CH 4 - How Cells Obtain Energy

The enzyme sucrase breaks down disaccharide sucrose; what would the enzyme do if you mixed it with disaccharide lactose?

Nothing happens because any other sugar won't attach

What molecules do the electrons that were used to generate ATP end up in?

O2 picks up the high energy electrons so the process doesn't stop

Your body converts unused glucose into glycogen. Is this a catabolic or anabolic reaction?

anabolic

NADH, FADH2, and NADPH are examples of?

electron carrier...

What contains more energy, ADP or ATP?

ATP

What is the formula for cellular respiration?

C6H12O6 + 6O2 -> 6CO2 + 6H2O

Vitamins contain many organic molecules that assist and activate enzymes. What are these called?

Coenzymes and cofactors

Where do NADH and FADH2 deliver their electrons?

Electron transport chain

Is a running car driven by an exergonic or endergonic chemical reaction?

Exergonic

Which stage of cellular respiration generates the most ATP?

Oxidative phosphorylation

If you were testing for the presence of amino acids in enzymes, what would you expect the test to be positive or negative?

Positive, because most enzymes are proteins, and proteins are made of amino acids

Why do cells regulate enzyme function?

So that they do not produce too much or too little products

competitive inhibition

a general mechanism of enzyme activity regulation in which a molecule other than the enzyme's substrate is able to bind the active site and prevent the substrate itself from binding, thus inhibiting the overall rate of reaction for the enzyme

noncompetitive inhibition

a general mechanism of enzyme activity regulation in which a regulatory molecule binds to a site other than the active site and prevents the active site from binding the substrate; thus, the inhibitor molecule does not compete with the substrate for the active site

feedback inhibition

a mechanism of enzyme activity regulation in which the product of a reaction or the final product of a series of sequential reactions inhibits an enzyme for an earlier step in reaction series

ATP synthase

a membrane-embedded protein complex that regenerates ATP from ADP with energy from protons diffusing through it

substrate

a molecule on which the enzyme acts. They bind to enzymes to make products

enzyme

a molecule that catalyzes a biochemical reaction. They lower the activation energy of chemical reactions

citric acid cycle

a series of enzyme-catalyzed chemical reactions of central importance in all living cells that harvests the energy in the carbon-carbon bonds of sugar molecules to generate ATP; the citric acid cycle is an aerobic metabolic pathway because it requires oxygen in later reactions to proceed

electron transport chain

a series of four large, multi-protein complexes embedded in the inner mitochondrial membrane that accepts electrons from donor compounds and harvests energy from a series of chemical reactions to generate a hydrogen ion gradient across the membrane

active site

a specific region on the enzyme where the substrate binds

The energy currency used by cells is _____. a) ATP b) ADP c) AMP d) adenosine

a) ATP

Which of the following is not true about enzymes? a) They are consumed by the reactions they catalyze. b) They are usually made of amino acids. c) They lower the activation energy of chemical reactions. d) Each one is specific to the particular substrate(s) to which it binds.

a) They are consumed by the reactions they catalyze. After they catalyze, they still retain their shape

The cholesterol synthesized by cells uses which component of the glycolytic pathway as a starting point? a) glucose b) acetyl CoA c) pyruvate d) carbon dioxide

a) glucose

Which of the following fermentation methods can occur in animal skeletal muscles? a) lactic acid fermentation b) alcohol fermentation c) mixed acid fermentation d) propionic fermentation

a) lactic acid fermentation

Enzymes lower the _________ of a chemical reaction

activation energy

metabolism

all the chemical reactions that take place inside cells, including those that use energy and those that release energy

ATP

also called adenosine triphospate, it is the cell's energy currency

Energy is stored long-term in the bonds of _____ and used short-term to perform work from a(n) _____ molecule. a) ATP : glucose b) an anabolic molecule : catabolic molecule c) glucose : ATP d) a catabolic molecule : anabolic molecule

c) glucose : ATP

Chemiosmosis involves a) the movement of electrons across the cell membrane b) the movement of hydrogen atoms across a mitochondrial membrane c) the movement of hydrogen ions across a mitochondrial membrane d) the movement of glucose through the cell membrane

c) the movement of hydrogen ions across a mitochondrial membrane

When you digest food, your body breaks it down to release the energy. Is this a catabolic or anabolic reaction?

catabolic

Which of the following is not an example of an energy transformation? a) Heating up dinner in a microwave b) Solar panels at work c) Formation of static electricity d) None of the above

d) None of the above

The glucose that enters the glycolysis pathway is split into two molecules of _________. a) ATP b) phosphate c) NADH d) pyruvate

d) pyruvate

endergonic

describes a chemical reaction that results in products that store more chemical potential energy than the reactants

exergonic

describes a chemical reaction that results in products with less chemical potential energy than the reactants, plus the release of free energy

catabolic

describes the pathway in which complex molecules are broken down into simpler ones, yielding energy as an additional product of the reaction

anabolic

describes the pathway that requires a net energy input to synthesize complex molecules from simpler ones

What process is kept running by fermentation?

glycolysis

Which stage of cellular respiration generates the most NADH

glycolysis

glycolysis

the breakdown of glucose into three-carbon molecules with the production of ATP and NADH

bioenergetics

the concept of energy flow through living systems

aerobic cellular respiration

the process by which cells use oxygen to obtain usable energy from an energy source

oxidative phosphorylation

the production of ATP by the transfer of electrons down the electron transport chain to create a proton gradient that is used by ATP synthase to add phosphate groups to ADP molecules

fermentation

the steps that follow the partial oxidation of glucose via glycolysis to regenerate NAD+; occurs in the absence of oxygen and uses an organic compound as the final electron acceptor

anaerobic cellular respiration

the use of an electron acceptor other than oxygen to complete metabolism using electron transport-based chemiosmosis. Used in fermentation