Cellular Respiration: How our body uses what we eat

Question 1

_______________is stored in food due to the arrangement of the electrons in the bonds?

Answer 1

potential energy

Question 2

Bonds must be ___________to release energy?

Answer 2

Broken

Question 3

What are the two pathways of cellulular respiration?

Answer 3

• aerobic
• anaerobic

Question 4

energy harvested is used to produce__________

Answer 4

ATP

Question 5

the equation for aerobic respiration is?

Answer 5

: C6H12O6 + 6O2 ——————> 6 CO2 + 6 H2O + ATP

Question 6

What role do redox reactions play in respiration?

Answer 6

transfer of electrons releases energy stored in organic molecules.

: C6H12O6 + 6O2 ——————> 6 CO2 + 6 H2O + Energy (ATP and heat)

is exergonic

Question 7

energy is harvested in a _____manner?

Answer 7

stepwise

-electrons stripped from glucose at key steps in the process

e- don’t travel alone-travel with a proton=hydrogen atom

Question 8

if glucose were oxidized all at once?

Answer 8

too much energy would be lost

Question 10

Hydrogen atoms are not tranferred directly to oxygen. They are passed to ______________

Answer 10

electron carrier–NAD+ (NADH reduced)

Question 11

What are the stages of cellular respiration?

Answer 11

1. Glycolysis
2. Pyruvate Oxidation and the Citric Acid Cycle
3. Oxidative Phosphorylation

Question 12

What is the equation for glycolysis?

Answer 12

glucose+2ATP+2NAD+—->2 pyruvate +4 ATP (2 NET) + 2NADH

Question 13

2. Pyruvate Oxidation and the Citric Acid Cycle

Answer 13

Pyruvate + Coenzyme A + NAD+ Acetyl CoA + CO2 + NADH Acetyl CoA + H2O + 3 NAD+ + FAD 2 CO2 + H2O +3 NADH + FADH2 + GTP (ATP)

Question 14

Oxidative Phosphorylation

Answer 14

NADH + FADH2 + ½ O2 + ADP + Pi ATP + H2O + NAD+ + FAD

Question 15

where does glycolysis take place?

Answer 15

cytosol

Question 16

what happens during glycolysis?

Answer 16

glucose split into two molecules of pyruvate

Question 17

How much ATP does glycolysis require? how much does it yield?

Answer 17

2, yields 4

net yield: 4 ATP

Question 18

An enzyme transfers a phosphate group from a substrate molecule to ADP instead of using ______

Answer 18

pi

in image–products used in the next step

Question 19

in Pyruvate Oxidation:

1. Pyruvate enters the mitochondria through?

Answer 19

active transport

Question 20

What reactions take place?

Answer 20

reactions take place – COO‐ is removed and given off as co2

– Remaining 2‐carbon molecule is oxidized :NADH

formed – Coenzyme A is added to form acetyl CoA (high potential energy)

Question 21

Citric Acid Cycle (Krebs/TCA Cycle) consists of 8 steps–each step is catalyzed by a specific enzyme..

What kind of reactions?

where does it occur?

Answer 21

redox

mitochondrial matrix

Question 22

one krebs cycle produces?

how many products are produced per glucose molecule?

Answer 22

2 CO2

1 GTP (ATP)

3 NADH

1 FADH2

2X that produced by one cycle

Question 23

in the citric(krebs/TCA cycle) what is recycled?

Answer 23

coA and oxaloacetate

Question 24

• Per glucose molecule…

Answer 24

– glycolysis + 2 ATP

– krebs+ 2 ATP TOTAL

= Net + 4 ATP

Question 25

Most of the energy extracted from glucose is tied up in ________ and _________ So how do we use these molecules to make ATP?

Answer 25

NaOH

FADH2

Question 26

what does Oxidative Phosphorylation do?

Answer 26

Generates ATP by adding Pi to ADP

Question 27

what are the steps of oxidative phosphorylation?

Answer 27

electron transport chain

chemiosmosis

This is where the majority of ATP is produced

Question 28

What is the electron transport chain?

Answer 28

collection of molecules embedded in the mitochondrial inner membrane

Question 29

_______are dropped off by NADH and FADH2?

Answer 29

Electrons

electron carriers alternate between redced and oxidized states as they accept and donate electrons.

