recitation 11 ncRNA

Question 1

what are ncRNAs

Answer 1

any RNA that does not encode polypeptide used in DNA replication, gene regulation, genome defense and other cell processes

Question 2

general function of ncRNAs can perform

Answer 2

scaffold, guide, alteration of protein function, ribozyme, blocker, decoy

Question 3

scaffold

Answer 3

binding sites for multiple components

Question 4

guide

Answer 4

can guide 1 molecule to a specific location in a cell

Question 5

alteration of protein function

Answer 5

can alter that protein structure and can have variety of effects

Question 6

ribozyme

Answer 6

RNA molecule with catalytic activity

Question 7

Blocker

Answer 7

physically prevent and block a cellular process from happening

Question 8

decoy

Answer 8

some ncRNAs recognize other ncRNAs and sequester them and prevents them from working

Question 9

HOTAIR

Answer 9

ncRNA that can change chromatin structure, and acts as scaffold which guides 2 histone-modifying complexes to correct target genes

Question 10

CRISPR-Cas system

Answer 10

defends against bacteriophages in prokaryotes

Question 11

Cas9

Answer 11

a protein that binds to RNA allowing it to target and destroy foreign DNA

Question 12

PIWI interacting RNAs (piRNAs) and PIWI proteins

Answer 12

interact with PIWI proteins and inhibit movements of transposable elements

Question 13

Mutations

Answer 13

change in the DNA sequence

Question 14

what is the need for mutations

Answer 14

introduces genetic variability, foundation for evolutionary change, mutation rate

Question 15

Types of Mutations

Answer 15

neutral, deleterious, beneficial, conditional, suppressor, point mutations, frameshift mutations,

Question 16

neutral mutation

Answer 16

does not alter protein function

Question 17

deleterious mutation

Answer 17

lowers chance of survival and/or reproduction

Question 18

beneficial mutation

Answer 18

enhances survival and /or reproductive success

Question 19

conditional mutation

Answer 19

only affects phenotype under specific conditions

Question 20

suppressor

Answer 20

a second mutation that counters the phenotypic effect of the first mutation

Question 21

point mutations

Answer 21

base substitutions in which one base pair is altered

Question 22

frameshift mutations

Answer 22

insertions or deletions causing a shift in reading frame

Question 23

transition point mutations

Answer 23

changes of a pyrimidine to another pyrimidine or a purine to another purine

Question 24

transversion

Answer 24

change of a purine to a pyrimidine or vice versa

Question 25

missense mutation in coding sequence

Answer 25

alter the amino acid sequence

Question 26

silent mutations in the coding sequence

Answer 26

does not alter the amino acid sequence

Question 27

nonsense mutations in coding sequence

Answer 27

change a codon to a stop codon

Question 28

spontaneous mutation occurrence

Answer 28

mutations arise from replication errors and base modifications

Question 29

induced mutation occurrence

Answer 29

mutation occurs by contact with environmental agents

Question 30

deprivation in a spontaneous mutation

Answer 30

removal of a purine resulting in a purification site

Question 31

reanimation in spontaneous mutations

Answer 31

removal of an amino group from cytosine

Question 32

tautomeric shift

Answer 32

change in base structure allowing A-C and G-T base pairing

Question 33

oxidative stress in spontaneous mutations

Answer 33

reactive oxygen species damage DNA

Question 34

chemical mutagens- induced mutations

Answer 34

covalently modify nucleotide structure

Question 35

physical mutagens- undecided mutations

Answer 35

ionizing radiation

Question 36

DNA repair mechanisms

Answer 36

repair systems counteract genetic damage that would result in genetic diseases and cancer

Question 37

direct repair- DNA repair mechanims

Answer 37

fixes structure

Question 38

base excision repair

Answer 38

fixes abnormal nucleotide

Question 39

mismatch repair mechanism

Answer 39

fixes base pair mismatch

Question 40

homologous recombination repair

Answer 40

fixes double-stranded breaks

Question 41

non-homologous end joining

Answer 41

fixes double-stranded breaks

Question 42

photoreactivation repair

Answer 42

removes thymine dimers caused by UV light

Question 43

Nucleotide excision repair

Answer 43

repair of a damaged single strand where you have another strand to use as a template to repair the damaged information

Question 44

homologous recombination repair

Answer 44

fixes double stranded breaks by using sister chromatid as the template to allow DNA polymerase to copy the undamaged sequence into the damage strand

Question 45

why are double-stranded breaks more difficult to repair

Answer 45

you can lose large portions of a chromosome