June 2013 B7

Question 1

1 Jason is concerned that he may be overweight.

(a) He wants to calculate his Body Mass Index (BMI).

He knows that his mass is 86.0 kg and his height is 1.70 m.

The formula used to calculate BMI is

mass (kg) [height (m)]2

Use the formula to calculate Jason’s BMI to three significant figures. Show your working.

BMI = …………………………………………………. [2]

Answer 1

86/(1.7*1.7)

29.8

Question 2

1 Jason is concerned that he may be overweight.

(a) He wants to calculate his Body Mass Index (BMI).

He knows that his mass is 86.0 kg and his height is 1.70 m.

The formula used to calculate BMI is

mass (kg) [height (m)]2

Use the formula to calculate Jason’s BMI to three significant figures. Show your working.

BMI = …….29.8…………………………………………… [2]

(b) Use the result of your calculation and the table below to determine Jason’s condition.

BMI reading Condition

30.0 obese

Jason’s condition …………………………………….. [1]

Answer 2

Overweight

Question 3

(c) Jason has weighed himself, and calculated his BMI.

Jason is concerned about the repeatability of the data he has collected and the accuracy of the equipment that he has used.
Explain what is meant by repeatability and accuracy in this case. [2]

Answer 3

Accuracy is how close the reading is to the true value

Repeatability means that the readings taken will remain the same.

Question 4

(d) Jason knows that the greater his BMI, the greater his risk of having heart disease.
(i) Jason looks at this table of data that he sees on the internet.

BMI Increased risk of heart disease

23–25 50%

26–29 72%

He concludes that the increased risk is reduced from 72% to 50% if the BMI is reduced from 26 to 25.

What is the problem with Jason’s interpretation of the data? Explain your answer.
[2]

Answer 4

Jason is not realising that the risk has been averaged out over the range. A small reduction in BMI does not therefore cause a large drop in the risk.

Question 5

(ii) Jason loses weight.

His doctor tells him that his probability of having a heart attack within the next ten years is 0.3%.
Use this example to discuss the risk to Jason, by referring to probability and consequence.
[2]

Answer 5

Probability is low, but the consequence (death) is very high.

Question 6

2

   (a)                       

The table shows the normal level of three different blood components.
It also shows the level in three different people, A, B and C.

normal level 15 8500 250 000

person A 15 3000 255 000

person B 9 9000 245 000

person C 15 8000 130 000

What is the consequence of this data for the health of each person?Explain your answer.

person A …………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………

person B …………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………………

person C …………………………………………………………………………………………………………………..

…………………………………………………………………………………………………………………………… [3]

Answer 6

A - low white cell count - increased likelihood of contracting infections.

B - low haemoglobin - tired/out of breath/anemic

C -low platelets - blood will not clot

Question 7

(b) Red blood cells are adapted to the job that they do.
Draw one straight line from each feature to the correct description of its function.

feature description of function

                                           only survives for six weeks  contains haemoglobin	      smaller volume to hold oxygen
                                           to bind with oxygen

no nucleus able to divide to produce new cells
more space for haemoglobin

FEATURE :biconcave shape

FUNCTIONS: hinders the red blood cells movement through the blood

increased surface area for oxygen exchange

[3]

Answer 7

contains haemoglobin to bind with oxygen

no nucleus more space for haemoglobin

biconcave shape increased surface area for oxygen exchange

Question 8

A student draws a diagram to show the movement of oxygen and carbon dioxide between the blood in the capillaries and muscle cells

low pressure blood high pressure blood
at start of capillary at end of capillary

direction of blood flow ————————->

O2 O2 O2
! ! !
\/ \/ \/
/\ /\ /\
! ! !
CO2 CO2 CO2

Muscle cells (were drawn on the exam paper)

He says:

“This explains how oxygen passes from the blood to muscle cells and carbon dioxide passes from muscle cells to the blood.”

Evaluate his diagram and explanation and suggest how both could be improved.

The quality of written communication will be assessed in your answer.                                                          [6]

Answer 8

Include:

Diffusion - oxygen diffuses into tissue fluid around muscle cells, then into the cells. Carbon dioxide goes the other way, both are diffusing from areas of high concentration to areas of low concentration - this is called the concentration gradient.

There is more oxygen at the beginning of the capillary.

