Carbohydrates 1

Question 1

What is a carbohydrate?

Answer 1

Sugar and starch molecules

Question 2

Why are carbohydrates and major energy source?

Answer 2

They are high oxidisable, containing large amounts of high energy H atoms and associated electrons

Question 3

What are some functions of carbohydrates?

Answer 3

Store potential energy

Structural and protection functions (EM)

Cell to cell communication

Question 4

How are carbohydrates used to store potential energy?

Answer 4

As glycogen

Question 5

What are monosaccharides?

Answer 5

Any class of sugar that cannot be hydrolysed to give simpler sugars

Question 6

What are the 3 important hexoses (6C sugars)?

Answer 6

Glucose

Fructose

Galactose

Question 7

What are disaccharides?

Answer 7

Formed from monomers that are linked by glycosidic bonds

Question 8

How do monosaccarides combine to form disaccharides?

Answer 8

Covalent bonds are formed when hydroxyl groups of one monosaccharid reactions with another anomeric carbon of another

Question 9

What is the anomeric carbon of glucose?

Answer 9

C₁ on glucose

Question 10

What are properties of the anomeric carbon of glucose?

Answer 10

Stabalises the structure and is the only one that can be oxidised

Question 11

What are different anomers to each other?

Answer 11

Mirror images

Question 12

What are 3 important disaccarides?

Answer 12

Maltose

Lactose

Succrose

Question 13

Do we get much maltose in our diet?

Answer 13

No, it is found in starch and beer

Question 14

Why is maltose termed a reducing sugar?

Answer 14

Anomeric C₁ is available for oxidation

Question 15

What forms maltose?

Answer 15

Two molecules of glucose

Question 16

What is a reducing sugar?

Answer 16

A sugar that can be oxidised

Question 17

What is lactose the main sugar of?

Answer 17

Milk

Question 18

How is lactose formed?

Answer 18

Glycosidic bond between galactose and glucose

Galactose + Glucose ⇔ Lactose

Question 19

Why is lactose a reducing sugar?

Answer 19

Anomeric carbon in the glucose available for oxidation

Question 20

Where is succrose commonly found?

Answer 20

Table sugar

Question 21

What is succrose only made by?

Answer 21

Plants

Question 22

Is sucrose a reducing sugar?

Answer 22

No, because no free anomeric carbon atom

Question 23

How is succrose formed?

Answer 23

By glucose and fructose

Glucose + Fructose ⇔ Succrose

Question 24

What are polyassacharides?

Answer 24

Carbohydrate whole molecule consists of a number of sugar molecules bonded together

Question 25

How can polyassacharides differ from one another?

Answer 25

Types of monomers Length of chain Types of bonds linking monomers Amount of bonding

Question 26

What are the 2 types of polyassacharides?

Answer 26

Homopolyassacharides (single monomer spieces) Heteropolyassacharides (two or more monomer spieces)

Question 27

What 2 types of glucose monomers does starch contain?

Answer 27

Amylose (D glucose in a1-4 linkage) Amylopectin (glycosidic a1-4 bonds join glucose in chain but branches are a1-6)

Question 28

What does aX-Y refer to in terms of bonding?

Answer 28

The number of carbon in the sequence connected to each other

Question 29

How many reducing and non reducing ends does starch have?

Answer 29

Many non reducing and very few reducing ends

Question 30

Do enzymes act of non reducing or reducing ends?

Answer 30

Reducing ends

Question 31

What allows for glycogen to have lots of non reducing ends?

Answer 31

Branch points (a1-6) every 8 to 12 residues

Question 32

What do lots of branches in glycogen allow for?

Answer 32

To be quickly broken down or built up

Question 33

Where is 90% of glycogen found?

Answer 33

Liver Skeletal muscle

Question 34

What is the purpose of the glycogen in the liver?

Answer 34

Replenish blood glucose whilst fasting

Question 35

What is the purpose of glycogen in skeletal muscles?

Answer 35

Catabolism to produce ATP for contraction

Question 36

Why is glycogen osmotically inactive?

Answer 36

It is not in solution

Question 37

Why is glycogen being osmotically inactive important?

Answer 37

If it was free glucose (osmotically active) it would constantly leave the cell down its concentration gradient

Question 38

What are glycoproteins?

Answer 38

Proteins that have carbohydrates covalently attatched

Question 39

What may carbohydrates attached to proteins do?

Answer 39

Increase protein solubility Influence protein folding Protect it from degradadtion Act as communication between cells

Question 40

What are glycoaminoglycans (GAGs)?

Answer 40

Unbranched polymers made from repeating units of hexuronic acid and an amino-sugar

Question 41

What are properties of glycosaminoglycans (GAGs) and where are they found?

Answer 41

Slimy, sticky molecules found in mucous and synovial fluid

Question 42

What are proteoglycans?

Answer 42

Formed from glycosaminoglycans (GAGs) covalently attatched to proteins, more carbohydrates than protein

Question 43

Where are proteoglycans found?

Answer 43

In connective tissue

Question 44

What do proteoglycans do?

Answer 44

Allow the cell to connect to the extracellular matrix (EM)

Question 45

Do glycoproteins have more protein or carbohydrate?

Answer 45

Protein

Question 46

Where are glycoproteins often found?

Answer 46

On the outside of the cell membrane and in the extracellular matrix (EM)

Question 47

What do you generally find anywhere you need to stick things together?

Answer 47

Proteins attatched to carbohydrates

Question 48

What are mucopolyassacharides?

Answer 48

Group of genetic disorders caused by absence or modification of enzymes that are required for breakdown of glycosaminoglucans (GAGs)

Question 49

What do mucopolyassacharide disorders cause?

Answer 49

A build up of glycosaminoglycans in cells which is damaging

Question 50

What is an example of a mucopolyassacharide disorder?

Answer 50

Hurler syndrome