3.10 - Gene Control Mechanism

Question 1

What is cell specialization?

Answer 1

When a cell activates a specific set of genes & deactiving others. This allows the cell to be used for a specific purpose.

Question 2

What are undecided cells called?

Answer 2

Stem cells

Question 3

What are the 2 types of stem cells?
Describe them.

Answer 3

• Pluripotent: stem cells with the potiential to be specialized. Not all stem cells are pluripotent.
• Multipotent: this type of cell can become varitey of different cells within the same family (i.e. different type of blood cells) but nothing else.
• there are methods that are being developed to turn normal somatic cells into pluripotent stem cells (iPS) with the hope of being used for medical purposes.

Question 4

Where do the possible control mechanisms occur and how?
Hint: there are 4

Genetics

Answer 4

1) During transcription: control how often a gene undergoes transcription (a gene that produces more mRNA is expressed more strongly
2) After transcription: change the splicing arrangement of the transcript; occurs after the addition of the poly-A tail b/c a transcript with a longer tail will last longer
3) During translation: control how many ribosomes translate the mRNA transcript; control how many times an mRNA transcript is translated
4) After translation: make modifications to the polypeptide chain before it becomes a fully functional protein

Question 5

What are transcription factors?

Answer 5

• proteins that influence how often RNA polymerase can transcribe a gene
• usually a specific transcription factor will bind to a promotor region for a gene
• Positive transcription factor: encourages RNA polymerase to make transcripts
• Negative transricption factor: will break RNA polymerase from making transcripts