1. TOPIC 6.1
Digestion

2. Series of events in order:
Ingestion- eat the food
Digestion- series of chemical rxs to convert food to smaller molecules
Absorption- small molecules are absorbed through the cells of your digestive system into blood or lymphatic vessels
Transport- circulatory system delivers the small molecular nutrients to body cells

3. DIGESTION process of making food absorbable
it must be changed into simpler chemical compounds
nutrients can't be used by the body until they are absorbed into the cells & tissues
They can't be absorbed unless they are small & soluble

4. Before & After Digestion
Molecular Form Ingested
Form After Digestion
Protein
Triglycerides
poly, di and monosaccharides
DNA and RNA
Amino acids
Glycerol and fatty acids
Monosaccharides
Nucleotides

5. Breaking food into smallest components
HYDROLYSIS
Breaking food into smallest components
ex. albumin in egg whites
contain the amino acid serine
needed in pancreas to produce insulin

6. Organs of the Digestive System
You can think of the digestive system as two sets of structures
First set called the alimentary canal:
consists of organs that food passes through directly
it’s a one-way tube with two openings

7. The Second Set
accessory organs outside of but connected to the alimentary canal
these organs produce digestive enzymes
Liver, pancreas, gall bladder, salivary glands, etc.

8. Enzyme-catalysed rxs Increase rate of rx at lower T° (37°C)
Lower energy of activation
Amylase in salivary glands of mouth
Pepsin (a protease) in stomach cells
Lipase in pancreas cells

9. Proteins (polypeptides)
Salivary Amylase
Pepsin
(a protease)
Lipase
Source
Salivary glands
Stomach cells
Pancreas cells
Substrate
Amylose (starch)
Proteins (polypeptides)
Lipids
Products
Maltose & glucose
Amino acids
Glycerol & fatty acids
Optimum pH
Neutral (pH 7)
Acidic (pH 3)
TOPIC 6.1.3

10. Be able to draw and label!!!!!!!!!!
6.1.4

11. Complete Biozone page 269

12. ALIMENTARY CANAL

13. Mouth- amylase (in saliva)
mechanical digestion of all food (teeth chewing & grinding)
chemical digestion of carbohydrates begins
esophagus- passageway to stomach
smooth muscle- peristalsis

14. http://www.youtube.com/watch?v=Q- n_Q0qKXzg&safe=active

15. Stomach Gastric Juices:
Pepsin – protease enzyme
HCl – creates optimium pH for pepsin to be active & helps degrade and breakdown food
Mucus – lines and protects stomach from HCl
mechanical digestion of food (churning of stomach walls)

16. Small Intestines 1st portion called duodenum
Accessory organs secrete juices:
Bile – produced in liver, stored in gall bladder (emulsifies fats)
Trypsin (protease), lipase, amylase and bicarbonate from pancreas
absorption: small soluble nutrients (sugars, amino acids, fatty acids)

17. Villi of Small Intestines - greatly increase surface area for absorption
Contain capillaries and lacteals (small vessel of the lymph system)
lacteal
Small molecules taken into capillaries, except fatty acids which are absorbed into lacteals

18. Inside the Villi
inside are two types of vessels, capillaries & lacteal
the capillaries web around the lacteal
protein & carbohydrates (amino acids & simple sugars) are absorbed by capillaries
lipids (fatty acids & glycerol) are absorbed in the lacteal

19. Circulatory System delivers absorbed molecules to body cells
Nutrient molecules used by cells:
For energy (e.g. glucose)
For buiding larger molecules (e.g. amino acids)
Assimilation= the process of bringing nutrients to a body cell and using it to build larger molecules

20. Large Intestines Contains undigested and unabsorbed food and water
water is absorbed from indigestible wastes (feces)
Also contains naturally occurring bacteria (including E. coli)
Mutualistic relationship-we supply nutrients, water and warm environment and they synthesize vitamin K and maintain a healthy environment in our large intestines
Faeces or solid waste is egested from our body

21. Complete Biozone pages270-275

22. http://www.youtube.com/watch?v=nM 5kMSjBrmw
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23. Complete Biozone page 276
Write the answer beside the clue

24. Two Questions for You:
1. A single sandwich is likely to contain carbohydrates, lipids and proteins. From a biochemical viewpoint, what will happen to each type of molecule on digestion?

25. 2. You ingest a glucose. molecule in the starch of a. breakfast cereal
2. You ingest a glucose molecule in the starch of a breakfast cereal. State as many specific locations as you can for this single glucose molecule from the time it is in your mouth to the time it enters a muscle cell of your right forearm.