Transcript Topic 6_1 Digestion

Digestion




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
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

MOLECULAR
FORM INGESTED




Protein
Triglycerides
poly, di and
monosaccharides
DNA and RNA
FORM AFTER
DIGESTION




Amino acids
Glycerol and fatty
acids
Monosaccharides
Nucleotides
 Breaking
food into
smallest components
 ex. albumin in egg whites
contain amino acid serine
needed in pancreas to
produce insulin
 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
 accessory
organs outside
of but connected to the
alimentary canal
 these organs produce
digestive enzymes
 Liver, pancreas, gall
bladder, salivary glands,
etc.


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
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)
Neutral (pH 7)
Be able to draw and label!!!!!!!!!!
 Mouth-
amylase (in saliva)
 mechanical digestion of all food
(teeth chewing & grinding)
 chemical digestion of
carbohydrates begins
esophagus- passageway to
stomach
smooth muscle- peristalsis
 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)
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)
Contain capillaries and
lacteals (small vessel
of the lymph system)
lacteal
Small molecules
taken into capillaries,
except fatty acids
which are absorbed
into lacteals
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


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
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?
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.