Chapter 6 Flashcards by Enide Clerizier

All cells need to accomplish two fundamental tasks

Synthesize new parts
Harvest energy to power reactions

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Sum of all chemical reaction in a cell:

metabolism

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two types of metabolism

Catabolism

Anabolism

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Degradation of compounds to release energy
Cells capture energy to make ATP

catabolism

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Assemble subunits of macromolecules
Use ATP to drive reactions

Anabolism

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another name for Anabolism

Biosynthesis

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Produced during
catabolism

Precursor metabolites

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Contains just glucose, inorganic salts

glucose-salts medium

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source of energy for glucose-salts medium

glucose

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is starting point for all
cellular components

glucose

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glucose molecules
are broken into smaller

precursor metabolites

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why do the precursor
metabolites exit the catabolic
pathway early

to be used in biosynthesis

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are intermediates of
catabolism that can be used in anabolism

Precursor metabolites

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is the capacity to do work

Energy

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Two types of energy

potential and kinetic

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stored energy

Potential

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energy of movement

Kinetic

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Energy in universe cannot be

created or destroyed,

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what can energy do to change

it can be converted between forms

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Light powers synthesis of organic compounds from CO2

Photosynthetic organisms

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what powers Photosynthetic organisms

Light powers synthesis of organic
compounds from CO2

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what kind of energy does Photosynthetic organisms convert

kinetic energy

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what does Photosynthetic organisms convert KE to

potential energy of chemical bonds

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Obtain energy by degrading organic matter to make other organic compounds

Chemoorganotrophs

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how do Chemoorganotrophs get energy

degrading organic matter to make other organic compounds

what kind of energy does Chemoorganotrophs convert

potential energy of chemical bonds

what does Chemoorganotrophs convert PE to

other potential energy of chemical bonds

is energy available to do work

Free energy

Energy released when chemical bond is brok

free energy

Energy is released in reaction

Exergonic reactions

what has more energy in Exergonic reactions product or reactants

reactants

Reaction requires input of energy

Endergonic reactions

what has more energy in Endergonic reactions product or reactants

products

series of chemical reactions that convert starting compound to an end product

Metabolic pathways

types of Metabolic pathways

linear, branched, cyclical

energy currency of the cell

ATP (Adenosine triphospate)

accepts free energy

ADP

releases free energy

ATP

Cells produce ATP by adding what to ADP using energy

Three processes to generate ATP

-Substrate-level phosphorylation (chemoorganotrophs) -Oxidative phosphorylation (chemoorganotrophs) -* Photophosphorylation (photoautotrophs)

Addition of phosphate using energy released during an exergonic reaction

Substrate-level phosphorylation

Using energy from a proton motive force powered by the oxidation of nutrients

Oxidative phosphorylation

Using energy from a proton motive force powered by sunlight

Photophosphorylation

what kind of trophs use Photophosphorylation

photoautotrophs

what kind of trophs use Substrate-level phosphorylation

chemoorganotrophs

what kind of trophs use Oxidative phosphorylation

chemoorganotrophs

Electrons removed through series of

oxidation-reduction reactions or redox reactions

Substance that loses electrons is

oxidized

Substance that gains electrons is

reduced

what atom usually does the moving

Electron-proton pair, or hydrogen atom,

Dehydrogenation

oxidation

Hydrogenation

reduction

OILRIG

Oxidation Is Loss Reduction Is Gain

what happens when Some atoms, molecules are more electronegative than others

Greater affinity for electrons

electrons move from molecule that has low affinity for

electrons (energy source)

Energy released when

electrons move from molecule that has low affinity for electrons (energy source) to a molecule that has high affinity for electrons (terminal electron acceptor)

electrons move from molecule that has low affinity for electrons (energy source) to a molecule that has high affinity for

electrons (terminal electron acceptor)

More energy released when difference in electronegativity is

greater

used as energy source

Organic (ex: glucose), inorganic compounds (ex; H2S)

used as terminal electron acceptor

O2 (for aerobes), other molecules

transfer electrons to the terminal electron acceptor

Electron Carriers

Electrons transferred to

Electron Carriers

(oxidized) Electron Carriers

NAD+

(reduced) Electron Carriers

NADH

Electron carriers represent

reducing power

why do Electron carriers represent reducing power

because they easily transfer electrons to chemicals with higher affinity for electrons

speed up conversion of substrate into product

Biological catalysts:

how do Biological catalysts speed up conversion of substrate into products

by lowering activation energy

energy required to start a reaction

activation energy

are biological catalysts, they increase the rate of a reaction

Enzymes

how are Enzymes named

ends in –ase

on surface of enzyme binds substrate(s) weakly

Active site

Causes enzyme shape to change slightly

Active site

what do Active site do to activation energy

lower

are used to break large molecules into smaller ones or to build large molecules from its subunits

