sugars and polysaccharides Flashcards by l b

what part of plants harvests energy (photons) from sun

chloroplast

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what process produces carbohydrates

photosynthesis

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what ratio of CHO are carbohydrates in

1:2:1

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monosaccharides contain 3-? carbons

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What type of bond is HC=O

aldehyde

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what type of bond is C=O

ketone

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mirror images of a chiral molecule are called

enantiomers/ optical isomers

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what are the 2 enantiomers of glucose

D and L

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which glucose is a laxative and why

L-glucose cannot be digested so it remains in the gut lumen and reaches the colon where it binds to water by osmosis, changes water content so softens stools

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monosaccharides with 5-6 carbons from what type of structure

cyclic

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what carbon does the ketone/aldhyde group react with in a ring

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cylization of glucose produces a new asymmetric centre at which C

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which is the anomeric carbon in glucose

c1 (functional group)

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which D-glucose anomer a or b has CH20H and OH on same side

beta

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what form of glucose is most stable

b-D-glucose

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which form of glucose is highest energy conformation

D-glucose straight chain

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what are the 4 monosaccharides

glucose, fructose, galactose, mannose

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what are the 3 disaccharides

glc+glc= maltose
glc+frc= sucrose
glc+gal= galactose

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anomers a and b are called

stereoisomers

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anomers are recognised by _ enzymes

different enzymes

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disaccharides are joined by what type of bond

glycosidic bond

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glycosidic bond is what type of bond

covalent

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a glycosidic bond is between what groups

2 OH

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what type of reaction joins monosaccharides to make di/poly

dehydration (water is lost)

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what enzyme is used to make a glycosidic bond

glycosyl transferase

how many specific glycosyl transferases are there

>250

what glycosidic bond is in sucrose

a-1,2

what glycosidic bond is in lactose

b-1,4

what glycosidic bond is in maltose

a-1,4

what is 3-10 monosaccharides joined together

oligosaccharide

example of oligosaccharide found in cruciferous vegetable eg. broccoli, Brussel sprouts

Raffinose

Raffinose is made up of what

Gal-Glc-Fru

humans don't have enzyme to break down raffinose but microbiome does, this is called a _ relationship

symbiotic relationship- bacteria break them down

galacto-oligosacc and fructo-oligosaccharides are examples of what

prebiotics

heparin and blood group antigens are examples of what

oligosaccharides

polysaccharides contain >? monosaccharides

>10

starch, glycogen and cellulose are polymers of what

glucose

2 types of starch and their bonds

amylose (a-1,4) | amylopectin (a-1,4 and 1,6)

glycogen bonds

a-1,4 and 1,6

cellulose bonds

b-1,4 glycosidic bonds

what enzyme in digestive tract hydrolyses glc a-1,4 bonds of glycogen but NOT glc b-1,4 in cellulose

amylase

what glycosidic bond is branching and which polysaccharides have it

a-1,6 | glycogen, amylopectin

what is the core protein in glycogen

glycogenic

what is glycogenic surrounded by

glucose units

carbohydrates consumed raises blood glucose levels causing release of what

insulin

what does insulin act on to stimulate what

hepatocytes to stimulate glycogen synthase

glucose molecules are added to chains of glycogen when insulin and glucose levels are high/low

high

what enzyme breaks down glycogen for energy

glycogen phosphorylase

when all the monosaccharides are the same the polysaccharide is called and different

homopolysaccharide/ homoglycan (e.g glycogen) | heteropolysaccharide/heteroglycans (mucopolysacc)

which 2 polysaccharides have branching

cellulose and amylopectin

sugar modifications replace which group

what enzyme phosphorylates glucose to glc-6-phosphate

hexokinase

what sugar modification is important in metabolism of sugars

phosphorylation

what process enables metabolism of glucose / fructose

glycolysis

phosphorylation of glucose makes

glucose-6-phosphate

the 1st step in glycolysis is

phosphorylation of glucose

what does glycolysis do

enables metabolism of glucose (6C) to pyruvate (3C)

what do you replace OH with to get an amino sugar

NH2

what are 3 uses of amino sugars

precursor in lipid biosynthesis, glycoprotein formation part of the structure chitin (insects) and bacterial cell wall

what enzyme is used for glycosylatoin

glycosyl transferase

what is glycosylation used for in ER

tags proteins with sugars

activity of different _ leads to generation of different end-group sugars containing amino sugars

glyscosyl transferases

different glycosylation determines different _ - antigen

blood group

the response to antigen in blood group is

agglutination

addition of what gives sulphated sugars

SO4

sulphated sugars are common constituents of _ in the ECM

glycosaminoglycans GAGs

what properties do sulphate groups on GAGs give

highly negatively charged, bind water (hydrophilic) and hence withstand pressure

example of GAG

cartilage

what is the sulphated polysaccharide produced by endothelial cells at sites of damage to blood vessels

heparin

what is heparin known for

anticoagulant/ blood thinner discovered 1916

what does heparin consist of

variably sulphated repeating dissacharide units (of 2-O-sulphated iduronic acid and 6-O-sulphated N-sulphated glucosamine)

heparin prevents what

coagulation

antithrombin is a good/ bad inhibitor or the blood coagulation factor Xa and thrombin

bad

heparin binding to antithrombin bound to Xa is sufficient to enhance by over _times the rate at which factor Xa and thrombin can be inhibited

100 times

antithrombin mainly inhibits _ and _

Xa and IIa

heparin and antithrombin prevent formation of

clot

addition of lipid group forms

glycolipids

what is a glycolipid

lipid with a carbohydrate attached by a glycosidic bond

glycolypids maintain what in the cell membrane and facilates what

stability and cellular recognition (crucial to immune response)

what is an example of a microbial pattern recognition receptor of the innate response

Toll-like receptors TLR4

what does TLR4 respond to

Lipopolysaccharide from microbes

what does TLR4 do

activates an inflammatory and immune response which produce anti-LPS(liposaccharide) antibodies that are bactericidal

TLR4 are part of which immune response

innate

what stimulates innate immunity by LPS

TLR4

where is TLR4 present

bone marrow mesenchymal stem cells- destroy bacteria in blood vessels

replacing OH with O gives what type of sugar

deoxy-sugar

example of deoxy-sugar

deoxyribose

ribose(RNA) to deoxyribose(DNA) uses what enzyme

ribonucleotide reductase RNR

the backbone of DNA is a repeated pattern of a _ group and a _group

sugar and phosphate