Sec 3 Biology Nutrition in Humans topical questions

Place these processes in order: assimilation, ingestion, egestion, digestion, absorption.

For fat digestion in the small intestine, name the enzyme, its substrate and its end-products.

State the functions of the colon and of the rectum.

Where is amylase made, where does it act, and what does it produce?

Name the organ that produces bile and the organ that stores it before release.

Describe how peristalsis moves food along the alimentary canal.

Explain how three structural features of a villus are adapted to absorption.

Trace a molecule of starch from the mouth to the liver, naming every enzyme and vessel involved.

Explain why the liver deaminates excess amino acids and what it produces.

Identical starch samples are digested by the same volume of amylase: at pH 6 the iodine end-point arrives after 8 minutes; at pH 2 no end-point appears within 30 minutes. (a) Calculate the rate of digestion at pH 6. (b) Explain the result at pH 2.

Trace the fat in a creamy meal from the duodenum to the body’s fat stores, naming the roles of bile, lipase and the lacteal on the way.

Blood entering the hepatic portal vein after a heavy carbohydrate meal carries glucose at 2.1 g/dm³, compared with 1.4 g/dm³ at rest. Calculate the percentage increase, and describe how the liver responds to the extra glucose.

Lipase digests 2.0 g of emulsified fat in 10 minutes, but only 1.0 g of unemulsified fat in the same time. Calculate both rates and explain the difference.

Explain how the liver keeps the body supplied with glucose between meals and after a sugary meal.

A driver’s reaction times are 0.25 s sober and 0.40 s after four drinks. Calculate the percentage increase and explain the biological reason and one social danger.

Explain how long-term heavy drinking damages the liver, and link that damage to two liver functions whose loss would harm the whole body.

Plan an investigation to show that bile increases the rate at which lipase digests fat. State the two set-ups, the variables that must be controlled, how the rate would be measured, and the expected result.

After a glucose-rich meal, samples from four vessels read: oesophagus 1.0 g/dm³, hepatic portal vein 2.1 g/dm³, hepatic vein 1.3 g/dm³, and the lacteal — negligible glucose but abundant fat. Explain each value.