cell biology

Question 1

what is the equation for microscopy?

Answer 1

magnification=image size/real size

Question 2

give examples for specialised cells

Answer 2

sperm cells-reproduction 
nerve cells-rapid signalling 
muscle cells-contraction 
root hair cells-absorbing water and minerals 
phloem and xylem-transporting substances

Question 3

how many pairs of chromosomes do we have in our body?

Answer 3

23 pairs

Question 4

what is the cell cycle used for?

Answer 4

growth, development and repair

Question 5

describe mitosis

Answer 5

• the cell has to grow to increase amount of sub cellular structures like mitochondria
• it then duplicates its DNA sothat there is one copy for each new cell
• chromosomes line up in the middle of the cell and get dragged away by cell fibres
• then cytoplasm and cell membrane divide making two identical daughter cells

Question 6

what is binary fission?

Answer 6

the pay prokaryotic cells replicate

Question 7

what has exchage happens in the lungs

Answer 7

oxygen into the blood, carbon dioxide out

Question 8

what is villi?

Answer 8

provide a big surface area inside small intestine

Question 9

what is alveoli?

Answer 9

specialised to maximise the diffusion of gasses in the lungs

Question 10

how does gaseous exchange occur in leaves?

Answer 10

via the stomata/guard cells

Question 11

how does gaseous exchange occur in the gills?

Answer 11

water (containing oxygen) enters through the mouth and out through the gills
as this happens, oxygen diffuses into the blood and carbon dioxide diffuses into water