DAT Bootcamp Biology Chapter 3: Understanding Cellular Energy

Laws of Thermodynamics

1) energy can not be created or destroyed, only converted from one form to another,

2) entropy always increasing. combined entropy (system and surroundings) must be positive

3) entropy of substance at absolute zero is 0

metabolism is

all metabolic pathways that happen in organism

metabolic pathways are

series of chemical reactions

catabolic pathways

break down large molecules for energy

catabolic pathways are more/less ordered states

less

catabolic pathways increase/decrease entropy

increase

catabolic pathways are endergonic / exergonic

exergonic

catabolic pathways are spontaneous / nonspontaneous

spontaneous

anabolic pathways

use energy to build larger molecules

anabolic pathways are in less / more ordered state

more

anabolic pathways increase/decrease entropy

decrease

anabolic pathways are endergonic / exergonic

endergonic

anabolic pathways are spontaneous / nonspontaneous

nonspontaneous

2 ways that cells can break down carbohydrates for energy, how do these two processes work

1. aerobic cellular respiration (consumes O2, more energy produced)

2. anaerobic cellular respiration/fermentation (no O2, less energy produced

components of ATP

adenine nitrogenous base, ribose sugar, 3 phosphate groups

ATP is a

RNA nucleoside triphosphate

ATP full name

adenosine triphosphate

ATP is used as cellular ____ _____ because of the

energy currency ; high energy bonds between phosphate groups

ATP's phosphate groups release energy upon

hydrolysis

ATP loses a phosphate it becomes

ADP

ATP is more / less stable than ADP

less

Why is ADP more stable than ATP?

has one less charged phosphate group

reaction coupling is

powering an energy-requiring reaction with an energy-releasing one

reaction coupling makes a _____ delta G

net negative

negative delta G is

exergonic, releases energy, spontaneous

Mitochondria produce ATP through cellular respiration, this is a ______ process

catabolic

mitochondria membrane called

inner and outer

inner mitochondrial membrane has

infoldings called cristae

the inner mitochondrial membrane increases

surface area

mitochondria is found more in ____ cells than ____ cells

muscle then red blood

what is between the inner and outer mitochondrial membranes

intermembrane space

what part of the mitochondria is acidic

intermembrane space

where is the mitochondrial matrix located

inside the inner membrane

endosymbiotic theory states that eukaryotes developed when ___ ______ were internalized as _____ while ____ ______ become ____

aerobic bacteria internalized as mitochondria while photosynthetic bacteria became chloroplasts

5 evidence for endosymbiotic theory

1. same size

2. possess circular DNA

3. ribosomes with small and large subunits

4. reproduce independently of host cell

5. contain double membrane

aerobic cellular respiration is performed by ____________

phosphorylating ADP to ATP by breaking down glucose and moving electrons around (redox rxns)

aerobic cellular respiration has 4 catabolic processes

1. glycolysis

2. pyruvate oxidation

3. Krebs cycle

4. oxidative phosphorylation

1. Glycolysis turns glucose into a net of

2 atp + 2 NADH + 2 pyruvate

glycolysis takes place in the

cytosol

glycolysis requires / doesn't require oxygen

doesn't require

glycolysis is also shown in

fermentation

glycolysis has 2 phases

energy investment phase and energy payoff phase

first step of glycolysis

1. hexakinase uses 1 ATP to phosphorylase glucose into glucose-6-phosphate which can't leave cell (trapped by phosphorylation)

hexakinase turns ____ into _____ by using

glucose into glucose 6 phosphate by using 1 ATP

second step of glycolysis

isomerase modifies glucose-6-phosphate into fructose-6-phosphate

isomerase modifies ____ into ______

glucose-6-phosphate into fructose-6-phosphate

Third step of glycolysis

phosphofructokinase uses 2nd ATP to phosphorylate fructose-6-phosphate to fructose-1,6-bisphosphate

first 4 steps of glycolysis is the

energy investment phases

phosphofructokinase (PFK) is an

important regulatory enzyme in glycolysis

fourth step in glycolysis

fructose-1,6-bisphosphate broken down into DHAP and G3P (DHAP and G3P are in equilibrium)

how many steps are in payoff phase of glycolysis

2 steps

fifth step of glycolysis

DHAP converted into G3P (now 2 G3P per glucose molecule)

sixth step of glycolysis

G3P undergoes redox rxns to produce 4 ATP through substrate level phosphorlyation AND 2 pyruvate, 2 NADH

