Lecture 12-14: Catabolic Pathways

Question 1

Catabolic pathways:

Answer 1

release energy by breaking down complex molecules into simpler compounds

Question 2

aerobic respiration:

Answer 2

oxygen is consumed as a reactant along with organic fuel

Question 3

anaerobic respiration:

Answer 3

organic fuel is broken down without oxygen

Question 4

fermentation:

Answer 4

partial breakdown of organic fuel (sugars) without oxygen

Question 5

what is the chemical formula for cellular respiration?

Answer 5

C6H12O6 + 6O2 -> 6CO2 + 6H2O + Energy

Question 6

what kind of respiration is cellular respiration?

Answer 6

aerobic (and anaerobic)

Question 7

what do catabolic reactions depend on during chemical reactions?

Answer 7

transferring of electrons

Question 8

the transfer of electrons from one molecule to another is…

Answer 8

redox (always coupled!)

Question 9

catchphrase for loss or gain of electrons?

Answer 9

LEO goes GER

Question 10

what is nicotinamide adenine dinucleotide (NAD+)?

Answer 10

electron transporter (shuttle)
-> a coenzyme and oxidizing agent
-> cycles between oxidized (NAD+) and reduced (NADH)

Question 11

why do electrons move in a step-wise process?

Answer 11

if the transfer was uncontrolled, there would be one big release of energy with lots of heat loss
by using small releases of energy at each step, more ATP can be created

Question 12

two ways ATP is made:

Answer 12

substrate level phosphorylation
oxidative phosphorylation

Question 13

where does glycolysis/citric acid cycle/OxPhos happen in prokaryotes?

Answer 13

glycolysis/krebs: cytosol
oxphos: plasma membrane

Question 14

what does glycolysis mean in a nutshell?

Answer 14

sugar-splitting

Question 15

2 phases of glycolysis:

Answer 15

energy investment (cell “spends” ATP)
energy payoff (ATP is produced via substrate-level phosphorylation)

Question 16

what do you gain overall from glycolysis?

Answer 16

2 ATP and 2 NADH

Question 17

where is the pyruvate produced in glycolysis taken?

Answer 17

mitochondrion

Question 18

what is pyruvate converted into?

Answer 18

acetyl CoA

Question 19

what does the citric acid cycle produce per cycle?

Answer 19

1 ATP molecule via substrate-level phosphorylation, 2 total because two pyruvate start off the cycle

Question 20

total of ATP created per glucose molecule in glycolysis and krebs cycle?

Answer 20

4 ATP (2+2)

Question 21

collection of protein complexes within the inner membrane of the mitochondrion:

Answer 21

electron transport chain

Question 22

what does ATP synthase make?

Answer 22

ATP from ADP and inorganic P using oxidative phosphorylation

Question 23

what is chemiosmosis?

Answer 23

an energy-coupling mechanism
-> uses energy stored in the form of H+ gradient across the membrane to drive cellular work

Question 24

anaerobic respiration:

Answer 24

respiration in which the final electron acceptor is not oxygen

Question 25

fermentation:

Answer 25

does not have an ETC or oxygen as the final electron acceptor

Question 26

what does fermentation recycle?

Answer 26

NAD+ from NADH during glycolysis

Question 27

two types of fermentation:

Answer 27

alcohol fermentation and lactic acid fermentation

Question 28

alcohol fermentation:

Answer 28

pyruvate is converted to ethanol (aka ethyl alcohol)

Question 29

lactic acid fermentation:

Answer 29

pyruvate is reduced directly by NADH to form lactic acid, no release of CO2

Question 30

obligate anaerobes:

Answer 30

organisms that only carry out fermentation or anaerobic respiration

Question 31

facultative anaerobes:

Answer 31

organisms can utilise both fermentation and cellular respiration to make enough ATP