Metabolic diversity

Question 1

What are the basic requirements for life?

Answer 1

Carbon source (C/CO2)
Macronutrients (N, P, S, Mg, Ca, Fe).
Trace Elements (Mn, Co, Ni, W, Zn, Se, B, Mo, Cu)
Water and an energy source
Suitable environment (physical and chemical settings)

Question 2

What does the Redfield ratio represent?

Answer 2

The general composition of biomass as C106 N16 P1. However, more realistically shown as C106 H263 O110 N16 P1 S1-Vary significantly depending on availability of nutrients

Question 3

What are the main building blocks of microbes?

Answer 3

Protein, Polysaccharides and derivatives, nucleic acids, and lipids. Others include dry weight. 80% of cellular mass considered water.

Question 4

What factors should be taken into account in order to categorise the metabolism of an organism?

Answer 4

Source of energy
Electron source for biomass formation
The requirement of organic material for growth

Question 5

What do organisms need energy for?

Answer 5

Growth, mobility, maintenance, reproduction…

Question 6

What is a Phototroph and give examples

Answer 6

Photosynthesis-Cyanobacteria, algae, higher plants, anoxic phototrophs

Question 7

What is a Chemotroph

Answer 7

Respiration/Fermentation=Fauna, bacteria.

Question 8

Name examples of energy-rich compounds and the expected duration of the energy source

Answer 8

Long term: Lipids, Startch,

Short term: Adenosine Triphosphate (ATP)

Question 9

Formula for Anoxygenic photosynthesis

Answer 9

H2S—ADP+P>ATP—->So+2e-+2H+ (no elemental O2 formed)

Question 10

Formula for oxygenic photosynthesis

Answer 10

2H20—ADP+P>ATP–>O2+4e-+4H+ (Light used to drive endergonic reaction in order to oxidate O2 in water to produce ATP

Question 11

Define Endergonic

Answer 11

Energy Consuming

Question 12

Define Exergonic

Answer 12

Energy releasing

Question 13

Endothermic

Answer 13

Heat consuming

Question 14

Define Exothermic

Answer 14

Heat releasing

Question 15

Meaning of ATP

Answer 15

Adenosine Triphosphate (Energy-rich phosphate esters)

Question 16

Formula Aerobic reaction

Answer 16

C6H12O6 (glucose)+6O2–ADP+P>ATP—->6CO2+6H2O

Question 17

Formula Fermentation

Answer 17

C6H12O6—-ADP+P>ATP—->2C3H6O3 (Lactic acid)

Question 18

Electron donor is organic material, what does this make the organism?

Answer 18

Organotroph

Question 19

Electron donor is in-organic, what does this make the organism?

Answer 19

Lithotroph

Question 20

Lithotroph oxygenic photosynthesis equation?

Answer 20

2H20—ADP+P>ATP—->O2+4e-+4H+

Question 21

Lithotrophic sulphide oxidisation equation?

Answer 21

H2S+2O2—-ADP+P>ATP—->SO4^2-+SH+

Question 22

If the carbon source is organic material what does this make the organism?

Answer 22

Heterotroph

Question 23

If the carbon source is inorganic material what does this make the organism?

Answer 23

Autotroph

Question 24

Characteristics of lithotrophic organisms metabolism

Answer 24

Usually autotroph (Kelly, 1971), low energy yield due to limited supply of substrate=Low contribution to primary production of ecosystem

Question 25

Energy source, electron donor, and carbon source for Photolithoautotroph

Answer 25

Energy Source: Light Electron Donor: H20 Carbon Source: CO2

Question 26

Energy source, electron donor, and carbon source for Chemoorganoheterotroph (Homo sapien)

Answer 26

Energy Source: Oxidation of electron donor Electron Donor: Organic material Carbon Source: Organic material

Question 27

Chemolithoautotroph

Answer 27

Energy Source: Oxidation of electron donor Electron Donor: NH3, FE2+, H2S, H2 Carbon Source: CO2 i.e. Nitrosomonas europaea

Question 28

What are the 2 steps during degradation of organic material for chemolithoautotroph?

Answer 28

Step 1: Extracellular hydrolysis of polymeric compounds | Step 2: Uptake of dissolved materials

Question 29

What are the 3 steps during Chemoorganotrophic bacteria degradation of organic matter?

Answer 29

Step 1: Extracellular hydrolysis of polymeric compounds Step 2: Uptake of dissolved molecules Step 3: Metabolism

Question 30

Define redox reaction

Answer 30

Oxidation reaction i.e. when oxidation state of atoms change (electrons stripped from a compound=oxidation, electron added=Reduced)

Question 31

Why do cells avoid direct reaction with O2

Answer 31

As it is very reactive and would cause too much heat energy as a bi-product.