substrate-level phosphorylation is the

transfer of phosphate from substrate to ADP

in pyruvate oxidation, 2 pyruvate makes

2 CO2, 2NADH, 2 Acetyl Coa

how many steps in pyruvate oxidation

3

what enzyme carries out pyruvate oxidation steps

pyruvate dehydrogenase

First step of pyruvate oxidation

decarboxylation: a carboxyl group is removed from pyruvate, releasing carbon dioxide, forming 2-carbon molecule per pyruvate

pyruvate oxidation is located

mitochondrial matrix

Second step of pyruvate oxidation

oxidation: 2-carbon molecule converted to acetyl group (gives electrons to NAD+ to make it NADH)

Third step of pyruvate oxidation

CoA: coenzyme A binds to acetyl to make acetyl-CoA

Krebs cycle starts with 2 Acetyl CoA and makes

4CO2, 6NADH, 2FADH2, 2GTP

where does krebs cycle occur

mitochondrial matrix

how many steps in krebs cycle

5

first step of krebs cycle

acetyl co-A combines with oxaloacetate (4-C) to form citrate (6-C)

second step of the krebs cycle

citrate loses 2 carbons and gets rearranged, producing 2 CO2 and 2NADH

Third Step of Krebs Cycle

4-C molecule produces 1 GTP through substrate level phosphorylation

Fourth step of the Krebs Cycle

4 C molecule transfers electrons to 1 FAD which makes 1 FADH2

Fifth step of the Krebs Cycle

4 C molecule converted back to oxaloacetate, gives electrons to produce 1 NADH

how many cycles of krebs cycle for desired products

2

why does the krebs cycle need oxygen

FAD+ and NAD+ needs to be regenerated

krebs cycle starting reactants

2 Acetyl coA

pyruvate oxidation starting reactants

2 pyruvate

oxidative phosphorylation starting reactants

electron carriers (NADH, FADH2) and O2

oxidative phosphorylation starts with electron carriers and oxygen and makes

ATP and H2O

which 2 processes work together to produce ATP in oxidative phosphorylation

ETC and chemiosmosis

chemiosmosis is

ions moving down electrochemical gradient

What acts as the final electron acceptor? and what does it form?

oxygen ; forms water

what is the goal of ETC?

regenerate electron carriers and create an electrochemical gradient to power ATP production

Where is the ETC located?

inner mitochondrial membrane

where is glycolysis, pyruvate oxidation and krebs cycle located for prokaryotes

cytosol

where is ETC located for prokaryotes

cell membrane

the 4 protein complexes in oxidative phosphorylation are responsible for

moving electrons through series of redox reactions

what happens as series of redox reactions happen in protein complexes? This forms _______

protons pumped from mitochondrial matrix to intermembrane space forming electrochemical gradient

why is NADH more effective than FADH2 in oxidative phosphorylation

NADH drops electrons off at complex 1

FADH2 drops electrosn off at complex 2, resulting in fewer protons because it by-passes complex 1

NADH and FADH2 are oxidized / reduced in oxidative phosphorylation

oxidized

what is the goal of chemiosmosis

use the proton electrochemical gradient (proton-motive force) to synthesize ATP

What is ATP synthase role in oxidative phosphorylation (specifically chemiosmosis)?

provides hydrophilic tunnel for protons to flow down electrochemical gradient

ATP synthase is a

channel protein enzyme

chemiosmosis uses what force to synthesize ATP

proton motive force

ATP synthase pushes protons from ___ to _____

intermembrane space back to mitochondrial matrix

the movement of protons from chemiosmosis generates

energy used to convert ADP + Pi to ATP

converting ADP + Pi to ATP is spontaneous / nonspontaneous

nonspontaneous

converting ADP + Pi to ATP is exergonic / energonic

energonic

converting ADP + Pi to ATP is a condensation/hydrolysis reaction

condensation reaction

when it is non spontaneous and requires energy it is -/+ delta G

+ delta G

specifically what is delta G per glucose molecule in aerobic respiration

-686 kcal/mol of glucose

1 NADH produces _____ ATP and 1 FADH2 produces _____ ATP

3 ATP ; 2 ATP

Why does NADH from glycolysis yield less ATP?

ATP shuttles NADH from cytosol to mitochondrial matrix

prokaryotes produce how much ATP during glycolysis through NADH, and why?

6 ATP, don't need to shuttle NADH from cytosol to matrix like eukaryotes do