Bio Exam 3 part 2 chap 12, 13, 15

What is a mutation?

An heritable change

What are point mutations?

Specific mutations of one thing like T to A on RNA, also add or delete a single base pair

What is a frame shift?

When a new amino acid sequence is produced from a point mutation

How does sickle cell occur?

A missence of one amino acid base

What is a mutagen?

Chemical or physical agents that cause a change

What are the three types of repair?

Direct, nucleotide excision repair, and methyl-directed mismatch repair

What is direct repair?

a repair enzyme recognizes error in DNA and converts it back

What is nucleotide excision repair?

DNA strand containing abnormal nucleotide is removed and replaced

What is methyl-directed mismatch repair?

A base pair mismatch is detected and the surrounding DNA is removed and replaced

What are tumor suppressor genes?

Encoded proteins to help fight tumors

What are oncogenes?

A form of gene that controls cell growth and division with hormones

What is ras?

An intracellular signaling protein that hydrolyses GTP, promoting cell division

What are chromosomal translocations?

One segment of a chromosome is rearranged with another

what are retroviral insertions?

Viral DNA inserts into s chromosome putting a viral promoter next to a proto-oncogene, if overexpressed, will promote cancer

What are missense mutations?

Changes a single amino acid in a protein, can be cancerous

What are Gene amplifications?

Increase in copy number resulting in too much protein

What are the main functions of tumor-supressor genes

Maintain genome integrity and ability to inhibit cell division

What is p53?

A transcription factor that acts as a sensor of DNA damage, can promote repair and apoptosis

What is Rb?

proteins inhibit the transcription factor E2F which activates genes for G1 and S phase for cell cycle progression?

What are stem-loop structures?

structures in the ncRNA that bind to pockets on proteins

What is a binding site?

multiple stem loop structures together

What are some ncRNA abilities?

Scaffolding, guide, alter function, ribosome, blocker, and decoy?

What does a decoy ncRNA do?

mimics an RNA in order to block it from functioning

What is HOTAIR?

ncRNa that alters chromatin structure and represses gene transcription

How does HOTAIR function?

acts as a scaffold for proteins that covalently modify histone proteins

What are miRNAs?

ncRNAs transcribed from genes in the eukaryotic genome

What are siRNAs?

Come from exogenous source, usually viral

What is a repressor?

Inhibits transcription, negative control

What is an activator?

Increase rate of transcription, positive control

What do small effector molecules do?

bind to regulatory transcription factor and cause conformational change

What is an operon?

in bacteria is a set of two or more genes under transcriptional control of one promoter

Which gene codes for the lacrepressor?

lacl

What does Lac-z, galactosidase do?

breaks down lactose

What does lacY – lactose permease do?

transports lactose into the cell

What does LacA – galactosidase transacetylase do?

attaches acetyl group to lactose

What is Catabolite repression?

When presence of one preferred energy source inhibits another

What happens when lactose and glucose are high?

The lac operon shuts off

What happens when lactose is high and glucose is low?

The lac operon turns on

What does tryptophan do?

represses transcription