Enzymes

Some enzymes require the assistance of an attached non-protein component called

Cofactors

are organic cofactors

Coenzymes

are organic cofactors

Coenzymes

increase doubles speed of enzymatic reaction up until maximum

10°C

Proteins denature at

higher temperatures

Enzyme activity can be controlled by regulatory molecules binding to allosteric site

Allosteric Regulation

Enzyme activity can be controlled by regulatory molecules binding to

allosteric site

Distorts enzyme shape, prevents or enhances binding of substrate to active site

Allosteric Regulation

Regulatory molecule is usually

end product

Regulatory molecule is usually end product

feedback inhibition

inhibitor binds to active site

Competitive inhibition

Chemical structure of inhibitor usually similar to

substrate

Blocks substrate

Competitive inhibition

inhibitor binds to a site different than the active site

Non-competitive inhibition

Allosteric inhibitors are example of what

Non-competitive inhibition

are all Non-competitive inhibition reversible

Central metabolic pathway

* Glycolysis * Pentose phosphate pathway * Tricarboxylic acid cycle

Key outcomes of Catabolism

* ATP * Reducing power * Precursor metabolites

The Central Metabolic Pathways

1) glycolysis 2) pentose phosphate pathway 3) Tricarboxylic acid cycle (TCA)

types of Reducing power

NADH FADH2 NADPH

two fates of Glucose molecule

- Can be completely oxidized to CO2 for maximum ATP - Can be siphoned off as precursor metabolite for use in biosynthesis

Gradually oxidize glucose to

CO2

central metabolic are catabolic or anabolic

catabolic

Pathways generate what?

precursor metabolites + reducing power (for use in biosynthesis)

Splits glucose (6C) to two pyruvate (3C)

Glycolysis

Glycolysis splits glucose into how many pyruvate

what does Glycolysis use to make pyruvate

glucose

Primary role is production precursor metabolites, NADPH

Pentose phosphate pathway

primary role of Pentose phosphate pathway

production of precursor metabolites, NADPH

Oxidizes pyruvates from glycolysis

Tricarboxylic acid cycle (TCA)

primary role of Tricarboxylic acid cycle (TCA)

Generates reducing power, precursor metabolites, ATP

does aerobic respiration use electron transport chain

yes

what terminal electron acceptor does aerobic respiration use

does anaerobic respiration use electron transport chain

yes

what terminal electron acceptor does aerobic respiration use

anything other than O2 usually nitrate, nitrite, sulfate

does fermentation use electron transport chain

what terminal electron acceptor does fermentation use

organic molecule (pyruvate or derivative)

ATP made by substrate-level phosphorylation with aerobic respiration

ATP made by oxidative phosphorylation with aerobic respiration

total ATP made with aerobic respiration

ATP made by substrate-level phosphorylation with anaerobic respiration

less than aerobic respiration

ATP made by oxidative phosphorylation with anaerobic respiration

less than aerobic respiration

total ATP made with anaerobic respiration

less than aerobic respiration

ATP made by substrate-level phosphorylation with fermentation

ATP made by oxidative phosphorylation with fermentation

total ATP made with fermentation

net gain of Glycolysis

2 ATP and 2 NADH

Glycolysis phases

Investment phase Pay-off phase

which steps of Glycolysis is the investment phase

Step 1 through 5

which steps of Glycolysis is the pay-off phase

Step 6 through 10

trick to know glycolysis products

“Girls Get Fine Food; Gentlemen Dine Girls; Boys Prefer to Pick up Pepperoni Pizza” Glucose Glu-6-P Fru-6-P Fru-1,6-bP G3P + DHAP 2x G3P 2x 1,3-BPG 2x 3-PG 2x 2-PG 2x PEP 2x Pyr

