step assessment Flashcards
Recall Question
Which organelle do you think is shown in the electron micrograph below?
Image
A. Golgi Apparatus
B. Ribosome
C. Nucleolus
D. Mitochondrion
D. Mitochondrion
Recall Question
Which organelle listed below is not bound by a membrane?
A. Centriole
B. Chloroplast
C. Nucleus
D. Smooth endoplasmic reticulum
A. Centriole
Recall Question
Which of these structures modifies complete proteins to produce glycoproteins?
A. Rough endoplasmic reticulum
B. Smooth endoplasmic reticulum
C. Golgi Apparatus
D. Mitochondria
C. Golgi apparatus
Recall Question
Which function does a lysosome carry out?
A. Produces enzymes which digest damaged organelles and foreign matter.
B. Transports hydrophobic lipids around the cell.
C. Produces steroid hormones and cholesterol.
D. Froms a protective envelope around the nucleus.
A. Produces enzymes which digest damaged organelles and foreign matter.
Recall Question
Which description below is not true of prokaryotic cells?
A. They store their genetic material in the form of DNA.
B. They have more chloroplasts per cell on average than eukaryotic cells do.
C. They have cell walls made of murein (also known as peptidoglycan).
D. They are usually smaller than eukaryotic cells.
B. They have more chloroplasts per cell on average than eukaryotic cells do.
Recall Question
Which of these is not found in any prokaryote?
A. Plasmids
B. Capsule
C. Flagella
D. Mitochondria
D. Mitochondria
Recall Question
Which unit would be most appropriate for measuring the length of an average plant cell?
A. am (attometres)
B. mm (milimetres)
C. nm (nanometres)
D. um (micrometres)
D. um (micrometres)
Recall Question
Why can a light microscope not produce useful images at greater than 1500x magnification?
A. The magnification is limited by our ability to perfect the fine shape of lenses.
B. It is not possible to cut slices of tissue thin enough without destroying cellular structure.
C. The wax used for embedding tissue samples distorts light too much at higher magnifications.
D. The resolution is limited by the wavelength of light waves.
D. The resolution is limited by the wavelength of light waves.
Recall Question
Students measure a structure as 12mm long when studied under the microscope. Its actual size is 29.7 um. What approximate magnification is being used?
A. 40x
B. 360x
C. 400x
D. 3600x
C. 400x
Maths Skills
Convert the following numbers from standard form into decimal notation.
- 3.26 x 104
- 8.4 x 10-3
- 32600
- 0.0084
Exam Question
Place a tick in the box next to the sequence that shows the correct order of magnitude of these measurements.
50nm < 0.5μm < 5 x 10^-2mm < 0.5 x 10^-5m
50nm < 0.5μm < 0.5 x 10^-5m < 5 x 10^-2mm
0.5μm < 50nm < 0.5 x 10^-5m < 5 x 10^-2mm
0.5μm < 50nm < 5 x 10^-2mm < 0.5 x 10^-5m
0.5μm < 50nm < 5 x 10^-2mm < 0.5 x 10^-5m
Maths Skills
Using the formula 2 x 3.14 x radius and given that the mean radius of the earth is 6378000m, calculate the approximate circumference of the Earth leaving your answer in standard form to two significant figures.
4.0 x 107
Exam Question
Identify structures labelled D and E.
D = Granum
E = Starch
Maths Skills
There are 86400 seconds in a day. Calculate the number of seconds in a year leaving your answer in standard form to two significant figures.
3.2 × 107
The details shown above would not be seen using an optical microscope.
Explain why.
- Has low resolution
- Because wavelength of light is too long
Maths Skills
The current world population is approximately 7.4 x 109. The united kingdom population accounts for 0.88% of the total world population. Using this information, approximate the number of people living in the united kingdom leaving your answer as a decimal number.
6.512 × 107
Name an organelle found in both a chloroplast and a prokaryotic cell.
(70S) Ribosome.
Place a tick in the box that shows the correct order of magnitude of these measurements.
50nm < 0.5μm < 5 x 10^-2mm < 0.5 x 10^-5m
50nm < 0.5μm < 0.5 x 10^-5m < 5 x 10^-2mm
0.5μm < 50nm < 0.5 x 10^-5m < 5 x 10^-2mm
0.5μm < 50nm < 5 x 10^-2mm < 0.5 x 10^-5m
0.5μm < 50nm < 5 x 10^-2mm < 0.5 x 10^-5m
Exam Question
Volume of plant cell = 17, 500μm³. Volume of all mitochondria in plant cell = 262.5μm³. Volume of all mitochondria and all chloroplasts in plant cell = 44.1% of volume in plant cell. Use info to calculate volume of all chloroplasts in a plant cell.
44.1% of 17, 500 = 17, 500 x 0.441 = 7717.5μm³ - 262.5μm³ = 7455μm³.
