5.5 Photosynthesis - plant cells

Question 1

define photosynthesis:

Answer 1

the process in which light energy is used to build complex organic molecules e.g. glucose

Question 2

in photosynthesis light energy is made into what? and where is it stored?

Answer 2

chemical energy

stored in bonds of the complex organic molecules made

Question 3

what are autotrophs?

Answer 3

organisms that can photosynthesise e.g. plants, algae

Question 4

what are heterotrophs?

Answer 4

organisms which obtain complex molecules through eating

Question 5

both autotrophs and heterotrophs breakdown complex organic molecules in which process? and what is the purpose of this?

Answer 5

respiration

to release energy for metabolic processes

Question 6

where in a plant cell does photosynthesis take place?

Answer 6

chloroplast

Question 7

chloroplasts have a network of membranes, for what purpose?

Answer 7

to give a large surface area to maximise light absorption

Question 8

the membranes within chloroplasts form flattened sacs called what?

Answer 8

thylakoids

Question 9

(chloroplasts) thylakoids are stacked to form what?

Answer 9

grana

Question 10

(chloroplasts) grana are joined by lamellae what is lamellae?

Answer 10

membranous channels

Question 11

(chloroplasts) light is absorbed by what and where are they found?

Answer 11

pigments e.g. chlorophyll

found embedded in thylakoid membranes

Question 12

(chloroplasts) what is the fluid inside the chloroplasts and what is its purpose?

Answer 12

stroma

site of chemical reactions resulting in formation of complex organic molecules

Question 13

why are leaves green?

Answer 13

due to pigment chlorophyll - it reflects green light

Question 14

what is the primary pigment in plants?

Answer 14

chlorophyll a

Question 15

what are some other pigments in plants?

Answer 15

chlorophyll b
xanthophylls
carotenoids

Question 16

why are plants sometimes different colours?

Answer 16

different combinations of pigments which reflect different wavelengths of light

Question 17

what are the two stages of photosynthesis?

Answer 17

light dependant stage

light independent stage

Question 18

in the light dependant reaction light is converted to what type of energy?

Answer 18

chemical energy

Question 19

in the light dependant reaction, electron flow is created by what?

Answer 19

the effect of light on the chlorophyll causing photolysis

Question 20

what is photolysis?

Answer 20

splitting of water into protons, electrons and oxygen

Question 21

what are the products of the light dependant reaction?

Answer 21

reduced NADP
ATP
oxygen

Question 22

in the light independent reaction protons are used to reduce what?

Answer 22

CO2

to produce sugars and other organic molecules