Cells
Unit
Test
Time
allowed: 70 minutes
You
may use a calculator
Write
all answers on this paper
Section
A: Multiple Choice (12 marks)
Section B:
Structured Factual Recall (15 marks)
Section C:
Structured Data Analysis (9 marks)
Section D:
Extended Response (14 marks)
Name:
_______________________
Date:
_______________________
Score: ___/ 50
= ____ % (IB Grade ___)
Section A: Multiple Choice (circle the correct answer)
1. Which of the following is considered acellular or non-living?
A. Eukaryote cell
B. Prokaryote cell
C. Amoeba
D. Virus
2. A plasma membrane is 10nm thick. On a diagram, a student draws it 20mm thick.
What is the magnification of the drawn image?
A. X 5,000
B. X 100,000
C. X 2,000,000
D. X 2,000
3. Which of the following are fundamental statements of cell theory?
i. Cells come only from other cells
ii. Cells maximize their SA:Vol ratio
iii. All living things consist of cells
iv. Cells are the smallest units of life
A. i and ii
B. i, iii and iv
C. ii, iii and iv
D. i, ii, iii and iv
4. Which of the following organelles are present in prokaryotes but not eukaryotes?
A. Plasma membrane
B. Cytoplasm
C. Nucleoid
D. Nucleus
5. Which part of the plasma membrane is involved in recognition of other cells?
A. Phospholipid bilayer
B. Integral proteins
C. Peripheral proteins
D. Cholesterol
6. The diagram below shows a channel protein in a plasma membrane.
Channel proteins allow polar molecules to pass through by facilitated diffusion.
Which labeled parts of the channel proteins are likely to be polar?
A. I and II only
B. III and IV only
C. I and III only
D. All parts
7. How do animals use cholesterol?
A. To store energy
B. To form part of the plasma membrane
C. To insulate neurons (nerve cells)
D. To increase blood pressure
8. Which cell organelle is responsible for the production of proteins to be exported from the cell?
A. Rough endoplasmic reticulum
B. Free ribsomes
C. Mitochondrion
D. Lysosome
9. Which of the following correctly describes the process of osmosis?
A. The passive movement of water molecules from areas of low solute concentration to high solute concentration, through a selectively permeable membrane.
B. The passive movement of water molecules from areas of high solute concentration to low solute concentration, through a selectively permeable membrane.
C. The active movement of water molecules from areas of high solute concentration to low solute concentration, using a membrane pump protein.
D. The passive movement of water molecules from areas of low solute concentration to high solute concentration, through a channel protein.
10. During which phase of the cell cycle is the plasma membrane divided to give two new daughter cells?
A. Interphase
B. Prophase
C. 
Anaphase
D. Cytokinesis
11. Which labels match ‘i’ and ‘ii’ respectively?
A. Centromere and chromosomes
B. Centriole and chromosomes
C. Centromere and sister chromatids
D. Centriole and sister chromatids
12. Which process is used to export a macromolecule from the cell?
A. Exocytosis
B. Endocytosis
C. Facilitated diffusion
D. Pinocytosis
End of Section A. 12 marks.
Section B: Structured Factual Recall
1.
|
a. Calculate the length of the cell ‘A’.
|
[2.2µm – 2.8µm if work shown]
b. By which method do prokaryotes reproduce?
……………………………Binary fission…………………………………. (1)
2. a. Explain how the surface area to volume ratio influences cell size.
the rate of
material / heat exchange / diffusion is proportional to surface area;
the rate of metabolism is proportional to mass / volume;
as a cell grows, the volume increases faster than the surface area / as a cell
grows,
surface area to volume ratio decreases;
(without cell division) material / heat cannot be exchanged fast enough to meet
the needs of the cell (3)
b. Compare prokaryotic and eukaryotic cells with regard to three features: [3 max]
Award [1]for
each of the following pairs.
Mark first answer only in boxes 1, 2 and 3.
Allow [1] only
for a similarity.
prokaryotic cells eukaryotic cells
nucleoid
/ no nucleus / nuclear membrane vs. nucleus / nuclear
membrane;
naked DNA / no histones vs. NA associated with
protein /histone; NA
associated with protein / histone;
no mitochondria vs. mitochondria present;
no Golgi / no ER vs. Golgi / ER present;
circular DNA vs. linear DNA;
no / very few membrane-bound organelles vs. membrane-bound
organelles;
ribosomes smaller / 70S vs. ribosomes larger / 80S;
no mitosis / meiosis vs. mitosis / meiosis;
flagella lack internal microtubules vs. flagella have
microtubules (9+2);
c. State one function of each of the following organelles.
i. lysosome: hydrolysis / digestion / break down of materials (macromolecules);
ii. ribosome: translation / site of synthesis
of proteins
iii. Golgi apparatus: synthesis /
sorting / transporting / secretion of cell products (3)
3. a. Differentiate between diffusion and osmosis.
Must have both
for [1].
diffusion is
the movement of molecules from an area of high
concentration to an area of low concentration;
osmosis is the diffusion of water across a
partially
permeable
membrane; (2)
b. An animal cell is placed in a hypotonic (very weak) sugar solution.
Will the cell increase or decrease in mass?
……………………… increase ………………………………………………………………………………………… (1)
End of Section B. 15 marks.
Section C:
Structured Data Analysis
1. A study was carried out to
determine the relationship between the diameter of a molecule and its movement
through a membrane. The graph below shows the results of the study.
