Scientific Methods, Cell Cycle, Central Dogma & p53

Question 1

What are the 3 domains of p53?

Answer 1

DNA Binding domain, transactivation domain, complexing domain.

Question 2

What is the function of the DNA binding domain?

Answer 2

Responsible for p53’s ability to bind to the regulatory sequences of genes.

Question 3

Most mutations in the p53 protein found in cancers are in ________ domain.

Answer 3

DNA binding domain

Question 4

What is the function of the transactivation domain?

Answer 4

Helps p53 activate other genes after binding to their regulatory regions. The domain recruits RNA polymerase and other enzymes that transcribe RNA.

Question 5

What is the function of the complexing domain?

Answer 5

Responsible for bringing 4 individual p53 molecules together.

Question 6

What is the central dogma?

Answer 6

The central dogma is necessary for gene expression. it describes the processes (transcription and translation) of how DNA is turned into a protein and how these processes are regulated.

Question 7

Is p53 DNA or a protein?

Answer 7

Protein

Question 8

Is the promoter region DNA or a protein?

Answer 8

DNA

Question 9

Is a gene DNA or a protein?

Answer 9

DNA

Question 10

What are the 3 components that make up a nucleotide?

Answer 10

At least one phosphate group, a pentose sugar, and a nitrogenous base.

Question 11

What makes yeast a good model system for what we are doing in this class?

Answer 11

• Easy to work with and inexpensive to maintain
• Breed quickly
• Easy to manipulate the system genetically
• Accessible to all students and requires minimal training

Question 12

What is the purpose of a checkpoint in the cell cycle?

Answer 12

Checkpoints ensure that the phase has been completed correctly and completely.

Question 13

Explain how p53 functions as a checkpoint protein during the G1/S and G2/M transitions in the cell cycle.

Answer 13

If DNA is damaged, the p53 protein will stop cell cycle progression until the damage is repaired. If the damage is excessive and can’t be fixed, p53 can initiate cell death, or apoptosis.

Question 14

What is a reporter gene?

Answer 14

It’s a DNA sequence which is attached to regulatory sequence. One whose production can be measured or visualized.

Question 15

What are the nucleotides (names/letters) that make up DNA? What about RNA?

Answer 15

DNA: Thymine, Adenine, Guanine, Cytosine
RNA: Uracil, Adenine, Guanine, Cytosine

Question 16

Is p21 a reporter gene or a response element?

Answer 16

Response element

Question 17

What is transcription?

Answer 17

The process of constructing a messenger RNA molecule using a DNA molecule as a template with resulting transfer of genetic information to the messenger RNA.

Question 18

What is translation?

Answer 18

The process in living cells in which proteins are produced using RNA molecules as templates. The generated protein is a sequence of amino acids. (Decoding the mRNA)

Question 19

What is a model system?

Answer 19

A non human organism that is used to understand a specific biological phenomena.

Question 20

What is apoptosis?

Answer 20

The death and elimination of cells.

Question 21

What makes a good hypothesis?

Answer 21

• The hypothesis must be based on a question
• A hypothesis is a statement not a question
• This statement is clear and specific
• Keep the variables in mind
• Make sure hypothesis is testable

Question 22

What are the phases of the cell cycle?

Answer 22

Interphase (G1, Synthesis, G2), Mitosis

Question 23

How does p53 regulate the eukaryotic cell cycle?

Answer 23

Activated p53 promotes cell cycle arrest to allow DNA repair and/or apoptosis to prevent the propagation of cells with serious DNA damage through the transactivation of its target genes implicated in the induction of cell cycle arrest and/or apoptosis.

Question 24

Why is the p53 protein known as the guardian of the genome?

Answer 24

Due to its activities directed at maintaining genomic stability through the repair of damaged DNA and the integration of cell birth/death signaling pathways with DNA damage checkpoints.

Question 25

What is the role of RNA polymerase?

Answer 25

• Binds to specific regions of DNA
• Opens up the DNA duplex
• Transcribes RNA using DNA as a template

Question 26

How does p53 activate (“turn on”) transcription of its target genes?

Answer 26

p53 is a transcription factor, meaning it can turn transcription on or off depending on the environmental conditions by binding directly or indirectly with specific regions of the DNA.

Question 27

Once p53 is activated, what are the 2 options cells have if their DNA is damaged?

Answer 27

The DNA can either be repaired, or if the damage is too extreme, the cell will undergo apoptosis.

Question 28

How does a mutation in the complexing domain affect p53’s ability to activate transcription?

Answer 28

One single p53 molecule is not functional and therefore cannot bind to the DNA sequence and activate other genes. Four p53 molecules are needed for that.

Question 29

DNA is made up of _______ strands that run ________.

Answer 29

antiparallel/two; 5 prime to 3 prime and 3 prime to 5 prime

Question 30

Transcription turns ds DNA into _________.

Answer 30

mRNA

Question 31

Adenine pairs with ___________.

Answer 31

Thymine (DNA) or uracil (RNA).

Question 32

In RNA there is no ________ it is instead replaced with __________.

Answer 32

Thymine; Uracil