Biochemistry Of Digestion - Dr. Estuart Flashcards
(128 cards)
1
Q
Food is broken down into smaller compounds for absorption by the intestines
A
Digestion
2
Q
Uptake of products of digestion by enterocytes and their delivery to blood or lymph
A
Absorption
3
Q
Regulated by the nervous system, hormones, and paracrine factors
A
Digestion and absorption
4
Q
Food is physically broken down into smaller fragments
A
Mechanical digestion
- Chewing (mouth), churning (stomach), segmentation (small intestine)
5
Q
Enzyme-mediated, hydrolysis process that breaks down large macronutrients into smaller molecules.
A
Chemical digestion
- Hydrolysis, digestive enzymes
6
Q
Macronutrient for AMYLASE
A
Carbohydrates
7
Q
Macronutrient for PROTEASE
A
Proteins
8
Q
Macronutrient for LIPASE
A
Fat
9
Q
All digestive enzymes are ___________.
A
Hydrolyases
10
Q
Any chemical reaction in which a molecule of water ruptures one or more chemical bonds.
A
Hydrolysis
11
Q
Low weight for height
A
Wasting
12
Q
Low height for age
A
Stunting
13
Q
Low weight for age
A
Underweight
14
Q
A glucose-polymer cleavage enzyme
A
Salivary amylase
15
Q
Comprises a small portion of the total amylase excreted
A
Salivary amylase
16
Q
Breaks down starch
A
Salivary amylase
17
Q
Begins carbohydrate digestion
A
Salivary amylase
18
Q
Alpha 1-4
A
Amylose
19
Q
Alpha 1-6
A
Amylopectin
20
Q
Amylose a(1-4) undergo HYDROLYSIS:
A
Dextrins
Maltose
Maltotriose
Glucose
21
Q
Begins fat digestion
A
Lingual lipase
22
Q
Digests triglycerides into diglycerides and free fatty acids
A
Lingual lipase
23
Q
Catalytic triad of lingual phase:
A
aspartate
histidine
serine
24
Q
Triacylglycerol undergo hydrolysis:
A
Diacylglycerols Fatty acids
25
Role in digestion is conduit
Esophagus
26
(+) mechanical digestion “churning”
Stomach
27
_______ stops action of salivary amylase
Low pH
28
Is there a chemical digestion in the stomach?
No.
*NO chemical digestion in the stomach
29
Mechanical breakdown is ongoing in ___________
Stomach
30
Strong peristaltic contractions of the stomach mix the carbohydrates into the more uniform mixture of chyme (__________)
Homogenization
31
Proteins have to be _________ to make them more accessible to proteases
denatured
32
Inactive precursor to an enzyme
Zymogens / Proenzymes
33
Prevent auto-digestion
Zymogens or proenzymes
34
Protein Digestion begins in the _________.
Stomach
35
From parietal cells
HCl
36
From chief cells
Pepsin
37
Hydrophobic
Lipids
38
Limited surface area for enzyme action
Lipids
39
Large lipid globules are broken down into several small lipid globules
Emulsification
40
Digests short and medium-chain fatty acids
Lingual phase or gastric lipase
41
Stomach can absorb some substances:
Aspirin
| Alcohol
42
breaking down of food into smaller compounds for absorption
Digestion
43
uptake of products of digestion by enterocytes and their delivery to blood or lymph
Absorption
44
Macronutrients are broken down into their oligomers, dimers, or monomers through ____________.
Hydrolysis
45
____________ digestion begins in the mouth due to salivary amylase.
Carbohydrate
46
_________ digestion begins in the stomach, with denaturation by HCl then hydrolysis by pepsin, into peptides and free amino acids
Protein
47
_________ digestion begins in the mouth due to lingual lipase, and is further digested by gastric lipase into diglycerides and free fatty acids
Lipid
48
Liver produces __________.
Bile
49
Bile stored and concentrated in the _________.
Gallbladder
50
Enzyme production
Bile and CCK
51
Bicarbonate-rich fluid
Secretin
52
Uses ATP, Proteins as pumps, Lower to higher concentration
Active transport
53
Higher to lower concentration
Passive diffusion
54
Higher to lower concentration using a carrier protein in cell membrane
Facilitated diffusion
55
Uses movement of one molecule from Higher to lower to power movement of another from lower to higher
Co-transport/Secondary active transport
56
Cell membrane engulfs material, uses ATP
Endocytosis
57
Lactase activity falls __________.
after weaning
58
Lactose remains in the intestinal lumen and becomes a substrate for bacterial fermentation.
