MYTUTOR SUBJECT ANSWERS

178 views

What are the main parts of the digestive system, and how are they involved in digestion?

The main parts of the digestive system are the...

- mouth

- oesophagus

- stomach

- liver

- gall bladder

- pancreas

- small intestine

- large intestine

There are three main enzymes involved in digestion:

Amylase:

- produced by the salivary glands in the mouth, the pancreas, and the small intestine

- catalyses the breakdown of starch into sugars

Lipase:

- produced in the pancreas and small intestine

- catalyses the breakdown of lipids (fats and oils) into fatty acids and glycerol

Protease:

- produced in the stomach, pancreas, and small intestine

- catalyses the breakdown of proteins into amino acids

The process of digestion is as follows:

In the mouth:

1. In the mouth, the salivary glands secrete salivary amylase. This enzyme begins to break down large starch molecules into smaller sugar molecules.

2. The food is swallowed, and travels down the oesophagus into the stomach.

In the stomach:  

3. The stomach produces hydrochloric acid. This establishes a low pH, which is the optimum pH for the activity of the protease enzymes. These enzymes catalyse the breakdown of proteins to amino acids.

The role of the liver, gall bladder, and pancreas:

4. The liver produces bile, which is stored in the gall bladder.
5. The pancreas produces pancreatic amylase, protease, and lipase.

In the small intestine:

5. Bile is released from the gall bladder into the small intestine. The bile neutralises the acid that was added to the food in the stomach, and establishes alkaline conditions in the small intestine, which allow the enzymes in the small intestine to work most effectively.
6. Amylase, protease, and lipase from the pancreas break down large, insoluble molecules into small, soluble molecules (see section on digestive enzymes).
7. The small, soluble molecules are absorbed by cells in the lining of the small intestine.

In the large intestine:
8. Water is absorbed from undigested food, to produce faeces.

Heather D. GCSE Biology tutor, GCSE Chemistry tutor, GCSE French tuto...

5 months ago

Answered by Heather, a GCSE Biology tutor with MyTutor


Still stuck? Get one-to-one help from a personally interviewed subject specialist

187 SUBJECT SPECIALISTS

£18 /hr

Georgia C.

Degree: English (Bachelors) - St. Andrews Unversity University

Subjects offered: Biology, Science+ 5 more

Biology
Science
Maths
Geography
English Literature
Chemistry

“I am currently studying English at St Andrews, and have always enjoyed and been passionate about reading. I have experience in tutoring in several different areas over a wide range of ages. Within the sessions, I think it is important ...”

£18 /hr

Polly G.

Degree: BSc Geography (Bachelors) - Bristol University

Subjects offered: Biology, Geography+ 2 more

Biology
Geography
Economics
Art

“About Me: I am currently studying Geography at The University of Bristol, I grew up in London and attended Latymer Upper School. I chose Geography because of my interest in cultures, societies and communities around the world, my A Le...”

£18 /hr

Madhangi P.

Degree: MBBS (Bachelors) - Newcastle University

Subjects offered: Biology, Maths+ 3 more

Biology
Maths
Chemistry
.UKCAT.
-Medical School Preparation-

“Hey Guys, I am Maddy, a third year medical student at Newcastle University and I would be interested in teaching Biology...”

About the author

£18 /hr

Heather D.

Degree: Medicine (Bachelors) - Edinburgh University

Subjects offered: Biology, French+ 3 more

Biology
French
Chemistry
-Personal Statements-
-Medical School Preparation-

“About me: I am a first-year medical student at Edinburgh University. As such, I take a strong interest in many areas of science, particularly those relating to biology and chemistry. I hope that through our sessions you will develop a...”

MyTutor guarantee

You may also like...

Other GCSE Biology questions

Explain the process of eutrophication.

What is the difference between a recessive and dominant allele?

How does evolution occur by natural selection?

What is the difference between an artery and a vein?

View GCSE Biology tutors

Cookies:

We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok