Unit 2

Question 0

Describe starch and how it’s suited for it’s role?

Answer 0

It’s a polysaccharide in the form of small granules
It’s in branched chain is wound into a coil so it’s compact
It’s insoluble so doesn’t draw water into cells by osmosis
Compact so lots can be stored
Made from a-glucose which is easily transported and readily used in respiration

Question 1

What’s Selective breeding?

Answer 1

Involves identifying individuals with desired characteristics and using then to part the next generation

Question 2

Describe glycogen

Answer 2

Has shorter chains and Is more highly branched
It’s stored as granules in muscle and liver cells
As it has shorter chains it’s even more readily hydrolysed to a-glucose
Coiled a-glucose chain

Question 3

Describe cellulose

Answer 3

Made from B-glucose the OH group is at the top
Have to be rotated 180
Has straight unbranched chains allowing hydrogen bonds to form cross linkages and many of them strengthen it
Cellulose molecules grouped together form microfibrils
Major component in cell wall providing rigidity by exerting an inward pressure

Question 4

How are leaf palisade cells adapted?

Answer 4

Long thin cells for continuous layer for absorption of sunlight
Many chloroplasts arrange in the best position to collect sunlight
Large vacuole pushes cytoplasm and cloroplasts to edge of cell

Question 5

How are chloroplasts adapted for photosynthesis?

Answer 5

The granal membranes provide a large surface area for attachment of chlorophyll
Fluid in the stroma possess all enzymes needed to carry out 2nd stage of photosynthesis
Chloroplast contain DNA and ribosomes to quickly manufacturer proteins for photosynthesis