web viewthe table shows the rate of blood flow to various parts of the body at rest ... a...

1. There are many different species of annelid worm. Some are very small, only a few millimetres in length. Others, such as lugworms, are much larger. The drawing shows a lugworm and part of one of its gills.

(a) Smaller species of annelid do not have gills. Explain why these small worms do not need gills to obtain sufficient oxygen.

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(b) In many of the lugworm gills, the blood flows in the opposite direction to the current of water passing over them. Explain the advantage of this arrangement.

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Woodford High School 1

(c) Explain two ways, other than that described in part (b), in which the structure of a lugworm gill is adapted for efficient gas exchange.

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(d) Explain why water is always lost from the gas exchange surfaces of terrestrial organisms.

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The table shows the ratio of the amount of water lost to the amount of oxygen gained for two terrestrial animals, an annelid worm and an insect.

Organism

Ratio 1–1–3

–1–1

minutegup/cmtakenoxygenofVolumeminuteglost/mgwaterofMass

Annelid worm 2.61

Insect 0.11

(e) Both the annelid and the insect take up oxygen at a rate of 2.5 cm3 g–1 minute–1 Calculate the rate at which water would be lost in meeting these requirements in:

(i) the annelid;

Answer.......................mg g–1 minute–1

(ii) the insect.


Answer........................mg g–1 minute–1

(2)

(f) Give two explanations as to why the rate of water loss during gas exchange is very low in most insects.

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(g) Annelids like the lugworm have blood which contains haemoglobin. The graph shows the oxygen dissociation curves for lugworm haemoglobin and for human haemoglobin.

1 0 0

8 0

6 0

4 0

2 0

00 2 4 6 8 10

P ercen tag esa tu ra tio n o fh a em o glo b inw ith o x y g en

L u g w o rmh aem o g lo bin

H u m anh ae m o g lo b in

P artia l p ressu re o f o x y g en /k P a

(i) During exercise, the rate of respiration of muscle cells increases. Explain what causes human haemoglobin to unload more oxygen to these cells.

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(ii) The lugworm lives in a burrow in the sand on the seashore. When the tide is out, water bringing a fresh supply of oxygen no longer flows through the burrow. Suggest how the lugworm’s haemoglobin allows it to survive in these conditions.

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(Total 20 marks)

2. (a) A garlic root tip was examined for stages of mitosis. The root tip was cut off, stained and put on a microscope slide. A cover slip was placed on top. The root tip was squashed and then viewed through a microscope.

Give one reason for each of the following:

(i) staining the root tip;

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(ii) squashing the root tip.

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(b) The graph shows the amount of DNA in a cell during a cell cycle.

A m o u n t o fD N A in ce ll/

a rb itra ry u n its

4

3

2

0

x

x

x

x

P Q RTim e

(i) Name the stage occurring between time P and time Q. Give the reason for your answer.

Stage .................................................................................................................

Reason ..............................................................................................................

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(ii) Explain the decrease in the amount of DNA present at time R.

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(Total 5 marks)


3. The table shows the rate of blood flow to various parts of the body at rest and during vigorous exercise

P a rt o f b o d y R a te o f b lo o d flo w

S k ele ta l m usc le sH ea rt m usc leS k inK idn e y sL iv e r a n d g u tB ra in

1 0 0 02 5 05 0 0

1 0 0 01 2 5 0

7 5 0

1 6 0001 200

750300375

a t res t d u r in g v ig o ro u s e xe rc ise

(a) (i) Suggest suitable units for the rate of blood flow.

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(ii) Suggest a suitable value for the rate of blood flow to the brain during vigorous exercise. Give a reason for your answer.

Value ................................................................................................................

Reason ..............................................................................................................

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(b) Use information from the table to suggest why it is recommended that vigorous exercise should not be undertaken until at least two hours after a meal.

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(Total 4 marks)


4. The graph shows the dissociation curve for adult human haemoglobin.

1 0 0

9 0

8 0

7 0

6 0

5 0

4 0

3 0

2 0

1 0

00 2 4 6 8 1 0 1 2 1 4 1 6In resp ir ing t issu e In lu n g s

P ar tia l p re ssu re o f o x yg e n / k P a

S a tu ra tion o fh ae m o g lo b inw ith o x y g en /%

(a) What is the percentage saturation of haemoglobin at the partial pressure of oxygen found in

(i) the lungs;

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(ii) respiring tissue?

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(b) 1 dM3 blood leaving the lungs carries 200 cm3 oxygen. Use the graph to calculate the amount of oxygen that this volume of blood will unload to the respiring tissue. Show your working.

Answer .......................................................... cm3

(2)

S (c) A mutation in one of the genes coding for the production of haemoglobin could lead to a decrease in the oxygen-carrying capacity of the blood. Explain how.