Breaks down glucose

Pentose Phosphate Pathway

why is Pentose Phosphate Pathway important

it produces precursor metabolites for biosynthesis

Produces reducing power: Variable amount of NADPH (Yields vary depending upon alternative taken)

Pentose Phosphate Pathway

which product of Pentose Phosphate Pathway can enter glycolysis

glyceraldehyde-3-phosphate

does Pentose Phosphate Pathway require o2

where does Pentose Phosphate Pathway occur

cytoplasm or chloroplast (plants)

Does Pentose Phosphate Pathway produce or use ATP

what happens in the Transition Step

1. CO2 is removed from pyruvate 2. Coenzyme A added to 2-carbon acetyl group to form acetyl-CoA 3. Produces reducing power 4. Produces 1 precursor metabolite:

CO2 is removed from pyruvate

decarboxylation step

added to 2-carbon acetyl group to form acetyl-CoA

Coenzyme A

where does the transition step occur

cytoplasm (prokaryotes) or mitochondria (eukaryotes)

Kreb’s Starting Substrate For Making Oxaloacetate

Citrate

cool way to remember kreb cycle products

“Our City Is Kept Safe & Secure From Monsters” Oxaloacetate Citrate Isocitrate α-ketoglutarate Succinyl CoA Succinate Fumarate Malate

Completes oxidation of glucose

Tricarboxylic Acid (TCA) Cycle

how many turns of Tricarboxylic Acid (TCA) Cycle occur for one molecule of glucose

what do two turns of Tricarboxylic Acid (TCA) Cycle produce

- 4 CO2 - 2 ATP (energy) - 6 NADH (reducing power) - 2 FADH2 (reducing power)

tricarboxylic Acid (TCA) Cycle Produces which 2 precursor metabolites

α-ketoglutarate; oxaloacetate

does the TCA cycle require O2

yes

where does the TCA cycle occur

cytoplasm (prokaryotes) or mitochondria (eukaryotes)

transfers electrons from glucose to electron transport chain

Respiration

how is reducing power generated

glycolysis, transition step, and TCA cycle to synthesize ATP

what are the two processes involved in respiration

➢Electron transport chain ➢Harvested to make ATP

generates proton motive force using reducing powers

Electron transport chain

Harvested to make ATP by

ATP synthase

ATP is generated by

oxidative phosphorylation

O2 is terminal electron acceptor

Aerobic respiration

Molecule other than O2 as terminal electron acceptor

Anaerobic respiration

is membrane-embedded electron carriers

Electron transport chain

the Electron transport chain accepts electron from?

NADH and FADH2

how does the Electron transport chain pass electrons

sequentially (energy gradually released), eject protons in process

Protons pumped across the membrane create electrochemical gradient =

proton motive force

is used to synthesize ATP

proton motive force

does the Electron transport chain need O2

yes

where is the electron transport chain located

cytoplasm (prokaryotes) or mitochondria (eukaryotes)

Most carriers grouped into large protein complexes that function as

proton pumps

Lipid-soluble, move freely, can transfer electrons between complexes

Quinones

Contain heme, a molecule that holds and iron atom in its center

Cytochromes

example of Quinones

ubiquinone (“ubiquitous quinone”)

can be used to distinguish bacteria

Cytochromes

Proteins to which a flavin is attached

Flavoproteins

Some carriers accept only hydrogen atom

proton-electron pairs

When hydrogen carrier accepts electron from electron carrier, it picks up proton from

from inside cell (or mitochondrial matrix)

When hydrogen carrier passes electrons to electron carrier, protons released to

outside of cell (or intermembrane space of mitochondria)

is movement of protons across membrane to create a concentration gradient

Net effect

another name for Complex I

NADH dehydrogenase complex

Accepts electrons from TCA cycle via FADH2, “downstream” of those carried by NADH

Complex II

Complex II Transfers electrons to

ubiquinone

another name for Complex II

(succinate dehydrogenase complex

Accepts electrons from ubiquinone from Complex I or II

Complex III

how many protons are pumped by Complex III

electrons transferred to cytochrome c

Complex III

Accepts electrons from NADH, transfers to ubiquinone

Complex I

how many protons does Complex I pump

another name for Complex III

cytochrome bc1 complex

another name for Complex IV

cytochrome c oxidase complex

how many protons does Complex IV pump

Accepts electrons from cytochrome c

Complex IV

meaning transfers electrons to terminal electron acceptor (O2)