-the final electron acceptor is oxygen which also picks up 2 ions to form H2O (still no atp production)

Question 30

Chemiosmosis •

Answer 30

Exergonic flow of electrons is used to pump H+ across the membrane (into the intermembrane space) – Generates a gradient = proton motive force

Question 31

chemiosis

Answer 31

the energy‐coupling mechanism that uses energy stored in a H+ gradient to drive cellular work NOTE: NADH and FADH2 enter the ETC at different complexes = less energy for ATP synthesis when e‐ come from FADH2

Question 32

Using the Proton‐Motive Force to Generate ATP

ATP synthase

Answer 32

• ___________= uses energy of the H+ gradient to power ATP synthesis – Located in the mitochondrial inner membrane •

H+ ions flow through ATP synthase down their concentration gradient – Bind to active sites and cause __________________ = rotor spins – Activates catalytic sites that generate ATP

bulk of ATP produced

Question 33

H+ ions flow through ATP synthase down their concentration gradient – Bind to active sites and cause __________________ = rotor spins – Activates catalytic sites that generate ATP

Answer 33

confrontational change

Question 34

why does the amount of atp that we get vary?

Answer 34

1. # of NaDH molecules to ATP molecules aren’t in a 1:1 ratio

of NADH molecules to ATP molecules produced not 1 to 1 • 1 NADH = 10H+ pumped across membrane and ~4H+ =1 ATP • 1 NADH = 2.5 ATP and 1 FADH2 = 1.5 ATP

– ATP yield varies depending on shuttle used to transport e‐ into mitochondria

– Use of proton motive force to drive other work (i.e the uptake of pyruvate)

– Proton leakage (wear and tear on membranes, not working as efficiently, not using proton t run ATP synthase

Question 35

____ of the PE of glucose is transferred to ATP?

what happens to the rest?

Answer 35

34%

released as heat

Question 37

what does anaerobic respiration use?

Answer 37

still uses electron transport chain but O2 isn’t the final electron acceptor

• other electronegative substances can also work
• some marine bacteria use so42-, produce h2s instead of water

other substances include: NO3, CO2, S, Fe, uranium (used to clean radioactivity)

Question 38

what is fermentation?

Answer 38

process to generate energy without using oxygen on the electron transport chain

Basically an extension of glycolysis (glucose splits to pyruvate)– Glycolysis + a process to regenerate NAD+

• Different types of fermentation – Differ in the end products formed – Two common types: alcohol and lactic acid fermentation

Question 39

Alcohol Fermentation

Answer 39

allows glycolysis by making sure that NAD+ is available

• Pyruvate is reduced to ethanol–> biproduct

purpose: regenerate NAD+–wouldn’t be able to pick up more

pyruvate looses co2 as bread rises, pocket where co2 was before evaporation

• Used by some bacteria and yeast
• Used to make beer, wine, liquor and bread!

Question 40

What is the purpose of lactic acid fermentation?

Answer 40

NAD+

• pyruvate is reduced directly to by NADH to form lactate
• used to make yogurt, cheese

muscle cells uses this process when supply of oxygen is unable to keep up with the energy demand-

-working out–not enough oxygen–> switch to LAF (no oxygen to anaerobic. cooling down is important for flushing out extra lactic acid (muscle soreness)

Question 41

what is the purpose of fermentation?

Answer 41

to regenerate NAD+ so that glycolysis continues,

need to have NAD+ to pick up electrons for glycolysis

form NaDH–>NAD+

Question 42

What happens when you’re deprived of oxygen?

Answer 42

oxygen–final electron acceptor if its blocked Electron chain shuts down–no protons are in the inner membrane, no gradient, can’t make atp–cells will die without receiving the energy that they need

Question 43

why can’t cells switch to fermentation when suffocating?

Answer 43

fermentation can’t make enough ATP (2 net atp, not enough to keep cell alive)

cellular 30 for 2 glucose

Question 44

How do we use other molecules for energy?

Answer 44

-glucose isn’t the only molecule that can be broken down-other carbs, fats, proteins can be used.

Question 45

A gram of fat produces 2x the ATP generated from 1g of carbohydrate. WHY? Why does this make it hard to lose weight?

Answer 45

fat 2x atp- a lot more hydrogens can be stripped off

2x as hard to burn it off, 2x as much energy

Question 46

Biosynthesis •

Answer 46

Cells need building blocks to make their own molecules – Food provides the carbon skeletons necessary in addition to energy

• Amino acids can be incorporated into cell’s own proteins • Many intermediates from glycolysis and the Krebs cycle can be used as precursors for molecules the cell requires • Requires energy (anabolic)

Question 47

How is Cellular Respiration Regulated?

Answer 47

• Follows principles of supply and demand
• Prevents cell from wasting energy making something it already has
• Main mechanism of control is feedback inhibition