Lecture 2-Carbohydrates

Question 1

What are carbohydrates?

Answer 1

Biological molecules containing C, H & O

Question 2

What is the empirical formula of carbohydrates?

Answer 2

Cm(H20)n

Question 3

What are the functions of carbohydrates?

Answer 3

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

Question 4

What is the general formula for MONOSACCHARIDES?

Answer 4

(CH20)n

Question 5

What is an OLIGOSACCHARIDE?

Answer 5

Polymer of 3-20 monosaccharides

Question 6

What is a POLYSACCHARIDE?

Answer 6

+20 monosaccharides

Question 7

Examples of monosaccharides?

Answer 7

Glucose, Ribose, Fructose

Question 8

What do monosaccharides tend to do?

Answer 8

Provide INSTANT energy

Question 9

How many C atoms do a monosaccharide tend to have?

Answer 9

3-10

Question 10

What functional groups do monosaccharides contain?

Answer 10

Aldehyde/Ketone & hydroxyl group

Question 11

What makes a monosaccharide “deoxy”?

Answer 11

The replacal of a hydroxyl group with a H

Question 12

What are the 2 forms of stereoisomerism in monosaccharides?

Answer 12

D and L

Question 13

Stereoisomers have the same……

Answer 13

chemical formula, orders, types of bonds

Question 14

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

Answer 14

spatial arrangements, biological functions

Question 15

Stereoisomers require what?

Answer 15

A CHIRAL centre

Question 16

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

Answer 16

D

Question 17

How do monosaccharides tend to exist?

Answer 17

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

Question 18

What is CYCLIZATION?

Answer 18

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

Question 19

Cyclization of an aldose sugar forms what?

Answer 19

A hemiacetal

Question 20

Cyclization of a ketose sugar forms what?

Answer 20

A hemiketal

Question 21

Cyclization of D-glucose forms what?

Answer 21

D-glucopyranose

Question 22

Why are there 2 hemiacetal products of D-glucopyranose?

Answer 22

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

Question 23

What type of bonds do glucose have?

Answer 23

7 energy rich bonds

Question 24

When are glucose bonds broken down?

Answer 24

During cellular respiration (releasing energy stores as ATP)

Question 25

Where is fructose found?

Answer 25

Fruits,honey,berries

Question 26

What type of structure does fructose form?

Answer 26

A FURAN-BASED RING STRUCTURE

Question 27

Examples of disaccharides?

Answer 27

Sucrose, Maltose, Lactose

Question 28

What type of bonding exists in disaccharides?

Answer 28

Glycosidic links

Question 29

What is the primary function of disaccharides?

Answer 29

Nutritional source of MONOSACCHARIDES

Question 30

What is the structure of MALTOSE?

Answer 30

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

Question 31

How can maltose be generated?

Answer 31

The breakdown of starch

Question 32

How is maltose digested to individual glucose monosaccharides?

Answer 32

via MALTASE

Question 33

Where is maltose present?

Answer 33

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

Question 34

What is the structure of LACTOSE?

Answer 34

Glucose + Galactose joined via beta 1,4 glycosidic links

Question 35

How is lactose produced?

Answer 35

By lactating animals for their young

Question 36

How is lactose digested?

Answer 36

Via LACTASE

Question 37

What is the structure of SUCROSE?

Answer 37

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

Question 38

Where can you find sucrose?

Answer 38

In plant sap (sugar cane/beet)

Question 39

How is sucrose digested?

Answer 39

Via SUCRASE

Question 40

What is a hydrolysis reaction?

Answer 40

The cleavage of chemical bonds by the addition of water

Question 41

Why do organisms convert soluble sugars to insoluble sugars?

Answer 41

``` For storage (starch/glycogen) For building structures (cellulose) For cellular processes (Glucose generation) ```

Question 42

Describe the 2 polysaccharide components of STARCH?

Answer 42

Amylose + Amylopectin

Question 43

What is AMYLOSE?

Answer 43

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

Question 44

What is AMYLOPECTIN?

Answer 44

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

Question 45

STARCH is the main dietary source of......

Answer 45

Carbohydrate

Question 46

STARCH is a main ................. in plants

Answer 46

Storage polymer

Question 47

Where is starch found?

Answer 47

In amyloplasts + chloroplasts

Question 48

What are AMYLOPLASTS?

Answer 48

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

Question 49

How is starch digested?

Answer 49

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

Question 50

What bonds do amylase + maltase break down in starch?

Answer 50

alpha 1,4 glycosidic links

Question 51

What bonds do isomaltase break down in starch ?

Answer 51

alpha 1,6 glycosidic links

Question 52

What is GLYCOGEN?

Answer 52

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

Question 53

What difference in structure is there between amylopectin and glycogen?

Answer 53

Branch points occur more frequently in glycogen | 8-12 residues VS 24-30 residues

Question 54

Where is glycogen found?

Answer 54

In the liver + muscle cells

Question 55

How much glucose does the blood typically maintain?

Answer 55

5-6mM

Question 56

What does the body do during starvation?

Answer 56

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

Question 57

What are glycoproteins?

Answer 57

Proteins that contain oligosaccharide chains attached covalently to a protein structure

Question 58

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

Answer 58

GLYCOSYLATED MEMBRANES

Question 59

Secreted glycoproteins make up what 2 things?

Answer 59

Mucins + Glycocalyx

Question 60

What are mucins?

Answer 60

Principal components of mucous membranes + saliva

Question 61

What are glycocalyx glycoproteins?

Answer 61

Cover cell membranes of epithelial + other cell types

Question 62

What are glycolipids?

Answer 62

Lipids that contain oligosaccharide chains attached covalently to a lipid structure

Question 63

What are glycolipids often associated with?

Answer 63

Phospholipids - Recognition signals - Attachment factors - Membrane stabilisers

Question 64

Describe sphingolipids?

Answer 64

- Ceramide (signalling molecule) - Sphingomyelin (membranes) - Inflammation

Question 65

Describe glycosphingolipids?

Answer 65

- Cerebrosides (found in muscles + nerves) | - Gangliosides (found in plasma membranes)