Biology 12
Digestion Practice Test - KEY
Section 1: Digestion Structures and Functions
1.
The exit from the stomach is the
a) cardiac sphincter
b) epiglottis
c) pyloric sphincter
d) uvula
2.
Heartburn could be caused by a poorly working
a) uvula
b) pyloric sphincter
c) cardiac sphincter
d) epiglottis
3.
The structure which prevents food going down the airway is the
a) uvula
b) epiglottis
c) cardiac sphincter
d) tonsils
4.
In the digestive process, where is physical digestion first started?
a) mouth
b) esophagus
c) stomach
d) small intestine
5.
Where may peristalsis not occur?
a) esophagus
b) epiglottis
c) small intestine
d) stomach
6.
E. coli bacteria, found in the colon, are useful to humans because they
a) lubricate the intestines
b) compact fecal matter
c) increase the surface area for digestion
d) produce vitamins, amino acids and other growth factors
7.
Identify the structure labeled X in the diagram.
a) Bile duct
b) duodenum
c) cardiac sphincter
d) pyloric sphincter
8.
Blockage of the bile duct would most likely
a) decrease bile production
b) affect the digestion of fats
c) raise the pH of the duodenum
d) decrease the quantity of feces
9.
A major function of the colon is to
a) digest fats
b) absorb water
c) store protein
d) secrete hormones
Name:
10.
Which number represents the organ that secretes amylase?
a) 2
b) 3
c) 5
d) 6
11.
Digestive secretions from the liver and pancreas empty into the
a) colon
b) stomach
c) duodenum
d) esophagus
12.
During swallowing, which process does not occur?
a) secretion
b) digestion
c) breathing
d) peristalsis
13.
The function of saliva is to
a) digest fats & proteins
b) lubricate food and digest starch
c) stop the trachea from drying out
d) kill bacteria by acidic medium in mouth
14.
Surgical removal of the gall bladder would affect the digestion of
a) fats
b) proteins
c) minerals
d) carbohydrates
15.
What part of the digestive system secretes hydrochloric acid?
a) mouth
b) stomach
c) colon
d) small intestine
16.
During swallowing food is prevented from entering the trachea by
a) epiglottis
b) soft palate
c) cartilage rings
d) mucus in larynx
17.
The function of the stomach is to
a) store food and digest proteins
b) store nutrients and produce bile
c) absorb water and produce vitamins
d) absorb water and digest carbohydrates
18.
A ring of muscle that controls what enters and leaves different parts of the digestive system.
a) sphincter
b) epiglottis
c) appendix
d) gall bladder
19.
Which structure prevents food entering the nasal cavity?
a) epiglottis
b) pyloric sphincter
c) uvula
d) soft palate
20.
What is the name of the substance that emulsifies fat?
Bile
21.
What is the name of the substance which helps to neutralize stomach acid in the duodenum?
Sodium bicarbonate
22.
What structure stores bile in the body until it is needed?
Gall bladder
23.
Describe the role of the following structures during swallowing
a) soft palate
Close nasal cavity
b) uvula
“Kicker” – deflects large food – provides a gag reflex
c)
epiglottis
Closes trachea during swallowing
24.
Explain 3 functions of the colon (large intestine) (including E. coli bacteria) (3 marks)
Reabsorb water (into blood)
E. coli bacteria - help break down food, produce vitamins & amino acids
Rectum - compact feces
25.
Explain how the anatomy (structure) of the small intestine allows it to:
a) digest food
• Intestinal glands produce intestinal juice (enzymes)
• Large surface area to allow for more time for digestion
b) absorb nutrients
• Villi increase surface area
• Cells lining villi have microvilli to increase surface area
• Cells lining villi have many mitochondria to produce ATP for active transport of
nutrients into blood
• Capillaries (blood vessels) near surface of villi
• Lacteals inside villi absorb fats
c)
carry out peristalsis
• Esophagus, stomach and small intestine wrapped with smooth muscle
• Smooth contracts to push food along digestive tract
26. Label the following diagram.
Section 2: Enzymes
27. Which of the following enzymes are produced by more than 1 gland in the digestive system?
a) pepsin
b) trypsin
c) lipase
d) amylase
28.
