BCH 3025 MODULE 1 QUESTIONS & ANSWERS
A dynamic steady state results when
A. a molecule stops being degraded.
B. an organism is at equilibrium with its surroundings.
C. there is no net energy transfer.
D. the rate of intake or synthesis of a molecule equals the rate of its disappearance -
Answers - Choice D is correct.
A dynamic steady state results when the rate of synthesis or intake of a molecule
equals the rate of its breakdown, consumption, or conversion into some other product.
For example, a dynamic steady state in the blood maintains constant levels of
hemoglobin and glucose.
An open system is one
A. that exchanges neither matter nor energy with its surroundings.
B. that exchanges energy but not matter with its surroundings.
C. that exchanges both matter and energy with its surroundings.
D. that exchanges matter but not energy with its surroundings. - Answers - Choice C is
correct.
If a system exchanges energy and matter with its surroundings, it is called an open
system.
A living organism, for example, is an open system because it exchanges matter and
energy with its surroundings.
Which of the following is true about the energy from sunlight?
A. All organisms obtain their energy directly from the radiant energy of sunlight.
B. Photosynthetic cells use light energy to drive electrons from one molecule to another.
C. Photosynthetic cells use light energy to produce CO2 that can be used as energy by
non-photosynthetic cells.
D. Photosynthetic cells absorb light energy and use it to break down compounds such
as starch and sucrose. - Answers - Choice B is correct.
Photosynthetic cells absorb light energy and use it to drive electrons from water to
carbon dioxide to form energy-rich products such as glucose, starch, and sucrose
Which of the following is true about carbon bonding?
A. Carbon-carbon double bonds have freedom of rotation.
B. Carbon atoms can form covalent bonds with up to four other atoms.
C. Carbon can form double bonds with hydrogen.
, D. Carbon-carbon single bonds cannot rotate. - Answers - Choice B is correct.
Carbon atoms have four unpaired electrons and therefore can share electron pairs
(covalent bonds) with up to four other atoms. In addition to forming single covalent
bonds with four atoms, carbon can form two single and one double bond, etc.
The amino acid alanine contains all of the following functional groups except
A. an amino group.
B. a methyl group.
C. an ester group.
D. a carboxyl group. - Answers - Choice C is correct.
Alanine does not contain an ester group
what are diasteromers
Which of the following is true about the two molecules shown below?
A. They have the same configuration.
B. They are cis-trans isomers.
C. They are enantiomers of each other.
D. They are diastereomers of each other. - Answers - Diastereomers are pairs of
stereoisomers that are not mirror images of each other. (see p. 16
what are enantiomers - Answers - pairs of sterioisomers that are mirror images of
eachother
The difference between phototrophs and chemotrophs is
A. whether they are aerobic or anaerobic.
B. their energy source.
C. their source of carbon.
D. whether they are prokaryotic or eukaryotic. - Answers - Choice B is correct.
Phototrophs obtain energy from sunlight and chemotrophs obtain their energy from
chemical compounds.
Both prokaryotic and eukaryotic cells possess which of the following? - Answers -
Choice D is correct. Prokaryotic and eukaryotic cells both have a plasma membrane
that encloses the cytoplasm
Exergonic and endergonic reactions differ in that
A dynamic steady state results when
A. a molecule stops being degraded.
B. an organism is at equilibrium with its surroundings.
C. there is no net energy transfer.
D. the rate of intake or synthesis of a molecule equals the rate of its disappearance -
Answers - Choice D is correct.
A dynamic steady state results when the rate of synthesis or intake of a molecule
equals the rate of its breakdown, consumption, or conversion into some other product.
For example, a dynamic steady state in the blood maintains constant levels of
hemoglobin and glucose.
An open system is one
A. that exchanges neither matter nor energy with its surroundings.
B. that exchanges energy but not matter with its surroundings.
C. that exchanges both matter and energy with its surroundings.
D. that exchanges matter but not energy with its surroundings. - Answers - Choice C is
correct.
If a system exchanges energy and matter with its surroundings, it is called an open
system.
A living organism, for example, is an open system because it exchanges matter and
energy with its surroundings.
Which of the following is true about the energy from sunlight?
A. All organisms obtain their energy directly from the radiant energy of sunlight.
B. Photosynthetic cells use light energy to drive electrons from one molecule to another.
C. Photosynthetic cells use light energy to produce CO2 that can be used as energy by
non-photosynthetic cells.
D. Photosynthetic cells absorb light energy and use it to break down compounds such
as starch and sucrose. - Answers - Choice B is correct.
Photosynthetic cells absorb light energy and use it to drive electrons from water to
carbon dioxide to form energy-rich products such as glucose, starch, and sucrose
Which of the following is true about carbon bonding?
A. Carbon-carbon double bonds have freedom of rotation.
B. Carbon atoms can form covalent bonds with up to four other atoms.
C. Carbon can form double bonds with hydrogen.
, D. Carbon-carbon single bonds cannot rotate. - Answers - Choice B is correct.
Carbon atoms have four unpaired electrons and therefore can share electron pairs
(covalent bonds) with up to four other atoms. In addition to forming single covalent
bonds with four atoms, carbon can form two single and one double bond, etc.
The amino acid alanine contains all of the following functional groups except
A. an amino group.
B. a methyl group.
C. an ester group.
D. a carboxyl group. - Answers - Choice C is correct.
Alanine does not contain an ester group
what are diasteromers
Which of the following is true about the two molecules shown below?
A. They have the same configuration.
B. They are cis-trans isomers.
C. They are enantiomers of each other.
D. They are diastereomers of each other. - Answers - Diastereomers are pairs of
stereoisomers that are not mirror images of each other. (see p. 16
what are enantiomers - Answers - pairs of sterioisomers that are mirror images of
eachother
The difference between phototrophs and chemotrophs is
A. whether they are aerobic or anaerobic.
B. their energy source.
C. their source of carbon.
D. whether they are prokaryotic or eukaryotic. - Answers - Choice B is correct.
Phototrophs obtain energy from sunlight and chemotrophs obtain their energy from
chemical compounds.
Both prokaryotic and eukaryotic cells possess which of the following? - Answers -
Choice D is correct. Prokaryotic and eukaryotic cells both have a plasma membrane
that encloses the cytoplasm
Exergonic and endergonic reactions differ in that
