Lecture 18 Flashcards Preview

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Flashcards in Lecture 18 Deck (13):
1

snoRNAs (structural ncRNAs) function in _______ and ______ of rRNA and ______ of trNA.

snoRNAs function in modification and maturation of rRNA and maturation of tRNA.

2

Large ncRNAs regulate ______ of mRNA.

Large ncRNAs regulate transcription (i.e. X-inactivation.)

3

What are the rRNA modifications carried out by snoRNAs?

They convert critical Uridines to Pseudouridines, and they Methylate 2' OHs of ribose on particular NTs.

4

U1 spliceosome subunit binds the _____ splice site, which confers ______, and the U2 subunit binds the 3' A _____.

The U1 subunit binds the 5' splice site, which confers Specificity, and the U2 subunit binds the 3' A Branch Point.

5

How many transesterification rxns?

2 transesterification rxns are carried out.

6

snRNAs are components of RNPs. What does RNP stand for?

Ribonucleoproteins

7

The C/D family of snoRNAs is responsible for ______, while the H/ACA family is responsible for______.

The C/D family of snoRNAs is responsible for METHYLATION, while the H/ACA family is responsible for Uridine -->Pseudouridine conversion.

8

Though miRNA and Large ncRNAs both regulate gene activity across almost all genes, they inhibit different processes of gene expression. miRNAs complimentarily bind the ______ region of __RNA, while Large ncRNA bind the _____ and _____ regions of protein coding genes.

miRNA inhibits TRANSLATION of mRNA by complimentarily binding the 3'UTR region of mRNA, while Large ncRNAs inhibit TRANSCRIPTION of genes (turning euchromatin into heterochromatin) through binding at the PROMOTER and ENHANCER regions of protein coding genes.

9

miRNA processing begins in the nucleus where _____, a dsRNase, helps process pre-miRNA from its primary transcript. From there, the pre-miRNA is exported to the cytosol where it is further processed by ______ in conjunction with the RISC complex. When RISC binds, the miRNA become ______stranded. It is then active miRNA and can bind mRNA via complimentarity.

miRNA processing begins in the nucleus where DROSHA, a dsRNase, helps process the pre-miRNA from its primary transcript. From there, the pre-miRNA is exported to the cytosol where it is further processed by DICER in conjunction with the RISC complex. When RISC binds, the miRNA becomes SINGLE stranded.

10

IC (Imprinting center) RNA and XIST RNA are both _____ copy genes that regulate ______ of mRNA producing genes.

They are both SINGLE copy genes that regulate TRANSCRIPTION.

11

Which stage of development does X-inactivation occur, and is it the same in every cell or is it random?

It occurs in the embryonic stage, and it is random (mosaicism.)

12

What is the mechanism by which XIST RNA inactivates the X chromosome and Imprinting silences gene transcription?

Hypermethylation of C in CpG islands.

13

PWS (Prader Willi Syndrome) gene is transcriptionally silenced in ______, while AS (Angleman Syndrome) gene is transcriptionally silenced in ______ during meiosis.

PWS gene is silenced in FEMALES, while AS gene is silenced in MALES during meiosis.