Molecules

Question 1

What are the three main groups carbohydrates are split into?

Answer 1

Monosaccharides - basic carbohydrate monomer
Disaccharides - double sugars from two monosaccharide monomers
Polysaccharides - complex molecules, consist of many monosaccharide monomers

Question 2

What is the role of cellulose

Answer 2

It has a structural role

Question 3

What are disaccharides?

Answer 3

Formed when two monosaccharides react together in a reaction, condensation.
This is a reversible reaction.
Disaccharides can be broken down by hydrolysis.
Bond formed between two hexose sugars is a glycosidic bond
(a-1,4 gylcosidic bond)
General Formula = C12H22011
Maltose - formed when two a-glucose molecules are linked by condensation reaction
Sucrose - formed when an a-glucose molecule condenses with a fructose molecule
All disaccharides dissolve in water and produce a sweet taste.

Question 4

What is cellulose made of?

Answer 4

Monomers of B-glucose. Two B-glucose molecules join together to form a B-1,4 glycosidic bond. - Alternate molecules are rotated - this is necessary due to different structure of the B-glucose… this has two effects -
The unbranched chains become straighter
or
hydrogen bonds can form cross linkages between adjacent chains.
These form bundles called microfibrils

Question 5

What are microfibrils?

Answer 5

Each microfibril consisting of many cellulose molecules.

Plant cell walls are formed of the cellulose microfibrils, placed in a lattice structure to increase its strength.

Question 6

What are prions?

What are disease causing prions?

Answer 6

A particular type of protein. They are found in the nervous system, are involved in synaptic transmission.
Normal form of prion proteins can be converted into disease causing prions.
If a disease causing prion is present, they will convert normal prions into disease causing.
Disease causing prions have a higher proportion of beta sheets.
As the disease causing prions increase and the beta sheets, it will reach a level that will cause neurodegenerative disorders in the brain and nervous system - will lead to death.

Question 7

What causes a disease causing prion to form?

Answer 7

The normal prion can spontaneously adopt the disease causing form.
Mutations in the DNA that codes for prions can occur, meaning it can be passed from parent to offspring.
Can also occur through eating contaminated food.

Question 8

What are some prion diseases?

Answer 8

Scrapie found in sheep
‘BSE’ or ‘mad cow disease’ - normally cattle who have consumed contaminated food
vCJD - human version of BSE - usually due to eating contaminated beef.