Basic components of living systems: the ultrastructure of plant cells

Question 1

What is the plant cell wall made of? and what’s its function?

Answer 1

cellulose, a complex carbohydrate. They are permeable. The cell wall gives it shape and also acts as a defence mechanism against pathogens.

Question 2

Why are vacuoles important to keep the plant rigid?

Answer 2

the vacuole containing cell sap, pushes contents of the cell against the cell wall to maintain a rigid framework.

Question 3

What is the membrane of a vacuole in a plant cell called?

Answer 3

tonoplast, it is selectively permeable.

Question 4

Describe the structure of chloroplasts

Answer 4

• double membrane
• fluid enclosed is called storma
• internal network of membranes called thylakoids. several thylakoids stacked are called granum (plural for grana)
• grana are joined by membranes called lamellae
• grana contains chlorophyll, where photosynthesis occurs
• chloroplast contain their own DNA and are able to make their own proteins
• the internal membranes provide a large surface area for photosyntheis