Environment and Humans Revision MCQ Question

1. A bird feeds on a population of insects. The insects feed on the leaves of a tree. Which of the following shows the pyramid of numbers for the food chain?

kuo chuan Q40.PNG

2. The following diagram shows a food web.

st pat Q39.PNG

Which one of the following are secondary consumers?

A.    owl and badger
B.    snake and badger
C.    ladybird and shrew
D.    aphid and caterpillar

3. The diagram below shows the carbon cycle.yuying Q20 a.PNGIdentify processes G and H.yuying Q20 b.PNG

4. Which graph shows the most likely effect of pollution by sewage on the amount of oxygen dissolved in a river?

macpherson Q40.PNG

5.  Which one of the following processes may result in eutrophication in a lake?
A.    The disposal of excess bleach used in factories.
B.    The disposal of hot water entering from a power station.
C.    The use of fertilizers in farms washed off into water bodies.
D.    The use of pesticides entering from farmland into water bodies

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Answer: ACDAC

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Respiration: Gaseuos Exchange in Plants Revision Structured Question

1. A plant is left in a sunny position without being watered for ten hours.
The figure below shows the appearance of one of the stomata on the lower surface of a leaf from this plant every hour, for 10 hours.

serangoon Q4.PNG

(a) Describe and explain the way that the stoma changed from hour 6 onwards will help in the plant’s survival.

(b) The figure below shows the arrangement of guard cell and epidermal cell. After six hours the water content of the guard cells decreased compared to the surrounding epidermal cells.

serangoon Q4b.PNG

Explain the movement of water in guard cell that leads to decrease in size and results in the change in the shape of the stoma.

(c) Suggest and explain how the change shown in the diagram might affect photosynthesis taking place in the leaves of this plant.

 

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Answer:

1.(a)(i)  The stomata reduced in size; water loss was reduced
and this prevents wilting

(b) The movement of water from a region of higher water potential to a region of lower potential through a partially permeable membrane by osmosis; guard cells became flaccid they changed shape to close the stoma.

(c)  photosynthesis decreased; carbon dioxide could not enter through the closed stomata; By diffusion

 

Transport in Flowering Plants Revision Structured Question

1. The figure below shows the outline of a root hair cell.

o lvl 1.7 Q3.jpg

(a) (i) Complete a detailed and fully labelled diagram of a root hair cell within the outline provided.

(ii) Name the process by which water enters the vacuole of a root hair cell.

(iii) State two conditions which must exist so that this process will occur.

(b) State two advantages to a plant in having a large number of root hairs.

(c) (i) State two elements commonly supplied to plants by means of inorganic fertilisers.

(ii) State the form in which each of these elements is usually absorbed

(d) (i) Name the tissue in a plant which water ascends from root to leaf.

(ii) What is upward flow of water called?

(iii) Name the process by which most of the water that rises up a plant in this way escapes to the atmosphere.

2. Fig 2 is a graph showing the rates of water absorption and transpiration of a plant during a 24-hour Period.st pat Q3.PNG

Fig. 2

(a) (i) What is the difference between the rates of transpiration and water absorption between 0000 and 0600 hours?

(ii) State a reason for the difference observed in question (a) (i).

(b) A change in the environment occurred between 0600 hours and 1400 hours. ldentify two likely environmental changes.

(c)  Complete the following table:st pat Q3B.PNG

(d) (i) What does the area under graph X represent?

(ii) what do areas A represent?

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Answer:

2. (a) (i) The rate of water absorption is higher / greater / faster than transpiration.

(ii)

  • The water absorbed is used to maintain turgidity of cells
  • The water absorbed is stored by the plant (e.g. cacti)
    OR
  • Low light intensity –> stomata close –> decrease in rate of transpiration

(b)

  • An increase in air speed
  • A decrease in atmospheric humidity
  • An increase in light intensity
  • An increase in temperature

(c)

st pat Q3 Ans.PNG

(d) (i)  It represents the total amount of water lost
period.

(ii)  They represent the net amount of water gained by the plant from around 1500 to 2400 hours and from 0000 to 0700 hours.

 

o lvl 1.7 Q3.jpg

Transport in Humans Revision Structured Question

1. The figure below shows sections through two types of human blood vessel.

macpherson Q1.PNG

(a) Name the types of blood vessel shown in the figure above.

(b) (i) Describe two differences in the structure of blood vessels A and B.

(ii) For each of your answers in (b)(i), explain how the difference in structure relates to the function of the blood vessel.

(c)  Blood vessels can sometimes be damaged when a person cuts himself. Outline the main stages in blood clotting

2. (a)  Describe coronary heart disease.
It has been suggested that eating a balanced diet may help to prevent heart disease.
Besides a balanced diet, state one other factor that may decrease the risk of heart diseases.

(b)  ln the human body, blood carries out both protective and transport functions. Describe the role of white blood cells in protecting the body, the role of red blood cells and plasma in transport of substances.

3. Fig. 2.1 shows the results of five independent investigations into the effect of physical activity on heart disease.mansjuri Q7.PNG

Fig. 2.1

(a) With reference to data from Fig. 2, describe the effect of level of physical activity on the risk of heart disease.
Use information about the circulatory system to account for the trend observed.

