Carbon Metabolism Part 1

Question 1

What is metabolism? 4 Definitions

Answer 1

1. From greek: transition or change
2. Set of life-sustaining chemical reactions in all living organisms
3. The chemical process that occurs within a living organism in order to maintain life.
4. All chemical reactions involved in maintaining the living state of the cells and the organism

Question 2

What do reactions require?

Answer 2

Energy and carbon and other key nutrients

Question 3

In which forms can organisms harvest energy from nature?

Answer 3

Energy can be harvest via light or chemical energy in Phototrophs or chemotrophs & energy is harvested via carbon and organic carbon dioxide in autotrophs or heterotrophs.

Question 4

Another term for fueling reactions

Answer 4

catabolism or break down metabolism

Question 5

The opposite of fueling reactions

Answer 5

anabolism or build up metabolism

Question 6

Which three products are formed during fueling reactions?

Answer 6

ATP: Energy conservation
Reducing Power: Electrons for chemical reactions
Precursor metabolites: Carbon skeletons for biosynthesis

Question 7

What are the substrates for catabolism?

Answer 7

Energy and carbon sources.

Question 8

Describe Catabolism

Answer 8

Breakdown of molecules
Energy conservation
Conservation in the form of ATP

Question 9

Describe anabolism

Answer 9

Synthesis of macromolecules

• Proteins
• Nucleic acids
• Carbohydrates
• Complex lipids

Assembly of macromolecules into cell components

Question 10

A broad summary of metabolism:

Answer 10

Substrates are broken down to get to carbon and energy (catabolism), which is then used for the synthesis of cellular components (anabolism).

Question 11

ATP

Answer 11

ATP is a nucleotide
Molecule where energy is conserved
Energy is stored between bonds of phosphate molecules

Question 12

ADP and ATP

Answer 12

Energy is consumed when phosphate is added to ADP to form ATP.
Energy is released in a strongly exergonic reaction when phosphate is removed from ATP. (hydrolysis)
This energy is then used to drive endergonic reactions, usually associated with anabolism.

Question 13

Process of ADP to ATP is called

Answer 13

phosphorylation

Question 14

Process of ATP to ADP is called

Answer 14

hydrolysis

Question 15

Name the four electron carriers that are crucial for energy generation in the cell.

Answer 15

NAD+, FAD, NADH and Coenzyme Q

Question 16

Electrons donated from reactions

Answer 16

higher up in the tower to reactions lower down in the tower.
or with more negative to more positive standard reduction potentials

Question 17

Four steps of the electron transport chain

Answer 17

1. Electrons are harvested and carried to the transport system.
2. Electrons provide energy to pump protons across the membrane.
3. Oxygen joins with protons to form water.
4. Protons diffuse back down their concentration gradient, driving the synthesis of ATP.

Question 18

Cellular respiration steps

Answer 18

1. Glycolysis
2. Oxidation of Pyruvate
3. Citric acid cycle (Krebs cycle)
4. Electron transport chain

Question 19

Glycolosis

Answer 19

Break up of glucose
Occurs in cytoplasm
Glycolysis takes glucose and turns it into Pyruvic acid

Question 20

ATP

Answer 20

Currency of cellular energy

Adenine, ribosome and three phosphate molecules

Question 21

Three pathways of glycolysis

Answer 21

The Embden-Meyerhof Pathway - EMP (most common)
The Entner-Doudoroff pathway
Pentose Phophate pathway

Question 22

The Embden-Meyerhoff Pathway

Answer 22

1. 2 ATP molecules are consumed to phosphorylate the subsequent intermediate molecules.
   2.

Question 23

Amphibiotic pathways

Answer 23

The pathway can be catabolic or anabolic.

Question 24

Key takeaways of Pentose-phosphate pathway

Answer 24

1. Can run concurrently with the EM pathway
2. It does not require the presence of oxygen
3. Plays an important role in anabolism
4. It generates NADPH
5. Pathway is important for organisms growing on C5 sugar such as xylose as main carbon source.

Question 25

Pentose-phosphate pathway energy balance

Answer 25

Glucose-6-phosphate + 12NACP+ + 7H2O
–>
6CO2 + 12NADPH + 12H* + Pi

Question 26

Entner-Doudoroff pathway energy balance

Answer 26

Glucose + ADP + PI + NADP* + NAD*
–>
2 pyruvate + ATP + NADPH + NADH + 2H*

Question 27

Embden-Meyerhoff pathway

Answer 27

Glucose + 2ADP + 2Pi + 2NAD*
–>
2Pyruvate + 2ATP + 2NADH + 2H*

Question 28

Highlights of Pentose-phosphate pathway

Answer 28

Produces precursors for metabolic pathways.

• Erythrose 4-P
• Ribose 5-P

The only pathway that completely breaks down glucose with loads of NADPH.

Question 29

The different names of the tricarboxylic acid cycle:

Answer 29

1. Tricarboxylic acid cycle
2. Krebs cycle
3. Citric acid cycle

Question 30

Krebs cycle function

Answer 30

catabolism of pyruvate to CO2

generates more energy (NADH and ATP) than EMP.

Question 31

Steps in the Krebs Cycle

Answer 31

1. Pyruvate is decarboxylated (loses a carbon in the form of CO2) has a coproduct NADH. The two remaining carbons are attached to coenzyme A by a high-energy bond. The energy in this bond will be used to drive the next reaction. Acetyl-CoA is a precursor metabolite.
2. The two remaining carbons of pyruvate are combined with the four carbons of oxaloacetate. This forms the 6-carbon molecule citrate.

Question 32

Amino acids formed from..

Answer 32

Amino Acids are formed from the intermediates of the TCA cycle.