Chapter 7 Carbohydrates (slide notes)

Question 1

___________ are simplest carbohydrates:

• Aldose sugars if _______ functional group
• Ketose sugars if ______ functional group

Answer 1

monosaccharides

aldehyde
ketone

Question 2

most abundant in living cells are _____ and ______

Answer 2

hexose and pentose

Question 3

sugars with four or more carbons exist primarily in _______

Answer 3

cyclic forms

Question 4

ring formation occurs because aldehyde and ketone groups react reversiby with hydroxy groups in an aqueous solution to form ________ and __________

Answer 4

hemiacetals and hemiketals

Question 5

five membered rings are called ________ and six member rings are called _________

Answer 5

furanoses

pyranoses

Question 6

cyclic form of fructose is ________, while glucose in the pyranose form is ________

Answer 6

fructofuranose

glucopyranose

Question 7

monosaccharides exist in many ________ forms

Answer 7

isomeric forms

Question 8

define isomers

Answer 8

have the same molecular formula but different structures

Question 9

define constitutional isomers

Answer 9

differ in the order of attachment of atoms

Question 10

define stereoisomers

Answer 10

atoms are connected in the same order but differ in spatial arrangment

Question 11

define enantiomers

Answer 11

nonsuperimposable mirror images

Question 12

define diasteroisomers

Answer 12

isomers that are not mirror images

Question 13

define epimers

Answer 13

differ at one of several asymmetric carbon atoms

Question 14

define anomers

Answer 14

isomers that differ at a new asymmetric carbon atom formed on a ring closure

Question 15

monosaccharide stereoisomers:

an increase in the number of chiral carbons increases the number of possible optical isomers. whats a formula to quantify this?

Answer 15

2^n where n is the number of chiral carbons. this will tell you how many possible optical isomers there will be

Question 16

almost all naturally occurring monosaccharides are the ____form.

all can be considered to be dervied from _______ or non chiral ________

Answer 16

D form

derived from D-glyceraldehyde
or nonchiral dihydroxyacetone

Question 17

formation of a cyclic hemiacetal creates another diastereoisomeric form called an ________

Answer 17

anomer

Question 18

define mutarotation

Answer 18

the alpha and beta forms of monosaccharides are readily interconverted in aqueous environments

Question 19

oxidation of aldoses can make what? give examples

Answer 19

aldonic acid
uronic acid
aldaric acid
lactones
reducing sugar

Question 20

what enyzme can be used to make oxidation products of glucose

Answer 20

gluconolactone oxidase

Question 21

what are reducing sugars?

Answer 21

sugars that can be reduced by weak, oxidizing agent such as benedict reagent are called this.

Question 22

to be a reducing sugar what is required.

Answer 22

there needs to be an open chain. Ergo all aldoses are reducing sugars and frutose (ketose) is one to due to isomerization

Question 23

Sugar alcohols (______) are produced by the reduction of aldehyde and ketone groups of monosaccharides. Note for recution essentionally the =O is changed changed to OH.

Note: sugar alcohols are used in commercial food processing and in pharmaceuticals. (soribtol can prevent moisture loss thus perserving food)

Answer 23

alditols

Question 24

isomerization can yield products that show __________

Answer 24

epimerization

Question 25

define esterification=

Answer 25

free OH groups of carbohydrates can be converted to esters by reactions with acids. esterification often dramatically changes a sugars chemical and physical properties. sulfate esters of carbohydrate molecules are found predominatly in the proteoglycan components of connetive tissue participate in forming salt bridges between carbohydrate chains

Question 26

______formation-hemiacetals and hemiketals react with alcohols to form the corresponding _______and ______

Answer 26

glycoside formation acetal ketal

Question 27

when the cyclic hemiacetal or hemiketal form of the monosaccharide reacts with an alcohol, the new linkage is a _________ and the compound is a __________-

Answer 27

glycoside linkage glycoside

Question 28

acetals of glucose and fructose is ________ and ______-

Answer 28

glucoside | fructoside

Question 29

define glycosylation

Answer 29

attachment of glycan to protiens, lipids, or other organic molecules

Question 30

the result of covalent bonding of a __ or __________ with a sugar molecules (sometimes called non enzymatic _______)

Answer 30

the result of covalent bonding of a protein or lipid molecule with a sugar molecules (sometimes called non enzymatic glycosylation)

Question 31

glucose (D-glucose)

Answer 31

originally called dextrose, it is found in large quanitities throughout the natural world. it is the primary fuel for living cells. it is the perferred energy source for brain cells and cells without a mitochondria

Question 32

frutose

Answer 32

is often referred to as a fruit sugar, because of its high content in fruit. on a per gram bsis, it is twice as sweet as sucrose; therefore, it is often used as a sweetining agent in processed food. sperm use frutose as an energy source

Question 33

galactose

Answer 33

is necessary to synthesize a variety of important biomolecules. important biomolecules include lactose, gycolipids, phospholipids, proetoglycan, and glycoprotiens

Question 34

_________ is a genetic disorder resulting from a missing enzyme in galactose metabolism

Answer 34

galactosemia

Question 35

disaccharides

Answer 35

two monosaccharides linked by a glycosidic bond. linkages are named by alpha or beta conformation and by which carbons are connected

Question 36

oligosaccharids contain two or more _________ linked by _______ bonds

Answer 36

monosaccharides linked by O-glycosidic bonds

Question 37

what are some common disaccharides?

