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CELL BIOLOGY UNIT 1 HOMEWORK
Homework -- Cell Structure
1. Use the diagram below to complete the table which follows. (8)
Structure
1
Function
stores genetic information / controls cell activities
Cytoplasm
2
Cell membrane
3
Cell wall
4
5
site of photosynthesis
6
stores water and minerals help support the cell, and when
full it pushes outwards against the wall to help provide
support
Mitochondrion
8
7
site of protein synthesis
2. Use the diagrams below to answer the questions which follow.
B
A
C
(i) Identify the four cells shown.
D
(3)
(ii) Name a structure which is present in cell A but absent from the others, and give its
function. (2)
(iii) Name a structure which is absent from cell B but is present in the others.
(1)
(iv) How is the structure mentioned in part (iii) different in cell C compared to A and
D?
(1)
(v) Name a structure which is present in cell C but absent from the others.
(1)
(vi) Why would this structure not be found in cells from the same organism which are not
exposed to sunlight? (1)
(vii) Name a structure which is present in C and D but not A and B
(1)
3. (i) The diagram shows a number of cells as
seen under a microscope at a magnification
of 100X.
Field of view
Calculate the average length of one cell in
micrometres. (1)
1 millimetre
(ii) If a cell has a length of 40 µm, how many could fit end to end across a field of
view of 0.5mm? (1)
/ 20
Transport across the Membrane
Homework Exercise
1.
15
The diagram below shows a single-celled organisms called an amoeba. The arrows
indicate the diffusion of substances in and out of the cell.
A
C
B
a) Name the substances represented by the letters A, B and C.
(2)
b) Which part of the cell controls movement in and out of the cell?
(1)
c) Name the process by which materials enter or leave the cell.
(1)
2.
Three cylinders of potato were carefully dried on blotting paper and weighed.
Each piece weighed 3g. One piece was then placed in each tube as shown below
and the tubes were left for 24hrs and then reweighed.
A
B
25 cm3
distilled water
C
25 cm3
25 cm3
5% sucrose
20% sucrose
solution
solution
a) Which potato cylinders would be the heaviest and the lightest?
(2)
b) The movement of which substance was mainly responsible for the weight
changes in the potato cylinders?
(1)
c) Name the process which was responsible for this movement in the potato
cylinders.
(1)
d) Why were the surfaces of the discs dried before they were reweighed?
(1)
3.
The apparatus shown in the diagram was set up by groups of students.
Universal indicator paper
6
Cork
5
4
3
2
1
0
Wire gauze
Ammonia-soaked
Glass Tube
cotton wool
The cotton wool was soaked with ammonia solution before being placed against
the wire gauze and then the tube was corked at both ends.
Ammonia gas causes universal indicator paper to change colour from yellow to
blue. The time taken for this to happen was recorded.
The investigation was repeated with three different ammonia solutions.
The results are given in the table below.
Concentration of
Pieces of universal indicator paper
ammonia solution
Time taken for colour change to
occur (seconds)
1
2
3
4
5
1 Molar (dilute)
11
51
128
211 441
752
4 Molar
8
36
72
163 305
511
9 Molar (concentrated)
5
12
33
64
263
146
6
a) The pieces of indicator paper change colour in order. What process is taking place
which makes this happen and explain why it happens.
(1)
b) Look at the results for the fifth piece of indicator paper in each of the investigations.
c) Suggest a reason for the different times taken for the indicator paper to change
colour in each investigation.
(1)
(c) The indicator paper was moistened with distilled water to make it stick to the inside
of the tube. Why was distilled water used and not tap water?
(d) Suggest two reasons why the tubes were corked
(1)
(1)
(e) The tubes must be kept horizontal and not stood on end for these investigations.
Explain why?
(1)
DNA Genes and Chromosomes
Homework Exercise
1. Complete the passage below using the words from below:
chromomsomes
genes
DNA
nucleus
(4)
…………………………………. are found in the ……………………………….. of a cell. They are
threadlike structures made up of a chemical called …………………………… Each
chromosome is made up of sections of DNA called …………………………. Genes control
different characteristics in living things.
2. Below is a diagram of a cell and the structures found within its nucleus. Using
the words below, complete the diagram
cell
chromosomes
nucleus
DNA
From the Cell to DNA
(4)
National 4/5
1.
DNA and the Production of Proteins
How many strands make up a molecule of DNA?
…………………………
(1)
2.
Name the 4 different types of bases found in DNA
i.
……………………………………………………………
ii.
……………………………………………………………
iii.
……………………………………………………………
iv.
…………………………………………………………..
