LESSON 3b: Cellular Respiration

Question 1

• Step-by-step breakdown
  of high-energy glucose
  molecules to release
  energy
• Takes place day and
  night in all living cells
• Occurs in stages,
  controlled by enzymes

Answer 1

Cellular Respiration

Question 2

An ATP molecule contains potential energy, much like a
compressed spring. When a ________________________________
during a chemical reaction, energy is released

Answer 2

phosphate group is pulled away

Question 3

This cycle is the fundamental
mode of energy exchange in
biological systems.

Answer 3

ATP-ADP Cycle

Question 4

ATP—> ADP

Answer 4

-Motion
-Active Transport
-Biosynthesis
-Signal Amplification

Question 5

ATP is constantly
__________ in your cells

Answer 5

recycled

Question 5

ADP—> ATP

Answer 5

Oxidation of fuel molecules or Photosynthesis

Question 6

A ____________
recycles all of its ATP
molecules about once
each minute

Answer 6

working muscle cell

Question 7

How many ATP molecules is spent and regenerated per second?

Answer 7

10 million

Question 8

Types of Respiration

Answer 8

-Aerobic Respiration
-Anaerobic Respiration

Question 9

– Occurs in the presence of
oxygen
– When chemically breaking
down glucose completely,
this process releases large
amounts energy
- Releasing carbon dioxide and
water as waste products

Answer 9

Aerobic respiration

Question 10

-Occurs if there is a lack of
oxygen available for aerobic
respiration
-Only Glycolysis occurs
-Glucose is incompletely
broken down
-In this type of respiration a
lot less energy is -produced
and most of it is lost as heat.

Answer 10

Anaerobic respiration

Question 11

Breakdown of
Cellular Respiration

Answer 11

1. Glycolysis (splitting of sugar)
2. Grooming Phase
3. Krebs Cycle (Citric Acid Cycle)
4. Electron Transport Chain (ETC)
   and Oxidative Phosphorylation

Question 11

cytosol, just outside of
mitochondria.

Answer 11

Glycolysis (splitting of sugar)

Question 12

migration
from cytosol to matrix

Answer 12

Grooming Phase

Question 12

done in mitochondrial matrix

Answer 12

Krebs Cycle (Citric Acid Cycle)

Question 12

a. Also called Chemiosmosis
b. inner mitochondrial
membrane

Answer 12

Electron Transport Chain (ETC)
and Oxidative Phosphorylation

Question 13

Electron Transport Chain (ETC)
and Oxidative Phosphorylation is also called?

Answer 13

Chemiosmosis

Question 13

4 metabolic stages

Answer 13

– Anaerobic respiration
1. Glycolysis
– Aerobic respiration
2. Pyruvate oxidation
3. Krebs cycle
4. Electron transport chain

Question 13

– respiration without O2
– in cytosol

Answer 13

Glycolysis

Question 14

– respiration using O2
– in mitochondria

Answer 14

Aerobic respiration

Question 15

• Breaking down glucose
  – “glyco – lysis” (splitting sugar)
  – ancient pathway which harvests energy
• where energy transfer first evolved
• transfer energy from organic molecules to ATP
• still is starting point for all cellular respiration
  – but it’s inefficient
• generate only 2 ATP for every 1 glucose
  – occurs in cytosol

Answer 15

Glycolysis

Question 16

Glycolysis: Glucose (6C)——–>__________

Answer 16

2 Pyruvate (3C)

Question 17

Glycolysis: How many ATP is produced for every 1 glucose?

Answer 17

2 ATP

Question 18

first cells had no organelles

Answer 18

Prokaryotes

Question 19

– life on Earth first evolved without free oxygen (O2) in atmosphere – energy had to be captured from organic molecules in absence of O2

Answer 19

Anaerobic atmosphere

Question 20

Prokaryotes that evolved _________ are ancestors of all modern life.

Answer 20

glycolysis

Question 21

How many reactions does glycolysis have?

Answer 21

10 reactions

Question 22

In the last steps of glycolysis, where did the P come from to make ATP?

Answer 22

P is transferred from PEP to ADP

Question 23

How is ATP formed?

Answer 23

ATP is formed when an enzyme transfers a phosphate group from a substrate to ADP

Question 24

Glycolysis: Net Gain?

Answer 24

2 ATP

Question 25

only harvest ____ of energy stored in glucose

Answer 25

3.5%

Question 26

no O2= ______________

Answer 26

slow growth, slow reproduction

Question 27

______________ = more energy to harvest

Answer 27

more carbons to strip off

Question 28

Glycolysis Splits a glucose molecule into 2 - 3 Carbon molecules called _________

Answer 28

Pyruvate

Question 29

Product of Glycolysis

Answer 29

2 ATP, NADH and pyruvate

Question 30

General formula of Glycolysis

Answer 30

glucose + 2ADP + 2Pi + 2 NAD+ ----> 2 pyruvate + 2ATP + 2NADH

Question 31

without regenerating _____ energy production would stop

Answer 31

NAD+

Question 32

How is NADH recycled to NAD+?

