3.3 Digestion and absorption Flashcards

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1
Q

Define digestion

A

The hyrdolysis of large, insoluble molecules into smaller molecules that can be absorbed across cell membranes

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2
Q

Which enzymes are involved in carbohydrate digestion?

A
  • Amylase
  • Maltase
  • Sucrase
  • Lactase
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3
Q

Where are the enzymes involved in carbohydrate digestion found?

A
  • Amylase in mouth
  • Maltase, sucrase, lactase in the membrane of the small intestine
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4
Q

What are the substrates and products of the carbohydrate digestive enzymes?

A
  • Amylase –> starch into smaller polysaccharides
  • Maltase –> maltose into 2x glucose
  • Sucrase –> sucrose into glucose and fructose
  • Lactase –> lactose into glucose and galactose
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5
Q

Where are lipids digested?

A

The small intestine

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6
Q

What needs to happen before lipids can be digested?

A

They must be emulsifies by bile salts produced by the liver. This breaks down large fat molecules into smaller, soluble molecules called micelles, increasing surface area

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7
Q

How are lipids digested?

A

Lipase hydrolyses the ester bond between the monoglycerides and fatty acids

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8
Q

Which enzymes are involved in protein digestoin?

A
  • Endopeptidases
  • Exopeptidases
  • Dipeptidases
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9
Q

What is an endopeptidases role?

A

Break between specific amino acids in the middle of a polypeptide

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10
Q

What is an exopeptidases role?

A

Break between specific amino acids at the end of a polypeptide

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11
Q

What is a dipeptidases role?

A

Break between dipeptides into amino acids

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12
Q

How are certain molecules absorbed into the ileum despite a negative concentration gradient?

A

Co-transport

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13
Q

Which molecules require co-transport?

A

Amino acids and monosaccharides

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14
Q

Explain how sodium ions are involved in co-transport

A

Sodium ions are actively transported out of the cell into the lumen, creating a diffusion gradient. Nutrients are then taken up into the cells along with sodium ions

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15
Q

Why do fatty acids and monoglycerides not require co-transport?

A

The molecules are non-polar, meaning they can easily diffuse across the membrane of the epithelial cells

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