Ch03 Cell Metabolism

APK2105C @ UF | Dr. Nguyen | Ch 3 Cell Metablism

metabolism

sum total of all chemical reactions that occur in cells

energy metabolism

reactions involved in energy storage and use

anabolism

These are examples of…

• amino acids→ protein

• glucose → glycogen

catabolism

These are examples of…

• glycogen → glucose

• protein → amino acids

hydrolysis

Identify this reaction

condensation

Identify the reaction

condensation

What other reaction accompanies phosphorylation?

hydrolysis

What other reaction accompanies dephosphorylation?

oxidation

removal of electrons; electrons are removed from a reactant, resulting in the formation of an ion product (i.e., charged atoms)

reduction

acceptance/addition of electrons; electrons combine w/ ions to form uncharged atoms

reducing equivalents

H atoms (not ions) are commonly referred to as…

oxidation

When H atoms are removed, is this an oxidation or reduction reaction?

energy

the capacity to perform work

work

The following are examples of _____ in the body:

• movement

• urine production

• cellular repair and reproduction

  • exocytosis of neurotransmitters from axons

metabolic

All of the work in our bodies is driven by ________ reactions.

kinetic energy

energy associated w/ matter in motion

potential energy

energy stored in matter that can become kinetic energy

first law of thermodynamics

law that states energy can neither be created nor destroyed, just converted from one form to another

second law of thermodynamics

law that states natural processes tend to proceed in the direction that spreads energy

releases; more

If a reaction ________ energy, it’s because the reactant molecules had _____ energy than the products

direction

∆E determines the _______ of a reaction

product; reactant

∆E = E_??? - E_???

exergonic reaction

Are these characteristics of an endergonic or exergonic reaction?

• proceeds spontaneously

• ∆E = negative

• releases energy in the form of work or heat

endergonic reaction

Are these characteristics of an endergonic or exergonic reaction?

• does not proceed spontaneously

• ∆E = positive

• energy is used/added

exergonic-endergonic coupling

Energy released from catabolic reactions is used to drive anabolic reactions. This is known as…

calorie

amount of energy/heat necessary to raise the temperature of 1 gram of water 1º C

equilibrium

occurs when the reactant is converted into a product at the same rate that a product is converted to a reactant; ∆E = 0

concentration; large

If the energy difference b/t the reactants and products is large, then the _______ difference at equilibrium will be _______.

greater; greater concentration

If the energy per mole of the reactants (kcal/mole) is _______ than that of the products, at equilibrium there will be a _______ ________ of products.

law of mass action

law that states than an increase in [reactants] relative to [products] tends to push a reaction forward, and that an increase in [products] relative to [reactants] tends to push a reaction in reverse

equilibrium constant

mathematically describes the relationship b/t [products] and [reactants] at equilibrium; K = [product] / [reactant]

equal; equilibrium

if K=1, there is an ______ concentration of products and reactants at ___________

twice; product; reactant; less; exergonic

If K=2, there is ______ as many _________ molecules at equilibrium as ________ molecules. This means there is _______ energy/mole in the products, so it is an ________ reaction.

exergonic b/c reactants have more energy

Is this an exergonic or endergonic reaction? Why?

more

Will a reverse activation need more or less energy?

transition state

If reactants A and B collide against each other w/ enough energy, they enter a ________ ______, which surpasses the activation energy barrier, forming products C and D.

cellular demands

How fast reactants are consumed and products are made (reaction rates) must match the _________ _________ of the environment at any given moment.

reactant; product; temperature; height, enzymes

Factors affecting reaction rates:

• [?] and [?]

• ________

• ________ of the activation energy barrier

• ________

enzymes

• biological catalysts that speed up chemical reactions by lowering the activation energy

• do not change the nature of the reaction or the end product

• not changed by the reaction

lock and key model

substrate specificity model stating that the shape of the substrate complements the active site of the enzyme

induced fit model

substrate specificity model stating that both the substrate and the product can bind to the active site, allowing the action to be reversible

temperature

Affects rate of enzyme-catalyzed reactions. However, it is tightly regulated, so changes in it are rarely significant.

pH; increasing; structural; charge

Affects rate of enzyme-catalyzed reactions. _______ acidity (decreasing pH) decreases enzyme activity by causing _______ (conformational) changes, as well as altering the _______ at the active site.

cofactors

Affects rate of enzyme-catalyzed reactions. Locks the reacting substance into its active site. W/o it, the reaction can’t take place.

vitamins; minerals; cofactors

Most vitamin deficiency diseases happen by missing _______ and _______ which serve as ________.

coenzymes

• Affects rate of enzyme-catalyzed reactions.

• Vitamin-derived cofactors.

• Function to carry chemical groups from one reaction to another.