Trypsin and pepsin both act upon
a) fats
b) carbohydrates
c) proteins
d) disaccharides
29.
The end product of the action of amylase is
a) sucrose
b) amino acids
c) fatty acids
d) maltose
30.
Trypsin works in the
a) mouth
b) stomach
c) liver
d) duodenum
31.
Peptidases work in the
a) stomach
b) mouth
c) esophagus
d) small intestine
32.
The enzymes of the digestive system act by
a) oxidation
b) hydrolysis
c) dehydration
d) reduction
33.
Which of the following helps in the digestion of lipids?
a) bile
b) pepsin
c) amylase
d) HCl
34.
Which of the following helps in the digestion of starch?
a) bile
b) pepsin
c) amylase
d) HCl
35.
Which of the following helps in the digestion of protein?
a) bile
b) pepsin
c) amylase
d) lipase
36.
Which of the following chemical conditions produces the active enzyme pepsin?
a) neutral
b) high pH
c) acidic
d) alkaline
37.
Enzymes that work on all classes of foods are secreted by the
a) stomach
b) pancreas
c) small intestine
d) liver
38.
Which of the digestive enzymes is incorrectly matched to its substrate?
a) trypsin-nucleic acid
b) pepsin - protein
c) lipase - fat
d) amylase - starch
39.
Which of the following enzymes is correctly matched with its site of production?
a) trypsin-salivary glands
b) lipase-stomach
c) amylase-pancreas
d) pepsin- liver
40.
Trypsin works best in
a) pH 3
b) pH 7
c) pH 8
d) pH 2
41.
Amylase will work in
a) pH 3 or 4
b) pH 7 or 8
c) pH 5 or 6
d) pH 4 or 5
42.
After chewing a starchy food for a few minutes, a person experiences a sweet taste in the
mouth. Which of the following enzyme-substrate complexes was involved?
a) amylase-carbohydrate (polysaccharide)
b) trypsin-peptide
c) lipase-triglyceride
d) maltase-glucose
43.
What would occur if sodium bicarbonate ions were not present in pancreatic juice?
a) bile would not emulsify fat
b) trypsin would not break down proteins
c) protein digestion in stomach would not occur
d) water would not be reabsorbed in colon
44.
Which enzyme catalyzes the following reaction? fat
a) lipase
b) pepsin
c) maltase
d) trypsin
45.
Starch digestion begins in the
Mouth
The other place starch digestion occurs is in the
Small intestine
Which food type is the only one which is digested in the stomach?
Protein
Name the group of enzymes which act on peptides in the small intestine?
Peptidases
What chemical is needed to change pepsinogen into pepsin? Where does this happen?
Hydrochloric acid (HCl) in the stomach
46.
47.
48.
49.
50.
fatty acids
An experiment was conducted to study the ability of molecules to pass through a membrane
selectively permeable to nutrient building blocks.
Steps:
1. Three (3) labeled thistle tubes were prepared with the contents shown in the diagrams below.
2. Each tube was placed into a beaker of distilled water at 37 ° C for 1 hour.
3. After 1 hour, the H2O in the beaker was tested for the presence of various molecules.
Identify the molecules found in each beaker after the end of 1 hour. Give an explanation for your choice.
Experiment
Explanation
The protein in the egg white would not be digested
b/c pepsinogen needs an acidic environment to be
come activated pepsin. Therefore, there would be
no change in the contents of the beaker or thistle
tube.
Lipase would digest the fat in butter to produce
fatty acids. Therefore, fatty acids would diffuse
into the beaker (out of the thistle tube)
The lipase would be denatured by the extreme acid
conditions (HCl). The shape of the lipase enzyme
would be altered and the active site of the lipase
enzyme would be altered. The fat substrate would
not be able to “fit” into the active site of the lipase
enzyme and so the fat would not be broken down
(digested). There would be no change in the
contents of the beaker or thistle tube.
51. In an experiment designed to test the effectiveness of two protein digesting enzymes (X and Y)
under various conditions, the following procedure was carried out.
• Identical protein substrates were placed in a series of numbered beakers
• The temperature and pH of the beakers was varied
• Similar amount of enzyme (X & Y) were added to the beakers & resulting activity was observed (the
contents of the beakers were checked after 2 hours.
