chloroplasts

Question 1

shape

Answer 1

vary but are usually disc shaped

Question 2

size

Answer 2

vary but usually 1 um in diameter and 2-10um long

Question 3

main features

Answer 3

• chloroplast envelope
• grana
• thylakoids
• stroma

Question 4

chloroplast envelope

Answer 4

double plasma membrane that surrounds the organelle highly selective in what it allows to leave and enter the cell

Question 5

grana

Answer 5

stacks of up to 100 disc like thylakoids

where 1st stage of photosynthesis takes place (light absorption)

Question 6

thylakoids

Answer 6

contain photosynthetic pigment called chlorophyll. some have tubular extensions that join up with thylakoids in adjacent grana

Question 7

stroma

Answer 7

fluid filled matrix where the 2nd stage of photosynthesis takes place (synthesis of sugars). within the stroma are a number of other structures, such as starch grains

Question 8

functions

Answer 8

• granal membranes provide a large surface area for the attachment of chlorophyll, electron carriers and enzymes that carry out the first stage of photosynthesis
• fluid of stroma posseses all the enzymes needed to make sugars for 2nd stage of photosynthesis
• chloroplasts contain DNA and ribosomes so they can quickly and easily manufacture some of the proteins needed for photosynthesis