Cells Homework 1
1. Label the parts of the 2 cells in the diagram below.
(1)
(2)
2. Complete the table below.
Name of part
Nucleus
Function
Site of the chemical reactions of the cell
Cell
membrane
Gives shape to a plant cell
Chloroplasts
Contains cells sap, supports the cell
(6)
3. Read the following passage and answer the questions based on it.
Hayfever
Hayfever affects 2 to 3 million people in Britain. It is caused by an allergy to pollen or
sometimes the spores of fungi. The body’s immune system reacts by releasing excess
histamine. This results in an irritation and inflammation of the nose and eyes.
The symptoms vary and may involve sneezing, a runny or blocked nose and a sore throat.
The eyes may become red, watery or itchy. In addition, a wheezy chest may suggest that the
sufferer also has asthma. The peak pollen time is early summer when school and university
examinations take place. This can make it difficult to revise and perform well.
Hayfever is related to asthma and eczema. It is quite common to find members of the same
family with one or more of these conditions.
Various treatments are available without prescription. These include antihistamine tablets to
reduce the allergic response as well as nasal sprays and eye drops to reduce inflammation.
For severe cases, doctors may prescribe either tablets or injections containing steroids.
These can cause side effects so the benefits have to be weighed against the possible
disadvantages. Tablets are more favoured than injections. Other types of injections can
desensitise patients to the pollen causing their allergy. Unfortunately, they may produce
serious side effects and, as they can only be given under close hospital supervision, are
hardly ever used.
a) What effect does pollen have on the body’s immune system in hayfever sufferers?
____________________________________________________________________ (1)
b) What evidence is there that hayfever might have a genetic component?
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c) Which symptom suggests that a hayfever sufferer may also have asthma?
_____________________________________________________________________(1)
d) At what time of the year are hayfever sufferers likely to be worst affected?
_____________________________________________________________________(1)
e) What type of substance is found in treatments prescribed for severe cases of hayfever?
f)
_____________________________________________________________________(1)
Why are desensitising injections not used very often?
_____________________________________________________________________(1)
Cells Homework 2
1) What are chromosomes and where are they found?
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2) What are the two main stages involved in the division of an animal cell such as Amoeba?
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3) What is mitosis?
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4) Look at the diagram below
a) Describe what is happening at this stage of division.
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_______________________________________(2)
5) In the space below draw the next stage of cell division and describe what happens.
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________________________________________ (2)
(1)
6) Look at each statement below and decide if it is true or false. If you decide it is false, write a
correction to replace the underlined word in the correction box.
Statement
During division the cytoplasm divides before the nucleus
True
False
Correction
When plant cells divide, a new cell wall forms at the end of
division
The two strands of chromosomes, which separate during
division, are called chromatids
Chromosomes are attached to spindle fibres by a cytomere
Cell division is controlled by the cytoplasm
Cell division in unicellular organisms is a means of
reproduction
Chromosomes separate after they have lined up at the north
pole of the cell
(7)
Cells Homework 3
1.When a sample of food is burnt under a test tube of water, as shown in the diagram, the water
heats up.
a) What property of the food is being measured?
__________________________________________________________________(1)
b) What measurements must be taken before the food is set alight?
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c) What measurement must be taken after the food has finished burning?
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d) State 3 reasons why the results may be inaccurate.
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gives
e) What name is given to the piece of apparatus which would give a more accurate
result? ____________________________________________________________(1)
f) Suggest 2 reasons why that piece of equipment reduces errors in the result?
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__________________________________________________________________(2)
2. The following results were obtained using an accurate method of measuring the energy in
food.
Food
Energy released by 1g (kJ)
Fish (fried)
8.4
Kidney (Fresh)
4.2
Peas (tinned)
2.8
Chips (Fried)
9
Potatoes (Boiled)
3.6
a) Present these results as a bar chart.
(3)
b) Robert had a meal of 100g of fried fish and250g of chips. Calculate his energy gain
from this meal.
Space for Working
Answer______________________(1)
c) What is the ratio of energy in fried fish to that in fresh kidney?
Space for Working
Answer
_______:_________
(1)
Cells Homework 4
1) State two reasons why living cells need energy
_______________________________________________________________________________(2)
2) Write the equation for aerobic respiration
(1)
3) Look at each statement below and decide if it is true or false. If you decide it is false, write a
correction to replace the underlined word in the correction box.
Statement
Carbohydrates contain twice as much energy as protein
True
False
Correction
Both plants and animals respire and give out carbon dioxide
The energy from respiration is given off suddenly, all at once
The sum of all chemical processes in living organisms is
called metabolism
Energy is released during aerobic respiration
The carbon dioxide given off during respiration comes from
food
(6)
4) The following experiment was set up to compare heat production in a variety of organisms.
Mouse
Primrose
Woodlouse
Inside insulated,
ventilated glass box
Inside insulated,
ventilated glass box
Inside insulated,
ventilated glass box
The air temperature was measured every 10 minutes and the results are shown below.
Organism
Mouse
Primrose
Woodlouse
0 mins
20
20
20
10 mins
22
20
20
Temperature
20 mins
26
20
21
30 mins
30
21
21
a) Complete the table to show the rise in temperature for each organism.
40 mins
33
21
21
Total rise in
Temp (°C)
(1)
b) Calculate the average rise in temperature for the 3 organisms.
Space for Working
Answer__________________________(°C)
(1)
c) How can the experiment be improved to make the result valid.
__________________________________________________________________________________
________________________________________________________________________________(1)
4) It has been calculated that 50% of the energy released during human respiration is used for
movement, 20% is converted to a variety of storage compounds. A small amount (10%) is needed
for repair whilst the remainder is released as heat
Use this information to construct a pie chart on the uses of energy.
(3)
Cells Homework 5
1. The diagram below shows apparatus used to investigate heat production by
germinating peas.
(a) (i) Which gas, needed by the germinating peas, will pass through the
cotton wool plug?
_______________________________________________________________________________(1)
(ii) There was a 2 °C rise in temperature inside the flask after 24 hours.
What biological process caused this increase?
_______________________________________________________________________________(1)
(iii) Why is it important that the flask is surrounded by insulating material?
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(b) Give one reason why living cells need energy.
_______________________________________________________________________________(1)
(c) The results of the investigation are shown in the table below.
Time (days)
0
1
2
3
4
5
6
7
Rise in temperature (°C)
0.0
0.2
2.0
4.0
5.0
5.4
5.6
5.6
Use the results to complete the line graph by:
(i) completing the scale on the y axis;
(ii) adding a label to the y axis;
(iii) plotting the graph.
(1)
(1)
(1)
2. (a)
(i) What effect does cell division have on the number of cells in the
human body?
_____________________________________________________________________________(1)
(ii) What part of a cell controls cell division?
_____________________________________________________________________________(1)
(b) The following phrases describe stages in cell division.
Stage P—Chromosomes line up at the equator of the cell.
Stage Q—Nuclear membranes form and cytoplasm divides.
Stage R—Chromatids separate and move to opposite ends of the cell.
Stage S—Each chromosome doubles itself and appears as coiled threads.
Use the letters to arrange the stages into the correct order.
First stage __________
(1)
Second stage __________
(1)
Third stage __________
(1)
Fourth stage __________
(1)
(c) 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)
(d) Why is it important that daughter cells have the same number of chromosomes as the mother
cell?
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