5A - Chloroplasts

Question 1

What are chloroplasts?

Answer 1

Chloroplasts are organelles in plant cells where photosynthesis occurs.

Question 2

What is the structure of the chloroplast envelope?

Answer 2

The chloroplast envelope is a double-membrane surrounding the chloroplast, consisting of phospholipid bilayers.

Question 3

What is the stroma?

Answer 3

The stroma is a cytoplasm-like fluid within the chloroplast that contains enzymes, sugars, ribosomes, and chloroplast DNA.

Question 4

What might be found in the stroma if the chloroplast has been photosynthesizing?

Answer 4

Starch grains or lipid droplets may be present in the stroma.

Question 5

What is the membrane system in the stroma?

Answer 5

The membrane system consists of flattened fluid-filled sacs called thylakoids, surrounded by thylakoid membranes.

Question 6

What are grana and lamellae?

Answer 6

Grana are stacks of thylakoids, while lamellae are membranous channels that connect the grana, ensuring they are connected but distanced.

Question 7

What components are embedded in the thylakoid membranes?

Answer 7

Components embedded in the thylakoid membranes include ATP synthase enzymes and photosystems with photosynthetic pigments like chlorophyll a, chlorophyll b, and carotene.

Question 8

What is the function of the chloroplast envelope?

Answer 8

The double membrane of the chloroplast envelope encloses the chloroplast, keeping all components necessary for photosynthesis in close proximity.

Question 9

What is the function of the stroma?

Answer 9

The stroma contains enzymes that catalyze the reactions of photosynthesis.

Question 10

What is the role of chloroplast DNA?

Answer 10

Chloroplast DNA contains genes that code for some of the proteins involved in photosynthesis.

Question 11

What is the role of ribosomes in chloroplasts?

Answer 11

Ribosomes in chloroplasts enable the translation of proteins coded by chloroplast DNA.

Question 12

What is the significance of the thylakoid membrane?

Answer 12

The thylakoid membrane creates a space called the thylakoid space, which allows for the establishment of conditions different from the stroma, such as a proton gradient.

Question 13

What is the purpose of grana in chloroplasts?

Answer 13

Grana provides a large surface area, maximizing the number of photosystems and enhancing light absorption.

Question 14

What is the role of grana in ATP production?

Answer 14

Grana provide more membrane area for proteins like electron carriers and ATP synthase enzymes, facilitating ATP production.

Question 15

What are photosystems?

Answer 15

Photosystems are protein complexes containing photosynthetic pigments (e.g., chlorophyll a, chlorophyll b, carotene) that absorb light energy.

Question 16

How many types of photosystems are there?

Answer 16

There are two types of photosystems: photosystem I and photosystem II.

Question 17

What differentiates photosystem I and photosystem II?

Answer 17

Photosystem I absorbs light at a wavelength of 700 nm, while photosystem II absorbs light at a wavelength of 680 nm.

Question 18

Why are there different photosystems?

Answer 18

Different photosystems absorb light of different wavelengths, allowing for maximum light absorption and efficiency in photosynthesis.

Question 19

What is the function of photosystems in photosynthesis?

Answer 19

Photosystems capture light energy and initiate the process of converting light energy into chemical energy during photosynthesis.

Question 20

What is the role of carotene in photosystems?

Answer 20

Carotene is a photosynthetic pigment that assists in light absorption and helps broaden the range of light wavelengths that can be used in photosynthesis.