Digestion and Enzymes Ch.6

Question 1

What is the tube going from the mouth to the stomach called?

Answer 1

Esophagus

Question 2

Ingestion

Answer 2

Taking food into the alimentary canal

Question 3

Digestion

Answer 3

Hydrolysis of large insoluble food molecules to small soluble food molecules

Question 4

Absorption

Answer 4

The movement of small soluble food molecules (products of digestion) across the cell membrane of the intestine and into the blood stream by diffusion and active transport

Question 5

Egestion

Answer 5

The removal of undigested waste products

Question 6

What two methods of digestion take place in the mouth

Answer 6

Chemical- Enzyme amylase

Mechanical- mouth and teeth

Question 7

Where is amylase found in the body and where is it secreted from

Answer 7

Mouth-secreted by salivary gland.

Small intestine- secreted by pancrease

Question 8

What happens in the Stomach

Answer 8

HCL denatures enzymes, kills pathogens, and provides optimum pH for pepsin (endopeptidase). Stomach muscle walls pummel food

Question 9

What two parts are there to the small intetsting and which comes first?

Answer 9

Duodenum comes first

Ileum second

Question 10

What happens in the duodenum

Answer 10

Digestion continues. Pancreatic juice is secreted from the pancreas through the pancreatic duct. This contains enzymes amylase, lipase and peptidase (exopeptidase).

Question 11

Where is Bile produced, stored and secreted to.

Answer 11

Bile is a alkaline fluid produced by the liver and stored in the gall bladder. It is secreted into the small intestine (duodenum).

Question 12

What is the purpose of Bile

Answer 12

1) neutralise the semi-digested food coming from the stomach so enzymes from pancreas can function at optimum temperature
2) to emulsify lipids into micelles

Question 13

What happens in the Ileum

Answer 13

Absorption occurs

Question 14

How is the ileum adapted for its function

Answer 14

1) large surface area due to villi and micro villi
2) Thin, one cell thick walls
3) Good blood supply

Question 15

Why is there membrane bound enzymes in the cell membrane of the ileum/ small intestine

Answer 15

To completely digest any molecules not yet hydrolyses into its monomers

Question 16

What is the difference between endopeptidase, exopeptidase and dipeptidase

Answer 16

End- Hydrolyses molecules in the middle of the chain.
Exo- Hydrolyses molecules at the end of the chain
Di- is cell membrane bound and hydrolyses dipetides (two amino monomers)

Question 17

Describe how microorganisms make carbon in starch

available to plants.

Answer 17

• releases enzymes;
• to hydrolysis starch to glucose
• Respire product of digestion
• Produce carbon dioxide from respiration

Question 18

What happens in the large intestines?

Answer 18

Water is absorbed

Question 19

What and where does amylase take action?

Answer 19

In the mouth secreted by the salivary gland. It HYDROYLSES the glycosidic bonds in starch to form disaccharide maltose.

Question 20

What do lipids get digested into?

Answer 20

Fatty acids and glycerol

Question 21

Describe the digestion of carbohydrates?

Answer 21

In the mouth the salivary gland secretes amylase. This hydroylses starch into disaccharide maltose. Any remaining starch is turned to maltose by pancreatic amylase in the small instestine.The enzyme Maltase is produced by membrane-bound disaccharidase and further hydroylses the disaccharide into alpha glucose monosaccharide.

Question 22

How are lipids digested?

Answer 22

Bile produced by the liver is secreted into the small intestines and emulsifies lipid into micelles. Lipase produced and secreted from the pancrease hydrolyses the ester bonds in lipids to form fatty acids and monoglycerides.

Question 23

What is a micelle?

Answer 23

Vesicle made of phospholipid bilayer. Digestion occurs in the micelle.

Question 24

What is the purpose of emulsification?

Answer 24

Increases the surface area so lipid more enzymes can act an any given time.

Question 25

How are the products of lipid absorbed?

Answer 25

Micelles fuse with epithelium cell membrane and release the fatty acid and monoglycerides into the cell. The products diffuse into the endoplasmic reticulum and recombine to form triglyceride. It is then associated with cholesterol and lipoproteins to form chylomicrons. Chylomicrons exit by exocytosis and enter lacteal in the villi. Then pass into the blood system.

Question 26

What is Chylomicrons composed of?

Answer 26

Triglyceride, cholesterol and lipoproteins.

Question 27

What is exocytosis?

Answer 27

Substance is transported out of the cell using the cell membrane to from a vesicle around it.

Question 28

What is endocytosis?

Answer 28

Substance are transported into the cell by forming a vesicle around it.

Question 29

How is glucose and amino acids absorbed into the blood?

Answer 29

Na+ ions are actively transported out of epithelial cells and into the blood using a Na/K pump. This lowers the Na+ ion conc in the cell and makes it lower than in the lumen. Na+ ions therefore diffuse into the cell carrying an amino acid/ glucose with it through a channel protein. The glucose/amino acid then diffuses into the blood.

Question 30

What is an organ?

Answer 30

A group of tissues working to perform the same function

Question 31

What is an organ system?

Answer 31

A group of different organs working to perform the same functions.

Question 32

What is a tissue?

Answer 32

A collection of similar cells that perform a specific function

Question 33

What is a cell

Answer 33

The basic unit for the building block of life.

Question 34

What is a dicotyledonous plants?

Answer 34

A plant that has two cotyledons (embryonic leaves)

Question 35

Where is dipeptidases found?

Answer 35

In the cell membrane of the small intestines.

Question 36

What is Visking tubing?

Answer 36

A type of semi-permeable membrane tubing that only allows small molecules pass such as glucose but does not let large ones such as starch pass.

Question 37

How would you model the absorption of starch?

Answer 37

Use a visking tube and put starch in it. Put in the water and then add amylase. Periodically remove some of the water solution out. Test each sample with iodine and benedicts solution. As time increases you should see a a more positive result in the benedict but never a positive result with iodine.