Download Revision (61 marks) Topic 2: Cells 2.1 Cell Theory 2.2 Prokaryotic

Revision (61 marks)
Topic 2: Cells
2.1 Cell Theory
2.2 Prokaryotic Cells
2.3 Eukaryotic Cells
The following questions are revision for the topics listed above.
When revising – use the OBJECTIVES and ensure you understand each one.
Instructions
 Answer all questions on line paper.
 Hand draw diagrams using pencil where required.
Paper 1: Multiple Choice (20 marks)
Instructions
 Answer all the questions.
 For each question, choose the answer you consider to be the best. Simple record the letter.
1.
The resolving power of a light microscope is closest to:
A. 20 nm
B. 200 nm
C. 2000 nm
D. 2 mm
2. If it was desired to observe the true colour of a coral polyp of diameter 0.02 mm it would be
best to use:
A. the unaided eye
B. a light microscope with staining
C. a light microscope without staining
D. an electron microscope
3. The membrane-bound structures within eukaryotic cells are known as:
A. cytoplasm
B. nuclei
C. granules
D. organelles
4. The size of the nucleus of a typical cell is about:
A. 10-20 m
B. 50-70 m
C. 100-200 m
D. 10-20 mm
5. Two cubes have side lengths in the ratio 1:3. Their surface areas are in the ratio:
A. 1:3
B. 1:6
C. 1:9
D. 1:27
6. Large fish need to have gills because:
A. Their bodies have a large surface area through which they can exhange gases with the
surrounding water.
B. Their bodies have a small surface area compared with their volume. Gills provide additional
surface area through which they can exchange gases with the surrounding water.
C. Their bodies have a small surface area through which they can exchange gases with the
surrounding water.
D. They use them to adjust their buoyancy.
7. The DNA in the nucleus of eukaryotic cells is:
A. linear but not contained in the nucleus
B. linear and contained in the nucleus
C. circular but not contained in the nucleus
D. circular and contained in the nucleus
8. The largest cell organelle is generally the:
A. Golgi apparatus
B. Rough endoplasmic reticulum
C. Nucleus
D. Ribosome
9. The main reserve food for animal cells is:
A. glycogen
B. DNA
C. Starch
D. RNA
10. Mitochondria can be found in
A. Animal cells only
B. Animal and plant cells only
C. Prokaryotes
D. Prokaryotes and plant cells
11. Ribosomes are found
A. Only in eukaryotes
B. In prokaryotes
C. In viruses
D. In animal cells only
12. Ribosomes function in
A. Destruction of foreign materials
B. Making rough endoplasmic reticulum
C. Manufacturing proteins
D. Releasing hydrolytic enzymes
13. Cellulose cell wall can be found
A. In plant cells and bacteria
B. In all eukaryotes
C. In prokaryotes
D. In plant cells
14. The sap vacuole functions in
A. Support
B. Transport
C. Protein synthesis
D. Sugar synthesis
15. DNA can be found in the eukaryotic cell in the
A. Nucleus only
B. Mitochondria only
C. Golgi complex
D. Chloroplasts
16. Ribosomes are not present in
A. Prokaryotes
B. Eukaryotes
C. Rough Endoplasmic Reticulum
D. Golgi complex
17. Starch grains can be found in
A. Mitochondria
B. Chloroplasts
C. Golgi complex
D. Nucleus
18. The largest number of mitochondria can be found in
A. Sperm cell
B. Red blood cell
C. White blood cell
D. Epithelial cell
19. The Golgi complex functions in
A. Respiration
B. Photosynthesis
C. Protein synthesis
D. Protein secretion
20. Prokaryotes have all the following structures except
A. Ribosomes
B. Rough endoplasmic reticulum
C. DNA
D. Cell membrane
Paper 2: Section A: Short Structured (20 marks)
Instructions
 Number each question clearly.
 Leave at least two lines between each question.
 Short concise bullet point answers are best.
1.
Arrange the following by size. Start with the largest.
 Atom
 DNA double helix
 Thickness of membranes
 Organelle
 Prokaryotic cell
 Eukaryotic cell
(2)
2. A chichuahua (small dog) was gently wrapped up in a paper cylinder. Her surface area was
estimated to be approximately 0.13 m2. The volume was estimated (using a clay model) at 2 dm3.
The same method was used to estimate the surface area and volume of a child. The child was
estimated to have a surface area of 0.9 m2 and a volume of 24 dm3.
a.
State which organism has the largest surface area?
The child
b. Calculate the surface area over volume ratio for the dog and the child.
