Transcriptional control

Question 1

What is chromatin?

Answer 1

• DNA is very long
• has to be wound around protein called histones in eukaryotic cells
  
  • in order to bepacked into the nucleus of a cell
• resulting in a DNA/protein complex called a histone

Question 2

What is heterochromatin?

Answer 2

• tightly wound DNA
• causes chromosomes to be visible during cell division

Question 3

WHat is euchromatin?

Answer 3

• loosely wound DNA
• present during interphase

Question 4

Why is transcription of genes not possible when DNA is tightly wound?

Answer 4

• because RNA polymerase cannot access the genes
• the genes in euchromatin can freely be transcribed

Question 5

When does protein synthesis occur?

Answer 5

• during interphase
• not during division
  *

Question 6

How is this an effective form of control?

Answer 6

• this is a simple form of regulation that ensures the protein necessary for cell division are synthesised in time
• it also prevents the complex and energy-consuming process of protein synthesis from occuring when the cells are actually dividing