BIOL 200 Midterm Exam | Questions and Answers Latest Update 2026/2027
(Graded A+) - University of British Columbia
Instructions for Exam Regrades
The exams were carefully and consistently graded. However, if you feel that
an error was made in the grading of your exam, please follow these
instructions.
1. Carefully read this answer key, and compare to your answer.
2. You must submit a letter to your instructor that outlines why the regrading is
needed for each question. You must refer to the answer key in your
explanation. It is not sufficient to say “please regrade Question X.” Instead,
you have to explain why your answers should be given more points.
3. You will need to submit your exam paper as part of your regrade request.
4. The whole exam will be regraded. Therefore, there is a possibility that your
exam grade may go up, down or stay the same. The new grade will be your
final grade – you do not get to keep your old grade.
Please do not submit any requests for regrading until 48 hours after you
receive your mark.
Your request must be received no later than November 17th to be
considered.
1
, Question 1 ( /5 marks)
When doing research, scientists will often look at many
different images to try and learn more about the structures
they are studying. In this case, the scientists were studying the
yeast Saccharomyces cerevisiae, which reproduce by growing
a bud and then dividing asymmetrically into a mother cell and
a daughter cell. Cells that are in the process of forming the
daughter cell take on a characteristic shape, as shown in the
images below. (Note: N = nucleus).
A. What type of microscopy was used to generate the two images? What is the supporting basis for
your choice? (3 marks)
Type of microscopy Supporting basis
Image A: SEM (1)
0.5/1 – electron microscopy Image A is 3D showing a surface, which is a
characteristic of SEM (0.5)
Image B: TEM (1) Image B is a slice showing internal features / fine
0.5/1 – electron microscopy details of Golgi apparatus / cell wall, which is a
characteristic of TEM (0.5)
Instructor's note: Tutorial 2 on Microscopy had images of the 4 major types of microscopy, specifically for S.
cerevisiae. (This was based on the microscope 'Yeast' demo that was on the side bench in the tutorial rooms.)
B. State one advantage of using the type of microscopy used to generate image B over image A.
(1 mark)
Image B (TEM) will show you the fine details of the cytoplasm of the cell, whereas Image A (SEM) will only show
surfaces. (1 mark).
Common mistakes:
o You must state specifically why TEM has an advantage over SEM.
o Answers that say "that the inside of the cell cannot be seen with SEM." This is not correct as you can use
freeze-fracture to 'crack open' cells, and then use SEM to scan the surface of that half of the cell.
(Note: If you've misidentified the types of microscopy in part A, we will give credit for what you write here, if your
answers match the type of microscopy that you mentioned.)
C. In the image in Panel B, we can observe a large nucleus (N) in the mother cell at the bottom, and two
smaller nuclei in the budding daughter cell at the top. When this same daughter cell was observed using
other experimental techniques, only one nucleus was observed. Why do there appear to be 2 separate
nuclei in the daughter cell in this image? (1 mark).
Key idea: This is due to the plane of section of the sample.
Example answer: The way the sampled was sliced has cut the nucleus of the daughter cell into two, so the image
in Panel B looks like the daughter cell has two nuclei, when it only has one.
Common mistakes:
o Some answers seemed to indicate that it was normal to have 2 or 3 nuclei, which is incorrect!
o Some answers only mentioned sectioning without actually explaining how a section could make a single
nucleus appear as 2-3 nuclei.
2
(Graded A+) - University of British Columbia
Instructions for Exam Regrades
The exams were carefully and consistently graded. However, if you feel that
an error was made in the grading of your exam, please follow these
instructions.
1. Carefully read this answer key, and compare to your answer.
2. You must submit a letter to your instructor that outlines why the regrading is
needed for each question. You must refer to the answer key in your
explanation. It is not sufficient to say “please regrade Question X.” Instead,
you have to explain why your answers should be given more points.
3. You will need to submit your exam paper as part of your regrade request.
4. The whole exam will be regraded. Therefore, there is a possibility that your
exam grade may go up, down or stay the same. The new grade will be your
final grade – you do not get to keep your old grade.
Please do not submit any requests for regrading until 48 hours after you
receive your mark.
Your request must be received no later than November 17th to be
considered.
1
, Question 1 ( /5 marks)
When doing research, scientists will often look at many
different images to try and learn more about the structures
they are studying. In this case, the scientists were studying the
yeast Saccharomyces cerevisiae, which reproduce by growing
a bud and then dividing asymmetrically into a mother cell and
a daughter cell. Cells that are in the process of forming the
daughter cell take on a characteristic shape, as shown in the
images below. (Note: N = nucleus).
A. What type of microscopy was used to generate the two images? What is the supporting basis for
your choice? (3 marks)
Type of microscopy Supporting basis
Image A: SEM (1)
0.5/1 – electron microscopy Image A is 3D showing a surface, which is a
characteristic of SEM (0.5)
Image B: TEM (1) Image B is a slice showing internal features / fine
0.5/1 – electron microscopy details of Golgi apparatus / cell wall, which is a
characteristic of TEM (0.5)
Instructor's note: Tutorial 2 on Microscopy had images of the 4 major types of microscopy, specifically for S.
cerevisiae. (This was based on the microscope 'Yeast' demo that was on the side bench in the tutorial rooms.)
B. State one advantage of using the type of microscopy used to generate image B over image A.
(1 mark)
Image B (TEM) will show you the fine details of the cytoplasm of the cell, whereas Image A (SEM) will only show
surfaces. (1 mark).
Common mistakes:
o You must state specifically why TEM has an advantage over SEM.
o Answers that say "that the inside of the cell cannot be seen with SEM." This is not correct as you can use
freeze-fracture to 'crack open' cells, and then use SEM to scan the surface of that half of the cell.
(Note: If you've misidentified the types of microscopy in part A, we will give credit for what you write here, if your
answers match the type of microscopy that you mentioned.)
C. In the image in Panel B, we can observe a large nucleus (N) in the mother cell at the bottom, and two
smaller nuclei in the budding daughter cell at the top. When this same daughter cell was observed using
other experimental techniques, only one nucleus was observed. Why do there appear to be 2 separate
nuclei in the daughter cell in this image? (1 mark).
Key idea: This is due to the plane of section of the sample.
Example answer: The way the sampled was sliced has cut the nucleus of the daughter cell into two, so the image
in Panel B looks like the daughter cell has two nuclei, when it only has one.
Common mistakes:
o Some answers seemed to indicate that it was normal to have 2 or 3 nuclei, which is incorrect!
o Some answers only mentioned sectioning without actually explaining how a section could make a single
nucleus appear as 2-3 nuclei.
2
