The Four Stages of Food Processing 14 Digestion: A Closer...
4
The Four Stages of Food Processing • Ingestion is another word for eating. • Digestion is the breakdown of food into molecules small enough for the body to absorb. • Absorption is the uptake of the small nutrient molecules by cells lining the digestive tract. • Elimination is the disposal of undigested materials left over from food. © 2013 Pearson Education, Inc. 14 Digestion: A Closer Look • The dismantling of food molecules is necessary because food molecules are – too large to cross the membranes of animal cells and – different from molecules that make up an animal’s body. © 2013 Pearson Education, Inc. 15 • Mechanical digestion – begins the process and – involves physical processes like chewing. • Chemical digestion is the chemical breakdown of food by digestive enzymes. Digestion: A Closer Look © 2013 Pearson Education, Inc. 16 Figure 22.2 Cheese protein (a polymer of amino acids in a specific sequence) Amino acid monomer Amino acids Human protein Breakdown of protein by human digestive system Absorption of amino acids by cells lining the small intestine; transport via bloodstream to other cells Cells use amino acids from the cheese and other foods to produce new human proteins 1 2 3 17
Transcript of The Four Stages of Food Processing 14 Digestion: A Closer...
The Four Stages of Food Processing
• Ingestion is another word for eating.
• Digestion is the breakdown of food into molecules
small enough for the body to absorb.
• Absorption is the uptake of the small nutrient
molecules by cells lining the digestive tract.
• Elimination is the disposal of undigested materials
left over from food.
© 2013 Pearson Education, Inc.
14Digestion: A Closer Look
• The dismantling of food molecules is necessary
because food molecules are
– too large to cross the membranes of animal cells and
– different from molecules that make up an animal’s body.
© 2013 Pearson Education, Inc.
15
• Mechanical digestion
– begins the process and
– involves physical processes like chewing.
• Chemical digestion is the chemical breakdown of
food by digestive enzymes.
Digestion: A Closer Look
© 2013 Pearson Education, Inc.
16 Figure 22.2
Cheese protein(a polymer ofamino acids ina specific sequence)
Amino acidmonomer
Amino acids
Human protein
Breakdown of proteinby human digestivesystem
Absorption of amino acids by cells lining thesmall intestine; transport via bloodstream toother cells
Cells use amino acidsfrom the cheese andother foods to producenew human proteins
1
2
3
17
Figure 22.2a
Cheese protein(a polymer of amino acids in a specific sequence)
Amino acidmonomer
Amino acids
Breakdown of proteinby human digestivesystem
1
18 Figure 22.2b
Human protein
Absorption of amino acids by cells lining the small intestine; transport via bloodstream to other cells
Cells use amino acids from the cheese and other foods to produce new human proteins
2
3
19
Figure 22.2c 20
• Chemical digestion proceeds via hydrolysis,
chemical reactions that break down polymers into
monomers using water in the process.
• Like most biological reactions, digestion also
requires enzymes.
Digestion: A Closer Look
© 2013 Pearson Education, Inc.
21
Figure 22.3
Enzyme (pepsin)
Enzyme (amylase)
Enzyme (lipase)
Protein
Carbohydrate
Fat
Amino acid
Fatty acidGlycerol
Sugar
H2O
H2O
H2O
H2O
H2O
HOH
HOH
22 Figure 22.3a-1
Enzyme (pepsin)
Protein
H2O
23
Figure 22.3a-2
Enzyme (pepsin)
Protein
H2OAmino acid
HOH
24 Figure 22.3b-1
Enzyme (amylase)
Carbohydrate
H2O
25
Figure 22.3b-2
Enzyme (amylase)
Carbohydrate
SugarH2O
HOH
26 Figure 22.3c-1
Enzyme (lipase)
Fat
H2O
H2O
H2O
27
Figure 22.3c-2
Enzyme (lipase)
FatFatty acid
GlycerolH2O
H2O
H2O
28
![01 Lecture Presentation PC v2 [Read-Only]profwelday.weebly.com › uploads › 2 › 3 › 0 › 0 › 23005790 › lec_01-06...Campbell Essential Biology, Fifth Edition, and Campbell](https://static.fdocuments.us/doc/165x107/5f04d94c7e708231d41003a1/01-lecture-presentation-pc-v2-read-only-a-uploads-a-2-a-3-a-0-a-0-a.jpg)
