Can you sort out the statements into True and False? Carbohydrates, proteins and fats are all made up of carbon, hydrogen, nitrogen and oxygen.
Fats are made up of smaller units called amino acids Starch is a large carbohydrate molecule
Proteins are made up of one or more glucose molecules
Proteins are important for the growth and repair of cells
Starch molecules can be broken down by amylase.
Can you name the 2 different ways we breakdown food in our bodies? 1. Mechanical Digestion -teeth
2. Chemical Digestion -enzymes -bile -stomach acid
1. Parts of The Alimentary Canal
The alimentary canal (or gut) is the tube within the body through which food passes and is processed in various ways
mouth
salivary glands oesophagus
liver stomach pancreas large intestine small intestine anus
2. Role of the Mouth Teeth assist the mechanical breakdown of food Saliva is mixed with food during chewing Saliva contains the enzyme amylase which starts the digestion of food Salivary gland Salivary gland
Salivary gland
Saliva contains mucus that keeps the mouth moist and lubricates food for easier swallowing
3. Muscles of the Alimentary Canal • Food has to be kept moving along the alimentary canal whilst being mixed with various juices • These actions are brought about by muscles in the walls of the canal over which a person has little or no conscious control
3. Peristalsis The squeezing action of muscles that is used to move food along the alimentary canal
http://www.lionden.com/peristalsis.htm
Digestive Enzymes • What do the following enzymes breakdown? • What do they break the large moleculs down into? • Amlyases • Lipases • Proteases
Digestion ‘the breakdown of large insoluble molecules into soluble molecules’
Digestion and Digestive Juices Saliva
GASTRIC JUICE Bile
PANCREATIC JUICE
INTESTINAL JUICE
Sites of production of main digestive juices Site of digestive juice production Mouth
Main digestive juice produced Saliva
Stomach
Gastric juice
Liver
Pancreas
Bile (breaks down big fat droplets into little fat droplets Pancreatic juice
Small Intestine
Intestinal juice
Digestion and Digestive Juices SALIVA •Salivary amylase
GASTRIC JUICE Bile
•Hydrochloric acid •Pepsin (protease)
PANCREATIC JUICE
INTESTINAL JUICE •Pancreatic lipase
In the Mouth… Salivary amylase
Starch
maltose
• Broken down into glucose later by other amylases
In the stomach
pepsin
Protein
peptides
Broken down into amino acids later by other proteases
In the pancreas….
Pancreatic lipase
Fats
fatty acids and glycerol
After all the digestive enzymes have done their work… • Glucose
• Amino acids • Fatty acids • Glycerol
Finish the sentence…. • Something new I learnt today was….. • Something I found difficult to understand was… • The thing I need to revise from today’s lesson is…
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