digestion Flashcards
7 components for a healthy diet
carbohydrates, fibre, lipids, water, minerals, proteins and vitamins
role and deficiency disease of iron
- forms part of haemoglobin
- anaemia
role and deficiency of calcium
- needed to form teeth and bones
- rickets
role and deficiency of vitamin A
- chemical in the retina, protects the surface of the eye
- night blindness
role and deficiency of vitamin C
- needed for cells and tissues to stick together
- scurvy
role and deficiency of vitamin D
- needed to absorb calcium
- rickets
ingestion
taking food in through the mouth and swallowing
digestion
breaking down large insoluble molecules into smaller more soluble molecules
absorption
movement of smaller soluble molecules into the blood
egestion
passing out undigested food through the anus
assimilation
building larger molecules from the smaller ones in all cells
mechanical digestion
food is broken down by chewing
chemical digestion
saliva is released into the mouth by salivary glands and contains the enzyme amylase
amylase
- made in the pancreas and the salivary glands
- breaks down starch into maltose
peristalsis
wave like contractions that move food through the digestive tract
pepsin
- secreted from the stomach walls
- breaks down protein to peptides
trypsin
- made in the pancreas, secreted to the duodenum
- breaks down proteins to peptides
lipase
- made in the pancreas, secreted into the duodenum
- breaks down lipids to three fatty acids and glycerol
maltase
- secreted from the duodenum wall
- breaks down maltose to glucose
protease
- secreted from the duodenum wall
- breaks down peptides to amino acids
functions of bile
- neutralises the stomach acid
- emulsifies lipids, breaks larger droplets into smaller droplets
where is bile made and stored
- made by the liver
- stored in the gall bladder
how is the small intestine adapted to absorb molecules
- micro-villi increase the SA
- short diffusion distance
- high concentration gradient
describe the experiment that investigates the energy content of a food sample
- measure out 25cm3 of water
- record initial temperature
- record and measure mass of food
- light the food with a bunsen and hold under test tube
- keep re lighting until it cannot be lit anymore
- take final temp of water
- calculate energy content with equation
energy = mass of water x 4.2 x temperature increase
