradation of a substance such as glucose to smaller molecules such as lactic acid or alcohol with the extraction of energy. (2) Speaking generally, metabolic processes that occur in the absence of O2.

Which step in glycolysis is an example of substrate-level phosphorylation?

-Step 3: fructose 6-phosphate + ATP → fructose 1,6-bisphosphate + ADP + Pi -Step 1: glucose + ATP → glucose 6-phosphate + ADP + Pi

A metabolic pathway is

-a series of separate chemical reactions that together accomplish a complex chemical transformation. -a set of chemical transformational steps, each with a specific enzyme. -a means for transforming cellular energy. -vulnerable to inhibitors and activators that target some key enzymes.

0.5 mole of glucose is oxidized by glycolysis and lactic acid fermentation, the amount of ATP generated in the cytosol would be

1 mole.

In step 6 of glycolysis, the reaction glyceraldehyde 3-phosphate + NAD+ + Pi leads to which products?

1,3-bisphosphoglycerate + NADH

What role does water play in photosynthesis?

1.It acts as a source of oxygen atom found in the product O2. 2.It acts as an electron donor. 3.It serves as a reactant. 4.It serves as a solvent.

For each glucose molecule being oxidized, the citric acid cycle produces

2 FADH2.

The hydrolysis of ATP can be summarized by the equation below. ATP + H2O → ADP + Pi ΔG = -7.3 kcal/mol How many moles of ATP will a man hydrolyze in a day if he expends 2,300 kilocalories of free energy through this process?

315 mol

In green plant photosynthesis, water is A. oxidized to oxygen gas (O2) in the light. B. reduced to hydrogen gas. C. used to hydrolyze ATP. D. oxidized to O2 in the dark. E. an electron acceptor.

A

Photorespiration takes place in A. mitochondria, chloroplasts and peroxisomes B. chloroplasts and mitochondria C. the lysosomes. D. the microbodies. E. the cytoplasm and peroxisomes

A

Which of the following statements concerning the Calvin cycle is false? A. Light energy is not required for the cycle to proceed. B. CO2 is assimilated into sugars. C. RuBP is regenerated. D. It uses energy stored in ATP and NADPH + H+. E. All of the above are false.

A

coenzyme A (CoA)

A coenzyme used in various biochemical reactions as a carrier of acyl groups.

action spectrum

A graph of a biological process versus light wavelength; shows which wavelengths are involved in the process.

absorption spectrum

A graph of light absorption versus wavelength of light; shows how much light is absorbed at each wavelength.

reaction center

A group of electron transfer proteins that receive energy from light-absorbing pigments and convert it to chemical energy by redox reactions.

photosystem

A light-harvesting complex in the chloroplast thylakoid composed of pigments and proteins.

What is catabolic interconversion?

A metabolic pathway in which a large molecule is broken down into its constituent molecules and releases energy

glyceraldehyde 3-phosphate (G3P)

A phosphorylated three-carbon sugar; an intermediate in glycolysis and photosynthetic carbon fixation.

photon

A quantum of visible radiation; a “packet†of light energy.

electromagnetic radiation

A self-propagating wave that travels though space and has both electrical and magnetic properties.

pigment

A substance that absorbs visible light.

Which compound could act as a feedback inhibitor of an enzyme catalyzing an early step of glycolysis?

ATP

Reduction of carbon dioxide to the level of carbohydrates relies on energy from

ATP and NADPH.

oxidative phosphorylation

ATP formation in the mitochondrion, associated with flow of electrons through the respiratory chain.

Photophosphorylation requires

ATP synthase.

Which molecule from glycolysis or the citric acid pathway serves as the building block for lipid synthesis?

Acetyl CoA

ATP synthase

An integral membrane protein that couples the transport of protons with the formation of ATP.

autotroph

An organism that is capable of living exclusively on inorganic materials, water, and an energy source other than the chemical bonds of organic compounds. Some autotrophs (photoautotrophs) use sunlight as their energy source. Others (chemoautotrophs) use oxidation of inorganic compounds. (Contrast with heterotroph.)

heterotroph

An organism that requires preformed organic molecules as sources of energy and chemical building blocks. (Contrast with autotroph.)

lactic acid fermentation

Anaerobic series of reactions that convert glucose to lactic acid, in some bacteria and animal cells.

chlorophyll

Any of several green pigments associated with chloroplasts or with certain bacterial membranes; responsible for trapping light energy for photosynthesis.

