Year 11 Human Biology
Nutrient Procurement
Chapter 5 Text Questions - Solutions
REVIEW QUESTIONS
1. Difference between mechanical and chemical
digestion.
Mechanical is the physical breakdown of the food. Eg
tearing, ripping, dissolving.
Chemical is where enzymes are used to chemically break
the food down. eg Amylase. Breaking chemical bonds.
2. (a) Why is digestion necessary for some compounds?
Because their molecules are too large to be absorbed into
the bloodstream.
(b) What compounds in foods have to be chemically
digested?
Carbohydrates, protein, lipids, nucleic acids
(c) What compounds don't have to be chemically
digested?
Glucose, fibre, water and vitamins.
3. (a) Parts of the digestive system.
Mouth, tongue, pharynx, oesophagus, liver, stomach, small
intestine, large intestine, pancreas, rectum, anus, gall
bladder, bile duct.
(b) Which aren't the alimentary canal?
Teeth, tongue, liver, pancreas, gall bladder. (These are
associated organs)
4. Describe how the structure is suited to the following
functions.
(a) Ingestion of food
Mouth cavity holds the food whilst it's chewed.
(b) Movement of food along the canal.
The canal is made up of 4 layers with circular and
longitudinal muscle to push the food along. Peristalsis.
(c) Mechanical Digestion of food.
The teeth are sharp, the tongue and muscles of the
alimentary canal churn the food.
(d) Chemical Digestion of food.
Secrete enzymes and gastric juices from the lining of the
canal and associated organs. Large surface area so that
chemical digestion can happen more thoroughly.
(e) Absorption of food.
The villi have a large surface area and the small intestine is
long in length.
(f) Elimination of indigestible material.
The rectum holds the material and it's then passed out
through the anus.
5. The structure of each of the 4 types of teeth &
their function.
Each jaw…
4 x Incisors - chisel sharp for biting and cutting.
2 x Canines - Conical shape for tearing
4 x Pre-molars - Broad crowns with rounded cusps for
grinding.
6 x Molars
6. Diagram of a tooth.
See page 44 & student handout.
6. Functions of saliva.
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Lubricates the mouth & food
Dissolves food so taste receptors can be stimulated.
Form Bolus
Amylase breaks down starch, chemical digestion.
Contains anti-bodies that kill bacteria.
7. Explain the function of the following:
(a) Gastric Juice:
Chemical digestion in the stomach.
1. HCl,
2. pepsinogen,
3. water.
(b) Bile:
Emulsification of fats (droplets)
(c) Pancreatic Juice:
Digestion of all of the 4 main organic compounds.
(d) Intestinal Juice:
Digestion of carbohydrates, proteins and lipids.
Intestinal glands in the wall of the small intestine.
9. What gives the small intestine its large surface
area?
The folds of the intestine and the numerous villi.
10. (a) Differences in absorption of fatty acids &
glycerol compared to others.
Fatty acids and glycerol are absorbed by diffusion, the
others by active transport. Fatty acids and glycerol
absorbed into lacteals not capillaries.
(b) Differences in absorption of water compared to
monosaccharides. (glucose)
Water by osmosis in the villi.
11. What happens to substances absorbed in the:
(a) Capillaries
Carried to the portal vein.
(b) Lacteals
Transported in the lymphatic system…lipids.
12.
(a) The defecation process.
The semi-solid material is pushed into the rectum by
peristalsis. The rectum's stretch receptors are stimulated
triggering the defecation process. The sphincter muscles
relax passing the material through.
(b) What materials are contained in the faeces?
Undigested food, cellulose, bacteria, bile pigment, cellular
remains.
13. Difference between constipation and diarrhoea.
Constipation is where defecation is difficult, diarrhoea is
frequent defecation of watery faeces.
11.
(a) Blood supply to the liver.
From two arteries, the Hepatic artery and the hepatic
portal vein.
(b) Functions of the liver
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Blood glucose regulation
Deamination
Fat conversion
Bile formation
Plasma protein formation
Production of blood clotting factors
Storage
Toxin and hormone breakdown
Heat production
APPLY YOUR KNOWLEDGE:
1. Why do baby's contain rennin, where adults don't?
Because babies have more milk protein compared to adults.
2. (a) What are Vestigial Organs?
Unused organs
(b) Wisdom Teeth & appendix.
• Wisdom Teeth =
• Appendix = Cellulose digestion
3. Would a person be able to swallow upside down?
Yes due to peristalsis pushing the food towards the
stomach.
4. A Meal of sausages & fried potato chips
 Sausages & Protein by pepsinogen
 Fat by lipase
 Potato by amylase.
5. The dental formula of the Roo Boy.
Molars about the same.
Incisors have 3 on top for cutting the grass.
No canines for tearing as their herbivores.
5. Why does digestion occur in 3 places?
So more digestion can occur and it takes a long time to
break food down.
7. Explain why the small intestine has a larger surface
area than the
large intestine.
Because it's folded and longer than the large intestine so
more absorption can occur.
6. (a) What does enzyme specific mean?
They will act on one substance.
(b) Examples
Amylase only breaks down starch. etc