ch 17

Question 1

define growth

Answer 1

it is a permenant irreversible increase in the dry mass due to increase in the number of cells

Question 2

define development

Answer 2

it is a process by which the cells become more specialized and more differentiated to do a specicfic function

Question 3

what is seed germination

Answer 3

the seed germinate (embryo grows) by producing radicle and plumule using stored food in the seed

Question 4

steps of seed germination [3]

Answer 4

-water enters seeds through the micropyle to activate the enzyme
-water activates the enzymes which convert the stored food in the seed from large molecule to small molecule and insoluble molecule to soluble molecule
-the small soluble molecules are used by the growing embryo, radicle from the root and plumule for the shoot

Question 4

conditions for seed germination and why

Answer 4

-water, it activates seed enzymes
-oxygen, needed for respiration and production of energy
-suitable temperature , (optimum temp. is from 30 to 40) for maximum enzyme activity `

Question 5

experiment that shows water is needed for seed germination [4]

Answer 5

-get 2 petri dishes , put them in 2 pieces of cotton one dry and one moist
-in each dish , add 5 seeds leave them to germinate for 3 days
-only seeds in moist cotton germinate while those in dry cotton dont
-should use same diamter of dishes, same size of cotton, same number of seeds, same time interval,same conditions of germination

Question 6

compare fresh mass and dry mass [3]

Answer 6

-fresh mass is mass of the organism with water and dry mass is mass of the organism without water
-fresh mass is less accurate, because amount of water varies from time to time
-dry mass is found by putting the organism in hot oven to evaporate water