Tissue fluid - leaks out of capillaries when high pressure, goes back in later.

The pressure is labelled incorrectly, the end of the capillary nearer the heart will have higher pressure.

Question 9

In 1774 a scientist called Sir Charles Blagden designed an experiment to test the effect of high temperatures on the human body.The temperature of the human body is 37 °C.Blood boils just above 100 °C.

He entered a room where the air temperature was above 127 °C.

He placed an egg and a piece of meat in the room.The egg was cooked in 15 minutes and the meat in 35 minutes.

A student predicted that Sir Charles Blagden’s body temperature would rise and he would die very quickly.

Do you think the student’s prediction is correct?Justify your answer.

                                                                           [3]

Answer 9

Body will attempt to cool itself:

Hairs lie flat
Sweating removes heat with latent heat
Vasodilation

Also
Enzymes denature when body heats up

Question 10

Which of the following dietary factors can help Jenny to control her diabetes?Put ticks (✓) in the boxes next to the correct answers.

take vitamin supplements

have a high fibre diet

eat more protein

increase energy (food) intake

take mineral supplements [2]

Answer 10

have a high fibre diet

eat more complex carbohydrates

Question 11

Having an unhealthy lifestyle can increase the risk of some conditions.Which of the following conditions are most likely caused by lifestyle factors?
Put ticks (✓) in the boxes next to the three correct answers.

Huntington’s disease inherited from mother

obesity

sore throat caused by bacterial infection

heart disease

skin cancer

common cold caused by a virus

cystic fibrosis inherited from both parents

colour blindness inherited from father
[1]

Answer 11

obesity

heart disease

skin cancer

Question 12

Controlling glucose level in the blood is important.

This is a graph of blood glucose level against time.
_
/ \ ____
/ \A / \
/ \ / \B
/ \ / \
/____/\____________ \________________C__

time ->

Write the correct letter, A, B or C next to the most likely food in each meal.

type of food letter

fibre

glucose drink

complex carbohydrate (starch)

Answer 12

fibre C

glucose drink A

complex carbohydrate (starch) B

Question 13

Protein in food has to be processed by the digestive system in the same way as complex carbohydrates, before entering the blood stream.

Some people with type 1 diabetes do not produce enough of the hormone insulin.

These people inject themselves with insulin. Insulin is a protein. Why is insulin usually injected rather than taken as a tablet?
Put ticks (✓) in the boxes next to the two correct answers.

Insulin in tablets enters the blood stream too quickly.

Tablets are more likely to cause infection.

Insulin in tablets is more likely to cause an overdose.

Insulin in injections will work faster.

Insulin needs to be injected straight into the pancreas.

Insulin in tablets is likely to be digested and broken down.
[2]

Answer 13

Insulin in injections will work faster.

Insulin in tablets is likely to be digested and broken down.

Question 14

Natural ecosystems are a type of closed loop system.Describe what is meant by a closed loop system and give examples to explain how human activity can unbalance ecosystems so that they no longer work effectively as closed loop systems.

The quality of written communication will be assessed in your answer.

[6]

Answer 14

Description of closed loop:

No waste
Output from one organism is input to another organism
Sustainable

Give an example - eg rainforest, reef

Human activity - deforestation takes away trees

removal of biomass has opened the loop, so the ecosystem cannot recycle the nutrients.

Question 15

7 It is very important that the use of natural resources by humans is sustainable.

   (a)   What is meant by the sustainable use of natural resources?              Put a tick (✓) in the box next to the correct description.

Resources are not taken from the environment.

Resources are used faster than they are replaced.

Resources are only used if they are urgently needed.

Resources are used at the rate at which they are replaced.

Resources are looked for in new areas.
[1]

Answer 15

Resources are used at the rate at which they are replaced.

Question 16

b) Suggest two ways that North Sea fish stocks could be managed in a sustainable way.

[2]

Answer 16

Fishing quotas, restricting number/size/species taken.
Fishing only at some times of year.
Restricting fishing to certain areas.

Question 17

(c) Tensions sometimes exist between conserving a natural ecosystem and the needs of local
people.
Suggest why this tension may exist. [1]

Answer 17

Local people need the resources.

Question 18

This question is about genetic modification.

