chloroplast ultrastructure

describe the function of a chloroplast (2)

• absorbs light for photosynthesis

• produces sugars/glucose

what is the structure of a chloroplast?

• double plasma membrane

• thylakoids

• grana

• stroma

• DNA

• ribosomes

what is the function of the outer membrane of the double plasma membrane?

permeable to allow small molecules to diffuse in and out

what is the function of the inner membrane of the double plasma membrane?

regulates the passage of large substances in and out through transport proteins

what does the stroma contain? (5)

• enzymes

• starch granules

• proteins

• chloroplast DNA

• ribosomes

what is the structure and function of thylakoids? (3)

• membrane-bound compartments

• contain chlorophyll and other pigments to absorb light for photosynthesis

• also contain enzymes required for light dependent reactions

what is the structure of grana?

• formed from multiple thylakoids stacked on top one another

• joined together by lamellae (thylakoid membrane)

what does thylakoid membrane contain and what is its function?

ATP synthase enzymes which are required to make ATP in light dependent reactions

where do the light dependent reactions occur?

in the thylakoids

where do the light independent reactions occur?

in the stroma

what structural features of the chloroplast increase the rate of photosynthesis? (3)

• high S.A

• enzymes

• gas diffusion

how is the structure of a chloroplast adapted to its function in photosynthesis? (4)

• disc shape provides large surface for light absorption

• layering of membrane allows lots of pigment

• permeable membrane allows diffusion of gases

• stroma containing enzymes for calvin cycle / light independent reaction

describe how you would use cells fractionation to obtain a sample of chloroplasts from leaf tissue (don’t include info about solutions) (3)

• homogenise cells

• then centrifuge at increasing speeds until a chloroplast fraction is obtained