(4)
3.
The bases found in a molecule of DNA are said to complimentary. What does this
mean?
……………………………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………………………..(1)
4.
The diagram below shows a molecule of DNA. Complete the diagram by inserting the
correct names of the structures
(2)
5. The diagram shows part of a single strand of DNA.
T
G
A
Draw the complimentary strand with the bases in the correct order.
6. Name the nucleic acid needed to makes proteins from DNA.
…………………………………………………..
(1)
7.
Explain how proteins are made from DNA.
……………………………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………………………………….
……………………………………………………………………………………………………………………………………………….
(2)
Cell Division
10
1. State the two uses for the new cells produced from cell division.
(2)
2. What effect does cell division have on the number of cells in the body?
(1)
3. Name the structure within a cell which controls cell division.
(1)
4. Below is a diagram of a human cell. Name the structure labelled X.
(1)
X
5. Complete the following sentences by deleting the incorrect word from each pair to
create a correct sentence.
The number of chromosomes in the new cells produced by cell division will be
the same as/half that of the parent cell.
During cell division each parent cell produces two/four new cells.
The cells produced by cell division will be different/identical to each other.
(3)
6. Cell division can be described as a controlled cycle. What might occur if cell division
is uncontrolled?
(1)
7. An onion cell contains 16 chromosomes. It divides to form two new cells, which then
divide again. How many chromosomes will these new cells have?
(1)
Cell Division–
Extension
9
1. The diagrams below show six stages of a cell process.
The stages are shown in pairs. The diagrams in each pair are in the correct order.
The three pairs of diagrams are NOT in the correct order.
(a)
(b)
(c)
(a) Name the process shown in the diagrams.
__________________________________________________
(1)
(b) Write the letters of each pair in the order in which they occur in this process.
1. _____________
2. ______________
3. _____________
(1)
(c) Name the cell structure which controls this process
___________________________________
(1)
2. A cell can divide to produce two daughter cells. Each daughter cell grows and then
divides.
The beginning of these divisions is shown in the diagram below.
1st division
1st
generation
2nd division
2nd
generation
Calculate the number of cells in the 4th generation.
Space for calculation
Answer: __________ cells (1)
3. The diagram below shows some of the stages in cell division occurring in the cells of
a plant root. Describe the stages of cells division (mitosis) shown in the cells labelled
X, Y, and Z.
X:
___________________________________________________
___________________________________________________ (1)
Y:
___________________________________________________
___________________________________________________ (1)
Z:
___________________________________________________
___________________________________________________ (1)
4. Describe the meaning of the term ‘diploid cell’
_______________________________________________________________(1)
5. Typical timings of the stages of mitosis are shown in the table below.
Stage
A
B
C
D
Time (minutes)
88
33
25
54
What percentage of the total time for mitosis is taken by stage C?
Space for calculation
Answer: _____________%
(1)
S3 Biology - Extension
Cell Division
18
Homework Exercise 3
1. The diagrams below show stages in mitosis (cell division).
(a) Complete the table below to place the stages in the order in which they occur.
Order
1
Stage
B
2
3
4
5
6
(2)
(b) What name is given to the thread-like structures labelled X?
(1)
2. Scientists can grow liver tissue in the laboratory. This is done by making a few liver
cells divide by mitosis to form a large mass of cells. Why is it important that the
daughter cells contain the same number of chromosomes as the original mother cells?
(1)
3. A cell divides every 20 minutes. How many cells would be produced from one original
cell at the end of two hours?
Space for calculation
Answer:
___________cells (1)
4. Stages of mitosis are shown in their correct order in the diagrams below.
(a) Label the spindle on one of the diagrams.
(1)
(b) Stage C would be followed by stage D. Describe what would happen in
stage D.
(1)
(c) Where in a cell would structure X normally be found?
(1)
(d) Explain the importance of structure X.
(1)
5. Below is a list of events which occur during mitosis.
Complete the table below to show the order in which these events take place.
Order
List of events
A. Chromatids separate
B. Two nuclei are formed
C. Chromosomes replicate
D. Chromatids move to opposite ends of the cell
E. Chromosomes visible as pairs of chromatids
F. Cells divides
G. Chromatids line up along the middle of cell
H. Two identical cells are formed (3)
Letter
1
2
3
4
5
6
7
8
6. The diagram below represents chromosomes at one stage of
cell division.
Spindle
fibres
P
(a) Name the structure labelled P.
(1)
(b) Describe what happens to the chromosomes at the next stage of cell division.
(1)
(c) This cell contains 8 chromosomes.
