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biochem > ch 7 > Flashcards

ch 7 Flashcards

1
Q

what is the anomeric carbon

A

the carbonyl carbon (of aldehyde or ketone) in the open chain form of the sugar or the carbon bonded to the ring oxygen and a hydroxyl group in the cyclic form.

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2
Q

what is mutarotation

A

the observed change in the optical rotation of the alpha or beta anomers of glucose upon dissolution in solvent

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3
Q

is the anomeric carbon considered a chiral carbon

A

no because its constantly changing between the open and closed form of glucose.

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4
Q

how is the anomeric carbon generated in carbohydrates

A

when the open chain monosaccaride cyclizes OH in C-5 attacks the carbonyl causes equilibrium between open and closed forms

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5
Q

what is the furanose form?

A

five membered ring

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6
Q

what is the pyranose form

A

six membered ring

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7
Q

alpha carbohydrates have OH on anomeric carbon up or down

A

down

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8
Q

beta carbohydrates have OH on anomeric carbon up or down

A

up

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9
Q

what are aldoses

A

sugars with aldehydes attached to them

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10
Q

what are ketoses

A

sugars with ketones attached to them

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11
Q

how to find stereoisomers of a sugar

A

2 to the number of chiral carbons ex 2^4=16 stereoisomers

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12
Q

what is characteristic of an alpha glyosidic bond

A

down

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13
Q

what is characteristic of an beta glyosidic bond

A

up

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14
Q

what is a reducing sugar

A

any sugar with a free anomeric carbon

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15
Q

lactose is made up of what

A

glucose with galactose

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16
Q

sucrose is made up of what

A

glucose with fructose

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17
Q

what are two sugars used for energy storage

A

glycogen (animals) and starch

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18
Q

what are two examples of starch

A

amylopectin and amylose

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19
Q

glycogen and starch are what kind of polysaccharides

A

homopolysaccharides

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20
Q

energy storage sugars have what linkage

A

alpha 1 to 4

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21
Q

what are two sugars used for structural

A

cellulose and chitin

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22
Q

cellulose and chitin are what kind of polysaccharides

A

homopolysaccharides

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23
Q

cellulose has what kind of linkage

A

beta 1 to 4

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24
Q

chitin has what kind of linkage

A

beta 1 to 4

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25
Q

what sugar is used for signaling

A

glyconjugates (sugar with protein/sugar with lipids)

26
Q

lactose has what linkage

A

beta 1-4

27
Q

sucrose has what linkage

A

beta 1 to alpha 2

28
Q

cellulose is made up of what monosaccharides? what linkage does it have and what is its function?

A

its monosacc is glucose, linkage beta 1to 4 and function is structural

29
Q

glycogen is made up of what monosaccharides? what linkage does it have and what is its function?

A

its monosacc is glucose, linkage alpha 1 to 4 and function is energy

30
Q

peptidoglycan is made up of what monosaccharides? what linkage does it have and what is its function?

A

its monosacc is NAM+ NAG, linkage beta 1 to 4 and structure is structural

31
Q

peptidoglycan is what kind of polysaccaride

A

it is a heteropolysaccaride

32
Q

which structural homopolysaccaride combines with protein or CaCO3 to harden the exoskeleton

A

chitin, in between the acetyl groups you put something strong in between

33
Q

what is bacterial cell walls made of

A

peptidoglycan (NAG and NAM)

34
Q

what is the difference between gram positive and gram negative bacteria

A

gram positive has pentaglycine bridges/crosslinks that connect the amino acids while gram negative have a direct amide bond joining the tetra peptides together

35
Q

explain how lyzosyme and penicillin can affect gram + but not gram - bacteria (4 things) forth is most important for lysozyme

A
  1. penicillin is an irreversible inhibitor of the bacterial enzyme that produces the pentaglycine crosslink.
  2. lyzozyme cant reach the peptidoglycan because they have another membrane making it harder to reach by lysozyme
    3.lysozyme is thin so between two membrane in gram - making it difficult to reach
  3. lysozyme isnt able to reach the outer membrane because peptidoglycan protects the membrane from lysozyme
36
Q

sugar with lipid is called what

A

lipopolysaccharides/glycolipid

37
Q

sugar with a lot of protein is called

A

glycoprotein

38
Q

sugar with a little protein is called

A

proteoglycans

39
Q

what do we call glycolipids on the surface of gram - bacteria and why do we call them that

A

we call them endotoxins and we call them that because they elicit a strong immune response due to weird sugars

40
Q

preteoglycans have what kind of characteristic

A

they are very feather like

41
Q

glycoproteins have what type of sugar chains? what is the percent of protein content? what charge do they have?

