Carbohydrates Flashcards Preview

NBDE PART 1 BIOCHEM/PHYSIOLOGY > Carbohydrates > Flashcards

Flashcards in Carbohydrates Deck (88):
1

cellulose linkage

Beta (1-4)

2

cellulose is storage/structural molecule

structural

3

glycogen linkage

glucose only alpha (1-4) and alpha (1-6)

4

glycogen is storage/structural molecule

storage in animals

5

starch is storage/structural molecule

storage in plants

6

starch made of what 2 polysaccharides? linkages?

amylase and amylopectin
(amylase is alpha 1-4) amylopectin is like glycogen = alpha (1-4) and alpha (1-6) = branched

7

homopolysaccharide means

contains only a single monosaccharide species. ie only glucose in dextrans, glucans, starch, glycogen, cellulose.

8

heteropolysacharride contain a number of different monosaccharides. give an example

glycosaminoglucans (GAGs)

9

the most common organic compound on earth

cellulose (beta 1-4) glucose

10

dextran linkages

alpha (1-3) links the straight chain alpha (1-6) glucose straight chains. Dextran is synthesized from sucrose by certain lactic-acid bacteria. Dental plaque is rich in dextrans

11

both amylose and amylopectin are hydrolyzed by the enzyme ____, which is secreted by the pancreas and?

alpha amylase
parotid gland

12

is cellulose digestible in humans

no. it is dietary fiber aka roughage. hydrophobic bulking agent in feces.

13

glycan refers to a

polysaccharide (more than 12 monosac) or an oligosaccharide (2-12 monosacharrides

14

when designating alpha or beta we look at which carbon

the anomeric carbon (C1) in a ring form!! alpha = looks like a fish = fish swim below. beta looks like a bird. fly above the chain

15

when designating D/L sugar we look at which carbon

pentameric carbon (5th carbon in the chain form). if OH is on the right is in D form

16

sugars are most commonly found in nature in D or L form?

D -to remember think of Disaccharide = D

17

amino acids most commonly found in nature in D or L form?

L form (opposite of sugars)

18

which has more sugars Oligosaccharide or polysach?

POLYSACH = remember P comes after O ==gets bigger

19

Polysaccharides are made of many sugar units covalently bonded by condensation reactions which leads to a ___ glycosidic bond

O

20

glycogen is found mainly where

liver and muscle. but most is in the liver

21

glycogen is a branched polymer of how many glucose residues

10,000 - 40,000 held together by alpha 1-4 linkages. every 12th carbon has a branch point forming an alpha 1-6 bond

22

what 3 enzymes are in the small intestine that break down disaccharides into monosach?

maltase
sucrase
lactase ==> to remember think beer sugar, milk sugar, and table sugar

23

maltase breaks maltose into?

glucose and glucose

24

sucrase breaks sucrose into

glucose and fructose

25

lactase breaks lactose into

glucose and galactose

26

glycogen can be broken down into single glucose units by which enzyme

glycogen phosphorylase

27

the cleavage of glycogen beyond a branching point requires what 2 enzymes

glucantransferase and amylo-alpha 1, 6-glucosidase

28

glyceraldehyde and dihydoxyacetone are:
trioses/tetroses/pentoses/hexoses

trioses

29

glucose
trioses/tetroses/pentoses/hexoses

hexose

30

ribose
trioses/tetroses/pentoses/hexoses

pentose

31

erythrose
trioses/tetroses/pentoses/hexoses

tetrose (4 C)

32

how many carbons do you need at least to form a monosaccharide cyclic rings

5 -8 in nature will form cyclic rings

33

simple sugars are aka

monosaccharides

34

are lactose/maltose monosaccharides

no disach

35

the naming of configurations of SIMPLE sugars (L and D) and amino acids are based on the ___ configuration of which structure

Absolute of glyceraldehyde

36

the L and D refer to the absolute configuration of the 4 constituents around a specific __ carbon

chiral

37

what is a chiral carbon

it is an ASYMETRIC CARBON

38

in the __L/D form the hydroxyl is on the left

L

39

a glycosidic bond forms when the __ group on the anomeric carbon (C1) reacts with an __ group of another compound

OH, OH or NH

40

if nitrogen is involved in a glycosidic bond it is called

N-glycosidic bond - found in glycoproteins and nucleotides

41

Glycoproteins are conjugated proteins containing one or more saccharides in repeated units bound to a protein. Proteoglycans are macromolecules that contain __% carbs and resemble polysaccharides more than proteins

95%

42

The carb chains on Proteoglycans are called

glycosaminoglycans (GAGs)

43

glycosaminoglycans (GAGs) are branched/unbranched

unbranched

44

are glycosaminoglycans (GAGs) homopolysaccharides or hetero?

hetero

45

This glycosaminoglycans (GAGs) is found in synovial fluid, vitreous humor, ECM of loose CT. it is large and shock absorbing and is the only glycosaminoglycans (GAGs) that does not contain sulfate and is not attached to a protein

Hyaluronate
to remember look at the U in the word. V is right after U. so Vitreous humor and synoVial fluid.

