5A - C3 Photosynthesis

Question 1

photoautotroph

Answer 1

 an organism
capable of undertaking
photosynthesis
(make their food rather than consuming it)

Question 2

photosynthesis

Answer 2

the process of
capturing light energy to power the production of glucose and oxygen
from carbon dioxide and water

Question 3

glucose and what its used as

Answer 3

• primary product of photosynthesis.
• used immediately as a source of energy for cellular respiration
• stored as starch
• used to form more complex molecules such as cellulose

Question 4

elaborate on leaves and the main organelles used in it for photosynthesis

Answer 4

Leaves are the main site of photosynthesis in plants (large SA to maximise light)
- mesophyll cells - contain large populations of chloroplasts - filled w chlorophyll

Question 5

stomata

Answer 5

open to allow carbon dioxide in the
atmosphere to diffuse into the leaf.
close to prevent water loss from the leaf in dry conditions.

Question 6

xylem

Answer 6

vascular tissue in plants
responsible for transporting water
and minerals from the roots to
the leaves

Question 7

where does the light dependent stage occur

Answer 7

on the chlorophyll-filled
thylakoid membranes which make up the grana inside a chloroplast

Question 8

what is the purpose of the light dependent stage

Answer 8

generate the high energy coenzymes NADPH and ATP to power the second
stage of photosynthesis.

Question 9

general steps of light dependent stage

Answer 9

Sunlight excites an electron within chlorophyll.
* Water is split into O2 and H+ as it donates one electron to the chlorophyll.
* The excited electron and H+ ion from water lead to the production of the coenzymes
NADPH and ATP.
* The oxygen is released out of the chloroplast, and the coenzymes are ready for the second stage of photosynthesis.

Question 10

input and output molecules of light stage

Answer 10

12 H2O, 12 NADP+,
18 ADP+ Pi
e ATP synthase catalyses the reaction ADP + Pi  ATP using
energy from the flow of H+ down its concentration gradient
into:
6 O2, 12 NADPH,18 ATP

Question 11

ATP synthase catalyses the reaction

Answer 11

ADP + Pi -> ATP using
energy from the flow of H+ down its concentration gradient

Question 12

NADPH _____ while ATP ______

Answer 12

transfers hydrogen ions
transfers energy

Question 13

During the second stage of photosynthesis,

Answer 13

glucose is produced from carbon dioxide,
NADPH, and ATP through a cycle of reactions occurring in the stroma of chloroplasts.

Question 14

The inputs of the light-independent stage are:

The outputs of the light-independent stage are:

Answer 14

• 6 carbon dioxide (CO2) molecules
• 12 NADPH
• 18 ATP

outputs:
* glucose (C6H12O6)
* 6 water (H2O) molecules
* 12 NADP+
* 18 ADP + Pi

Question 15

summary of light independent stage

Answer 15

CO2 collected from the stomata in leaves enters a cyclic reaction.
* The carbon, from CO2, undergoes reactions powered by ATP and NADPH to produce a
series of carbon-based molecules.
* Eventually, a specific carbon molecule is reached that goes on to contribute to the
formation of glucose, with water also being produced in this stage.