Answer 32

Another molecule must accept H from NADH

Question 32

Fermentation (anaerobic): Bacteria, yeast

Answer 32

pyruvate (3C) ----> ethanol (2C) + CO2 (1C)

Question 33

Fermentation (anaerobic): Animals, some fungi

Answer 33

pyruvate (3C) ---> lactic acid (3C)

Question 34

Example of recycling NADH to form NAD+

Answer 34

Fermentation (Anaerobic Reaction)

Question 35

Alcohol Fermentation

Answer 35

Dead end process

Question 36

Lactic Acid Fermentation

Answer 36

Reversible Process

Question 37

Why is alcohol fermentation a dead end process

Answer 37

-at ~12% ethanol, kills yeast -can’t reverse the reaction

Question 38

Why lactic acid fermentation a reversible process?

Answer 38

once O2 is available, lactate is converted back to pyruvate by the liver

Question 39

Pyruvate is a ___________

Answer 39

branching point

Question 40

3 fates of pyruvate produced by glycolysis

Answer 40

-Anaerobic (Lactic Acid fermentation) -Aerobic Oxidation -Anaerobic (Alcoholic fermentation)

Question 41

Process of ATP Synthase

Answer 41

– set up a H+ gradient – allow H+ to flow through ATP synthase – powers bonding of Pi to ADP

Question 42

ADP + Pi-->_____

Answer 42

ATP

Question 43

Oxidation of Pyruvate happens where?

Answer 43

mitochondria

Question 44

3 Step oxidation (of pyruvate) process

Answer 44

– releases 1 CO2 (count the carbons!) – reduces 2 NAD --->2 NADH (moves e-) – produces acetyl CoA

Question 45

Acetyl CoA enters __________

Answer 45

Krebs Cycle

Question 46

Pyruvate oxidized to ___________

Answer 46

Acetyl CoA

Question 47

* aka Citric Acid Cycle – in mitochondrial matrix – 8 step pathway * each catalyzed by specific enzyme * step-wise catabolism of 6C citrate molecule * Evolved later than glycolysis – does that make evolutionary sense? * bacteria -->3.5 billion years ago (glycolysis) * free O2 -->2.7 billion years ago (photosynthesis) * eukaryotes -->1.5 billion years ago (aerobic respiration = organelles ® mitochondria)

Answer 47

Krebs cycle

Question 48

Krebs Cycle: Net Gain (Product)

Answer 48

= 2 ATP = 6 NADH + 2 FADH2

Question 49

If the yield is only 2 ATP then how was the Krebs cycle an adaptation?

Answer 49

– value of NADH & FADH2 * electron carriers & H carriers – reduced molecules move electrons – reduced molecules move H+ ions * to be used in the Electron Transport Chain

Question 50

– series of molecules built into inner mitochondrial membrane * along cristae * transport proteins & enzymes – transport of electrons down ETC linked to pumping of H+ to create H+ gradient – yields ~34 ATP from 1 glucose! – only in presence of O2 (aerobic respiration

Answer 50

Electron Transport Chain

Question 51

Electron Carriers produced in Glycolysis and Krebs Cycle?

Answer 51

Glycolysis: 4 NADH Krebs Cycle: 6 NADH and 2 FADH2

Question 52

* The diffusion of ions across a membrane – build up of proton gradient just so H+ could flow through ATP synthase enzyme to build ATP -links the Electron Transport Chain to ATP synthesis

Answer 52

Chemiosmosis

Question 53

* Proposed chemiosmotic hypothesis – revolutionary idea at the time

Answer 53

Peter Mitchell

Question 54

What is the final electron acceptor in Electron Transport Chain?

Answer 54

O2

Question 55

So what happens if O2 unavailable?

Answer 55

- ETC backs up >nothing to pull electrons down chain >NADH & FADH2 can’t unload H -ATP production ceases -cells run out of energy -and you die

Question 56

– Break into AA’s – Deaminate – Alanine to pyruvate – Glutamate to α ketoglutarate – Aspartate to oxaloacetate

Answer 56

Proteins

Question 57

– Degrade into individual fatty acids & glycerol – Oxidized in matrix—enzymes attack long fatty acid chains and remove 2C chunks – Entire chain is converted into acetyl-CoA – Called Beta oxidation – Glycerol is converted into pyruvate.

Answer 57

FATS

Question 58

* When there is an excess of intermediates they can be used to build necessary molecules. * Lipids can be generated from excess acetyl CoA * Glycogen is generated from excess pyruvate * Amino acids are generated from different stages of the krebs cycle.

Answer 58

BIOSYNTHESIS

Question 59

_____join the Krebs cycle at different points

Answer 59

AA’s

Question 60

_____can be generated from excess acetyl CoA

Answer 60

Lipids

Question 61

______ is generated from excess pyruvate

Answer 61

Glycogen