A

type of sugar chains: varied, protein content: 50-60%, charge: (-) or neutral

42
Q

glycoproteins are located where? and what is function?

A

located in blood or cell bound and function is signaling

43
Q

proteoglycans have what type of sugar chains? what is the percent of protein content? what charge do they have?

A

sugar chains: repeated disaccharide units
protein content: 10-15%, charge: (-)

44
Q

proteoglycans are located where? and what is function?

A

location: extracellular matric in connective tissue and function is structural

45
Q

what are glycosaminoglycans

A

glucosamine or galactosamine paired with an acid to bind to the protein part of the preteoglycan

46
Q

what amino acids are part of o linked glycoproteins

A

Ser or Thr

47
Q

what amino acids are part of n linked glycoproteins

A

Asn

48
Q

antifreeze glycoprotein are O linked glycoproteins that allow fish to survive the cold waters near the poles. explain how the Thr bound disaccharides can achieve that

A

sugars hydrogen bond to incipient to disrupt the freezing process.

49
Q

what does sialic acid do

A

they tend to be at the end of a sugar chain like a cap and an enzyme determines its half life by how many molecules of sialic acids its cut off to reach the sugar.

50
Q

explain the following statement: the half life of a protein can be regulated by the number of added sialic acid units on the end of the oligosaccharide N linked to the protein

A

as these are hydrolyzed galatose is exposed and the liver has receptors for galactose and we internalized this and digest to break apart

51
Q

what is A1c and what is a normal level? this is used as a diagnostic tool for disease

A

A1c is hemoglobin A1c is the amount of sugar attached to the hemoglobin. the normal level is <5.6% diabetes is 6-5% and anything in between in prediabetes

52
Q

proteoglycans in the ECM interact with what proteins and what glycoproteins

A

with integrin and collagen and the glycoprotein is fibronectin

53
Q

what makes a good anticoagulant

A

it has a negative charge strengthen the interaction with antithrombin

54
Q

Heparin is a proteoglycan (core protein + glycosaminoglycan) that acts as an anticoagulant. Describe what structural feature makes the glycosaminoglycan portion a good anticoagulant. What would make a good antidote to heparin?

A

heparin binds to antithrombin III and it accelerates its activity 1000 fold. antithrombin is a serine protease inhibitor that inhibits the conversion of prothrombin to thrombin thus preventing coagulation

55
Q

what is the sugar code

A

glycoconjugates are recognized and bound by a class of proteins called glycan-
binding proteins (GBPs or lectins), produced by all types of cells.

56
Q

Lectins are ??? that recognize and bind to specific ??? . Selectins are a type of
lectin that are embedded in the inner wall of blood vessels. They bind to the ??? ligands on the surface of circulating ???, slowing down their movement until they reach a site of inflammation.

A

lectins are PROTEINS, and bind to specific SUGARS in glyconjugates. selectins binds to SUGAR ligands on the surface of circulating LYMPHOCYTES

57
Q

????, released by macrophages at the site of inflammation, cause the
glycoprotein ????? to bind and immobilize these cells, until they can move out of the
circulatory system towards the site of tissue damage or infection in a process called ????

A

CHEMOKINES, released by macrophages at the site of inflammation, cause the
glycoprotein INTEGRIN to bind and immobilize these cells, until they can move out of the circulatory system towards the site of tissue damage or infection in a process called EXTRAVASATION

58
Q

What are lectins

A

proteins that can read the suagr code and has a high affinity for certain sugar coating cells (glycoconjugates)

59
Q

MBP and CRP are what

A

lectins that coat foreign antigens

60
Q

what does MBP bind to

A

to mannose rich glycans in microbes with mannose as the terminal sugar

61
Q

what CRP bind to

A

binds to the microbe promoting phagocytosis as part of the immune response

62
Q

what is the most dominant surface feature of the outer membrane of gram negative bacteria.

A

lipopolysaccaride

biochem (9 decks)

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