• Unchanged by reactions → recycled

FAD, NAD, and CoA

What are 3 important metabolic coenzymes?

saturation; faster

Point of [substrate] or [enzyme] that affects rate of enzyme-catalyzed reactions. Higher concentrations of substrates or enzymes result in a ______ reaction rate.

affinity

• Affects rate of enzyme-catalyzed reactions.

• How tightly substrate molecules bind to their active site.

• A lower… means the enzyme is less likely to increase in reaction rate, and vice-versa.

allosteric regulation

enzyme regulation — a modulator binds reversibly to the regulatory site on an enzyme, inducing a change in its conformation and activity

left

Will an allosteric activator cause a left- or rightward shift in reaction rate?

right

Will an allosteric inhibitor cause a left- or rightward shift in reaction rate?

covalent regulation

enzyme regulation — changes in an enzyme’s activity occur as a result of the covalent bonding of a specific chemical group to a site on the enzyme molecule; usually a phosphate group

protein kinases

covalent regulation — enzymes that ADD phosphate groups (phosphorylation) to another enzyme, catalyzing the formation of a covalent bond b/t the chemical group and enzyme molecule

phosphatases

covalent regulation — enzymes that REMOVE a phosphate group (dephosphorylation) from another enzyme

feedback (end-product) inhibition

enzyme regulation — an intermediate product of an metabolic pathway that allosterically inhibits an enzyme that catalyzes an earlier reaction in the same pathway

ATP hydrolysis

process where high-energy phosphate bonds in ATP molecules, containing potential energy, are broken

hydrolyze

When cells need energy to perform work, they must ________ previously formed ATP to obtain energy.

substrate level phosphorylation

mechanism of ATP synthesis where a phosphate group is transferred from a metabolic intermediate (x) to ADP to form ATP; DOES NOT require O₂

oxidative phosphorylation

mechanism of ATP synthesis where ADP binds w/ an inorganic phosphate by harnessing the energy released when atoms or electrons are transported through the ETC in the inner mitochondrial membrane; REQUIRES O₂

6; 6

Glucose oxidation requires 6 O₂ molecules and produces how many molecules of CO₂ and H₂O?

cytosol

Where does glycolysis occur?

mitochondrial matrix

Where does the Krebs Cycle occur?

across inner mitochondrial membrane

Where does oxidative phosphorylation occur?

2; 4; 2; 2

In glycolysis, for EACH molecule of glucose (6-C), how many pyruvate and ATP molecules are produced? How many ATP molecules are consumed? How many NAD⁺ molecules are reduced to NADH?

anaerobic

Is glycolysis an aerobic or anaerobic reaction?

glycolysis

First step in glucose oxidation where each glucose molecule is broken down into two pyruvate molecules w/ a net gain of 2 ATP and 2 NADH

linking step

process where each pyruvate molecule is converted into acetyl CoA before entering the Krebs cycle, producing NADH and releasing CO₂

1 NADH and 1 CO₂

What does EACH pyruvate molecule produce during the linking step?

linking step

During what step of glucose oxidation is CO₂ first produced?

Krebs Cycle

Second step in glucose oxidation in which acetyl CoA is a reactant used to produce CO₂ and coenzymes; aka citric acid cycle

3; 1; 2; 1

For EACH acetyl CoA, how many NADH, FADH, CO₂ and ATP are produced?

oxidative phosphorylation

Third step in glucose oxidation where NADH and FADH release electrons to the ETC. As the electrons pass along the chain, ATP molecules are generated.

ATP synthase

enzyme that synthesizes ATP from ADP by adding a phosphate group; in the ETC

4

How many H⁺ ions does the first pump (I) release?

4

How many H⁺ ions does the second pump (III) release?

2

How many H⁺ ions does the third pump (IV) release?

4

How many H⁺ are required to produce 1 ATP?

2.5 ATP; 10/4

What is the average number of ATP produced per NADH molecule? Why?

1.5 ATP; 6/4

What is the average number of ATP produced per FADH molecule? Why?

2; 2

What is the total number of NADH and CO₂ produced in the linking step?

6; 2; 4

What is the total number of NADH, FADH, and CO₂ produced in the Krebs Cycle?

metabolic demand

the rate at which oxygen must be supplied depends on how fast tissues are consuming it

skeletal and nervous

What are two tissues that are most metabolically active?

slow down; NAD+

If metabolic demand outweighs O₂ delivery, the ETC will ____ ____, leaving little to no _____, which is necessary for glycolysis.

lactic acid fermentation

Process that converts glucose into energy w/o using oxygen, producing lactic acid as a byproduct.

cytosol

Where does lactic acid fermentation occur?

lactate dehydrogenase (LDH)

enzyme that catalyzes the conversion of pyruvate to lactate during anaerobic respiration (lactic acid fermentation)

NAD+; ATP

What is the product of lactic acid fermentation? What is it reused for?

interstitial; detrimental

Accumulation of lactate (lactic acid) in the _______ fluid and blood will eventually become _______ for normal cellular functions.