Photosynthesis

Question 1

what are the three organelles unique to plant cells?

Answer 1

cell wall
vacuoles
plastids

Question 2

what are the three types of plastid?

Answer 2

amyoplasts
chloroplasts
chromoplasts

Question 3

how large are plant cells?

Answer 3

up to 5x the size of animal cells

Question 4

what is the cell wall composed of ?

Answer 4

polysaccharides

Question 5

what are unique features of the cell wall?

Answer 5

they mean the plant cell cannot change shape
they mean that the plant cells are firmly fixed to each other
they stop the plant cell ingesting food by endocytosis
the cell wall stops the plant cell bursting osmotically
the cell wall stops attacks by pathogens

Question 6

why is a plant cell autotrophic?

Answer 6

it makes its own energy as the cell wall prevents ingestion by endocytosis

Question 7

how big is a cell walls vacuole?

Answer 7

30-50% of the cells volume

Question 8

what are vacuoles made from?

Answer 8

ER and Golgi

Question 9

what do vacuoles do for the cell?

Answer 9

they sequester any compounds reaching toxic quantity in the cell
they keep compounds that are toxic to pests
they are important to cell growth without using a lot of energy
they contain digestive enzymes like lysosomes

Question 10

what are chromoplasts?

Answer 10

plastids that contain pigments

Question 11

what are amyoplasts?

Answer 11

plastids that store starch

Question 12

what are proplastids?

Answer 12

the precursor to plastids that can develop into whichever plastid type is needed by the cell

Question 13

what are the internal structures of a chloroplast?

Answer 13

inner and outer membrane
membrane structures known as thylakoids
granums (stacks of thlakoids)
stroma - the colourless fluid surrounding the granum
copies of parts of their own genome
proteins and structures necessary for proteinsynthesis

Question 14

can different plastids interconvert?

Answer 14

yes

Question 15

how many plant proteins are encoded and stored in chloroplasts?

Answer 15

120/2,000 - 5,000

Question 16

where are most plant proteins synthesised?

Answer 16

the cytoplasm of the cell

Question 17

what processes make up photosynthesis?

Answer 17

the light reaction and the Calvin cycle

Question 18

which proteins and pigments are involved in the light reaction?

Answer 18

chlorophyll a, b and carotenoids

Question 19

what are the stages of the light reaction?

Answer 19

light is absorbed by the light harvesting complexes in the photosystem 2.
this results in 2 electrons aquiring energy
these electrons proceed through the electron transport chain resulting in the production of energy that can be used by the cell

Question 20

what happens when water is split during the light reaction?

Answer 20

oxygen and H+ are released resulting in the high energy state of the electrons in the photosystem

Question 21

where is the electron transport chain embedded ?

Answer 21

in the thylakoid membrane

Question 22

how is NADPH produced?

Answer 22

the electrons reduce NADP+

Question 23

how is a proton motor force created in the light reaction?

Answer 23

the build up of H+ ions in the thylakoid space from the break down of water plus the addition of H+ ions in the space as a consequence of the movement of electrons

Question 24

what happens as a consequnce of the proton motor force?

Answer 24

ATP is generated

Question 25

what are the 3 phases of the Calvin cycle?

Answer 25

carbon fixation
reduction
regeneration of the CO2 acceptor

Question 26

where does the cavlin cycle take place?

Answer 26

the stroma

Question 27

what happens during the calvin cycle?

Answer 27

CO2 is fixed and NADP and ATP are regenerated and sugars are synthesised

Question 28

how are the calvin cycle reactions catalysed?

Answer 28

the enzyme rubisco

Question 29

how affective is rubisco as an enzyme?

Answer 29

very ineffective hense plant cells have large amounts of it

Question 30

how can biologists use and improve the photosynthetic pathway?

Answer 30

research into improving the efficiency of rubsico is being done to increase crop yields