Table 1: Product levels resulting from the
action of enzyme X
Table 2: Product levels resulting from the
action of enzyme Y
a)
Identify enzyme X
Pepsin
b) Identify enzyme Y
Trypsin
c) What is the common product of these enzymatic reactions?
Peptides
d) Where in the body does each enzyme function best?
Pepsin – in the stomach
Trypsin – in the small intestine
e)
f)
How would the amount of product change if a heavy metal such as lead were added to beaker
1 at the start of the experiment? Give an explanation for your answer.
The amount of product would decrease b/c
The heavy metal would denature the enzyme
Altering its active site and the substrate would not “fit”
There would be less digestion of the substrate and less product formed.
Which experiment condition appears to be the least suitable for the functioning of both
enzymes?
62 ° C - extreme temperatures denature the enzymes
Section 3: Absorption of Nutrients
52. Fatty acids and glycerol are first absorbed into the
a) blood capillaries of the villi
b) blood capillaries of the stomach
c) lacteals
d) lymph veins
53.
Which of the following are absorbed by lacteals?
a) starches
b) fatty acids
c) amino acids
d) monosaccharides
54.
Absorption of digested food products occurs largely in the
a) liver
b) stomach
c) large intestine
d) small intestine
55.
After products of digestion are absorbed, they travel through the blood stream to the
a) pancreas
b) liver
c) colon
d) lungs
56.
What is the only category of carbohydrates which can be absorbed by the intestinal villi?
Monosaccharides
57.
When fatty acids pass through the walls of the villi they are first drained away by the
Lacteals
58.
Into what substances must all proteins be converted before they can be absorbed into the blood
stream?
Amino acids
59.
To be absorbed into lacteals, fats must be changed to
Fatty acids
Section 4: Liver Functions
60. Damage to the liver may impair which function?
a) produce bile
b) convert glycogen to glucose
c) detoxifying blood
d) all of the above
e) none of the above
61.
Describe each of the following functions of the liver.
a) Produce bile
Produce bile to emulsify fats added to duodenum
b) Detoxification of drugs and alcohol
Breakdown drugs and alcohol with enzymes
c) Homeostasis of blood glucose – after a meal
(After a meal - Convert excess glucose to glycogen)
d) Homeostasis of blood glucose – between meals
(Between meals - Convert glycogen to glucose)
e) Production of NH3 (ammonia) and urea
Liver uses amino acids (from proteins in the body like muscle) as emergency glucose – this
produces the waste products NH3 which the liver converts to urea (a less toxic form that can
be excreted from body in sweat and urine)
Section 5: Pancreas, Insulin, Glucagon and Blood Glucose
62. Where is insulin produced? Where is glucagon produced?
Both hormones produced in the pancreas
63.
Insulin and glucagon are examples of secreted proteins that travel through the blood stream and are
classified as?
Hormones
64.
When would insulin be secreted? List 3 functions of insulin.
After a meal when blood glucose levels rise
Functions of Insulin
Lower blood glucose levels
Increase glucose uptake by cells
Increase glycogen formation in liver and muscles
Increase amino acids taken in by muscles (help build muscles)
Increase storage of fat in fat cells
65.
When would glucagon be secreted? List 3 functions of glucagon.
Between a meal when blood glucose levels fall
Functions of glucagon
Raise blood glucose levels
Decrease glucose uptake by cells
Convert glycogen in liver and muscles to glucose
Decrease amino acids taken in by muscles (amino acids used for emergency glucose)
Minimal effect of fat – some fat will be used as an energy source
66.
What are negative feedback cycles?
A mechanism to maintain homeostasis.
A problem in the body requires a solution.
The solution ‘fixes’ the problem (brings condition back to normal = homeostasis)
Therefore, the solution can be turned off (inhibited)
67.
Give an example of a negative feedback cycle in the homeostasis of blood glucose.
After a meal – blood glucose levels rise
Pancreas releases insulin (solution)
Insulin causes blood glucose levels to drop
Insulin can be shut off (inhibited)
Between meals – blood glucose levels drop
Pancreas releases glucagon (solution)
Glucagon causes blood glucose levels to rise
Glucagon can be shut off (inhibited)