Download Assignment 1

5. (a)
What is meant by deamination?
(b) Draw the chemical
(c)
structure for a typical amino acid. Use 'R' to denote the side chain.
The schematic diagram below shows the process of deamination. Fill in the blank in the boxes
provided.
amino group
*
'*
amino acids
glycogen
6. (a)
What is detoxification?
(b)
Name the enzyme that is responsible for breaking down alcohol
(c)
What is the name of the product of alcohol when it is broken down by this enzyme?
(d) Excessive
alcohol consumption can lead to cirrhosis. What is cirrhosis?
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a
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Topical Practice Questions 5
Section A: Multiple-Choice Questions
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Which secretion, released into the alimentary canal, contains no enzymes but speeds up fat
digestion?
A
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Danyal Education
Animal Nutrition Assignment 1
pancreatic
juice B
intestinal
juice C saliva
D
bile
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2.
The diagram shows a section through a villus
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M
What is the function of structure M?
A to absorb glucose
C
to transport fats
B
D
to absorb amino acids
to transport blood
Questions 3 and 4 refer to the diagram of part of the human alimentary canal.
A
B
C
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D
ln which region are most glucose absorbed into the bloodstream?
4.
Which region produces an enzyme which works best at pH 1?
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3.
5
Asample of milk is mixed with lipase. After half an hour, the milk had become more acidic. What
were the substrate and product in this reaction?
A
B
C
D
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substrate
fats
fats
proteins
proteins
product
amino acids
fatty acids
amino acids
fatty acids
Which region of the alimentary canal has the greatest internal surface area?
A duodenum B colon
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C ileum
D
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stomach
BIOLOGY O Level Conceptual Learning |
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Which part of the alimentary canal is most acidic?
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A stomach
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B mouth
C
D
ileum
colon
Which of the following substances would be increased in production in the liver when the diet
contains large amounts of proteins?
I
C glycerol
B urea
Which one of the following is an enzyme secreted by the pancreas?
L0.
B pepsin
C
D
lipase
maltose
maltase
tio
A insulin
D
n
A glucose
The diagram shows some food moving along the alimentary canal by peristalsis
z
food bolus
l E
du
ca
I
direction of
movement
of food
wall of alimentary canal
ln which state are the muscles in the wall of the alimentary canal at point Z?
A
circular muscles
longitudinal muscles
relaxing
relaxing
relaxing
contracting
D
contracting
contracting
relaxing
contracting
ny
a
B
C
Section B: Short Answer Questions
L.
The diagram below shows part of the human digestive system
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P
a
S
R
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A patient has Structure P removed. A young medical student insisted that fats in this patient's
diet could no longer be emulsified. ls he correct? What should have been the correct
consequence?
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Will there be any effect of removing Structure R? Explain.
(d) Patients whose Structure
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(c)
part of Structure S.
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(b) Explain the probable effect of removing
on
(a)
[2m]
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Q is diseased usually require a transplant or they will die. Give three
reasons why structure Q is so
[3m]
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important.
2.
Examine the diagrams below and answer the following questions.
Animal
stomach
A
Animal B
stomach
cecum
ANUS
C
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BIOLOGY O Level Conceptual Learning I
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Animal A is a carnivore while Animal B is a herbivore.
(i)
State one main structural difference, other than the presence of the cecum, in the
alimentary canals of these two
(ii)
(b)
animals.
[1m]
Suggest one reason for this difference
[1m]
The following diagram shows the alimentary canal of a lizard.
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A
n
(a)
D
F
mouth
anus
E
C
Based on your knowledge of the digestive system,
State which of the organs A-F would never contain undigested food.
[1m]
(ii)
[6m]
(i)
Name Organs A, B and C. State one function of each organ.
Organ A:
Organ B:
Organ C:
(c)
B
Animals have evolved
a
one-way movement of food substances through their digestive
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animals.
[1m]
The following diagram shows the liver with some associated vessels.
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3.
ny
a
system.
Suggest a reason why this is advantageous to the
I
liver
a
F
direction of
blood flow
R
small
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(a)
ldentify P, Q and R
[3m]
a
P
R
(c) (i)
P.
Account for this difference in concentration of materials.
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(ii)
A refugee has not eaten in a day. Compare the types and concentrations of materials in
blood vessels Q and
[2m]
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(b) (i)
[2m]
An alcoholic man felt unwell and consulted his doctor. He presented the following
symptoms:
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L. Oily and pale coloured faeces
2. Poor blood clotting
(ii)
4.
Suggest a possible reason for each of his symptoms
[4m]
Describe what might happen if he continues to drink excessively.
[2m]
The diagram below shows a representation of a polypeptide formed from various amino acids.
Specific enzymes hydrolyse specific bonds between amino acids.
Legend
amino acid 2
amino acid 1
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amino acid 3
a
amino acid 4
(a) How many enzymes would be required to split up the polypeptide
into 10 amino acids? [1m]
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BIOLOGY O LevelConceptual Learning | $$
(b)
curdled.
[2m]
Read the following passage carefully,
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5.
A baby regurgitates soon after he drinks some milk. Explain why the milk that comes up appears
Aside from a little amylase secrefed by the salivary glands, enzymatic digestion really begins
with the secretion of pepsin in the stomach. Pepsin, a carbohydrase, is excepfionally active at
a basic pH. lt is actually secreted as a pro-enzyme, called pepsinogen, which is activated by
the salivary amylase found mixed with the food. The main function of the stomach is to liquefy
food so that it can pass through the body quickly.
Liquefied foodstuffs, now called chyle, flow into the small intestine. Here they will be exposed
fo secreflons from the pancreas and the gall bladder. The principal enzymes secreted by the
pancreas include:
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Profeases like trypsin, which unlike pepsin, are fully activated upon secretion into the
small intestine
Pancreatic lipase, which hydrolyses fats to yield fatty acids and monosaccharides
Amylase, which digests starch, into monosaccharides like maltose and sucrose
Bile is produced mainly by the gall bladder while excess bile is stored in the liver. Bile is rich in
blle sa/fs and it is critical in the digestion of both fats and proteins. lt emulsifies fats so enzymes
such as proteases can act on it.
List the errors that you can spot, pertaining to facts, concepts or interpretation. For each error,
it.
[13m]
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describe why you consider it to be incorrect and how you would correct
Section C: Free Response Questions
l-. (a) Describe the digestion of a piece of bread from the time it enters the mouth until digestion is
completed.
[6m]
(b) How and where is the end product in (a) taken into the blood and how is it transferred to the
liver?
[4m]
(c) A patient has pancreatic cancer that has spread to his liver, so both organs are now not
functioning well. Describe the implications this might have on the storage of carbohydrates in
his
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body.
[4m]
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