(i)
How many chromosomes will be present in each daughter cell when cell division is
complete?
(1)
(ii) Why is it important that each daughter cell has this number of chromosomes?
(1)
7. Below is a flow diagram which describes some of the stages of cell division.
Stage 1 - Chromosomes become visible as pairs of chromatids
Stage 2
Stage 3 - The spindle fibres contract pulling the chromatids of each chromosome
to opposite poles of the cell.
Stage 4 - A nuclear membrane forms around each nucleus.
Stage 5
a) Describe what occurs at stages 2 and 5.
(2)
S3 Biology
Properties of Enzymes & Uses in Industry
9
Homework Exercise 1
1. What is the function of an enzyme?
(1)
2. Describe two features of enzymes.
(1)
3. All living cells require enzymes. What would happen to chemical reactions in a cell if
enzymes were not present?
(1)
4. What is a substrate?
(1)
5. Enzymes can be described as being specific. Explain the meaning of the
term ‘specific’.
(1)
6. Enzymes can be involved in both build-up and break down reactions. Give an example
of an enzyme involved in each type of reaction.
(2)
7. Enzymes are used frequently in biotechnological industries. Name two examples of
these uses and describe their purpose.
(2)
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[10 marks]
Page 3
Uses of microbes
Read the following passage and answer the questions based on it.
Fight for your Life!
Adapted from Biological Sciences Review, September 2005
Every day there is a battle inside our bodies between invading micro-organisms and our immune
system. Bacteria are present inside and out. Most are harmless but others are pathogens which
cause disease. Infectious diseases are a major killer in developing countries. Vaccination
programmes, public health improvements and increasing the availability of antibiotics are required
to overcome them. However, there is a growing problem of resistance to antibiotics demonstrated
by the “super bug” MRSA. The first thing a micro-organism does is to find its way into a cell in the
body. Cells of the immune system have to recognise that this has happened and make the
appropriate response. The first cells on the scene are neutrophils. They engulf bacteria and kill them
with enzymes. The next cells to arrive are macrophages which have a variety of specialised killing
mechanisms. Dendritic cells are also involved. They are able to recognise pathogens and stimulate
other immune cells to react. Fortunately, our immune system has a memory. This means that when
we encounter a micro-organism for the second time, a much faster response is triggered that rapidly
wipes out the pathogen. Our immune system is very powerful, giving us the best chance to win the
battle with these invaders. Sometimes this system breaks down and immune cells wrongly target
and destroy our own body cells. This causes conditions such as rheumatoid arthritis and multiple
sclerosis.
(a) What name is given to micro-organisms such as bacteria which cause disease?
__________________________
1
(b) Give three actions which are needed by developing countries to overcome infectious
diseases.
1 __________________________________________________________________
2 __________________________________________________________________
3 __________________________________________________________________
3
(c) Why is MRSA a growing problem?
___________________________________________________________________
1
(d) Name three types of immune cells involved in a response to an attack by invading microorganisms.
1_______________________________________
2_______________________________________
3_______________________________________
1
(e) Why is the response of the immune system faster the second time a type of micro-organism
invades?
___________________________________________________________________
1
(f) What causes conditions such as rheumatoid arthritis?
___________________________________________________________________
___________________________________________________________________
1
(a) During an investigation into the activity of yeast in bread making, a pupil divided a batch of
dough into two equal portions. He added yeast to each portion before placing the dough
into identical beakers as shown in the diagrams.
The volume of dough in each beaker was measured at the start and end of the investigation.
The results are shown in the table below.
Volume of dough
(cm3)
(i)
Beaker
At start
At end
A
100
250
B
100
100
How many times greater was the volume of dough in beaker A at the end compared to
the start?
___________ times greater
1
(ii)
The production of which substance caused the increase in the volume of the dough?
________________________
1
(iii)
Give two factors, not already mentioned, which would need to be kept constant during
this investigation.
1 ____________________________________________________________
2 ____________________________________________________________
2
(iv)
What was the purpose of setting up control beaker B?
______________________________________________________________
1
(b) What type of micro-organism is yeast?
__________________________________________
1
(c) Give one use of yeast in a manufacturing process, other than the raising of dough.
___________________________________________________________________
1
(d) Bacteria are used to sour milk in the manufacturing of yoghurt.
Name the process carried out by the bacteria which causes the milk to sour.
__________________________________________
1
a) During the brewing of beer, ingredients including yeast and malted barley are added to a
fermentation vessel.
(i)
What does the malted barley provide for fermentation which ungerminated barley does
not?
