Chapter 9: Cellular Respiration

Question 1

Catabolic (Metabolic) Pathway

Answer 1

Rxns that extract energy from molecules (like glucose) by breaking them down into smaller pieces

Most is lost by heat, the rest is captured as ADP (through substrate phosphorlyzation) or ATP

Pathway involving breaking down molecules into smaller units that are oxidized (to release energy) or used in other anabolic reactions

Question 2

Fermentation (1 of 2 types of catabolic processes)

Answer 2

Partial breakdown of sugars/organic fuels

Makes a limited amount of ATP from organic molecules like glucose

No electron transport chain; No use of oxygen; less efficient than aerobic respiration

Produces characteristic end product like ethyl alcohol or lactic acid

Question 3

Aerobic respiration (2 of 2 types of catabolic processes)

Answer 3

Type of cellular respiration

Most efficient catabolic pathway

Oxygen used with organic fuel

Most eukaryotes and some prokaryotes can use this pathway

Question 4

Aerobic Respiration

Answer 4

Type of cellular respiration

Some prokaryotes can use this pathway

Uses substances other than oxygen

Question 5

Anaerobic Respiration

Answer 5

Type of cellular respiration; similar to combustion

organic compound + O2 goes to CO2, H2O and Energy (ATP and heat)

Some prokaryotes can use this pathway

Uses substances other than oxygen

Question 6

Cellular respiration

Answer 6

Umbrella term for Anaerobic and aerobic respiration

1. Glycolysis: spit glucose
2. Pyruvate Oxidation: oxidize
3. Citric Acid Cycle:
4. Electron Transport Chain

Question 7

Redox rxns

Answer 7

Sometimes don’t completely transfer electrons

Sometimes shifts the level of electron sharing in covalent bonds

Energy required to facilitate this shift, and electron(s) that get shifted (from the less electronegative region to the more electronegative region) loose potential energy to the surroundings

E then used to synthesize ATP

Question 8

Best cellular respiration fuels

Answer 8

Carbs and fats

Organic molecules with a lot of hydrogen (bc the hydrogen bonds are a good source of energy)

Hydrogens’ electrons shift from hydrogen to oxygen

Question 9

Activation Energy

Answer 9

The amount of energy needed to start a reaction

Question 10

Stepwise Energy Harvest

Answer 10

When fuel sources (like glucose) are broken down in a series of steps (rather than all at once)

exp electrons are shifted FROM glucose (on the hydrogen atoms?)

Question 11

NAD+ and NADH are for…

Answer 11

Transports electrons/hydrogen atoms (i.e. glycolysis)

Nicotinamide adenine dinucleotide derivative of vitamin niacin

Question 12

Dehydrogenases

Answer 12

Enzymes that remove hydrogen atoms in fuels (in pairs) from fuels (like glucose) trapping electrons/taking away glucoses’ electrons

Both of the snatched electrons and one of the protons go to NAD+ and the other proton is released at H+ in the surrounding sln

Question 13

Electron transport chain

Answer 13

Bunch of molecules (mostly proteins) in the mitochondria membrane (or the plasma membranes of respiring prokaryotes)

Has a high energy end and a lower energy end

Electrons snatched from glucose are brought to the high energy end by NADH and cascade down a series of increasingly electronegative carrier molecules/redox rxns, towards the low energy end (helps conserve energy)

Low energy end’s O2 captures electrons and H+ to make water

Question 14

Glycolysis

Answer 14

When a 6 carbon glucose molecule is split into two 3 carbon molecules, which are then oxidized and reordered to make pyruvate

Occurs in 2 phases: energy investment and energy payoff

Question 15

Pyruvate

Answer 15

Ionized version of pyruvic acid

Question 16

Glycolysis: Energy investment

Answer 16

Cell “spends” ATP

Question 17

Citric Acid Cycle

Answer 17

Further? oxidizes organic molecules (pyruvate) after they’ve been

Question 18

Phosphorylation

Answer 18

Adding a phosphate gap to another molecule

i.e. Making ATP by adding P to ADP

Question 19

Substrate-level Phosphorylation

Answer 19

Making ATP by adding P to ADP using an intermediate substrate (glucose:pyruvate)

Question 20

Oxidative Phosphorylation

Answer 20

Making ATP by adding P to ADP in the ATP synthase/electron transport chain

Chemiosmosis considered a part of this process

Question 21

3 steps of pyruvate oxidation (before citric acid cycle)

Answer 21

1. C removed to make CO2 (oxidation)
2. H/e- removed to make NADH (E released?)
3. CoA added to leftovers to make acetal CoA

Question 22

FAD and FADH2 involved in…

Answer 22

Transporting electrons/hydrogen atoms (citric acid cycle)

Question 23

How catabolic metabolism uses protein

Answer 23

amino acids are removed and the rest of the molecule(s) can be used in glycolysis

Byproduct NH3

Question 24

How catabolic metabolism uses fats

Answer 24

Fats digested into glycerol (for glycolysis)

Fatty acids broken down by BETA OXIDATION to generate acetyl CoA

Question 25

How catabolic metabolism uses carbohydrates

Answer 25

Basically any sugars (not just glucose) can be used in glycolisis

That’s why you can stick an intermediate sugar from citric acid cycle into a yeast and still have respiration