Lactose intolerance or lactase deficiency
59
Abdominal discomfort, diarrhea, congenital or acquired
Lactose intolerance or lactase deficiency
60
Two mechanisms for absorption of monosaccharides in the small intestine:
SGLT1
| GLUT 5
61
Exit from the cell for all sugars
GLUT2
62
Glucose and Galactose
SGLT1 transport protein
63
Secondary active transport (Na dependent)
SGLT1 transport protein
64
Duodenum and Jejunum
SGLT1 transport protein
65
Fructose, Glucose, Galactose via facilitated diffusion
GLUT5
66
Sodium independent
GLUT5
67
Down their concentration gradient
GLUT5
68
Facilitated diffusion
GLUT2
69
All sugars
GLUT2
70
Bloodstream —> Portal vein —> Systemic circulation
GLUT2
71
Increase in blood glucose after a test dose of a carbohydrate compared with that after an equivalent amount of glucose
Glycemic index
72
Food with _____ glycemic index is beneficial in DM
Low
* Prevents rapid rise in blood glucose
* Prevents rapid fluctuations in insulin secretion
73
Hydrolyze peptide bonds between specific amino acids
Endopeptides
* Pepsin, Trypsin, Chymotrypsin, Elastase
74
Hydrolyze peptide bonds from the ends of peptides
Exopeptidases
75
Carboxypeptidases
Pancreas
76
Aminopeptidases
Small intestine
77
Tripeptidases
Small intestine
78
Dipeptidase
Small intestine
79
Pepsin product
Peptide fragments
80
Trypsin / chymotrypsin
Dipeptides
81
Exopeptidases
Amino acids
82
Diacylglycerols product:
2 Monoacylglycerols
| Fatty acids
83
Derivative of cholesterol
Bile
84
Amphipathic
Bile
85
Contain both hydrophobic (lipid soluble) and polar (water soluble) faces
Bile
86
Emulsification of lipids —> increased surface area for lipases
Bile
87
Solubilization and transport of lipids in an aqueous environment
Bile
88
Lipid absorption occur in two phases:
1. Monoglycerides and free fatty acids emulsified by bile, forming micelles, absorbed by the cell, forming __________
Chylomicrons
89
Lipid absorption occur in two phases:
______________ directly enter the cell.
Short and Medium-chain fatty acids
90
Cholelithiasis
Gallbladder stones
91
Most common gallbladder stones:
cholesterol gallstones
92
Bile supersaturation in cholesterol
Gallbladder stones
93
Can cause obstruction of biliary tract, complications
Gallbladder stones
* Treatment: Surgery
94
Released from food during digestion and the Availability depends on the type of food
Vitamins and minerals
95
Fat-soluble vitamins (ADEK) are absorbed in lipid micelles with fat digestion via ____________.
simple diffusion
96
Water-soluble vitamins and most mineral salts are absorbed from the SI by __________ or _________ followed by binding to intracellular proteins
active transport or facilitated diffusion
97
Vitamin B12
Intrinsic factor
98
Dependent on Vitamin D
Calcium
99
Zinc-binding ligand secreted by exocrine pancreas
Zinc
100
Limited absorption
Iron
101
Required for intestinal absorption of calcium
Vitamin D
102
Intracellular calcium-binding protein
Calbindin
103
Induced by Vitamin D
Calbindin
104
Recruits calcium transports to the cell surface
Calbindin
105
Increases calcium absorption rapidly
Calbindin
106
Site of absorption in vitamin B12
Ileum
107
Requirement for vitamin B12 absorption
Intrinsic factor
108
Protein secreted by parietal cells in the stomach
Intrinsic factor
109
Lack of vitamin B12 absorption
Pernicious anemia
110
A gylcoprotein of M.W 4500
Intrinsic factor
111
Vit. B12 combine with intrinsic factor forming a complex that resist digestion by GIT enzymes. This complex is absorbed at terminal ileum by ____________
Pinocytosis
112
Vitamin B12 is transported to the ________ where it is stored.
Liver
113
Released Vit B12 from Protein by _______ and _______.
HCl and Pepsin
114
Vitamin B12 binds to ___________
Cobalophilin
115
Cobalophilin hydrolyzed in __________, releasing Vit B12
Duodenum
116
Vit B12 is bound to Intrinsic Factor and absorbed in __________.
terminal ileum
117
Products of nucleic acid digestion:
pentose sugars
nitrogenous bases
phosphate ions
118
Nucleic acids are transported by carriers across the villi via ____________.
active transport
119
Alcohol is _____ absorbed in the small intestine and _____ in the stomach.
80%
20%
120
Slower absorption when stomach is full.
Alcohol
121
Approximately 5 feet long
Large intestine
122
Processing chyme after most nutrients are absorbed in the small intestine
Large intestine
123
3 Primary functions of large intestine:
Absorbing water and electrolytes Producing and absorbing vitamins,
Forming and propelling feces toward the rectum for elimination
124
Water diffuses in response to an _____________ established by the absorption of electrolytes.
osmotic gradient
125
Fat soluble vitamin
Vitamin K
126
Important role in the production of clotting factors to prevent bleeding
Vitamin K
127
Babies born with low levels of Vitamin K
Hemorrhagic Disease of the Newborn
128
Absence of the bacterial intestinal flora normally responsible for the synthesis of vitamin K
Hemorrhagic Disease of the Newborn
