Lecture 2-Carbohydrates Flashcards

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1
Q

What are carbohydrates?

A

Biological molecules containing C, H & O

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2
Q

What is the empirical formula of carbohydrates?

A

Cm(H20)n

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3
Q

What are the functions of carbohydrates?

A

Provide a rapid + available supply of energy
Sugar phosphate backbone in DNA
Form markers on the cell surface ( Blood group markers)

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4
Q

What is the general formula for MONOSACCHARIDES?

A

(CH20)n

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5
Q

What is an OLIGOSACCHARIDE?

A

Polymer of 3-20 monosaccharides

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6
Q

What is a POLYSACCHARIDE?

A

+20 monosaccharides

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7
Q

Examples of monosaccharides?

A

Glucose, Ribose, Fructose

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8
Q

What do monosaccharides tend to do?

A

Provide INSTANT energy

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9
Q

How many C atoms do a monosaccharide tend to have?

A

3-10

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10
Q

What functional groups do monosaccharides contain?

A

Aldehyde/Ketone & hydroxyl group

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11
Q

What makes a monosaccharide “deoxy”?

A

The replacal of a hydroxyl group with a H

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12
Q

What are the 2 forms of stereoisomerism in monosaccharides?

A

D and L

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13
Q

Stereoisomers have the same……

A

chemical formula, orders, types of bonds

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14
Q

Stereoisomers are non-overlapping mirror images so they have different…..

A

spatial arrangements, biological functions

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15
Q

Stereoisomers require what?

A

A CHIRAL centre

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16
Q

If the OH on a fichier projection is to the right, what type stereoisomer is it?

A

D

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17
Q

How do monosaccharides tend to exist?

A

As open-chain / ring structures (via covalent bonds)

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18
Q

What is CYCLIZATION?

A

The OH on the 2nd to last C bonds to a carbonyl group

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19
Q

Cyclization of an aldose sugar forms what?

A

A hemiacetal

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20
Q

Cyclization of a ketose sugar forms what?

A

A hemiketal

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21
Q

Cyclization of D-glucose forms what?

A

D-glucopyranose

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22
Q

Why are there 2 hemiacetal products of D-glucopyranose?

A

The OH group can attach either side of the planar C=0 group

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23
Q

What type of bonds do glucose have?

A

7 energy rich bonds

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24
Q

When are glucose bonds broken down?

A

During cellular respiration (releasing energy stores as ATP)

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25
Q

Where is fructose found?

A

Fruits,honey,berries

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26
Q

What type of structure does fructose form?

A

A FURAN-BASED RING STRUCTURE

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27
Q

Examples of disaccharides?

A

Sucrose, Maltose, Lactose

28
Q

What type of bonding exists in disaccharides?

A

Glycosidic links

29
Q

What is the primary function of disaccharides?

A

Nutritional source of MONOSACCHARIDES

30
Q

What is the structure of MALTOSE?

A

2 glucose molecules joined via an alpha 1,4 glycosidic link

31
Q

How can maltose be generated?

A

The breakdown of starch

32
Q

How is maltose digested to individual glucose monosaccharides?

A

via MALTASE

33
Q

Where is maltose present?

A

In germinating seeds + grain + the metabolising via yeast —-> ethanol and co2

34
Q

What is the structure of LACTOSE?

A

Glucose + Galactose joined via beta 1,4 glycosidic links

35
Q

How is lactose produced?

A

By lactating animals for their young

36
Q

How is lactose digested?

A

Via LACTASE

37
Q

What is the structure of SUCROSE?

A

Glucose + Fructose joined via an alpha 1,2 glycosidic ink

38
Q

Where can you find sucrose?

A

In plant sap (sugar cane/beet)

39
Q

How is sucrose digested?

A

Via SUCRASE

40
Q

What is a hydrolysis reaction?

A

The cleavage of chemical bonds by the addition of water

41
Q

Why do organisms convert soluble sugars to insoluble sugars?

A
For storage (starch/glycogen)
For building structures (cellulose)
For cellular processes (Glucose generation)
42
Q

Describe the 2 polysaccharide components of STARCH?

A

Amylose + Amylopectin

43
Q

What is AMYLOSE?

A

A long, linear chain of alpha 1,4 linked D-glucose residues with a COILED STRUCTURE

44
Q

What is AMYLOPECTIN?

A

A linear chain of alpha 1,4 linked D-glucose residues joined through ALPHA 1,6 BRANCH POINTS

45
Q

STARCH is the main dietary source of……

A

Carbohydrate

46
Q

STARCH is a main …………….. in plants

A

Storage polymer

47
Q

Where is starch found?

A

In amyloplasts + chloroplasts

48
Q

What are AMYLOPLASTS?

A

Non-pigmented organelles that synthesise + store starch granules through the polymerisation of glucose

49
Q

How is starch digested?

A

Via AMYLASE , produced in the salivary glands + the gut
Via MALTASE
Via ISOMALTASE, produced in the gut only

50
Q

What bonds do amylase + maltase break down in starch?

A

alpha 1,4 glycosidic links

51
Q

What bonds do isomaltase break down in starch ?

A

alpha 1,6 glycosidic links

52
Q

What is GLYCOGEN?

A

A complex, branched polysaccharide of linear chains of alpha 1,4 linked D-glucose residues joined through an alpha 1,6 linked branch points

53
Q

What difference in structure is there between amylopectin and glycogen?

A

Branch points occur more frequently in glycogen

8-12 residues VS 24-30 residues

54
Q

Where is glycogen found?

A

In the liver + muscle cells

55
Q

How much glucose does the blood typically maintain?

A

5-6mM

56
Q

What does the body do during starvation?

A

Try to maintain 5-6mM of glucose in the blood at the expense of glycogen stores in the liver + muscle

57
Q

What are glycoproteins?

A

Proteins that contain oligosaccharide chains attached covalently to a protein structure

58
Q

What type of membranes play an important role in cell recognition?

A

GLYCOSYLATED MEMBRANES

59
Q

Secreted glycoproteins make up what 2 things?

A

Mucins + Glycocalyx

60
Q

What are mucins?

A

Principal components of mucous membranes + saliva

61
Q

What are glycocalyx glycoproteins?

A

Cover cell membranes of epithelial + other cell types

62
Q

What are glycolipids?

A

Lipids that contain oligosaccharide chains attached covalently to a lipid structure

63
Q

What are glycolipids often associated with?

A

Phospholipids

  • Recognition signals
  • Attachment factors
  • Membrane stabilisers
64
Q

Describe sphingolipids?

A
  • Ceramide (signalling molecule)
  • Sphingomyelin (membranes)
  • Inflammation
65
Q

Describe glycosphingolipids?

A
  • Cerebrosides (found in muscles + nerves)

- Gangliosides (found in plasma membranes)