2.4 Biological Molecules

Question 1

What is the function of haemoglobin?

Answer 1

To associate with oxygen at gas exchange surface

Disassociate with oxygen at tissues

Question 2

What is the effect of carbon dioxide?

Answer 2

When levels of carbon dioxide Decrease the pH increases.

The high pH changes the shape of haemoglobin so it can load oxygen

Question 3

What is starch?

Answer 3

Polysaccharide found in plants
Alpha glucose linked by condensation reactions
Unbranched – allows compact

Good energy store
Insoluble
Doesn’t diffuse
Hydrolysis forms alpha glucose for respiration

Question 4

What is glycogen?

Answer 4

‘Animal starch’
Similar to starch
Stored in muscles and liver

Question 5

What is cellulose?

Answer 5

Polysaccharide of alpha and beta glucose
Rotates to form glycosidic bonds
Hydrogen forms between each row of molecules this creates a turgid shape

Question 6

What is haemoglobin?

Answer 6

Four polypeptide chains

With the haem group of iron to bind oxygen

Question 7

What is the leaf Palisades cell?

Answer 7

Photosynthesise
Long thin cells absorb sunlight
Chloroplasts arrange to gain light
Large vacuole pushes chloroplasts to the edge

Question 8

What is a chloroplast?

Answer 8

The envelope has a double membrane
Grana – stacks of thylakoids
Thylakoids– Chlorophyll and tubular extensions link thylakoids
Stroma – fluid filled matrix

Question 9

How are chloroplasts adopted?

Answer 9

Granal a membrane has a large surface area for chlorophyll attachment
Stroma fluid contains enzymes

Question 10

What is the cell wall?

Answer 10

Polysaccharide such a cellulose
Middle lamella cements wall together
Mechanical strength
Allows water to pass