Eukaryotic Cell Ultrastructure (Plant)

Question 1

How are chloroplasts structured?

Answer 1

They consist of a double membrane which encloses the stroma.

Question 2

What does the stroma contain?

Answer 2

Starch grains, lipid stores, DNA, RNA, ribosomes.

Question 3

What key structures are found in the stroma?

Answer 3

Membrane bound, flattened discs known as thylakoids. Thylakoids that are stacked together are called grana, which contain chlorophyll. The grana are held together by lamellae.

Question 4

What is the function of chloroplasts?

Answer 4

To conduct photosynthetic reactions by trapping light energy in the chlorophyll.

Question 5

What is the structure of the cellulose cell wall?

Answer 5

The cellulose cell wall consists of beta glucose microfibrils, which is a complex carbohydrate.

It is fully permeable to substances, and there is a thin layer called the middle lamellae which marks the boundary between adjacent cell walls, “cementing” them together.

Question 6

What is the function of the cellulose cell wall?

Answer 6

• Gives the plant mechanical strength
• Gives the plant cell support and its shape
• Contents of the plant cell can push against the cell wall in a turgid cell, giving the cell good support

Question 7

What is the structure of the large permanent vacuole?

Answer 7

• Single membrane bound - membrane known as a tonoplast
• Contains a solution known as cell sap - consists of mineral salts, sugars, amino acids, wastes
• It has a selectively permeable barrier

Question 8

What is the function of the permanent vacuole?

Answer 8

• Stores cell sap
• Supports herbaceous plants by making cells turgid
• Helps maintain shape and gives support by maintaining turgor pressure
• Sugars and amino acids serve as a temporary food source