Group Activity 3 [50]
Suggested Answers
Question 1 [15]
Discuss the following terms or phrases
1.1. Photoautotrophs (5)
These organisms use light as their energy source and CO 2 as their carbon source.
Photosynthetic protists and cyanobacteria employ water as the electron donor and
release oxygen. Purple sulphur bacteria and green sulphur bacteria extract electrons
m
from inorganic donors such as hydrogen, hydrogen sulphide and elemental sulphur
er as
co
because they cannot oxidize water. Photoautotrophs are important primary producers in
eH w
ecosystems
o.
1.2. Chemoorganotrophs rs e (5)
ou urc
These are organisms which use the reduced organic compounds made by autotrophs
o
as sources of energy, electrons and carbon. Chemoorganotrophs contribute to
aC s
biogeochemical cycles such as nitrogen cycle and carbon cycle in which elements are
vi y re
converted into different forms. Glucose is used as an energy source by many
chemoorganotrophs during aerobic respiration, anaerobic respiration and fermentation.
ed d
When they oxidize an organic source energy source, the electrons released are
ar stu
accepted by electron carriers such as NAD+ and FAD.
is
1.3. Substrate level phosphorylation (5)
Th
This is the synthesis of ATP from ADP by phosphorylation coupled with the
exergonic breakdown of a high-energy organic substrate molecule. The direct
sh
production of ATP during glycolysis and TCA cycle takes place by substrate level
phosphorylation. For example during glycolysis, the conversion of 1, 3
bisphosphoglycerate to 3-phosphoglycerate produces ATP by substrate level
phosphorylation.
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, Question 2 [10]
Study the Tricarboxylic acid cycle below and answer the questions which follow
m
er as
co
eH w
o.
rs e
ou urc
o
aC s
vi y re
ed d
ar stu
2.1. Carbon skeletons for amino acid biosynthesis are supplied by intermediates of the
is
citric acid cycle. Which intermediate would supply the carbon skeleton for synthesis of
Th
five-carbon amino acid? (1)
α −¿ ketoglutarate
sh
2.2. How many reduced dinucleotides would be produced with four turns of the citric
acid cycle? (2)
4 FADH2 and 12 NADH
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https://www.coursehero.com/file/24312169/SuggestedAnswerstoGroupActivity3docx/
Suggested Answers
Question 1 [15]
Discuss the following terms or phrases
1.1. Photoautotrophs (5)
These organisms use light as their energy source and CO 2 as their carbon source.
Photosynthetic protists and cyanobacteria employ water as the electron donor and
release oxygen. Purple sulphur bacteria and green sulphur bacteria extract electrons
m
from inorganic donors such as hydrogen, hydrogen sulphide and elemental sulphur
er as
co
because they cannot oxidize water. Photoautotrophs are important primary producers in
eH w
ecosystems
o.
1.2. Chemoorganotrophs rs e (5)
ou urc
These are organisms which use the reduced organic compounds made by autotrophs
o
as sources of energy, electrons and carbon. Chemoorganotrophs contribute to
aC s
biogeochemical cycles such as nitrogen cycle and carbon cycle in which elements are
vi y re
converted into different forms. Glucose is used as an energy source by many
chemoorganotrophs during aerobic respiration, anaerobic respiration and fermentation.
ed d
When they oxidize an organic source energy source, the electrons released are
ar stu
accepted by electron carriers such as NAD+ and FAD.
is
1.3. Substrate level phosphorylation (5)
Th
This is the synthesis of ATP from ADP by phosphorylation coupled with the
exergonic breakdown of a high-energy organic substrate molecule. The direct
sh
production of ATP during glycolysis and TCA cycle takes place by substrate level
phosphorylation. For example during glycolysis, the conversion of 1, 3
bisphosphoglycerate to 3-phosphoglycerate produces ATP by substrate level
phosphorylation.
This study source was downloaded by 100000769268334 from CourseHero.com on 07-13-2021 16:29:04 GMT -05:00
https://www.coursehero.com/file/24312169/SuggestedAnswerstoGroupActivity3docx/
, Question 2 [10]
Study the Tricarboxylic acid cycle below and answer the questions which follow
m
er as
co
eH w
o.
rs e
ou urc
o
aC s
vi y re
ed d
ar stu
2.1. Carbon skeletons for amino acid biosynthesis are supplied by intermediates of the
is
citric acid cycle. Which intermediate would supply the carbon skeleton for synthesis of
Th
five-carbon amino acid? (1)
α −¿ ketoglutarate
sh
2.2. How many reduced dinucleotides would be produced with four turns of the citric
acid cycle? (2)
4 FADH2 and 12 NADH
This study source was downloaded by 100000769268334 from CourseHero.com on 07-13-2021 16:29:04 GMT -05:00
https://www.coursehero.com/file/24312169/SuggestedAnswerstoGroupActivity3docx/
