Last Quiz Cell & Molecular

What is a genetic mutation?

A permanant change in the nucleotide sequence

Mutation are usually negative because they can…

change the sequence of a gene, and genes encode proteins

How often does dna get damaged inside the cells?

All the time

What is deamination?

A nucleotide loses a amine group

What is the result of deamination?

An a-nucleotide being converted to a uracil nucleotide (A-U)

How often does deamination occur?

500 times a day in each cell

What is depurination?

Loss of a purine base

What is the result of depurination?

The nucelotide is missing

How ofted does depurination occur?

About 5000 times a day in each cell

The energy from ultraviolet light…

changes the structure of dna, and causes thymine residues on the same strand to become covalently linked to another

what are thymine residues on the same strand that become covalently linked to another?

thymine dimers

How do cells recognize that DNA has been damaged?

Changes the structure of the double helix

What do DNA repair enzymes do?

Recognize the damage of DNA and repairs it.

If there is a U in DNA..

the repair enzyme cleaves the uracil from the deoxyribose sugar

What is the repair enzyme that cleaves uracil?

Uracil-DNA glycosylase

What repair enzyme removes the sugar-phosphate group where the base is missing the DNA?

endonuclease

How can the cell repair the gap in the sugar phosphate?

DNA Polymerase incorporates nucleotide in the missing location of the genome

What is the last enzyme needed to repair a DNA strand?

DNA ligase then forms the phosphodiester bond.

Proffreading does not catch alll mistakes by DNA polymerase.

What is replication slippage?

Happens in repeated sequences and you get extra or fewer copies of the repeats.

Mutation will be inherited and passed onto the daughter cells

What is the likely effect of a point mutation in an individuals cell?

The cell will likely not be impacted.

What is a point mutation?

A mutation just in one nucleotide. one nucleotide change.

How could a mutation have no effect on a cell?

Occurs outside the gene, or could not change the amino acid sequence of the protein, or may not change the structure or the function of the protein

What is likely to happen if a point mutation occurs in a gene and changed a codon for an amino acid into a stop codon?

The protein encoded for by the gene will likely lose its activity

A mutation that changes the nucleic acid sequence but doesnt change the amino acid sequence

Synonymous mutation (No negative impact)

What are extra nucleotides?

Insertions

What are missing nucleotides?

Deletions

What happens if the indel is not a multiple of 3?

Frame shift mutation, changes the reading frame of the gene.

If there are more than 39 CAG repeats..

likely to get huntington’s disease

Disease where individuals cannot repair damage done by sunlight?

Xeroderma Pigmentosum

Can mutations be beneficial?

Yes.

Process of evolution is driven by…

mutations

What would be the issue if hemoglobin was bounds to o2 more tightly?

The hemoglobin needs to be released in the cells.

How were genes in cancer first identified?

Researchers studied the genes of the rous-sarcoma-virus and one of the genes encoded a protein kinase (SRC) which was responsible for the tumors.

What are the key differences between healthy and cancer cells?

Sustaining proliferative signaling, evading growth suppressors, enabling replicative immortality, activating invasion and metastasis, inducing angiogenesis, resisting cell death

What are the functions of oncogenes and tumor suppressor genes in cells? How are these genes mutated in cancers?

oncogenes drive cancer development by causing cells to grow, divide, and survive uncontrollably. tumor suppressor genes encode proteins that block cell division. in cancer cells tumor suppressor genes can be deactivated and have loss of function mutations. cancer cells have a higher mutation rate.

What is metastasizing?

Cancer cells spreading

what is angiogenesis

Create new blood vessels that give the ability to grow further

What is an oncogene?

cancer causing gene

oncology

study of cancer

protein kinases are

proteins that phosphorylate other proteins

If a bird does not have SRC,

the cells are regulated normally.

When birds have SRC

The src proteins start phosphorylating proteins involved with cell division activating them and the cells keep dividing

C-src

cellular version

V-src

viral version

homologs

evolutionarily related

the original src gene

csrc

benign tumors is

not cancerous

At some point a benign tumor will become..

malevolent

Why do traditional chemotherapy drugs cause severe side effects?

they target actively dividing cells (hair cells)

How are new cancer drugs different from traditional chemotherapy drugs?

New cancer drugs, such as targeted therapies and immunotherapies, differ from traditional chemotherapy by acting on specific molecular targets or immune cells, rather than killing all rapidly dividing cell

Why was chronic myelogenous leukemia used to develop new cancer drugs?

it is a disease in which the bone marrow makes too many white blood cells. caused by a single genetic event, very specific and can be tested to specify cancer cures.

protein phosphorylation is a method cells use to regulate the activity of proteins.

true

Why is cancer such a difficult disease to treat?

many different types of cancer, and mutations of cancer cells. metastasis, they arise from the bodies’ cells.

nitrogen mustards

old chemotherapy drugs

how do nitrogen mustards work

they alkolate and modify proteins in dna in cells. they can kill other cells in the body.

chromosomal translocation

results in the philadelphia chromosome.

major challenge

cells have a lot of protein kinases.