ATP is produced during the light reactions via A. CO2 fixation. B. chemiosmosis. C. reduction of water. D. glycolysis. E. noncyclic electron flow from photosystem I

B

During photorespiration, rubisco uses _______ as a substrate. A. CO2 B. O2 C. glyceraldehyde 3-phosphate D. 3-phosphoglycerate E. NADPH

B

Which statement about Photosystem I (PSI) and Photosystem II (PSII) is false?

Both photosystems can operate in a cyclic fashion.

How are ATP and NADH similar?

Both structures contain a ribose sugar, an adenine ring, and more than one phosphate group.

Cyclic electron transport A. involves photosystem II. B. results in the formation of NADPH. C. results in the formation of ATP. D. requires the oxidation of water. E. does not use the electron transport chain between the two photosystems.

C

Plants give off O2 because A. O2 results from the incorporation of CO2 into sugars. B. they do not respire; they photosynthesize. C. water is the initial electron donor, leaving O2 as a photosynthetic by-product. D. electrons moving down the electron chain bind to water, releasing O2. E. O2 is synthesized in the Calvin cycle.

C

Which is an example of a catabolic interconversion?

C16 fatty acid to 8 acetyl CoA

Which progression represents a path that a carbon atom could follow?

CO2 in atmosphere → glucose in plant → starch in plant → glucose in cow → protein in cow

In the citric acid cycle, carbon atoms end up as

CO2.

Which class of compounds is a direct product of photosynthesis?

Carbohydrates

Which sequence describes the general flow of free energy in the cell?

Catabolic reactions → NAD+ reduction → phosphoanhydride bond of ATP → anabolic reactions

pyruvate oxidation

Conversion of pyruvate to acetyl CoA and CO2 that occurs in the mitochondrial matrix in the presence of O2.

The Calvin cycle results in the production of A. glucose. B. starch. C. rubisco. D. G3P. E. ATP.

D

The first phase of photosynthesis, a series of reactions that requires the absorption of photons to form ATP and NADPH, is referred to as the _______ phase. A. reduction B. dark reactions C. carbon fixation D. light reactions E. None of the above

D

Chlorophyll is suited for the capture of light energy because A. certain wavelengths of light raise it to an excited state. B. in its excited state it gives off electrons. C. its structure allows it to attach to thylakoid membranes. D. it can transfer absorbed energy to another molecule. E. All of the above

E

Which of the following statements regarding the relationship between photosynthesis and cellular respiration in plants is true? A. Photosynthesis occurs in specialized photosynthetic cells. B. Cellular respiration occurs in specialized respiratory cells. C. Cellular respiration and photosynthesis can occur in the same cell. D. Photosynthesis is limited to specialized plant cells and cellular respiration does not occur in plant cells. E. Both a and c

E

If four molecules of ribulose 1,5-bisphosphate (RuBP) were added to a solution containing rubisco and CO2, what would be the product(s) of the reaction?

Eight molecules of 3-phosphoglycerate (3PG)

Which statement regarding glycolysis is true?

Energy from ATP must be expended in the early steps.

If a person eats a meal high in protein content, which enzyme(s) are most likely to be activated?

Enzymes in the citric acid cycle

Which is the correct sequence of phases in the Calvin cycle?

Fixation of CO2, reduction and sugar production, ribulose 1,5-bisphosphate regeneration

chemiosmosis

Formation of ATP in mitochondria and chloroplasts, resulting from a pumping of protons across a membrane (against a gradient of electrical charge and of pH), followed by the return of the protons through a protein channel with ATP synthase activity.

The reactions making up the citric acid cycle are important because they capture free energy in the form of

GTP, FADH2, and NADH.

Which is an example of an anabolic interconversion?

Gluconeogenesis

citric acid cycle

In cellular respiration, a set of chemical reactions whereby acetyl CoA is oxidized to carbon dioxide and hydrogen atoms are stored as NADH and FADH2. Also called the Krebs cycle.

light-harvesting complex

In photosynthesis, a group of different molecules that cooperate to absorb light energy and transfer it to a reaction center. Also called antenna system.

photosystem II

In photosynthesis, the complex that absorbs light at 680 nm, passing electrons to the electron transport chain in the chloroplast.

photosystem I

In photosynthesis, the complex that absorbs light at 700 nm, passing electrons to ferrodoxin and thence to NADPH.

cyclic electron transport

In photosynthetic light reactions, the flow of electrons that produces ATP but no NADPH or O2.

Which statement about metabolic pathways is false?

In prokaryotes, reactions in a pathway are located in multiple compartments.

How does a compound that uncouples ATP synthesis from electron transport help a person lose weight?

It diverts some of the chemical energy coming from glucose into heat instead of into ATP formation.

Which statement about rubisco is true?

