Lab11

Question 1

Digestion:

Answer 1

a catabolic process that break down large food molecules to monomers.

Question 2

monomers:

Answer 2

chemical building blocks

Question 3

digestion is accomplished by…

Answer 3

enzymes secreted into the lumen of the alimentary canal or GI tract by accessory glands

Question 4

enzymatic breakdown of any food molecule is hydrolsis because

Answer 4

it involves adding a water molecule to each molecular bond to be broken.

Question 5

most digestion occurs in the..

Answer 5

small intestine

Question 6

how to pancreatic enzymes help digestion.

Answer 6

they break larger chemicals into smaller pieces, that than get broken down into individual componnets by the intestinal brush border enzymes.

Question 7

_____ neutralizes the acidic chyme that enters the small intestine from the stomach.

Question 8

what two things are necessary for efficient fat breakdown?

Answer 8

pancreatic juice and bile

Question 9

absorption:

Answer 9

the process of moving substances from the lumen of the gut into the body

Question 10

what prevents substances from moving between cells of the epithelia?

Answer 10

tight junctions join the epithelial cells of the intestinal mucosa.

Question 11

how do materials pass through epithelial cells

Answer 11

enter its apical membrane and pass to the interstitial fluid on the other side of the cell.

Question 12

what happens once material makes it to the interstitial fluid of a cell

Answer 12

substances diffuse into blood capillaries

Question 13

from the capillary blood in the villus, substances are transported to the liver via the …

Answer 13

hepatic portal vein

Question 14

lipid digestion is different because…

Answer 14

some lipid digestion products enter the lacteal in the villus to be carried via the lymphatic fluid to the blood.

Question 15

nonpolar substances

Answer 15

lipid soluble

Question 16

which substances can dissolve in the lipid core of the membrane and be absorbed passively through simple diffusion?
why.

Answer 16

nonpolar (lipid soluble) substances
because of the structure of the plasma membrane

Question 17

how do substances (other than lipid soluble) get transported through the plasma cell membrane?

Answer 17

carrier mechanism

Question 18

most nutrients are absorbed by active transport driven directly or indirectly (secondarily) by

Answer 18

metabolic energy (ATP)

Question 19

enzymes:

Answer 19

digest small particles into components that can be absorbed.

Question 20

what is proteins chemical monomer?

Answer 20

amino acids

Question 21

what is carbohydrates chemical monomer?

Answer 21

monosaccarides

Question 22

what is triglycerides (fats) monomer:

Answer 22

free fatty acids and monoglycerides

Question 23

Pepsin is the only digestive enzyme that is maximally active at

Answer 23

acidic pH.

Question 24

pepsin cleaves proteins into :

Answer 24

peptide fragments and small amount of individual amino acids

Question 25

peptide:

Answer 25

a compound of two or more amino acids linked in a chain

Question 26

what happens when chyme is neutralized in the duedenum?

Answer 26

pepsin is denatured

Question 27

which organ supplies most of the enzymes used in digestion?

Answer 27

pancreas exocrine part of the pancreas produces and secretes most of the digestive enzymes

Question 28

neither amalyse or pepsin is required for digestion

Answer 28

pancreatic enzymes alone are sufficient

Question 29

pancreatic lipase is essential for what will happen without it?

Answer 29

fat digestion malabsorption

Question 30

which dietary component cannot be digested and absorbed by human?

Answer 30

cellulose: a polysaccaride in fruits and vegetables. dietary fiber

Question 31

where is most of the water absorbed in the GI tract?

Answer 31

small intestine

Question 32

salt and water may be absorbed through what 2 forms of transport?

Answer 32

trancellular: through intestinal epithelial cells paracellular transport: through leaky tight junctions between cells.

Question 33

which form of transport is passive and keeps the total osmolarity of intestinal contents to the osmolarity of blood plasma

Answer 33

paracellular transport

Question 34

brush border enzymes:

Answer 34

enzymes located in the brush border (microvilli of small intestine) that break down starch and dissacarides because only monosacharides are absorbed

Question 35

brush border:

Answer 35

microvilli of epithelial cells of the small intestine (apical surface)

Question 36

what is the purpose of microvilli on epithelial cells in small intestine?

Answer 36

greatly increase surface area for absorption

Question 37

after proteins, peptides from pepsin digestion, proteins from sloughed cells, and enzymes enter the small intestine for digestion these 4 things continue protein digestion in the lumen.

Answer 37

trypsin, chymotrypsin, caboxypeptidace, and major pancreatic proteases. these enzymes are maximally active at pH 7.

Question 38

what is the most abundant dietary fat?

Answer 38

triglycerides

Question 39

triglycerides are made from:

Answer 39

a glycerol molecule and three attached fatty acids (short, medium, or long chains of carbon and hydrogen)

Question 40

what breaks down triglycerides?

Answer 40

pancreatic lipase maximally active at pH7

Question 41

which compound results in the emulsification of fats?

Answer 41

bile salts

Question 42

which enzyme breaks down fat into the chemical building blocks?

Answer 42

lipase

Question 43

since fat molecules are insoluble in water, they tend to aggregate in large drops, leaving little surface area of lipase to work. what process is utilized to change this?

Answer 43

segmentation in the small intestine breaks the larger drops into smaller drops and disperses them throughout the chyme.

Question 44

emulsification:

Answer 44

a process in which large lipid globules are broken down into several small lipid globules. these small globules are widely distributed in the chyme rather than forming large aggregates (shaking water and oil)

Question 45

the function of bile is related to their function:

Answer 45

hydrophobic on one side, hydrophilic on the other side

Question 46

most absorption of dietary nutrients occurs in the small intestine. which breakdown of products of digestion can cross the plasma membrane of small intestine epithelial cells by simple diffusion?

Answer 46

monoglycerides and free fatty acids (nonpolar molecules that are lipid soluble)

Question 47

triglycerides are reassembled inside of the cell and packaged into ...

Answer 47

chylomicrons that are coated with lipoproteins to keep them emulsified

Question 48

lipoproteins:

Answer 48

soluble proteins that combine with and transport fat or other lipids in the blood plasma

Question 49

chylomicrons:

Answer 49

large triglyceride-rich lipoproteins produced in enterocytes from dietary lipids. namely fatty acids and cholesterol

Question 50

chylomicrons leave the cell by exocytosis. since they are too large to pass through the basement membrane of the capillaries, they enter lymph vessels called _____.

Answer 50

lacteals

Question 51

what is the correct substrate for proteases?

Answer 51

proteins (or peptides)

Question 52

what is the correct substrate for proteases?

Answer 52

proteins (or peptides)

Question 53

which major process involves removing nutrients and water from the lumen of the GI tract and delivering them to blood or lymph?

Answer 53

absorption

Question 54

most nutrients are absorbed into blood capillaries, and travel to the liver by way of the hepatic portal vein, most fats, however, are too large to be absorbed into blood capillaries and instead are absorbed into the larger _____.

Answer 54

lacteals

Question 55

where does segmentation occur?

Answer 55

small intestine (only organ who does this) purpose is mixing food with enzymes and bringing it close to intestinal walls.

Question 55

where does segmentation occur?

Answer 55

small intestine (only organ who does this) purpose is mixing food with enzymes and bringing it close to intestinal walls.

Question 56

how would you classify chewing food?

Answer 56

mechanical breakdown