Name: ________KEY Exam B________________ UID: _______________ Exam code: B
BSCI207: Principles of Biology III
Exam 1B – Fall 2025
Instructions:
• Put your name and UID on this first page.
• Read each question carefully and select the BEST answer.
• For multiple choice/fill in blank – put answers on answer sheet – last page
• For free response questions, answer in (and ONLY in) the space provided on the exam. Full credit
will only be given if you SHOW YOUR WORK
• You have 50 minutes for this exam.
Please read and sign that you agree to follow the University of Maryland honor pledge:
“I understand my obligation to uphold the University Code of Academic Integrity and pledge I have not
received or given any unauthorized assistance on this academic exercise.”
Signature Date
Questions 1 – 20 of 50 points
Question 21 of 8 points
Question 22 of 8 points
Question 23 of 9 points
Total of 75 points
Note: In the interest of fairness, I’ve decided to give those who got wrong the enzyme multiple choice
question the same 2 points that I gave those who got it wrong on exam A. Thanks for your understanding.
, 1. The outgroup and its placement in a molecular phylogenetic tree of related organisms can be useful for
several reasons. Which of the following is incorrect about the outgroup?
a. Its placement identifies the earliest time in the tree from which all organisms diverge.
b. Its characteristics might be indicative of those of the common ancestor of the group.
c. It is the most primitive organism compared to all the other taxa in the tree.
d. Its identity needs to be determined using external data such as the fossil record.
GAE2 – phylogenetic misconception
2. Organisms take in energy and release energy. Which one of the following is not possible?
a. Organisms can take in high energy molecules and produce chemical products and heat
b. Organisms can take in high energy photons and produce high energy chemicals and heat
c. Organisms can take in low energy heat and produce high energy molecules
d. Organisms can take in different forms of energy but must release as much energy as they take in
GAE 1 Key ideas 2&3 Conservation and transformation of energy from high to low energy
3. (4 pts) Early photosynthetic bacteria were in shallow seas bathed in sunlight. Sunlight photons have an
energy of 3.5 x 10-19 J of energy. To break a strong chemical bond requires 3.7 x 10-19 J.
How many photons would that take? 3.7 x 10-19 J / 3.5 x 10-19 J/photon ~1 photon
Is it likely for this many photons to occur in the same place at the same time? (see answer sheet)
GAE 1 Yes this is likely as it only takes about 1 photon
4. Which one of the following was a new benefit that organisms gained when their metabolism became
aerobic? Lecture 8 section 3
a. They were finally able to acquire more energy because of the strong electronegativity of oxygen
b. They were finally able to use ATP synthase to generate ATP
c. They were finally able to use glycolysis in extracting energy from high energy molecules
d. They were finally able to use electron accepting complexes and shuttles to pump protons
5. (4 pts) Select a key trait for each of the types of bacteria listed on the left.
____d, a__ a-proteobacteria a. diverse metabolic strategies
____c, d___ cyanobacteria b. halophilic
____f____ Gram positive bacteria c. photosynthetic
____a,c,d__ Gram negative bacteria d. symbiotic with eukaryotes
e. thermophilic
Lecture 7 section 2 f. thick peptidoglycan cell wall
You only had to pick one for each but I note all the answers I accepted
6. Which of the following are required for spontaneous, exergonic, biological reactions (select all that
apply)? Lecture 3 section 2
a. The products have more energy than the reactants
b. The reactants have more energy than the products
c. Heat is absorbed from the environment
d. Heat is released to the environment
7. (4pts) Of the organisms below, which evolved first ___d___ and which is the most recent ___a___.
a. algae Lecture 7 key ideas 4 and 5
b. a-proteobacteria
c. cyanobacteria
d. methanogenic archaea
2
BSCI207: Principles of Biology III
Exam 1B – Fall 2025
Instructions:
• Put your name and UID on this first page.
• Read each question carefully and select the BEST answer.
• For multiple choice/fill in blank – put answers on answer sheet – last page
• For free response questions, answer in (and ONLY in) the space provided on the exam. Full credit
will only be given if you SHOW YOUR WORK
• You have 50 minutes for this exam.
Please read and sign that you agree to follow the University of Maryland honor pledge:
“I understand my obligation to uphold the University Code of Academic Integrity and pledge I have not
received or given any unauthorized assistance on this academic exercise.”
Signature Date
Questions 1 – 20 of 50 points
Question 21 of 8 points
Question 22 of 8 points
Question 23 of 9 points
Total of 75 points
Note: In the interest of fairness, I’ve decided to give those who got wrong the enzyme multiple choice
question the same 2 points that I gave those who got it wrong on exam A. Thanks for your understanding.
, 1. The outgroup and its placement in a molecular phylogenetic tree of related organisms can be useful for
several reasons. Which of the following is incorrect about the outgroup?
a. Its placement identifies the earliest time in the tree from which all organisms diverge.
b. Its characteristics might be indicative of those of the common ancestor of the group.
c. It is the most primitive organism compared to all the other taxa in the tree.
d. Its identity needs to be determined using external data such as the fossil record.
GAE2 – phylogenetic misconception
2. Organisms take in energy and release energy. Which one of the following is not possible?
a. Organisms can take in high energy molecules and produce chemical products and heat
b. Organisms can take in high energy photons and produce high energy chemicals and heat
c. Organisms can take in low energy heat and produce high energy molecules
d. Organisms can take in different forms of energy but must release as much energy as they take in
GAE 1 Key ideas 2&3 Conservation and transformation of energy from high to low energy
3. (4 pts) Early photosynthetic bacteria were in shallow seas bathed in sunlight. Sunlight photons have an
energy of 3.5 x 10-19 J of energy. To break a strong chemical bond requires 3.7 x 10-19 J.
How many photons would that take? 3.7 x 10-19 J / 3.5 x 10-19 J/photon ~1 photon
Is it likely for this many photons to occur in the same place at the same time? (see answer sheet)
GAE 1 Yes this is likely as it only takes about 1 photon
4. Which one of the following was a new benefit that organisms gained when their metabolism became
aerobic? Lecture 8 section 3
a. They were finally able to acquire more energy because of the strong electronegativity of oxygen
b. They were finally able to use ATP synthase to generate ATP
c. They were finally able to use glycolysis in extracting energy from high energy molecules
d. They were finally able to use electron accepting complexes and shuttles to pump protons
5. (4 pts) Select a key trait for each of the types of bacteria listed on the left.
____d, a__ a-proteobacteria a. diverse metabolic strategies
____c, d___ cyanobacteria b. halophilic
____f____ Gram positive bacteria c. photosynthetic
____a,c,d__ Gram negative bacteria d. symbiotic with eukaryotes
e. thermophilic
Lecture 7 section 2 f. thick peptidoglycan cell wall
You only had to pick one for each but I note all the answers I accepted
6. Which of the following are required for spontaneous, exergonic, biological reactions (select all that
apply)? Lecture 3 section 2
a. The products have more energy than the reactants
b. The reactants have more energy than the products
c. Heat is absorbed from the environment
d. Heat is released to the environment
7. (4pts) Of the organisms below, which evolved first ___d___ and which is the most recent ___a___.
a. algae Lecture 7 key ideas 4 and 5
b. a-proteobacteria
c. cyanobacteria
d. methanogenic archaea
2
