Lec 3

Question 1

what is the function of DNA sequences that don’t code proteins?

Answer 1

They function as non-protein RNA molecules.

This differentiates higher eukaryotes from lower eukaryotes. i.e humans from other higher eukaryotes

Question 2

Define miRNA

Answer 2

miRNA (micro-RNA) are endogenous single stranded (ss) regulatory RNA molecules

Question 3

size of miRNA?

Answer 3

They are roughly 2023 nucleotides in length and usually have uridine at their 5’ end

Question 4

what are miRNA encoded by?

Answer 4

they are encoded by genes in genomes of all multicellular eukaryotes and some unicellular eukaryotes

Question 5

Around ___ miRNA genes have been identified

Answer 5

5000

Question 6

Size of LncRNAs

Answer 6

long non-coding RNAs are >200 nucleotides in length

Question 7

where are LncRNAs located

Answer 7

within the nucleus or cystoplasm

Question 8

true or false:

LncRNAs may or may not be polyadenylated

Answer 8

true

Question 9

LncRNAs are often transcribed from?

Answer 9

from either strand within a protein-coding locus

Question 10

Mammlian genomes encode ____ LncRNAs

Answer 10

more than 3300 LncRNAS

Question 11

Define pseudogenes

Answer 11

They are non-coding DNA sequences

They arise by coping the parent gene by:

1. duplication or
2. retrotransposition

Question 12

Define retrotransposition

Answer 12

.

Question 13

A/an ____ of the pseudogene and a/an ___ of its parent gene can then form a ___

Answer 13

An antisense transcript of the pseudogene and an mRNA transcript of its parent gene can then form a double-stranded RNA (dsRNA)

Question 14

Distinguish “sense RNA” from “antisense RNA”

Answer 14

sense RNA= mRNA with the coding information of the gene-encoded polypeptide

antisense RNA = complementary RNA to the mRNA

Question 15

___ was the first founding member of the miRNA family where it ___ the protein ___ in ___

Answer 15

Lin-4 was the first founding member of the miRNA family where it downregulates the protein lin-14 in Celegans

Question 16

__% of mammalian miRNA genes are located in ___

Answer 16

30% of mammalian miRNA genes are located in intergenic regions (between protein coding regions)

Question 17

Define intergenic regions

Answer 17

between protein coding regions

Question 18

___ is transcribed but __ are not translated into ____(non-coding RNA)

Answer 18

DNA is transcribed but miRNAs are not translated into protein (non-coding RNA)

Question 19

Many LncRNAs are associated with ___ and guide

in terms of chromatin

Answer 19

Many LncRNAs are associated with chromatin-modifying complexes and guide chromatin-modifying complexes to specific genomic loci to regulate gene expression

Question 20

___ of LncRNAs expressed in various cell types are bound by ____

Answer 20

20% of LncRNAs are expressed in various cell types are bound by polycomb repressive complex 2.