It generates a six-carbon molecule that splits into two 3-phosphoglycerate (3PG) molecules.

How is free energy that is captured in the molecules NADH and FADH2 passed on in the cell?

It is used to establish a proton gradient across a membrane.

photosynthesis

Metabolic processes carried out by green plants and cyanobacteria, by which visible light is trapped and the energy used to convert CO2 into organic compounds.

Which progression shows a ranking of light from lowest energy to highest energy?

Microwaves, infrared light, yellow light, blue light, X rays

Which organelle contains enzymes necessary for aerobic cellular energy production in eukaryotes?

Mitochondria

Reduced electron carriers are critical to the citric acid cycle because

NADH and FADH2 can donate their electrons to the electron transport chain and be regenerated to allow the citric acid cycle to continue.

anaerobic

Occurring without the use of molecular oxygen, O2. (Contrast with aerobic.)

Which process is responsible for the largest amount of ATP production during cellular respiration?

Oxidative phosphorylation

On what timescale would you need to capture data to study the mechanism of excitation in the reaction center of a photosystem?

Picoseconds (10-12 s)

Which statement describes ways that coenzymes are involved in cellular respiration and photosynthesis?

Reduced coenzymes act as carriers of energy released from cellular respiration and as carriers of energy absorbed from light during photosynthesis.

oxidation

Relative loss of electrons in a chemical reaction; either outright removal to form an ion, or the sharing of electrons with substances having a greater affinity for them, such as oxygen. Most oxidations, including biological ones, are associated with the liberation of energy. (Contrast with reduction.)

aerobic

Requiring molecular oxygen, O2. (Contrast with anaerobic.)

How are steps 1-3 of glycolysis different from steps 7-10?

Steps 1-3 catalyze reactions that require ATP, while steps 6-10 catalyze changes that produce NADH and ATP.

Which molecule shuttles energy from the leaf to the root cells in many plants?

Sucrose

gluconeogenesis

The biochemical synthesis of glucose from other substances, such as amino acids, lactate, and glycerol.

cellular respiration

The catabolic pathways by which electrons are removed from various molecules and passed through intermediate electron carriers to O2, generating H2O and releasing energy.

glycolysis

The enzymatic breakdown of glucose to pyruvic acid.

How does the oxidation of glucose carried out in a chemistry lab differ from its oxidation in a cell?

The forms of energy released differ.

light reactions

The initial phase of photosynthesis, in which light energy is converted into chemical energy.

electron transport

The passage of electrons through a series of proteins with a release of energy which may be captured in a concentration gradient or in chemical form such as NADH or ATP.

carbon-fixation reactions

The phase of photosynthesis in which chemical energy captured in the light reactions is used to drive the reduction of CO2 to form carbohydrates.

Which statement about oxidative phosphorylation is false?

The process requires a membrane that is permeable to protons.

What would happen if regeneration of NAD+ were inhibited during lactic acid fermentation?

The rate of lactic acid production would decrease.

Calvin cycle

The stage of photosynthesis in which CO2 reacts with RuBP to form 3PG, 3PG is reduced to a sugar, and RuBP is regenerated, while other products are released to the rest of the plant. Also known as the Calvinâ€"Benson cycle.

Which statement best describes the first three steps of glycolysis, in which glucose is converted to fructose 1,6-bisphosphate?

These reactions require energy in the form of 2 ATP per glucose molecule.

Fermentation is a process that occurs

in many organisms, including plants and vertebrates.

Pyruvate oxidation to acetyl CoA is a complex reaction because

it is a multistep chemical reaction involving five different coenzymes and 60 individual proteins.

The difference between oxidation and reduction is that

oxidation reduces the number of electrons in a reactant, while reduction increases the number of electrons.

Cellular respiration refers to the metabolic process that

oxidizes organic molecules to obtain a useful form of energy.

Under anaerobic conditions, _______ is absent.

oxygen

Cyclic electron transport involves _______ and indirectly generates _______.

photosystem I; ATP

Light is needed for photosynthesis, because it

provides energy, which is converted to chemical energy.

ATP synthase is the protein complex that

rotates when protons flow through it, causing ADP and Pi to combine.

Under anaerobic conditions, pyruvate

s fermented to lactate or alcohol.

Proteins are built from carbons that come from

the citric acid cycle.

All of the following can happen when a photon comes into contact with a pigment molecule except

the photon lowers the ground state of the molecule.

An action spectrum measures

the relative rate of photosynthesis as a function of wavelength.

The most important wavelengths of light for photosynthesis are

the visible wavelengths between 400 and 525 nm and between 600 and 700 nm.