 (a) There are many examples of genetic modification.Which of the following can be achieved by genetic modification?
Put ticks (✓) in the boxes next to the two correct answers.

sexual reproduction in plants

bacterial synthesis of medicines

testing for genetic disorders

selective breeding

asexual reproduction in animals

herbicide resistance in crop plants
[2]

Answer 18

bacterial synthesis of medicines

herbicide resistance in crop plants

Question 19

One example of genetic modification is the production of golden rice.Golden rice has a gene inserted that produces vitamin A.White rice does not contain vitamin A.Countries with people who eat mainly white rice have high levels of blindness due to a lack of vitamin A.

Suggest why people in these countries may be more in favour of the genetic modification of organisms than people who live in the United Kingdom. [2]

Answer 19

There is a greater need for the vitamin enhanced rice than there is here, in the UK people do not go blind due to lack of vitamin A.
When the benefit is greater people are more likely to be willing to take the risk.

Question 20

People with haemophilia lack the gene to make the protein Factor 8 (Factor VIII).As a result their blood cannot clot if they cut themselves.

Suggest how the process of genetic modification could be carried out to treat people with haemophilia.

The quality of written communication will be assessed in your answer.
                                                                                   [6]

Answer 20

Identify gene;
isolate gene;
replicate gene;
put gene into vector - eg plasmid/virus;
correct gene is spliced into DNA

this can be done in person or bacterium

if in bacterium, it now makes factor 8 which can be used
or if in person, the new gene makes factor 8.

Question 21

9 It is important in science to understand scale. Nanotechnology involves using structures that are about the same size as small molecules.

   (a)   Look at the list.

1	cells
2	DNA
3	nucleus
4	nanotechnology structures
5	human
6	heart

Write the list in the correct order starting with the smallest structure and ending with the largest structure.
The first one has been done for you.

4 ………… ………… ………… ………… …………

Answer 21

423165

nanotechnology structures; DNA; nucleus; cells; heart; human

Question 22

b) The structures used in nanotechnology are smaller than 100 nanometres in size.

A nanometre is one thousand millionth of a metre. 

Put a ring around the correct size for a nanometre.

                                               0. 001 
                                               0. 000 001 m
                                               0. 000 000 001 m
                                               0. 000 000 000 001 m
                                               0. 000 000 000 000 001 m

Answer 22

0.000 000 001 m

Question 23

(c) It is possible to see structures as small as 100 000 nm with the naked eye.
A light microscope can be used to see structures as small as 2000 nm.
To see structures smaller than that, an electron microscope is used.

A typical human cheek cell is 20 000 nm in diameter. A virus is about 20 times smaller.

What device could be used to see a virus? Explain your answer.

Answer 23

Virus is 1,000 nm in diameter, therefore you would use an electron microscope

Question 24

(e) Read the article about ‘smelly socks’ and nanoparticles:

____________________________________________________________

No more smelly socks

Scientists have developed socks that no longer smell after they have been worn. The socks are impregnated with silver nanoparticles that kill the bacteria that cause socks to smell.

A scientist said “One problem is that silver nanoparticles may be dangerous if released into the environment. We just do not know enough yet about nanoparticles.”

When the socks are washed, 10% of the silver nanoparticles are released into the washing water.
_________________________________________________________

Explain, using the example of the ‘smelly socks’, why this use of nanotechnology may not be completely safe. [2]

Answer 24

Not enough is known;

10% are released every time the socks are washed

Question 25

(e) Read the article about ‘smelly socks’ and nanoparticles:

____________________________________________________________

No more smelly socks

Scientists have developed socks that no longer smell after they have been worn. The socks are impregnated with silver nanoparticles that kill the bacteria that cause socks to smell.

A scientist said “One problem is that silver nanoparticles may be dangerous if released into the environment. We just do not know enough yet about nanoparticles.”

When the socks are washed, 10% of the silver nanoparticles are released into the washing water.
_________________________________________________________

Using the example of the ‘smelly socks’, suggest how scientists could reduce the risk in this case. [1]

Answer 25

Change the material so that fewer nanoparticles are released in the wash.

Question 26

Some people think that goods containing nanoparticles should be labelled.This could help people decide whether or not to buy the goods.A nanoparticle is defined as a particle smaller than 100 nm in size.Suggest why this definition may not be very useful when deciding whether or not to label goods containing nanoparticles.
{1}

Answer 26

101 nm may be just as dangerous as 99nm