Genes, Genomes, Nucleus, and Cancer Flashcards

Flashcards covering key concepts from genetics, genomics, the nucleus, and cancer biology. These flashcards are in a fill-in-the-blank format to enhance your understanding and retention of the material.

During transcription, the primary RNA transcript has the removed by splicing to form the mature mRNA.

introns

Regulatory elements control transcription, which can be located hundreds of kilobases away from the gene, upstream of the gene, or within or within _ of the gene

noncoding exons, introns

_ allows multiple proteins to be encoded by a single gene, 20,000 human protein coding genes to specify 80,000 different proteins.

Alternative splicing

Even though non coding genes do not make proteins, they play important roles in .

gene regulation

Pri-mRNAs are cleaved by nuclease , which then makes pre-miRNA which is cleaved by nuclease .

Drosha, Dicer

The miRNA then targets to the 3’ UTR of an mRNA, leading to repression of translation of mRNA degradation.

RISC

miRNA binds to rna directly (either degrading it in response to a perfect match or blocking translation with an imperfect match) and methylates the histones in a nucleosome complex which blocks transcription.

lncRNA

The key element in x chromosome inactivation is (Xist) which binds to the inactive X, blocking its transcription.

lncRNA

Pseudogenes are inactive gene copies when mRNAs are copied by yielding a cDNA copy lacking introns.

reverse transcription

The basic unit of chromatin, consisting of DNA wrapped around .

histones

The extent of chromatin condensation varies during the cell cycle and controls .

gene expression

Chromosome maintenance (buffer for degradation) and replication with repetitive DNA and simple sequence repeats of at the ends of chromosomes (only in eukary).

TTAGGG

Two for a dimer in the alpha helix region of two polypeptide chains wound in each other to make a coiled coil.

lamins

The nuclear pore complex (NPC) is the only channel that allows molecules (proteins and RNA) to pass across the .

nuclear envelope

Proteins are targeted to the nucleus by nuclear localization signals (specific AA sequences); these signals are recognized by nuclear transport receptors like which carry proteins in the nucleus.

importin

___ stimulates hydrolysis of GTP to GDP, releasing importin

GTPase activating protein (Ran GAP)

After the completion of splicing and polyadenylation, mRNAs are bound by an , which mediates their transport through the NPC

exporter complex

_ is a novel means for gene expression control because TFs are only functional in nucleus.

Regulation of TF import and export

_ is the majority of chromatin, decondensed, and transcriptionally active, located toward the interior of the nucleus

Euchromatin

Looped domains of transcriptionally inactive heterochromatin are associated with _ or .

lamina associated domains (LADs), nucleolus associated domains (NADs)

The middle of the nucleus, the site of rRNA transcription, rRNA processing, and ribosomal assembly is called .

nucleolus

__ help the processing of pre-rRNA by functioning in pre-rRNA cleavage, ribose methylation, and pseudouridylation.

small nucleolar RNAs (snoRNAs)

_ bodies function in gene silencing (transcriptional repression of genes) via methylation of histone H3 lysine 27 residues.

Polycomb

__ is the spread of malignant tumors- spread of cancer cells

Metastasis

_ cells proliferation until they reach a certain density and then stop (cease proliferation and enter G0) but _ cells continue to proliferate.

Normal, cancer

Many cancer cells produce growth factors that stimulate their own proliferation, leading to continuous autostimulation of cell division (), making cancer cells less dependent on growth factors from normal sources.

autocrine growth stimulation

Normal Raf consists of an N (regulatory domain) and C terminus than is inactive normally until activates it.

Ras

When both copies of the Rb gene were mutated will eliminate the tumor suppressor gene Rb, leaving an unregulated means uncontrolled transcription and growth.

E2F

Oncogenes are of function mutations, , not inherited, a single mutation event can enable oncogenes to promote cell transformations

gain, dominant

P53 regulates cell survival and cell cycle progression by inducing cell cycle arrest and for damaged DNA

apoptosis

Cancer cells secrete growth factors that promote the formation of new blood vessels which is called __.

angiogenesis

Heterochromatin is a minority of chromatin, highly condensed, and not transcribed, and usually found around the and .

Nuclear envelope, nucleolus