The diagram below is an electron micrograph of a chloroplast.
Identify structures labelled D and E
D = granum
E = starch
Exam Question
A biologist separated cell components to investigate organelle activity. She prepared a suspension of the organelles in a solution that prevented damage to the organelles.
Describe three properties of this solution and explain how each property prevented damage to the organelles.
- COLD - to reduce enzyme activity that might break down the organelles
- ISOTONIC - to prevent lysis of organelles as a result of osmotic gain or loss of water
- BUFFERED- so that the pH does not fluctuate-prevents denaturing of enzyme/proteins
Exam Question
Suggest why preventing the formation of spindle fibres stopped the cell cycle. (2)
- centromeres cannot attach
- so no metaphase
Exam Question
Suggest and explain why ABZ could be used as a treatment for cancer even though it affects some healthy cells. (1)
- cancer cells divide more rapidly
Exam Question
What can you conclude about the effect of ABZ on tumour cells? (4)
ABZ stopped mitosis by preventing the formation of spindle fibres, and it also affected some healthy cells.
Mitosis is controlled. Cyclin B is a protein in the nucleus. It regulates mitosis timing. M starts when CB conc rises sharply and ends when it falls. ABZ increased, and maintained, a high concentration of cyclin B in stomach tumour cells.
Programmed cell death = apoptosis. Two nuclear proteins, Bcl-2 and Bax control apoptosis. Apop is prevented when the Bcl-2 and Bax ratio is high, and is promoted when the ratio is low. The scientists found that ABZ decreased conc of Bcl-2 and increased Bax in stomach tumour cells.
- ABZ maintains Cyclin B
- so mitosis starts but does not end, so no tumour growth
- ABZ lowers ratio of Bcl-2 to Bax
- so apoptosis occurs and no tumour growth
Exam Question
Evaluate the suggestion that ABZ could be used for the successful treatment of stomach cancer. (3)
SUPPORT:
- stops mitosis so no tumour growth
AGAINST
- healthy cells damaged
- these results are from laboratory tests, not clinical trials involving people.
Exam Question
Structures A to E are parts of a plant cell.
A- Cell Wall
B- Chloroplast
C- Nucleus
D- Mitochondrion
E- Golgi apparatus
Complete Table 1 by putting the correct letter, A, B, C, D or E in the box next to each statement.
Has stacked membranes arranged in parallel and contains DNA = Chloroplast (B)
Is made of polysaccharide = Cell wall (A)
Is an organelle and is not surrounded by two membranes = Golgi apparatus (E)
Exam Question
Human breast milk is produced and secreted by gland cells. These gland cells have adaptations that include many mitochondria and many Golgi vesicles. The milk contains a high concentration of protein.
Explain the role of these cell adaptations in the production and secretion of breast milk.
Mitochondria release energy in the form of ATP for vesicle transportation.
Golgi Vesicles transport the protein out of the cell.
Figure box 3 shows part of a prokaryotic cell. Figure 3 0 4 . 1 Name the structures labelled W to Z in Figure 3.
W - (cell surface) membrane
X - cell wall
Y - capsule
Z - flagellum
Exam Question
Name the main biological molecule in: W & X
W - Phospholipids;
X - Murein / glycoprotein;
Exam Question
Name the process by which prokaryotic cells divide.
Binary fission
Exam Question
Some prokaryotic cells can divide every 30 minutes. A liquid culture contained a starting population of 1.35 × 104 cells. Assuming each cell divides every 30 minutes, calculate how many cells there will be after 3 hours. Assume no cells die during this time.
8.64 x 105
Exam Question
Describe how you would use cell fractionation techniques to obtain a sample of chloroplasts from leaf tissue. Do not include in your answer information about any solutions.
- Macerate / homogenise / blend / break tissues / cells (in solution);
- Centrifuge;
- At different / increasing speeds until chloroplast fraction obtained;
Exam Question
Table 3 shows features of a mitochondrion and a chloroplast.
Complete Table 3 with ticks where a feature is present.
Double Outer Memb: both yes
Starch Grains: mit no, chloroplast yes
Diff Oxygen into Org: yes mit, no chloro
Exam Question
Give the function of a mitochondrion.
to produce energy through cellular respiration.
Exam Question
Scientists investigated the effect of an exercise programme on the number and
size of mitochondria in skeletal muscle. They took samples of muscle from a
large number of volunteers before and after the exercise programme. From each
sample, they cut thin sections and used these to determine the mean number of
mitochondria per μm2 and the mean area of inner mitochondrial membranes.
Their results are shown in Figure 7 and Figure 8.
What do the data in Figure 7 and Figure 8 suggest about the effect of the
exercise programme on mitochondria?
[2 marks]
- Training made no difference to number (of
mitochondria per μm - Training led to an increase in the area (of
inner mitochondrial membrane);
