Chapter 20

Question 0

Pathway for digestion of food

Answer 0

Question 1

Energy

Answer 1

>comes from food we eat >ultimately comes from sun >can be conserved/converted

Question 2

ATP

Answer 2

• Universal energy molecule used by all living cells.
• produced inside the mitochondria (inner membrane)

Question 3

Metabolic pathways

Answer 3

• Catabolism: breaking molecules apart (energy released)
• Anabolism: refers to making molecules larger (energy used up)

Question 4

Acetyl-CoenzymeA (acetyl-CoA)

Answer 4

The common intermediate that carries acetyl groups into the citric acid cycle.

• intermediate in the break down of all classes of food

Question 5

Stages of energy production:

Answer 5

1. digestion
2. Acetyl-coenzyme A production
3. citric acid cycle
4. ATP production

Question 6

ATP & Energy transfer

Answer 6

• Energy of ATP is carried by negative charges on 3 phosphates ⇒high energy/charge repulsion
• ATP>ADP>AMP (energy release @ each step)

Question 7

Oxidation

Answer 7

• loss of electrons
• loss of hydrogens
• gain of oxygen

Question 8

NAD⁺ & FAD

Answer 8

• Electron carrier molecules.
• accept electrons in oxidation
• transport electrons to electron transport chain
• nicotine adenine dinucleotide, NAD⁺ (from niacin)
• flavin adenine dineucleotide, FAD (from riboflavin)

Question 9

Whenever FAD or NAD⁺ appears in a reaction:

Answer 9

• The biomolecule becomes oxidized

Question 10

Reduction of NAD⁺:

Answer 10

• Addition of electrons

Question 11

Reduction of FAD:

Answer 11

• Addition of electrons

Question 12

Purpose of citric acid cycle:

Answer 12

1. harvest energy by oxidation
2. provide starting material

• starting materials: acetyl-CoA & oxaloacetate
• products: CO₂,GTP,NADH,FADH₂

Question 13

Citric acid cycle

Answer 13

• 1st half oxidizes
• 2nd half regenerates oxacytelate
• Reactions: oxidation & decarboxylation

Question 14

Electron transport chain

Answer 14

Purpose:

1. use energy of moving electrons to pump H+ ions
2. recycle NADH & FADH2 back to NAD+ & FAD

Starting materials:

• electrons molecular oxygen

Products:

• recycled NAD⁺ & FAD for reuse in CAC
• waste water (urine)

Question 15

ATP synthesis:

Answer 15

ATP is made from ADP and HPO₄ ^2-

>H⁺ flowing through ATP synthase causes a shape change that fires P_i onto ADP

Question 16

Lack of oxygen causes:

Answer 16

Electron transport to stop!

Question 17

Superoxide ion

Answer 17

•O_2^-

• Oxygen with an extra electron
• free radical

Question 18

Hydroxyl radical

Answer 18

•OH

• Not a hydroxide ion
• free radical

Question 19

Hydrogen perioxide

Answer 19

H₂O₂

• Can split to form a radical

Question 20

Free radical

Answer 20

• Unpaired electron
• take an electron from any nearby molecule and break covalent bonds in that molecule and creates a new radical
• cause damaged membranes= cell death!

Question 21

Catalase

Answer 21

• Eliminates H₂O₂
• fastest know enzyme

Question 22

Superoxide dimutase

Answer 22

• Eliminates superoxide

Question 23

Reactive oxygen species (ROS):

Answer 23

• Microbial killers
• ROS that escapes enzymatic destruction are eliminated by Vitamin E (protects membrane), Vitamin C (protects aqueous componets), glutathione (eliminates radical)

Question 24

Free energy

Answer 24

• endergonic: Nonspontneous, absorbs,+ G
• exergonic: Sponateous,relaeases, - G

Question 25

Succinate acid

Answer 25