Cells

Question 1

Describe the structure (3) and function of the nucleus (4)

Answer 1

Structure:
- Nuclear envelope and pores / double membrane and pores
- Chromatin / DNA with histones
- Nucleolus

Function:
- Stores genetic info for polypeptide production
- DNA replication
- Production of tRNA or mRNA / transcription
-Production of rRNA / ribosomes

Question 2

Why are viruses acellular and non- living

Answer 2

• no cell surface membrane
• no metabolism / can’t respire / no nutrition

Question 3

Describe the role of lysosomes (2)

Answer 3

• Fuse with vesicles
• releases hydrolytic enzymes

Question 4

How are organelles isolated?

Answer 4

• Break open cells and filter
• In cold, isotonic, pH controlled solution
• Centrifuge and remove cell debris
• Centrifuge at higher speeds so organelles isolate