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(Total 5 marks)


5. The drawing shows some tracheoles that carry air to a muscle fibre in an insect.

B

M u sc le f ib re

Tra ch eo les

A

(a) (i) Explain how the structure of the gas exchange system of an insect ensures that there is a large surface area for gas exchange.

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(ii) Describe one way in which the transport of oxygen to a muscle in an insect is different from that in a fish.

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S (b) The diameter of the tracheole at point A is 20 m. Calculate the magnification of the drawing. Show your working.

Answer: magnification = ...........................................................................................(2)

S (c) Breathing movements can bring about the mass flow of air as far as point B. What causes the diffusion of oxygen molecules from B into a muscle fibre?

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(Total 5 marks)

6. Globin chains are polypeptides. The globin chains in adult haemoglobin differ from those in fetal haemoglobin. The graph shows the percentage of the different globin chains present in haemoglobin molecules of a human before and after birth.

A lp h ag lo b in

B e tag lo b in

G am m ag lo bin

P e rce n ta g eo f ea ch

g lo bin ch a in

5 0

2 5

00 2 4 6 8 1 0 1 2 1 4 1 6

Tim e / m o n th s B irth


(i) At birth, the red blood cells of a baby contain a mixture of adult haemoglobin and fetal haemoglobin. Using information in the graph, calculate the percentage of the total haemoglobin molecules at birth that are adult haemoglobin molecules. Explain how you arrived at your answer.

Percentage = ..................................................

Explanation

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S (ii) Suggest how the cells that become red blood cells are able to produce different forms of haemoglobin at different stages in development.

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(Total 4 marks)


7. The graph shows the expected and actual results of an experiment to investigate the uptake of glucose by human red blood cells.

R ate o fg lu co seu p tak e E x p ec te d re su lt

A ctu a l resu lt

0 5 10

C urv e A

C u rv e B

C o n c en tra tio n o f g lu c oseso lu tio n /m m o l d m – 3

(a) Curve B shows the result that would be expected if glucose enters the red blood cells by simple diffusion.

(i) State Fick’s Law.

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(ii) Explain how Curve B demonstrates one aspect of Fick’s Law.

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(b) Curve A shows the results obtained from the red blood cells. It shows that these cells took up glucose by facilitated diffusion.Explain the shape of the curve at glucose concentrations:

(i) less than 2 mmol dm–3;

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(ii) greater than 5 mmol dm–3.

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(Total 5 marks)

8. The total amount of product formed in an enzyme-controlled reaction was investigated at two different temperatures, 55 °C and 65 °C. The results are shown in the graph.

1 0

8

6

4

2

00 1 2 3 4 5 6 7

To ta lam ou n t

o fp ro d u c tfo rm ed /a rb itr a ry

u n its

Tim e / h o u rs

5 5 °C

6 5 °C


(a) (i) Explain how you would calculate the rate of the reaction at 55 °C over the first 2 hours of the investigation.

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(ii) Explain why the initial rate of this reaction was faster at 65 °C than it was at 55 °C.

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(b) Use your knowledge of enzymes to explain the difference in the two curves between 4 and 6 hours.

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(c) In this investigation, the enzyme and its substrate were mixed in a buffer solution.What was the purpose of the buffer solution?

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(Total 6 marks)

9. The drawing has been made from a photograph. It shows an organelle.


(a) Optical microscopes, transmission electron microscopes and scanning electron microscopes may be used to investigate the structure of cells

(i) What type of microscope was used in taking the photograph from which this drawing was made

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(ii) Give one piece of evidence for your answer.

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(b) Explain why a cell involved in active transport would contain a large number of these organelles.

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(c) The scale bar on this drawing represents a length of 1 m. Calculate the magnification of the drawing. Show your working.

Magnification = ......................................(2)

(Total 6 marks)

10. The diagram shows a section through part of a cell as it would appear when seen with an

electron microscope.

C

A

B

C is te rn a


(a) This cell produces and secretes a protein. Describe the part played by organelles A, B and C in producing and secreting this protein.

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(b) The table shows information about the different parts of this cell.

Part of cell Percentage of total cell volume

Number in the cell

Cytoplasm surrounding cell organelles 54 1

Mitochondria 22 about 1700

Nucleus 16 1

Lysosomes 11 about 300

Cisternae of rough endoplasmic reticulum 19 1

(i) Which organelle is larger, a mitochondrion or a lysosome?Use calculations based on figures from the table to support your answer.

Larger organelle; ..............................................................................................

(2)


(ii) In the drawing there appear to be a number of separate cisternae in the rough endoplasmic reticulum. The table gives the approximate number of cisternae as one. Suggest an explanation for the apparent difference.

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(iii) This cell produces a large amount of protein. Explain how the number of mitochondria in the cell may be linked to this.

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(Total 10 marks)


web viewthe table shows the rate of blood flow to various parts of the body at rest ... a...

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