Dog  SA:V = 0.13/2 = 0.065
Child  SA:V = 0.9/24 = 0.0375
The dog has a higher SA:V ratio than the child
c.
(1)
(2)
Predict which organism would need the most food per kg bodyweight. Explain your answer.
(3)
If the SA:V is larger, the organism is likely to lose more heat
The dog would need more food per kg bodyweight than the child
Food needed for respiration to produce heat
ALTERNATIVE ideas:
Depends on level of activity
Child may be growing, dog is not so child needs more
3. The diagram below shows an electron micrograph of a prokaryotic cell.
a. Label the following electron micrograph of a prokaryotic cell.
I.
II.
III.
IV.
(2)
plasma / cell membrane;
cell wall;
nucleoid (region) / DNA/genetic material;
cytoplasm/cytosol/protoplasm;
b. Calculate the magnification of the prokaryotic cell.
26000 × ( 1500);
Do not need to show working
4.
State one function of each of the following organelles.
lysosome:
hydrolysis/digestion / break down of material (macromolecules);
Golgi Apparatus:
(1)
(5)
synthesis/sorting/transporting/secretion of cell products;
rough endoplasmic recticulum: site of synthesis of proteins (to be secreted) / intracellular
transport of polypeptides to Golgi Apparatus;
nucleus:
controls cell activities/mitosis/replication of
DNA/transcription of DNA (to RNA)/directs protein synthesis;
mitochondrion: (aerobic) respiration/generates ATP;
5.
Explain how the surface area to volume ratio influences cell sizes.
small cells have larger ratio (than larger cells) / ratio decreases as size increases;
(3)
surface area/membrane must be large enough to absorb nutrients/oxygen/ substances needed;
surface area/membrane must be large enough to excrete/pass out waste products; need for
materials is determined by (cell) volume;
cell size is limited (by
SA
/ vol ratio) / cells divide when they reach a certain size;
Paper 2: Section B: Extended Questions (20 marks)
Instructions
 Number each question clearly.
 Leave at least five lines between each question.
1. Compare, with the aid of a diagram, the structure of generalised prokaryotic and eukaryotic
animal cells.
(8)
P is usually smaller in size, E is larger;
both have cytoplasm / protoplasm;
P has no nucleus / nucleoid region, E has (membrane-bound) nucleus;
P has one chromosome / circular, E has two or more chromosomes;
P has DNA only, E has DNA with protein (histones);
P has no membrane-bound organelles, E has some membrane-bound organelles;
E has mitochondria, P does not;
E has other example of organelle, P does not;
both can have a flagellum / flagella;
if flagella then E has 9+2 fibrils, P does not;
P can have pili / slime layer / capsule, E does not;
P can have plasmids, E does not;
both have ribosomes;
P has small ribosomes, E has larger ones;
both have cell membrane;
P has cell wall, E has no cell wall;
E has centriole, P has no centriole;
2.
Distinguish between the structure of plant and animal cells.
Award [1] per difference,
plant cells:
have cell walls, animal cells do not;
have plastids / chloroplasts, animal cells do not;
have a large central vacuole, animal cells do not;
store starch, animal cells store glycogen;
have plasmodesomata, animal cells do not;
animal cells:
have centrioles, plant cells do not;
have cholesterol in the cell membrane, plant cells do not;
plant cells are generally have a fixed shape / more regular whereas
animal cells are more rounded;
(6)
Question 1
An experiment was carried out to determine what happens to amino acids after they are absorbed
by animal cells. The cells were incubated for 5 minutes in a medium containing radioactively labelled
amino acids. The radioactive amino acids were then washed off and the cells were incubated in a
medium containing only non-radioactive amino acids. Samples of the cells were removed from the
medium every five minutes for 40 minutes. For each sample, the levels of radioactivity in three
different organelles, A, B and C, were determined.
The results of the experiment are shown in the graph below.
a.
Identify the organelles A, B and C by choosing from the list below.
Golgi apparatus  C
Mitochondria
Ribosomes  A
Rough endoplasmic reticulum  B
(2)
b. Give an explanation for your answer to part (a).
Ribosomes synthesise the proteins
Some protein synthesis occurs on RER
(Newly synthesised / eq.,) proteins / polypeptides transferred to Golgi ;
Where they are, modified / sorted / packaged ;
Then form, (secretory ) vesicles / lysosomes
(3)
c.
(2)
Calculate the fastest rate of uptake in organelle ‘A’. Show your working.
60/5 = 12 arbitrary units/ minute