Answer 37

sucrose, lactose, maltose

Question 38

what are homoglycans (aka polysaccharides that are homo)

Answer 38

contain only one type of monosaccharide. starch, glycogen, cellulose, chitin, no fixed molecular weight

Question 39

what are heteroglycans

Answer 39

contain two or more types of monosaccharides. | N and O linked oligosacchrides that are attached to prtoeins. glycosaminoglycans (GAGs)

Question 40

the _______ is the storage form of glucose in animal cells

Answer 40

polysaccharide glycogen Most glucose units in glycogen are lined by α-1, 4-glycosidic bonds, with branches formed by α-1, 6-glycosidic bonds every 10 glucose units.

Question 41

amylose

Answer 41

unbranched chains of D-glucose (alpha-1,4 linkages

Question 42

cellulose is a __ of glucose units linked by beta 1,4 glycocidic bond

Answer 42

homopolymer

Question 43

___________-formed between the anomeric carbon atom and a hydroxyl group of another molecule, and the product is called an GLYCOSIDE

Answer 43

O-glycosidic bond

Question 44

_________-formed between the anomeric carbon atom and an amine.

Answer 44

n-glycosidic bond

Question 45

carbohydrates can also form ester linkages to _________

Answer 45

phosphates

Question 46

glycoproteins:

Answer 46

the PROTIEN IS THE LARGEST COMPONENT by weight. glycoproteins play a variety of roles including as membrane proteins

Question 47

porteoglycans:

Answer 47

the proteins is attached to a particular type of polysaccharide called a GLYCOSAMINOGLYCAN. by weight, proteoglycans are MAINLY CARBOHYDRATE. proteoglycans play structural roles or act as lubricants

Question 48

mucins or mucoprotiens:

Answer 48

like proteoglycans, mucins are PREDOMINANTLY CARBOHyDRATE. the protein is characteristically attached to the carbohyddrate by N-acetylgalactosamine. mucins are often lubricants

Question 49

carbohydrates may be linked to ______,___, or _______ residues or proteins

Answer 49

asparagine, serine, or threonine

Question 50

what are the three main classes of glycoproteins?

Answer 50

glycoproteins proteoglycans mucins or mucoproteins

Question 51

erythropoietin

Answer 51

is a glycoprotein secreted by the kidney into the blood that stimulates the production of red blood cells

Question 52

proteoglycans are proteins attached to _______. which makes up 95% of the proteoglycan by weight

Answer 52

glycosaminoglycan where glycosaminoglycans are composed of repeating units of disaccharide, one of which is a derivative of an amino sugar and one which carries a negative charge, either as a carboxylate or sulfate

Question 53

cartilage is composed, in part, of the proteoglycan _____ and cartilage

Answer 53

aggrecan. not the glycosaminoglycan component of aggrecan cushions joints by releasing water on impact then rebinding water

Question 54

chitin, a glycosaminoglycan found in the exoskeleton of insects is __________________________________

Answer 54

one of hte most abundent carbohydrates in the world

Question 55

in _____, the protein component is extensively glycosylated to serine and threonine residues beginning with N-acetylgalactosamine. a region of the protein backbone rich in serines and theronines call variable number of tandem repeats, is the site of glycosylation mucins serve as lubricants

Answer 55

mucins

Question 56

the human ABO blood groups reflect the specificity of glycosyltransferases. all of the blood groups share the oligossaccharide foundation called O. in A, N-acetylgalactosamine is added to O by a specific glycosyltransferase in B, galactose is added by another transferase. the blood type O produced no active glycosyltransferase

Answer 56

General slide

Question 57

glycan

Answer 57

binding proteins bind to specific oliosaccharides on the cell surface

Question 58

lectins

Answer 58

are a particular class of glycans binding protiens

Question 59

selectins

Answer 59

are cell-surface carbohydrates binding proteins that mediate transient cell-cell adhesion in the blood stream and are important in many host defense mechanisms involving those cells

Question 60

glycome

Answer 60

the total set of sugars and glycans in a cell or organism

Question 61

is there a template for glycan biosynthesis?

Answer 61

no there is no template. it is done is a stepwise process

Question 62

_________ can result upon slight variations in glycan compostion of each glycoprotien

Answer 62

glycoforms