________________________________________________
1
(ii)
How does sterilising the fermentation vessel before the raw materials are added help to
provide optimum conditions for the yeast?
________________________________________________________________
1
b) The concentrations of lactic acid and lactose in a milk sample were measured every two hours for
100 hours. The results are shown in the graph below.
(i)
What evidence from the graph suggests that lactose is converted into lactic acid?
________________________________________________________________________
________
________________________________________________________________________
________ 1
(ii)
What evidence from the graph supports the theory that lactose is being converted into
compounds other than lactic acid?
________________________________________________________________________
________
________________________________________________________________________
________ 1
c) Calculate the average hourly rate of lactose breakdown over the 100 hours of this investigation.
Space for calculation
______________ g / l /hour
1
NATIONAL 5 BIOLOGY HOMEWORK
UNIT 1
Aerobic and Anaerobic Respiration
1. Which of the following statements concerning aerobic respiration is correct?
A
B
C
D
Two molecules of ATP are produced per molecule of glucose respired
Lactic acid builds up in the muscles
Ethanol and carbon dioxide are produced in plants
Carbon dioxide and water are produced
2. Which of the following equations concerning ATP is correct?
A
B
C
D
ATP
ATP + Energy
ADP + Pi
ADP + Energy
ADP + Pi + Energy
ADP + Pi
ATP + Energy
ATP
3. What are the end products of anaerobic respiration in animal cells?
A
B
C
D
ethanol + carbon dioxide + ATP
lactic acid + carbon dioxide + ATP
lactic acid + ATP
ethanol + ATP
4. During aerobic respiration in muscle cells oxygen will combine with
A
B
C
D
hydrogen to form water
pyruvic acid to form lactic acid
pyruvic acid to form ethanol
glucose to form pyruvic acid
5. To respire anaerobically, a yeast cell needs
A
B
C
D
alcohol
glucose
lactic acid
carbon dioxide
6.
Three clear glass containers were set up in light to investigate gas exchange by the organisms
shown. Each container was air tight. The experiment was left for 12 hours.
The colour change shown by the indicators are:
YELLOW
ORANGE
(Amount of Carbon dioxide increasing)
RED
(Amount of Carbon dioxide decreasing)
(a) Copy and complete the table below to show the expected colour change in tubes A and B after
12 hours.
Initial Colour
After 12 hours
A
Orange
B
Orange
C
Orange
Orange
D
Orange
Orange
(1)
(b) Why does no colour change occur in container C?
(c) Explain why the control tube D was included in the experiment.
(1)
(1)
7. An investigation into the effect of temperature on anaerobic respiration in yeast was carried
out.
1.
2.
3.
4.
5.
A glucose solution was boiled and cooled and poured into a conical flask.
A yeast suspension was added to the glucose solution.
Oil was poured over the surface of the liquid.
The number of bubbles of carbon dioxide produced in one minute was counted.
The procedure was repeated at a range of temperatures.
(i)
(ii)
(iii)
In this investigation temperature was the only variable altered. State two variables that
should be kept constant when setting up this investigation.
(2)
Explain the purpose of the layer of oil.
(1)
The results are shown in the table below.
Temperature (˚C)
4
20
35
45
50
70
Bubbles of Carbon dioxide
(number/minute)
0
3
6
22
20
0
Present the results in a suitable format on the graph paper provided.
(iv)
(v)
(vi)
(vii)
(2)
From the results, describe the effect of temperature on anaerobic respiration in yeast. (2)
Suggest one way in which the reliability of the results could be improved.
(1)
In addition to carbon dioxide, what will be produced in the flask during the investigation?
(1)
Explain why no carbon dioxide is produced when the temperature is 70 ˚C.
(1)
8. The diagram below shows some steps in respiration in muscle cells.
(a) Name process A.
(b) Name the products B, C and D.
(c) State the number of molecules of ATP produced from each molecule of glucose by;
(i)
Aerobic respiration
(ii)
Anaerobic respiration
(d) Why might a muscle cell switch from aerobic to anaerobic respiration?
9. Copy and complete the table below to compare the processes of aerobic and anaerobic
respiration in yeast.
(1)
(1)
(2)
(1)
Write the letters of the statements from the list into the correct columns.
Statements
A
B
C
D
E
F
Water is produced
Carbon dioxide is produced
1 molecule of glucose produces 2 molecules of ATP
Ethanol is produced
Glucose is broken down by several enzymes
Oxygen is required
Aerobic Respiration
Anaerobic Respiration
(2)
10. Describe the stages in Aerobic respiration.
(5)
Photosynthesis Homework
2.
3.
4.
5.
6.