Terminal oxidoreductase,

what kind of oxidoreductase is complex IV

Terminal oxidoreductase,

- Can use 2 different NADH dehydrogenases - Succinate dehydrogenase - Lack equivalents of complex III or cytochrome c - Quinones shuttle electrons directly to functional equivalent of complex IV - Ubiquinol oxidase

Aerobic respiration in E. coli

(one is equivalent to complex I of mitochondria)

2 different NADH dehydrogenases

(equivalent to complex II of mitochondria)

Succinate dehydrogenase

what does Aerobic respiration in E. coli lack

equivalents of complex III or cytochrome c

shuttle electrons directly to functional equivalent of complex IV

Quinones

equivalent to complex IV of mitochondria

Ubiquinol oxidase

another terminal oxidoreductase

Ubiquinol oxidase

- Harvests less energy – Lower electron affinities of terminal electron acceptors - Terminal electron acceptor is not O2

Anaerobic respiration in E. coli

Harvests less energy than aerobic respiration

Anaerobic respiration in E. coli

what is the terminal electron of Anaerobic respiration in E. coli

- can be nitrate and produce nitrite - can be Sulfate-reducers use sulfate and produce hydrogen sulfide (H2S)

why does Harvests Anaerobic respiration in E. coli less energy than aerobic respiration

Lower electron affinities of terminal electron acceptors

Harvesting the Proton Motive Force to Synthesize ATP

ATP Synthase

allows protons to flow down gradient in controlled manner

ATP Synthase

does ATP Synthase use energy to add phosphate group to ADP

yes

1 ATP formed from how many protons

how many ATP from 1 NADH

how many ATP from 1 FADH2

total ATP yield from proton motive force In prokaryotes

ATP yield in glycolysis from proton motive force In prokaryotes

2 NADH→ 6 ATP

ATP yield in transition step from proton motive force In prokaryotes

2 NADH → 6 ATP

ATP yield in TCA Cycle from proton motive force In prokaryotes

6 NADH → 18 ATP and 2 FADH2 → 4 ATP

total ATP yield from Substrate-level phosphorylation In prokaryotes

4 ATP

ATP yield in glycolysis from Substrate-level phosphorylation In prokaryotes

2 ATP

total ATP yield from oxidative phosphorylation In prokaryotes

ATP yield in glycolysis from oxidative phosphorylation In prokaryotes

ATP yield in transition step from oxidative phosphorylation In prokaryotes

ATP yield in TCA Cycle from oxidative phosphorylation In prokaryotes

total ATP yield from Aerobic Respiration In prokaryotes

If cells cannot respire, will run out of carriers available to accept/transfer electrons

Fermentation

what molecule can't be broken down in fermentation

glucose

uses pyruvate or derivative as terminal electron acceptor to regenerate NAD

fermentation

what step doesn't fermentation have

TCA

when when respiration not an option what is done

fermentation

when is another time where fermentation is the only option

When the organism lacks electron transport chain

serve as a terminal electron acceptor to regenerate NADH into NAD+ needed during glycolysis

Pyruvate or derivatives

end products of fermentation

* Lactic acid * Ethanol * Butyric acid * Propionic acid * 2,3-Butanediol * Mixed acids

Secrete hydrolytic enzymes

Microbes

Transport subunits into cell

Microbes

Microbes are degraded further to what

appropriate precursor metabolites

examples of Polysaccharides

* Starch * Cellulose

Digested by the enzyme amylase

starch

Digested by the enzyme cellulase

cellulose

where is cellulose located

in fungi and bacteria of ruminants

example of Disaccharides

Lactose, maltose and sucrose

types of lipids

Fats (fatty acids + glycerol)

hydrolyzed by lipases

Fats (fatty acids + glycerol)

Glycerol converted and enters

glycolysis

Fatty acids degraded and enter

TCA cycle

Hydrolyzed by proteases

proteins

Amino group removed

deaminated

converted into precursor molecules

Carbon skeletons

Prokaryotes unique in ability to use reduced inorganic compounds as

sources of energy

may serve as energy source for another

Waste products of one organism

examples of Waste products of one organism may serve as energy source for another

hydrogen sulfide (H2S) and ammonia (NH3)

Produced by anaerobic respiration from inorganic molecules (sulfate, nitrate) serving as terminal electron acceptors

hydrogen sulfide (H2S) and ammonia (NH3)

