Chapter 10 Carbohydrates Flashcards

1
Q

What are three things that saccharides do?

A

-Energy transport and storage
-Structural support e.g. bacterial cell walls, cellulose
-Information e.g. signals on proteins and membranes

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2
Q

What is an Oligosaccharides?

A

it is a sugar with several sugar units

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3
Q

What is a polysaccharides?

A

It consists of Glycans in long chains of 100s which include 1000s of sugars

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4
Q

How many carbons is the smallest monosaccharide composed of

A

3 carbons

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5
Q

How do you tell if the structure is a D side or a L side structure

A

If the OH is on the right its a D side
If the OH is on the left its a L side
And you look at the chiral carbon furthest from the double C=O bond to determine this

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6
Q

What is an enantiomers?

A

They are non-superimposable mirror images

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7
Q

What is a Diastereomers?

A

-Non mirror image stereoisomers

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8
Q

What is a Epimers?

A

-Diastereomers that differ in configuration at 1C

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9
Q

What does a Aldehyde sugar look like?

A

It has a carbon double bonded to O and the same carbon single bonded to H

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10
Q

What does a Ketone sugar look like?

A

It has a carbon double bonded to O and a CH3Osingle bonded to the same carbon as well

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11
Q

What are the Aldoses derived from ?

A

D-glyceraldhyde

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12
Q

What are Ketoses derived from ?

A

Dihydroxyacetone

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13
Q

At which end does the carbon numbering begin from ?

A

It begins from the end of the molecule nearest the carbonyl carbon

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14
Q

An Aldehyde can react with alcohol to form what? and what happens if you react with second alcohol

A

A hemiacetal is formed with one and if second is added an Acetal is formed

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15
Q

A ketone can react with alcohol to form what? and what happens if you react with second alcohol?

A

A hemiketal is formed with one and if second is added a Ketal is formed

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16
Q

What is the ring formed by glucose in a intramolecular hemiacetal called?

A

Its a six carbon ring called pyranose

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17
Q

What is the ring formed by ketohexose fructose in a intramolecular hemiketal called

A

Its a five carbon ring called furanose

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18
Q

What is an anomer?

A

Its another diastereoisomeric form that is made from the formation of a cyclic hemiacetal

19
Q

At the alpha form of the ring where is the OH at C-1

A

It is below the plane of the ring

20
Q

At the beta form of the ring where is the Oh at C-1

A

It is above the plane of the ring

21
Q

What is an anomeric form ?

A

The furanose form of fructose can exist in anomeric and this is when alpha and beta forms refer to the orientation of the OH at C-2

22
Q

How many types of conformation can a pyranose ring adopt and what are they called?

A

-There are two conformations and they are called boat and chair

23
Q

In the chair form, how many orientations of OH on the carbon ring atoms are there and what are they called?

A

there are 2 and they are called axial and equatorial

24
Q

A solution of glucose contains approximately _________ alpha anomer,__________ Beta anomer, and ________ of the open-chain form.

A

One third, two third, <1%

25
Q

What are sugars called that react with oxidizing agents and what are sugars called that aren’t reacting with oxidizing agents?

A

Reducing sugars, and nonreducing sugars

26
Q

What is an O-glycosidic bond and what is the product of this bond called

A

This is a bond formed between the anomeric carbon atom of glucose and a hydroxyl group of another molecule and the product is called glycoside.

27
Q

What is a N-glycosidic bond?

A

A bond formed between the anomeric carbon atom of glucose and an amine

28
Q

Oligosaccharides contain _____or more _________________ linked by ____________bonds

A

2,monosaccharides, O-glycosidic bonds

29
Q

The substrates for glycosyltransferases area activated by attachment to____________________

A

uridine diphosphate

30
Q

Enzymes on the outer surface of intestinal epithelium cleave common _______________

A

disaccharides

31
Q

Sucrase cleaves___________, lactase cleaves ___________ , Maltase cleaves__________

A

Sucrose, Lactose, Maltose

32
Q

What is it called if all the monosaccharides in the polysaccharide are the same ?

A

It is called a homopolymer

33
Q

Most glucose units in glycogen are linked by __________________, with branches formed by _______________every ___________ glucose units

A

alpha-1 4-glycosidic bonds, alpha-1 6-glycosidic bonds ,12

34
Q

In plants glucose is stored as what and how many forms are there?

A

starch and there are 2 forms

35
Q

What is an Amylose?

A

It is a linear polymer of glucose units linked by alpha-1,4-glycosidic bonds

36
Q

What is an Amylopectin?

A

It is a branched polymer with an alpha-1,6-glycosidic bond for every 30 alpha-1,4-glycosidic bonds

37
Q

What type of structure does a IAmylose form ?

A

it forms a tightly coiled helical structure stabilized by H-bonding with 6 residues per turn

38
Q

what is II Amylopectin?

A

Up to 200 amylose chains linked alpha 1–>6 at branch points. So just like iso-maltose

39
Q

what does saliva and pancreas secrete and what does it randomly cleave ?

A

Alpha-amylase is secreted and Alpha-1,4bonds are cleaved randomly

40
Q

Plants and bacteria secrete ________________ that removes __________units starting at the _____________end

A

Beta-amylase, Maltose, Non-reducing

41
Q

What do debranching enzymes hydrolyze?

A

alpha-1,6 bonds

42
Q

Cellulose is a homopolymer of glucose units linked by_______________________

A

Beta-1,4-glycocidic bonds

43
Q

The beta linkage yields a __________________ capable of interacting with other cellulose molecules to form ______________

A

Straight chain, strong fibrils

44
Q

The alpha linkages of starch and glycogen form _____________________ suitable for accessible storage

A

compact hollow cylinders