[Source: Knox, et al., Biology, Mcgraw
Hill, Sydney, 1994, page 65]
(a) From the information in the graph alone,
describe the relationship between the diameter of a molecule and its movement
through a membrane.
as the diameter
of the molecule increases the permeability / relative ability
to move decreases (accept converse);
the relationship is logarithmic / non-linear / negative;
for molecules above 0.6 (± 0.1) nm relative ability to move changes little /
for molecules below 0.6 (± 0.1) nm relative ability to move changes rapidly; 2 max
A second study was carried out to investigate the effect of passive protein channels on the movement of glucose into cells. The graph below shows the rate of uptake of glucose into
 |
erythrocytes by simple diffusion and facilitated diffusion.
(b) Identify the rate of glucose uptake at an
external glucose concentration of
4 mmol
dm-3by
(i) simple
diffusion. 10 mmol cm-3 hr-1 (accept ± 5) (1)
(ii) facilitated
diffusion. 370 mmol cm-3 hr-1 (accept ± 10) (1)
(c) (i) Compare
the effect of increasing the external glucose concentration on glucose uptake
by facilitated diffusion and by simple diffusion. (3 max)
• Rate of glucose uptake in facilitated diffusion levels out as external
glucose concentration increases whereas uptake in simple diffusion does not
level out / continues to rise.
• Rate of glucose uptake increases with both increasing external
concentration in both.
• Rate of glucose uptake is higher in facilitated diffusion (than in
simple diffusion).
• Increase in rate of glucose uptake in simple diffusion is constant/
linear, whereas in facilitated diffusion the rate of uptake increases rapidly
at the beginning / increase is not constant.
(ii) Predict,
with a reason, the effect on glucose uptake by facilitated diffusion of
increasing the external concentration of glucose to 30 mmol dm-3. (2
max)
Little/ no change in glucose uptake
because all/most (protein) glucose channels in use
2. Data based question
1)
State the time of day when:
(a)
Most DNA replication occurs 02:00 ± 2 h
(b)
mitosis is most likely to occur 04:00 – 07:00 ± 1 h [2]
2) Identify the cell cycle stage when most of the increase
in cell size
is
occurring. G1 [1]
3) Evaluate the claim that
the timing of the cell cycle in Emiliania huxleyi is an adaptation to
take advantage of light resources. [3]
[summary
required; worth 1 point]
This phytoplankton takes advantage of
light to make chemical energy and material / then in the dark it uses this
stored energy and material for other processes like DNA duplication, mitosis
and cell division / when the sun comes up there are now new cells ready to take
advantage of the light and the cycle repeats.
[Must
state two evidences with data explicitly taken from information above]
In this data most cells reach maximum
size about 18:00 (end of daylight) / size means more energy storage and
more organelles / more material in cell/ minimum size occurs at dawn 06:00 and
this is because cells have divided and are at their smallest
DNA duplicated after midnight/ cell uses
material from growth to duplicate DNA in next 2-4 hours/ Cycle reach maximum
size about noon each day;
Within 2 hours of S
phase/DNA duplication cell undergoes mitosis and divides;
End of Section C. 15 marks.
Section D: Extended Response Answer these questions on the paper provided.
1. Draw labeled
diagrams to show four stages of mitosis in an animal cell with 2 chromosomes. (5)
prophase showing spindle fibres;
prophase showing condensed chromatin;
prophase showing replicated chromosomes;
metaphase showing replicated chromosomes lining
up at the equator;
anaphase showing chromatids moving to opposite poles;
telophase showing nucleus reforming;
telophase showing cytokinesis occurring; 5
max
The four diagrams must have the name of the phase, otherwise
award [3 max].
The four stages must be included to receive [5]. If correct number of
chromosomes is not shown award [4 max].
Explain how mitosis ensures that daughter
cells are genetically identical. (4)
(Note this can be combined as
annotations to diagrams above.)
sister chromatids are two identical DNA molecules held
together by centromere;
sister chromatids are separated during mitosis to form two
genetically identical nuclei;
in prophase chromosomes shorten / thicken
/ become visible as double-stranded chromosomes / joined sister chromatids;
chromosomes condense by supercoiling;
chromosomes attach to spindle microtubules
at centromeres;
chromosomes begin to move towards equator
/ centre of cell;
during metaphase all chromosomes lined up
at equator separately / not in homologous pairs;
at start of anaphase centromeres divide
separating sister chromatids;
separated sister chromatids known as
(single stranded) chromosomes;
(identical sets of) chromosomes pulled to opposite poles;
move by contraction of microtubules;
nuclear envelope / membrane forms around each set of chromosomes;
2. Outline one therapeutic use of stems cells. (5)
stem cells are cells that retain the capacity to divide and
have the ability to differentiate along different paths into all types of cells
/ are pluripotent / totipotent;
stem cells are derived from blastocysts / human embryos, left
over from IVF / placenta / umbilical cord / some adult tissues;
new techniques / technologies rely on replacing diseased /
dysfunctional cells with healthy / functioning ones;
need to identify desired type of stem cell and grow in
culture / special solutions / controlled conditions;
develop biochemical solution that will cause cells to
differentiate into desired cell type;
develop means of implanting / integrating cells into
patient’s own tissues so that they function with the body’s natural cells;
danger of rejection of cells therefore need to suppress
immune system;
must make sure new cells do not become overgrown / develop
into cancerous tumours;
Award [2 max] for a specific example ie: [1]
for type of cells and [1] for proposed use:
eg retinal cells;
replace dead cells in retina to cure presently incurable
diseases such as glaucoma
and macular degeneration;
eg graft new skin
cells; to treat
serious burn victims;
eg nerve tissue; help repair
catastrophic spinal injuries / help victims of paralysis
regain movement; 6
max
(Plus up to [2] for quality)
End of Section D. 14 marks.
----END OF TEST: CHECK YOUR WORK ---