(d)  Fig. 2.2 shows how the blood pressure changes in artery, capillaries and veins.serangoon Q7c.PNG

Fig. 2.2

Describe how the pressure changes from arteries, capillaries to the vein. Explain how the structures of arteries and vein are adapted to the pressure and allow blood to flow continuously.

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Answer:

1. (a) A: Artery; B: Vein

(b) (i) A/artery is thicker walled than vein;
A/artery has smaller lumen than vein;
B/vein has valve, artery does not

(ii) artery has to withstand greater (blood) pressure; (reject if students use ‘generate’)
blood moves at a faster speed in artery than in vein;
valve needed to prevent backflow in vein as blood is at low pressure in veins

(c) damaged tissue and platelets produce enzyme thrombokinase;
thrombokinase converts inactive prothrombin into thrombin:
thrombin converts soluble fibrinogen into insoluble fibrin;
red blood cells and platelets are trapped in the mesh of fibrin threads to form a blood clot.

2. (a) Besides a balanced diet, state one other factor that may decrease the risk of heart diseases.
Coronary heart disease is due to the deposition of fats and cholesterol in the lumen of the coronary arteries.
This reduces the blood supply to the heart muscles. hence decreasing supply of oxygen and glucose to the heart muscles.
Resulting in lower rate of respiration, hence lesser energy release for heart muscle contraction, resulting in heart attack.  To reduce the risk of coronary heart disease, a person should exercise regularly/do not smoke/do not drink excessively/maintain healthy weight.

(b)

  • Lymphocytes produce antibodies/ cause bacteria to clump
  • Lymphocytes recognise and reject foreign tissue
  • Phagocytes engulf and ingest foreign bacteria
  • Red blood cells transport oxygen from lungs to all body cells
  • Plasma transport blood cells/ions/soluble food substances; hormones/carbon dioxide/urea/vitamins/plasma proteins

3. (a) As the level of physical activity increases. the risk of dying from the heart disease decrease. As the level of physical activity increases, there is increased blood flow, hence increasing supply of oxygen and glucose to the heart muscles.
This allows sufficient oxygen and glucose available for cellular respiration, hence releasing sufficient energy for heart muscle contraction.
Exercise also helps keep the arteries elastic, allowing fats and cholesterol to be able to move easily in the blood.
Exercise also improves blood circulation so that it reduces the chances of blood clots leading to heart attack.

(b)

  •  The pressure is highest at arteries and the pressure decreases, the pressure is the lowest at the veins
  • The pressure changes at artery due to contraction and relaxation of the heart
  • The wall of artery is thicker to withstand the higher blood pressure
  • The pressure of vein is low and the wall is thinner
  • Valves are present in veins to prevent backflow of blood

 

Transport in Flowering Plants Revision MCQ Question

1. A destarched plant was exposed to radioactive carbon dioxide. After 24 hours, the plant was removed and sections were taken from the root and the stem. Which diagram shows the presence of radioactive substance?st joseph Q27.PNG

2. A plant has a ring of bark removed from its stem. A swelling occurs within a week of the experiment as shown in the diagram.

kuo chuan Q28.PNG

Which of the following best describes why the plant dies eventually?

A.    Supply of carbon dioxide to the roots is cut off.
B.    Supply of mineral salts to the leaves is cut off.
C.    Supply of sugars to the roots is cut off.
D.    Supply of water to the leaves is cut off.

3. Anhydrous cobalt chloride (or cobalt thiocynate) paper placed against the lower surface and the upper surface of a leaf has a faster change of colour on the lower surface. This information indicates that

A.    transpiration takes place through the stomata
B.    there are more stomata on the lower surface than on the upper
C.    the rate of transpiration of the upper surface of the leaf is faster than that of the lower
D.    the rate of transpiration of the lower surface of the leaf is faster than that of the upper

4.  Fig. A shows an experiment to study the movement of materials in a plant.
Fig. B shows how a ring of bark was removed at point Y.katong Q30.PNG

The plant was exposed to light for a few hours. All three leaves, F, G and H, were tested for the presence of radioactive sugar compounds. Which leaves contained radioactive sugar compounds?

Bkatong Q30.PNG

5. An herbaceous plant, growing in a nutrient solution, was placed in a well-lit experimental chamber through which humid air was being drawn slowly. The diagram below shows a section through a part of the plant.

o lvl 1.7 Q9 A.jpg

It was possible to measure the speed of movement of fluid in tissues P and Q. The humid air was then replaced by dry air and it was observed that changes in the speed of movement occurred. What are these changes?o lvl 1.7 Q 9.PNG

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Answer: BCDCA

Transport in Humans Revision MCQ Question

1. The diagram below shows blood after undergoing centrifugation, whereby blood is spun at high speeds to separate them into their components.

yuying Q8.PNG

Layer X is the liquid part of the blood. Which row of the table identifies each of the blood components X, Y and Z?yuying Q8B.PNG

2. The diagram represents the relationship between red blood cells, capillaries and tissue cells in the transport of carbon dioxide. Which correctly identifies the form in which carbon dioxide is transported around the body?junyuan Q7.PNG

3. The diagram shows a vertical section through the heart. Which blood vessel carries oxygenated brood from the lungs?st joseph Q28.PNG

4.  The graph shows pressure change in the left ventricle and left atrium in one cycle of contraction of the heart. During which period of time is ventricle contracting?kuo chuan Q30.PNG

5. Which one of the following describes the functions of the tricuspid and bicuspid valves? They prevent backflow of blood from ________________________________.

