5.2.3 - Chloroplasts : Structure & Function

Question 1

Describe The Structure Of The Chloroplasts

Answer 1

~ Flattened organelles found in plant cells, where photosynthesis occurs.

~ Surrounded by a double membrane, known as the chloroplast envelope, keeping all the components needed for photosynthesis close together.

~ Contains the stroma, contained within the inner membrane and surrounding the thylakoids.

~ Contains the thylakoids.

~ Contains ATPase enzymes, to produce ATP in the light-dependant reactions.

~ Contains photosystems.

Question 2

Describe The Structure & Function Of The Stroma

Answer 2

Contains all the enzymes, sugars, ribosomes and chloroplast DNA required for the light-independent reactions to take place.

Question 3

Describe The Structure & Function Of The Thylakoids
(4 Points)

Answer 3

~ Each surrounded by a thylakoid membrane.

~ They stack up to form grana.

~ Grana are connected by membranous channels called lamellae, ensuring the stacks of membrane are connected but distanced from each other.

~ Have a large surface area to allow as much light energy to be absorbed as possible.

Question 4

Describe The Structure & Function Of Photosystems
(3 Points)

Answer 4

~ Contains photosystems 1 and 2, containing different combinations of photosynthetic pigments such as chlorophyll a, b and carotene.

~ These are coloured substances that absorb light energy needed for photosynthesis.

~ Each photosystem absorbs light of a different wave length, maximising light absorption.