46

this glycosaminoglycans (GAGs) is found in cartilage, bones and heart valves and is the most abundant of all GAGs

chondroitin sulfate:
to remember think we have tons of cartilage in our body (so most abundant), then associate cartilage w bone, and then think he "conned" my heart = heart valves

47

this glycosaminoglycans (GAGs) is found in BM and cell surfaces

heparin sulfate = to remember think you put salt = sulfate on the surface (cell surface) and to remember BM, think, what is the opposite of cell surface? BM

48

glycosaminoglycans (GAGs) in skin, blood vessels, and heart valves

dermatin sulfate = to remember look at derma = skin, then think what is associated with skin --->blood vessels --> lead to heart valves

49

glycosaminoglycans (GAGs) found in cornea bone cartilage and aggregated with chondroitin sulfates. most heterogenous GAG

keratin sulfate = to remember: keratin: k sounds like C-ornea, also the K associates w/C-hondroitin sulfate, C-artliage, Bone

50

which glycosaminoglycans (GAGs) has the most sulfate

heparin

51

glycosaminoglycans (GAGs) in mast cell granules that line the arteries of lungs liver and skin, anticoagulant

heparin

52

does heparin or heparin sulfate contain more sulfate

heparin

53

is sucrose a reducing sugar

no it is a non reducing sugar

54

___ sugars contain a free anomeric carbon (C1) that can be oxidized in a redox rxn.

reducing

55

if the sugar is attached to any other structure at the C1 position is it reducing

no

56

the reducing sugar test is used to screen for

diabetes - to see if there are excess free glucose in the blood. and errors metabolizing these reducing sugars

57

glucosuria (glucose in urine) threshold

160-180 mg/dl

When the blood glucose level exceeds about 160 – 180 mg/dl, the proximal tubule becomes overwhelmed and begins to excrete glucose in the urine.

58

the ground substance of ECM is made up of:

a. type II collagen
b. type III collagen
c. proteoglycan molecules

proteoglycan molecules

59

these molecules function as lubricants, ECM, and molecular sieves (sieve, or sifter, is a device for separating wanted elements from unwanted material or for characterizing the particle size distribution of a sample, typically using a woven screen such as a mesh or net)

proteoglycans

60

glycoproteins = conjugated proteins w/ one or more saccharides. the carb portion differs from proteoglycans in that it is __ and __

shorter and branched.

61

glycoproteins functions

hormones, antibodies, structural proteins, enzymes often in cell membrane involved in cell to cell interactions

62

glycolipids aka

sphingolipids

63

glycolipids found in the __ with the __ portion extending into the extracellular space

cell membranes
carb

64

glycolipids are derived from

ceramides = cerebrosides, globosides, and gangliosides

65

Proteoglycans are made of

Protein and GAGs

66

Proteoglycans are long and straight/short and branched?

long and straight

67

Role of proteoglycans

lubrication, ecm, molecular sieve

68

glycoproteins are made of

protein + carb

69

glycoproteins are long and straight/short and branched?

short and branched

70

glycoproteins role

enzymes, hormones, antibodies, structural proteins

71

glycolipids made of ?
function?

LIPID and CARBs
(ceremide)
cell membrane receptors

72

the most abundant glycosaminoglycan in the body is

chondroitin sulfate:
major part of CT, cartilage, bone, heart valves
especially in the GROUND SUBSTANCE.
in cartilage it provides structure by holding water and nutrients and allowing molecules to move thru the cartilage which is important bc of no blood supply to cartilage

73

In connective tissue, the____, also called extrafibrillar matrix, is an amorphous gel-like substance surrounding the cells. In a tissue, cells are surrounded and supported by an extracellular matrix. does not include fibers (collagen and elastic fibers), but does include all the other components of the extracellular matrix. The components of the ground substance vary depending on the tissue. primarily composed of water, glycosaminoglycans, proteoglycans, and glycoproteins.

ground substance

74

dextrans are polysaccharides or oligosach?

polysaccharides of glucose (alpha 1-6) linkages with some alpha 1-3 branches

75

bacteria make dextrans extracellularly by using the enzyme and what substrate

glucosyl transferase aks dextran sucrase
use sucrose

76

side product of dextran production is __ which is formed into __ and stored intracellularly as reserve nutrients

fructose, levans/fructans

77

most notable bacteria that forms dextrans

streptococcus mutans

78

do fructans increase the adhesion of bacteria to teeth and formation of dental plaque

yes both dextrans and fructans increase adhesion.

79

fructans are formed by what enzyme

fructosyl transferase aka levan sucrase

80

glycogen structure is very similar to?

amylopectin (both alpha 1,4 and alpha 1,6) linkages. But glycogen branching and more glucose units. Both have alpha acetal

81

The structure of glycogen consists of long polymer chains of glucose units connected by an __linkage

alpha acetal = glycosidic linkages. The branches are formed by linking C # 1 to a C # 6 through an acetal linkages

82

In glycogen, the branches occur at intervals of __ glucose units, while in amylopectin the branches are separated by 12-20 glucose units.

8-10

83

Carbon # 1 in glycogen is called the anomeric carbon and is the center of an acetal functional group. A carbon that has two __attached is an acetal

ether oxygens


84

a hexose is

a monosaccharide with six carbon atoms, having the chemical formula C6H12O6

85

A reducing sugar is any sugar that either has an __ group or is capable of forming one in solution through isomerism.

aldehyde (can be oxidized)

The aldehyde functional group allows the sugar to act as a reducing agent, for example in the Tollens' test or Benedict's reagent, or the Maillard reaction, important in the browning of many foods

86

proteoglycan vs glycoprotein

they are compounds made up of proteins and carbohydrates with the major difference between them being the protein/carb ratio.. glycoproteins have more protein, less carbs whereas proteoglycans have more carbs,less proteins.

to remember, the end of the name is what it has more of:
glycoprotein = more protein
proteoglycan = more glycan

87

1. nucleotides have _ glycosidic bonds
2. polysaccharides like glycogen have _ glycosidic bonds
3. glycoproteins have _ glycosidic bonds

1. N-glycosidic
2. O-glycosidic
3. N-glycosidic
(think glyco-protien) ===> have lots of proteins so N

88

1. glucosyl transferase
2. glucan transferase

1. when glucosyl or fructoSYL = bacteria making glucan/dextran and fructan
2. glucan transferase is breaking down glycogen after a branching point