Gene regulation and Mutations

What is the purpose of gene regulation?

Controls transcription and translation so the cell produces the proper proteins at the right time in the appropriate amount.

What are the 5 levels of control?

Transcriptional, Post-transcriptional, Translational, Post-translational, Allosteric regulation

Explain Transcriptional control

Control the production of mRNA. An activator molecule activates a transcription factor, it binds onto promoter and makes it accessible to RNA polymerase.

Explain Post transcriptional control

mRNA isn’t modified(5’ cap and poly-a tail), ribosomes will no attach and carry out translation.

Explain translation control

Controls how often and how rapidly mRNA is read and converted to protein

Explain post-translation control

Controls rate of protein folding into active form

Explain Allosteric regulation

Molecules in all that activate or deactivate enzymes.

What is Lac Operon?

It controls the production of lactose enzymes. When lactose is absent the repress or binds onto the operator and prevents RNA poly. From binding onto promoter. When lactose is present lactose binds to repress or and deactivates it, RNApoly can bind onto promoter.

What is Tryp Operon?

Controls production of tryptophan. When there’s a low level of tryp the repressor is inactive so the cell can produce more tryp. When there’s a high level of tryp the repressor is active so RNA polymerase cannot bind. Tryp will not be made.

Define an Operon

a group of genes that work together to regulate the production of a certain enzyme or system of enzymes used for a chemical reaction.

3 Modulation situations in a cell.

1. Material becomes available and the cell wants to use it to gain energy and carry out cell jobs.

2. Material is not available so the cells have to synthesize its own until it becomes available. When available the synthesizing gene turns off.

3. Usable material is available but the cell already has a better material so the 1st gene is suppressed until better material is used up.

What is silent mutation?

When a mutation occurs in an intron or creates a codon that creates the same a.a. It will have no effect of the cell’s function.

What is missence mutation?

A change in DNA code that results in a different a.a. It can alter the protein shape/function. Might not impact the function if new a.a has similar properties.

What is Non-sense mutation?

Change in a DNA codon that results in a stop codon. Typically creates a protein that can’t function. Might have little affect if mutation occurs at end of a.a chain.

What is a frame shift mutation?

Addition or deletion of a nucleotide that causes a shift in the reading frame. A.A sequence is completely changed. Might have little impact if 3 nucleotides are added/deleted.

What is point mutation?

Silent insertion or deletion, typically involves 1 base pair.

What is translocation?

When portions of chromosomes are broken off and attached to different chromosomes.

What is Inversion?

Groups of genes of a chromosome reverse their order.