yeast

Question 1

Describe the structure of yeast

Answer 1

They are single celled (unicellular) fungi.
They are round or oval in shape.
They are tiny cells only seen using an electron microscope.
They have thin cell walls made of chitin and a dense cytoplasm that contains many food storage vacuoles.
This is why it appears grainy.
Each cell has one nucleus.

Question 2

Why does the cytoplasm of yeast cells appear grainy or granular?

Answer 2

Because they have a dense cytoplasm that contains many food storage vacuoles.

Question 3

What should be labelled in a yeast cell diagram?

Answer 3

cell wall, nucleus, food vacuoles, cytoplasm, vacuole

Question 4

Do yeasts respire aerobically or anaerobically?

Answer 4

Anaerobically, breaking down sugars and producing ethanol and carbon dioxide

Question 5

Give the equation for yeasts respiring anaerobically

Answer 5

glucose —> 2 ethanol + 2 carbon dioxide

Question 6

How do yeasts reproduce?

Answer 6

Yeasts reproduce asexually by budding

Question 7

Explain budding

Answer 7

1. The parent cell divides by mitosis and one nucleus and some cytoplasm enter a small bud.
2. This bud may separate to form an individual yeast cell.
3. Sometimes the bud remains attached to the parent cell. Each new bud may divide again and eventually, a colony may form.
4. The colony is temporary and later divides to form single cells again.