L4 Metabolism Of Organic Molecules

Question 1

What method is used by most life

Answer 1

Chemoheterotrophy

Question 2

What 2 things are carbon comounds used for in chemoheterotrophy

Answer 2

Generating energy and the biosynthesis of macromolecules

Question 3

What are some potential carbon sources in nature

Answer 3

Proteins
Lipids
Carbohydrates
Aromatics

Question 4

Why is wood hard to breakdown

Answer 4

Its a mix of many different C sources

Question 5

Why are amino acids not often used for biosynthesis

Answer 5

The cost of breaking down amino acids releases little energy, onlt need to be broken down if nitrogen is needed

Question 6

How many main routes in microbes are there to breakdown glucose

Answer 6

3
Glycolysis (EMP), Enter-doudoroff (ED), and pentose phosphate pathway (PPP)

Question 7

3 energy generating metabolic processes

Answer 7

Aerobic respiration
Anaerobic respiration
Fermentation

Question 8

What is broken down in fermentation and when does it occur

Answer 8

Carbohydrates broken down in absence of oxygen

Question 9

What kind of electron acceptors are used in fermentation

Answer 9

Organic e.g. NAD+

Question 10

What is released in fermentation

Answer 10

Small organic molecules e.g. Ethanol
Nor carbon dioxide and water

Question 11

What happens in aerobic respiration and when does it occur
What electron acceptor is used
What is produced

Answer 11

Breakdown of carbohydrates in prescence of oxygen
Oxygen
Carbon dioxide and water

Question 12

Why can oxygen and FAD+ be bad for anaerobes

Answer 12

They generate reactive oxygen species (ROS)
Hydroxides or can react to form hydroxyl ions damaging DNA, RNA and membranes
Anaerobic microbes cannot detoxify ROS

Question 13

How many ATP’s are produced in aerobic respiration per one molecule of glucose

Answer 13

38

Question 14

How many ATP’s are produced in bacteria under artobic respiration

Answer 14

~20

Question 15

What are H+ and NADH used for in bacteria during aerobic respiraton that effects ATP output

Answer 15

H+ to maintain memebrane proton potential
NADH is a co-factor in some enzymes

Question 16

What is the glyoxylate bypass
When is it used

Answer 16

When the full TCA cycle is not used
The step releasing carbon dioxide is skipped when in low carbon environemt or when carbon is needed more for respiration and byosynthesis

Question 17

What is disimilation

Answer 17

Successive reduction

Question 18

What is dissimilation of nitrogen and sulfur important for

Answer 18

Successive reduction of nitrogen and sulfur is vital in the N and S cycles

Question 19

What is fumurate (trimethylamine oxide) reduced to and how can you tell if this is present

Answer 19

Trimethylamine
Fishy smell

Question 20

Name a metal often involved in dissimilatory metal reduction
What can be produced

Answer 20

Fe3+
Metal precipitation

Question 21

What completes the glucose-pyruvate catabolism pathway

Answer 21

Fermentation

Question 22

What are the conditions in the bottom of the winogradsky column

Answer 22

Anaerobic

Question 23

What are 2 drawbacks of fermentation

Answer 23

Lower energy yield
Potential organic energy excreted

Question 24

What are 2 possible reasons for fermenting

Answer 24

Suitable electron acceptors not available
Excreted producs can inhibit other organisms