A.    ventricles to atria
B.    atria lo ventricles
C.    aorta/pulmonary artery to ventricles
D.    ventricles to aorta/pulmonary artery

6. The diagrams below show the cross-sections of the three blood vessels. Which of the following correctly states its function?northland Q28.PNGnorthland Q28B.PNG

7. The diagram shows section through four hearts
Which of the following has arrows correctly showing the direction of blood passing through all the valves?kuo chuan Q31.PNG

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Answer: DCDBAAA

 

Nutrition in Humans Revision Structured Question

1.  Table 1.1 shows the relative amounts of fatty acids and amino acids found in a person’s alimentary canal. Neither fatty acids nor amino acids were found in the original meal taken by this person.

st pat Q2.PNG

Fig. 1.1

(a) Name the process that facilitates the movement of food to move through the alimentary canal.

(b) Explain the changes in the amounts of fatty acids.

(i) in the duodenum

(ii) in the ileum

(c)  Fig. 1.2 shows the internal structure of a part of the mammalian alimentary canal.

st pat Q2B.PNG

Fig. 1.2

(i) Name the structures A, B and C.

(ii) How is C adapted for its function?

2.  Fig. 2.1shows some structures associated with the digestive enzyme system of a mouse which is very much similar to that found in humans.seng kang Q2.PNG

(a)  Name the parts labelled S and T.

(b) Two groups of mice were surgically treated as shown in Table 2.1.

seng kang Q2B.PNG

The two groups of mice were fed over a week and the effect of the treatment for each group was recorded. Provide explanation for each of the effect recorded below.

(i) The mice from Group A egested faeces containing a very high percentage of fats.

(ii) The average weight of mice from Group B dropped from 25 g to 18 g over the week.

(c)  Fig. 2.2 shows a structure found in the digestive system of the mouse.

seng kang Q2C.PNG

(i) On Fig. 2-1, place an ‘X’ to show where the structure shown in Fig. 2.2 can be found.
(ii) ln Table 2.2, place ticks in the boxes to show the nutrients that would be transported in the vessels labelled P and Q in the structure shown in Fig. 2.2.seng kang Q2D.PNG

==================

Answer:

1. (a) Peristalsis

(b) (i)  This is due to the presence of the pancreatic lipase and intestinal lipase digest/hydrolysis; fats into fatty acids and glycerol

(ii) As absorption/diffusion of fatty acids; into lacteals/lymph vessels of villi which decrease the amount of fatty acids

(c) (i) A – lacteal/lymphatic capillary; B – blood capillaries; C- villus

(ii) One-cell thick + faster rate of absorption; microvili + increases surface area to volume ratio for faster rate of absorption

2. (a) S – gall bladder; T – pancreas

(b) (i) Most fats cannot be digested as bile is not present to emulsify the fats. Hence most fats remains undigested/not digested and passed out as faeces.
Reject- S produce bile to digest fats or Bile breakdown fats

(ii) Enzymes from pancreatic juice are not present to digest the food. Food cannot be digested/ Nutrients are not absorbed into bloodstream causing the loss of weight.

(c) (i)

seng kang Q2 Ans.PNG

(ii)

seng kang Q2 Ans B.PNG

 

 

Nutrition in Humans Revision MCQ Question

 

1. The secretions below are vital for healthy digestion in the human body.

I. Saliva         II. Gastric Juice          III. Bile          IV. Intestine

Which of the secretions above contain proteases?

A.    1 and 2 only
B.    2 and 3 only
C.    2 and 4 only
D.    3 and 4 only

2. The diagram shows some organs of the human body. Which structure does not move its contents by peristalsis?chij katong Q27.PNG

3. The diagram shows the liver and associated blood vesselspasir ris crest Q5.PNG

ln which blood vessel will the level of glucose be the highest after a meal?
A.    P
B.    Q
C.    R
D.    S

4. The graphs show the concentrations of glucose and insulin in the blood of a healthy person. Which graph shows the changes expected after a meal containing starch?

serangoon Q35.PNG

5.  The diagram below shows part of a mammalian digestive system.

junyuan Q5.PNGAn experiment was conducted with juices W and Z on vegetable oil. What shows the possible result obtained?

 

A.    Juice W mixed with vegetable oil results in highest amount of fatty acids formed.
B.    Juice W and Z mixed with vegetable oil results in, highest amount of fatty acids formed
C.    Juice Z mixed with vegetable oil results in no fatty acids formed
D.    Juice Z mixed with vegetable oil results in highest amount of fatty acids formed

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Answer: CDCAB