Glycolysis and Fermentation

metabolism

all chemicla reactions in a cell

anabolic pathways

synthesize cellular components, often polymers

Anabolic Pathways involve a ____ in order and a ____ in entropy

increase; decrease

endergonic reaction

energy requiring

catabolic pathways

involved in the breakdown of cellular constituents

the synthesis of polymers such as starch and glycogen is an example of a __ reaction

anabolic/endergonic reaction

Hydrolysis of glucose is an example of a ___ reaction

catabolic/exergonic reaction

exergonic reactions

energy liberating reactions

Catabolic reactions involve a ___ in order and a ___ in entropy

decrease; increase

The molecule most commonly used as an energy intermediate

adenosine triphosphate (ATP)

GTP and creatine are ____ molecules and have what function in metabolism

high energy; store chemical energy that can be converted to ATP

chemical energy can be stored as ____ ____ such as NADH

reduced coenzymes

What two energy rich bonds does ATP have?

Phosphoanhydride bonds

Phosphoanhydride bonds link ____ in ATP

phosphate groups

phosphoester bonds link ___ in ATP

phosphate and ribose

how is energy released from phosphoanhydride bonds

by hydrolyzing the bond

what three things make the hydrolysis of ATP exergonic?

1. charge repulsion

2. resonance stabilization

3. increased entropy

ATP and ADP are ____ energy than AMP

higher

Chemotrophic energy metabolism

describes the reactions and pathways by which cells catabolize nutrients and conserve the released energy in the form of ATP

describe oxidation reactions

they yield energy by removal of hydrogen ions and electrons

another name for oxidation

dehydrogenation

many of the the enzymes involved in oxidation are called ____ because they remove 2 hydrogen atoms

dehydrogenases

In a redox reaction, the molecule receiving electrons is _____

reduced

reduction is a ____ process

endergonic

(redox) what kind of reaction is hydrogenation?

reduction; Hydrogen ions accompany the transferred electrons

Why are coenzymes in low concentration in the cell?

because they are recycled

What role does NAD+ play in redox reactions?

it serves as an electron acceptor, adding two electrons and a proton to its aromatic ring

The most common coenzyme involved in energy metabolism

Nictotinamide adenine dinucleotide

How do most chemotrophs meet their energy needs?

by oxidizing organic food molecules

Why is glucose a good source of energy?

its oxidation is a highly exergonic process

In relation to oxygen, what conditions yield the most energy from glucose catabolism?

In the presence of oxygen

aerobic respiration

complete oxidation of glucose in the presence of oxygen

Obligate aerobes

have an absolute requirement for oxygen

obligate anaerobes

cannot use oxygen as an electron acceptor; oxygen is toxic to these species

Facultative organisms

can function in aerobic or anaerobic conditions

How does glycolysis generate ATP?

By catabolizing glucose to pyruvate

Name the important features of glycolysis that involves Gly-1 and Gly-3

the initial input of 2 ATP

Name the important features of glycolysis that involves Gly-4

the sugar-splitting reaction, in which glucose is split into two three carbon molecules

Name the important features of glycolysis that involves Gly-6

the oxidative event that generates NADH, concurrent with phosphorylation

Name the important features of glycolysis that involves Gly-7 and Gly-10

the two steps at which the reaction sequence is coupled to ATP generation

Energetically describe glycolysis

the pathway is extremely exergonic in the direction of pyruvate formation

Summarize glycolysis

THe two molecules of ATP formed in hte second phosphorylation event (Gly-10) represent the net yield of ATP for the glycolytic pathway

What happens to pyruvate in the absence of oxygen?

It undergoes fermentation to regenerate NAD+ from NADH

How do cells regulate their redox state, or general level of oxidation of cellular components)?

by monitoring and stabilizing DNA+/NADH ratio

What are the two possible outcomes of transferring electrons to pyruvate?

Lactate or Ethanol

What enzyme catalyzes the conversion of pyruvate to lactate?

Lactate dehydrogenase (LDH)

What enzymes catalyze the conversion of pyruvate to acetylaldehyde and acetyladehyde to ethanol respectively?

Pyruvate Dehydrogenase (PDC), Alcohol Dehydrogenase (ADH)

Proprionate fermentation

bacteria reduce pryuvate to proprionate

Butylene glycol fermentation

the process by which bacteria cause food spoilage

What do process that yield acetone, isopropyl alcohol, or butyrate have in common?

they reoxidize NADH by the transfer of electrons to an organic acceptor

describe the electron acceptor and net oxidation of fermentation?

there is no external electron acceptor and no next oxidation occurs

aerobic glycolysis

cancer cells ferment glucose to lactate, even in the presence of oxygen

How does the use of aerobic glycolysis allow cancer cells to out grow healthy cells?

1. they dramatically increase the amount of glucose consumed

2. they display an increase in activity of nutrient transporters

What do cancer cells use aerobic glycolysis for?

primarily to produce carbon skeletons for biosynthesis of substances in high demand by proliferating cells

Do cancer cells primarily use aerobic glycolysis for energy production?

no

Fluorodeoxyglucose

a radioactive glucose analogue that is given to patients and them imaged as it accumulates in cancer cells

How do radiotracers work?

they rely on the existence of naturally occuring isotopes of common elements

what is isotopic labeling used for?

used to follow thefate of biochemical intermediates in metabolic studies

how are other sugars and glycerol catabolized by the glycolytic pathway?

they are hydrolyzed into monosaccharides and then converted into a glycolytic intermediate

____ and ____ enter most directly after phosphorylation on carbon atom 6, while ___ and ___ require more steps

glucose and fructose, mannose and fructose