8A1 Homework- Spring 2 Summary Questions

Name:________________________________

Q1.          One evening Jenny and Leah ate chicken sandwiches which had been in their school bags all day. There were harmful bacteria in the food. The next day both girls became very ill. Their doctor gave them antibiotics to take for eight days.
          The graph represents how antibiotics affect the number of bacteria in the body.

(a)     Use the graph to explain why the girls did not become ill until the day after eating the sandwiches.
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1 mark

(b)     After taking the antibiotics for eight days Jenny was completely better. Explain why she got better.
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1 mark

(c)     Leah should have taken the antibiotics for eight days. She felt much better after five days and stopped taking the antibiotics. Two days later she felt very ill again.
Use the graph to help you explain why Leah became ill again.
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2 marks

(d)     Food will keep longer if it is placed in a refrigerator at 2°C.
Refrigeration does not kill bacteria.
What effect does the low temperature have on bacteria?
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1 mark
Maximum 5 marks
 
          (a)     The graphs show the number of deaths from lung cancer and from tuberculosis of the lungs, in England and Wales, between 1920 and 1960.

(Data obtained from Key Science Biology, Applin;
published by Stanley Thornes 1994)

(i)      Between which two dates on the graph did the number of deaths from lung cancer rise fastest?
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1 mark

(ii)     Lung cancer may be caused by cigarette smoking.
         What substance in cigarette smoke causes lung cancer?
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1 mark

(b)     The number of deaths from tuberculosis of the lungs went down because of better medical treatment and preventive medicine.
          What type of treatment is given to young people nowadays to prevent them from getting tuberculosis?
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1 mark
Maximum 3 marks
 
Q3.          Sara investigated making bread.
She described what she did below.

          Sara repeated the experiment with the water bath at different temperatures.
Her results are shown below.
 
temperature of	volume of dough (cm3)	
water bath (°C)	at the start 	after 30 minutes	
30	50	66	
45	50	73	
60	50	77	
75	50	71	
90	50	60	

(a)     Use the table of results.
What question did Sara investigate?
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1 mark

(b)     At each temperature Sara used dough from the same mixture.
(i)      Give one other way Sara made her experiment fair.
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1 mark

(ii)     Why would using dough from a different mixture make Sara's experiment unfair?
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1 mark

(c)     Sara plotted her results on the graph below.

          Describe the relationship between the variables on the graph from 30°C to 90°C.
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2 marks

(d)     Sara made a prediction.
                           
          What could she do to test her prediction?
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1 mark
maximum 6 marks
 
Q4.          The photograph below shows bacteria that have developed resistance to antibiotics.
They are called MRSA bacteria.
                   
(a)     When MRSA bacteria reproduce, they pass on their resistance to antibiotics to
the next generation.
          What part of a cell passes on information?
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1 mark
(b)     MRSA bacteria can cause serious infections in people who are ill in hospital.
The bacteria can live on a healthy person’s skin or in their lungs without causing
any harm.
          Use this information to fill in the table below.
Suggest two ways MRSA bacteria can be spread from person to person.
Suggest how the spread of the bacteria can be prevented for each method.
 
 	method of spread	method of prevention	
1	 	 	
2	 	 	

2 marks
(c)     People can be vaccinated against some diseases caused by bacteria or viruses.
          Describe how vaccination prevents a person getting a disease.
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3 marks
maximum 6 marks
 
Q5.          The life cycle of the housefly is shown below.
          
                                                                                                               not to scale

          Before the seventeenth century, people believed that maggots found on rotting meat
came either from the meat or from the air and not from eggs of the housefly.
          In 1668, a doctor named Francesco Redi placed some meat into three separate
containers:
•        container 1, left open to the air
•        container 2, sealed with a lid
•        container 3, covered with a fine mesh.
          He left the containers for several days in a room containing adult houseflies.
His results are shown below.

(a)     Look at the drawings and read the sentences beneath them.
(i)      How do Redi’s results show that maggots do not come from rotting meat?
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1 mark

(ii)     How do Redi’s results show that maggots do not come from the air?
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1 mark

(b)     The maggots that hatched on the meat in container 1 could complete their life
cycle.
          Explain why the maggots that hatched on the mesh on container 3 could not complete their life cycle.
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1 mark

(c)     Give two reasons why meat should be kept in a refrigerator.
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2 marks
maximum 5 marks
 Q6.          Cholera is a disease caused by bacteria. These bacteria produce a poison.
The poison prevents the large intestine from absorbing water from the food passing through it.
People with cholera can lose more than a litre of water per hour.
(a)     Give one function of water in the body.
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1 mark

(b)     People can be injected with a vaccine against cholera. The vaccine contains a tiny amount of the cholera poison and not the cholera bacteria. As a result, people become immune to cholera.
          Describe how vaccination makes a person immune to cholera.
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2 marks

(c)     The cholera poison makes the skin permeable. A new method of vaccinating against cholera is to put a small amount of the poison, mixed with other vaccines, on a plaster. The plaster is left on the skin for a day. The vaccines pass through the skin and the person becomes immune to cholera and to other diseases.
(i)      Why should only a tiny amount of the poison be used?
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1 mark

(ii)     Suggest one advantage of vaccinating people in this way.
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1 mark
Maximum 5 marks

 

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          (a)     In 1967 a national immunisation programme against measles began. Children were injected with a measles vaccine to make them immune to the disease.

          The graph shows how the number of people with measles varied between 1950 and 1980.

(Data obtained from New Scientist, 18 November 1982)

(i)      What does ‘immune’ mean?
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1 mark

(ii)     Complete the following sentence.
When a person is vaccinated, white blood cells produce
.................................................................. which kill micro-organisms.
1 mark

(iii)     What is present in a vaccine to cause white blood cells to respond in this way?
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1 mark

(b)     Explain how a new born baby can have immunity to measles for a short time without being vaccinated.
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1 mark

(c)     The national immunisation programme worked well.
Explain how the graph shows this.
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1 mark

(d)     An increasing number of children are not being immunised.
Predict what is likely to happen to the number of cases of measles as a result of this.
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1 mark
Maximum 6 marks
 
Q8.          Jane stored some milk at room temperature for five days in a sealed container.
She used a pH sensor and data logger to record the pH of the milk for 5 days.
          Her results are shown below.
          graph 1

(a)     Jane predicted that the number of live bacteria in the milk would change as shown below.
          graph 2

(i)      Suggest one reason why the number of live bacteria would start to decrease after 3 days.
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1 mark

(ii)     What evidence from graph 1 suggests that there were still some live bacteria in the milk on day 5?
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1 mark

(b)     Jane put some fresh milk in a sealed container in the fridge.
She measured the pH of the milk every day for five days.
(i)      On graph 3 below, draw a line to show the pH of the refrigerated milk for five days.
         graph 3
            
2 marks

(ii)     On graph 4 below, draw a line to predict how the number of live bacteria in refrigerated milk will change over five days.
         graph 4
             
1 mark
maximum 5 marks