Used as energy sources for sulfur bacteria and nitrifying bacteria

hydrogen sulfide (H2S) and ammonia (NH3)

is the source of carbon

CO2

energy from sunlight carbon from CO2

Photoautotrophs:

energy from sunlight carbon from organic compounds

Photoheterotrophs

energy from inorganic compound carbon from CO2

Chemolithoautotrophs or chemoautotrophs, or chemolithotrophs

energy and carbon from organic compounds

Chemoorganoheterotrophs or chemoheterotrophs, or chemoorganotrophs

Four general groups of chemolithotrophs

* Hydrogen bacteria oxidize * Sulfur bacteria * Iron bacteria * Nitrifying bacteria

can use simple organic compounds for energy

Hydrogen bacteria oxidize

can live in pH of less then 1

Sulfur bacteria

has iron oxide present in sheaths

Iron bacteria

important in nitrogen cycle

Nitrifying bacteria

extract electrons from inorganic energy sources

Chemolithotrophs

Pass electrons to an electron transport chain that generates

proton motive force

incorporate CO2 into an organic form

chemolithotrophs

capture and conversion of radiant energy into chemical energy

Photosynthesis

In cyanobacteria and photosynthetic eukaryotic cells

Oxygen

In Purple and green bacteria

sulfur

Two distinct stages in photosynthesis

Light reactions Light-independent reactions

light-dependent reactions)

Light reactions

Capture radiant energy and use it to generate ATP and reducing power

Light reactions

(dark reactions)

Light-independent reactions

Use ATP and reducing power to synthesize organic compounds

Light-independent reactions

Involves carbon fixation

Light-independent reactions

Photosynthetic pigments

- Chlorophylls - Bacteriochlorophyll - Carotenoids - Phycobilins

(in plants, algae, cyanobacteria)

Chlorophylls

in anoxygenic bacteria

Bacteriochlorophylls

Absorb different wavelengths than chlorophylls

Bacteriochlorophylls

many photosynthetic prokaryotes and eukaryotes

Carotenoids

cyanobacteria, red algae

Phycobilins

Pigments are located in protein complexes

photosystems

capture and use light energy

Photosystems

funnel light energy to the reaction-center pigments

Antennae pigments

excited by radiant energy (=energy of light); emit electrons that are passed to the electron transport chain

Reaction-center pigments

photosystems in membranes of thylakoids (inside cell)

Cyanobacteria

what goes through Light-dependent reactions:

cyanobacteria and eukaryotes (plants and algae)

Two distinct photosystems (I and II)

Cyclic photophosphorylation Non-cyclic photophosphorylation

– Photosystem I alone – Produces ATP (using energy from the proton motive force) – Reaction-center chlorophyll is the electron donor and the terminal electron acceptor

Cyclic photophosphorylation

is the electron donor and the terminal electron acceptor of Cyclic photophosphorylation

Reaction-center chlorophyll

what does Cyclic photophosphorylation produce

ATP

– Produces both ATP and reducing power – Electrons from photosystem II drive photophosphorylation – Electrons are then donated to photosystem I – Photosystem II replenishes electrons by splitting water – Generates oxygen (process is oxygenic) – Electrons from photosystem I reduce NADP+ to NADPH

Non-cyclic photophosphorylation

what does Non-cyclic photophosphorylation produce

both ATP and reducing power

what does Non-cyclic photophosphorylation generate

oxygen

replenishes electrons by splitting wate

Photosystem II

Electrons from photosystem II drive

photophosphorylation

anoxygenic photosynthetic bacteria

Light-dependent reactions

how many photosystems does Light-dependent reactions have

one

can Light-dependent reactions use water

what electron donors does Light-dependent reactions use

hydrogen gas (H2) hydrogen sulfide (H2S) organic compounds

photosystem similar to photosystem II

Purple bacteria

photosystem similar to photosystem I

Green bacteria

Chemolithoautotrophs and photoautotrophs use CO2 to synthesize organic compounds:

carbon fixation

Consumes lots of ATP, reducing power

carbon fixation

most commonly used to fix carbon but others are possible

Calvin cycle

Three essential stages

- Incorporation of CO2 into organic compounds - Reduction of resulting molecule - Regeneration of starting compound

Chapter 6 Flashcards

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