12. (a) (i) Write the dental formula for an adult human - Leaving Cert Biology - Question 12 - 2006
Question 12
12.
(a) (i) Write the dental formula for an adult human.
(ii) Give a function of any one of the teeth indicated in the dental formula.
(b) The diagram shows th... show full transcript
Worked Solution & Example Answer:12. (a) (i) Write the dental formula for an adult human - Leaving Cert Biology - Question 12 - 2006
Step 1
Write the dental formula for an adult human.
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Answer
The dental formula for an adult human is typically expressed as:
2-1-2-3 / 2-1-2-3,
where the numbers represent the number of teeth in each quadrant of the mouth:
2 Incisors
1 Canine
2 Premolars
3 Molars.
Step 2
Give a function of any one of the teeth indicated in the dental formula.
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Answer
One function of the molars (3 per quadrant) is to grind and chew food, facilitating the digestive process. They have a flat surface that is well adapted for breaking down tough food materials.
Step 3
Identify A, B, C, D and E in the diagram.
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A = Duodenum (small intestine)
B = Liver
C = Stomach
D = Pancreas
E = Colon (large intestine)
Step 4
What is an amylase? Name a site of amylase action. What is the approximate pH value at this site?
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Answer
Amylase is an enzyme that breaks down starch into simpler sugars. A site of amylase action is the mouth or duodenum (small intestine), where the approximate pH is around 7 to 9.
Step 5
Give one function of symbiotic bacteria in the human digestive system.
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Symbiotic bacteria in the human digestive system help in digestion or produce vitamins, and they can also kill harmful bacteria, contributing to overall gut health.
Step 6
State a benefit of dietary fibre.
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A benefit of dietary fibre is that it aids in peristalsis, which prevents constipation and promotes regular bowel movements.
Step 7
What is meant by absorption?
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Absorption refers to the movement of digested nutrients across the intestinal wall into the bloodstream or lymphatic system.
Step 8
Where in the digestive system are the products of digestion absorbed? State one way in which this part of the system is adapted for absorption.
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The products of digestion are absorbed mainly in the small intestine (especially the ileum). This part of the system is adapted for absorption due to its large surface area, which is increased by villi and microvilli.
Step 9
Name the blood vessel that joins the part of the digestive system that you have named in (i) to B in the diagram.
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The blood vessel that joins the ileum (small intestine) to B (liver) is the hepatic portal vein.
Step 10
In which part of the digestive system is water absorbed? Give another function of this part of the digestive system.
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Water is absorbed in the colon (or rectum). Another function of the colon is to store faeces before expulsion.
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