WORKSHEET25HL

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LIFE LEAVING CERTIFICATE BIOLOGY

1. Explain each of the following terms. Give a named example of an organism that has each form of nutrition.

(a) Heterotroph:

(b) Autotroph:

(c) Carnivore:

(d) Herbivore:

(e) Omnivore:

2. (a) What is digestion?

(b) Name the four stages in human digestion, in order, and describe each stage.

Stage Name Description

1

2

3

4

(c) There are two types of digestion in humans. Name each type and describe how each is carried out in the alimentary canal.

(i)

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LIFE LEAVING CERTIFICATE BIOLOGY

(ii)

(d) Explain the term peristalsis.

(e) What is the role of peristalsis in the digestion of food?

(f) How might you help this process by your diet?

3. Indicate on the diagram the location of the following using the letters A to M. Include the functions of each part in the table.

Name Function

A oesophagus

B salivary gland

C anus

D pancreas

E gall bladder

F rectum

G ileum

H stomach

I sphincter muscle

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LIFE LEAVING CERTIFICATE BIOLOGY

Name Function

J duodenum

K colon

L liver

M appendix

4. (a) Give the location in the alimentary canal of the structure in the diagram below.

A

B

C

(b) Name and give the functions of the structures A, B and C.

Name Function

A

B

C

(c) What product of digestion would you expect to find in large quantities in B but in very small quantities in C?

(d) Describe the breakdown of this food from when it enters the mouth until it arrives in B.

(e) Describe the pathway of the food in B as the food travels to the liver.

(f) B is part of another body system. Name that system.

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LIFE LEAVING CERTIFICATE BIOLOGY

5. (a) Describe the role of the large intestine in the digestive system.

(b) What is the role of symbiotic bacteria in the large intestine?

(c) Why would these bacteria not survive in the stomach?

(d) Explain the term symbiosis.

(e) What is a balanced diet?

(f) Explain why there is no one identical balanced diet for everyone.

6. What are the benefits of the following dietary recommendations?

(a) Increase the amount of fibre eaten per day.

(b) Eat less sugar.

(c) Increase the amount of fruit and vegetables consumed.

(d) Reduce the intake of salt.

(e) Reduce the amount of fats consumed, particularly animal fats.

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LIFE LEAVING CERTIFICATE BIOLOGY

7. A hundred students took part in an investigation to measure the pH of their saliva and compare it with the number of their teeth which had been filled. The table shows the results of this investigation.

pH of saliva No. of students in each pH range Average no. of fillings per student in each pH range

7.4–7.2 22 3

7.2–7.0 58 5

7.0–6.8 20 7

(a) What percentage of students has saliva in the 7.2–7.0 range?

(b) Describe how you would measure the pH of a student’s saliva.

(c) Suggest how eating an orange might affect the pH readings.

(d) What hypothesis is being tested in this investigation?

(e) Do the results support the hypothesis? Explain your answer.

(f) What conclusion can you draw from these results?

(g) Suggest one way you could improve this investigation.