Carbohydrates 1 Flashcards Preview

01. Year 1: Science for Medicine > Carbohydrates 1 > Flashcards

Flashcards in Carbohydrates 1 Deck (50)
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1
Q

What is a carbohydrate?

A

Sugar and starch molecules

2
Q

Why are carbohydrates and major energy source?

A

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

3
Q

What are some functions of carbohydrates?

A

Store potential energy

Structural and protection functions (EM)

Cell to cell communication

4
Q

How are carbohydrates used to store potential energy?

A

As glycogen

5
Q

What are monosaccharides?

A

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

6
Q

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

A

Glucose

Fructose

Galactose

7
Q

What are disaccharides?

A

Formed from monomers that are linked by glycosidic bonds

8
Q

How do monosaccarides combine to form disaccharides?

A

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

9
Q

What is the anomeric carbon of glucose?

A

C1 on glucose

10
Q

What are properties of the anomeric carbon of glucose?

A

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

11
Q

What are different anomers to each other?

A

Mirror images

12
Q

What are 3 important disaccarides?

A

Maltose

Lactose

Succrose

13
Q

Do we get much maltose in our diet?

A

No, it is found in starch and beer

14
Q

Why is maltose termed a reducing sugar?

A

Anomeric C1 is available for oxidation

15
Q

What forms maltose?

A

Two molecules of glucose

16
Q

What is a reducing sugar?

A

A sugar that can be oxidised

17
Q

What is lactose the main sugar of?

A

Milk

18
Q

How is lactose formed?

A

Glycosidic bond between galactose and glucose

Galactose + Glucose ⇔ Lactose

19
Q

Why is lactose a reducing sugar?

A

Anomeric carbon in the glucose available for oxidation

20
Q

Where is succrose commonly found?

A

Table sugar

21
Q

What is succrose only made by?

A

Plants

22
Q

Is sucrose a reducing sugar?

A

No, because no free anomeric carbon atom

23
Q

How is succrose formed?

A

By glucose and fructose

Glucose + Fructose ⇔ Succrose

24
Q

What are polyassacharides?

A

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

25
Q

How can polyassacharides differ from one another?

A

Types of monomers

Length of chain

Types of bonds linking monomers

Amount of bonding

26
Q

What are the 2 types of polyassacharides?

A

Homopolyassacharides (single monomer spieces)

Heteropolyassacharides (two or more monomer spieces)

27
Q

What 2 types of glucose monomers does starch contain?

A

Amylose (D glucose in a1-4 linkage)

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

28
Q

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

A

The number of carbon in the sequence connected to each other

29
Q

How many reducing and non reducing ends does starch have?

A

Many non reducing and very few reducing ends

30
Q

Do enzymes act of non reducing or reducing ends?

A

Reducing ends

31
Q

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

A

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

32
Q

What do lots of branches in glycogen allow for?

A

To be quickly broken down or built up

33
Q

Where is 90% of glycogen found?

A

Liver

Skeletal muscle

34
Q

What is the purpose of the glycogen in the liver?

A

Replenish blood glucose whilst fasting

35
Q

What is the purpose of glycogen in skeletal muscles?

A

Catabolism to produce ATP for contraction

36
Q

Why is glycogen osmotically inactive?

A

It is not in solution

37
Q

Why is glycogen being osmotically inactive important?

A

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

38
Q

What are glycoproteins?

A

Proteins that have carbohydrates covalently attatched

39
Q

What may carbohydrates attached to proteins do?

A

Increase protein solubility

Influence protein folding

Protect it from degradadtion

Act as communication between cells

40
Q

What are glycoaminoglycans (GAGs)?

A

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

41
Q

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

A

Slimy, sticky molecules found in mucous and synovial fluid

42
Q

What are proteoglycans?

A

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

43
Q

Where are proteoglycans found?

A

In connective tissue

44
Q

What do proteoglycans do?

A

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

45
Q

Do glycoproteins have more protein or carbohydrate?

A

Protein

46
Q

Where are glycoproteins often found?

A

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

47
Q

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

A

Proteins attatched to carbohydrates

48
Q

What are mucopolyassacharides?

A

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

49
Q

What do mucopolyassacharide disorders cause?

A

A build up of glycosaminoglycans in cells which is damaging

50
Q

What is an example of a mucopolyassacharide disorder?

A

Hurler syndrome