Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCBM Part 1 > Mitsouras - Carbohydrates > Flashcards

Mitsouras - Carbohydrates Flashcards

1
Q

what are the 3 functions of carbohydrates

A
  1. metabolism (fuel/energy source)
  2. structural components of nucleic acids and enzyme cofactors
  3. modify other biomolecules (glycoconjugates)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how are carbohydrates classified

A

by number of carbons (triose, tetrose, pentose, and hexose) –> (CH2O)n n= # of Carbon atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

which 3 hexoses are of particular interest

A

glucose, fructose, and galactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the smallest unit of a carbohydrate

A

monomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the 2 most oxidized functional groups

A

aldehyde (aldose) or keto group (ketose)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is an isomer

A

same chemical formula but different 3D structures - asymmetric carbon has 4 different chemical groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is D-glucose and how many isomers does it have

A

C6H12O6 - m (asymmetric carbons) =4 so there are 16 isomers (2^m isomers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the 3 types of isomers

A

epimers, entaniomers, and anomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is a epimer

A

different configurations around a single asymmetric carbon (not around carbonyl C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is an entaniomers

A

isomers that are mirror images of each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is an anomer

A

formed by cyclization of monosaccharides: alpha (below ring) or beta (above plane)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what C are galactose and glucose epimers at

A

C-4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what C are glucose and mannose epimers at

A

C-2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what form enantiomer do almost all sugars occur in the human

A

D anantiomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what monosaccharides can exist as a ring structure

A

5+ carbons (99% are rings)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what happen in cyclization

A

the aldehyde or keto group reacts with OH group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is pyranose

A

a 6-membered ring (5 carbons and 1 oxygen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is furanose

A

5-membered ring (4 carbons and 1 oxygen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how do anomers (alpha and beta) forms interconvert

A

by mutarotation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are disaccharides

A

dimers - 2 monosaccharides linked by glycosidic bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what are the components and type of glycosidic bond in sucrose

A

glucose + fructose (table sugar)

glucose α (1 → 2) fructose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are the components and type of glycosidic bond in lactose

A

galactose + glucose (milk and dairy)

galactose β (1 → 4) glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what are the components and type of glycosidic bond in maltose

A

glucose + glucose

glucose α (1 → 4) glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what are the components and type of glycosidic bond in isomaltose

A

glucose + glucose

glucose α (1 → 6) glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what are the functions of polysaccharides
metabolic fuels and energy sources (common: glycogen, starch, and cellulose)
26
what type of bond does glycogen contain (liver and muscle)
Glucose (linear chain) α(1,4) and glucose (branchpoints) α (1,6)
27
what type of bond does starch from plants have in amylose
(unbranched) Glucose α(1,4)
28
what type of bond does starch from plants have in amylopectin
(branched) glucose α(1,4) and α (1,6)
29
what type of bond does cellulose from plants have (fiber-undigestible)
(unbranched) β (1,4) bonds
30
what are the 2 parts in the digestive process for dietary carbohydrates
digestion- mechanical (chewing and mixing foods) and chemical - cleavage of glycosidic bonds by glycosidases (breakdown of food)
31
what are polysaccharides (starch and glycogen) broken down into and what breaks them down
oligosaccharides, tri- and disaccharides in mouth by salivary α-amylase
32
what bonds does salivary α-amylase break in the mouth
glucose a(1,4) bonds cleaved =>oligosaccharides (a-dextrins), tri & disaccharides
33
what breaks down the oligosaccharides into tri- and disaccharides
pancreatic α-amylase in the small intestine
34
what bonds does pancreatic α-amylase break in the small intestine
glucose a(1,4) bonds cleaved => trisaccharides & disaccharides
35
what is D-glucose polymer
plant origin and composed of amylose and amlyopectin (unbranched) - not digestible fiber in diet
36
what bonds of amylopectin are cleaved by the brush border disaccharides in the internal mucosa
glucose a(1,6) glucose bonds
37
what do the brush boarder disaccharides break down in sucrose
glucose α(1,2) fructose bonds
38
what do the brush boarder disaccharides break down in lactose
galactose β (1,4) glucose bonds
39
what do the brush boarder disaccharides break down in maltose
glucose α(1,4) glucose bonds
40
what do the brush boarder disaccharides break down in isomaltose
glucose α(1,6) glucose bonds
41
where do glucose, fructose, and galactose get absorbed
in the gut
42
how do the monosaccharides go into circulation
from the intestinal epithelium into circulation by transporters
43
what happens to blood glucose levels after the monosaccharides enter circulation
blood glucose levels increase - onset of fed state and insulin signaling cascade
44
why is transport of monosaccharides critical
to lower blood glucose levels after a meal and prevent hyperglycemia
45
what are 2 types of transportation for monosaccharides
facilitated and active transport
46
what is facilitated transport
down the concentration gradient (high glucose: extracellular -> low glucose: intracellular) NO ATP required
47
what is active transport
against concentration gradient (low glucose: intracellular -> high glucose: extracellular) Needs ATP
48
when is there a high affinity
active at low (fasting) and high (fed) glucose concentrations
49
when is there a low affinity
active at high (fed) glucose concentrations
50
what is the specificity of a monosaccharide transporter
which type of monosaccharide is transported (glucose,fructose, or galactose)
51
what is the affinity of a monosaccharide transporter
sensitivity of the transporter
52
what is the capacity of monosaccharide transporters
what concentrations of glucose saturates the transporter
53
when is there a low capacity
saturated at low glucose levels
54
when is there a high capacity
saturated at hight glucose levels
55
what are the 4 properties of monosaccharide transporters
specificity, affinity, capacity, and hormonal regulation
56
what is the hormonal regulation of monosaccharide transporters
insulin-dependent transporters -> transport in presence of insulin
57
what do basal glucose uptake transporters do
constant supply at both high and low blood glucose
58
what do insulin-dependent uptake transporters do
important in fed state during insulin signaling to lower blood glucose levels
59
what do high-capacity glucose uptake transporters do
equilibrate intracellular with blood glucose levels in fed state in glucose-sensing organs
60
what do Na+ dependent co-transporters do
(ATP required) for complete absorption of glucose from GI to circulation (low glucose -> high glucose)
61
what is the tissue-specificity and function of GLUT1
most cell types (RBCs, brain) but not kidney or SI - glucose and galactose transporter, high affinity, basal glucose uptake
62
what is the tissue-specificity and function of GLUT2
hepatocytes, pancreatic b-cells, SI, and kidney - glucose, galactose, fructose transporter high capacity, low affinity glucose sensor: exports glucose into blood after uptake from lumen of SI
63
what is the tissue-specificity and function of GLUT3
most tissues/organs (brain, testes, placenta) glucose and galactose transporter high affinity and basal glucose uptake
64
what is the tissue-specificity and function of GLUT4
skeletal muscle and adipocytes glucose transporter high affinity and insulin dependent
65
what is the tissue-specificity and function of GLUT5
SI, sperm, kidney, brain, muscle, adipocytes fructose transporter high affinity
66
what is the tissue-specificity and function of GLUT7
membrane of ER in heaptocytes | glucose transporter, transports free glucose from ER to cytoplasm to be taken by GLUT2
67
what is the tissue-specificity and function of SGLUT1
epithelial cells of SI and apical surface of kidney tubules glucose, galactose co-transporter with Na+ uptake of sugar from lumen of SI against gradient

MCBM Part 1 (29 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions