Topic 3

Question 1

central dogma of bio

Answer 1

DNA =>(transcription) RNA =>(Translation) Protein

Question 2

Promoter

Answer 2

DNA sequence that tells cell where to start making mRNA

Question 3

in what direction is RNA made

Answer 3

5’ to 3’

Question 4

exons

Answer 4

e=expressed

are going to be made into protein

Question 5

introns

Answer 5

i=interspersed

not made into protein

Question 6

splicing

Answer 6

takes out introns and leaves the exons

Question 7

pathway of posttranscriptional mRNA processing

Answer 7

DNA template (3' - 5')
-transcription
Pre-mRNA (5'-3')
-cap and tail added
Processed pre-mRNA
-splicing
Spliced mRNA

Question 8

relationship between exons and proteins

Answer 8

exons correspond to protein domains

Question 9

start codon is always

Answer 9

AUG (MET)

Question 10

what is the start codon

Answer 10

where the cell starts translation (starts polypeptide)

Question 11

promoters

Answer 11

sequence of DNA that proteins bind to, to initiate transcription of 1 RNA from the DNA

Question 12

silencers

Answer 12

a DNA sequence capable of binding transcription regulation factors (repressors)

prevent genes from being expressed as proteins

Question 13

enhancers

Answer 13

short pieces of DNA that increase transcription of target genes

Question 14

origins of replication

Answer 14

sequence where replication is initiated

Question 15

telomeres

Answer 15

the end of a chromosome (repetitive sequences of non-coding DNA that protect the chromosome from damage)

Question 16

centromeres

Answer 16

what separates into short and long arm during cell division, holds together the sister chromatids

Question 17

tRNA

Answer 17

transfer RNA - read codons on RNA & mRNA and deliver the appropriate amino acid to the ribosome for protein sythesis

Question 18

rRNA

Answer 18

ribosomal RNA

carries out protein synthesis in ribosomes

Question 19

snRNA

Answer 19

processes pre-mRNA in the nucleus

Question 20

noncoding DNA

Answer 20

used to be called “junk DNA”, but now scientists are finding out that noncoding DNA does have function

codes for things like regulatory regions, origins of rep, chromosomal structures and transcriptions of RNA mols

Question 21

can you change the amount of gene product and why?

Answer 21

yes for example, in a stressed environment, more gene products will be created more quickly

Question 22

which regulatory region of DNA sequence do you hypothesize that genes that control the same processes have in common?

Answer 22

promoters, because they are all responding to the same promotion signal

Question 23

what are single nucleotide polymorphisms (SNP)

Answer 23

the most common type of genetic variation among people

Question 24

what does each SNP represent

Answer 24

a difference in a single nucleotide change in DNA

Question 25

how often do SNPs occur

Answer 25

occur once in very 300 nucleotides, roughly 10 million SNPs in the human genome

Question 26

alternative splicing

Answer 26

enables an mRNA to directly synthesize defferent protein variants (this is why worms and humans are different)

Question 27

what things can mutations effect

Answer 27

- promoter/enhancer/inhibitor sequences - termination signals - splice donor and acceptor sites - ribosome binding sites - also effects noncoding regions

Question 28

point mutations or base substituation

Answer 28

change from one base pair to another

Question 29

missense mutation

Answer 29

results in new triplet code for different amino acid

Question 30

nonsense mutation

Answer 30

results in triplet code for stop codon (translation terminated prematurely)

Question 31

silent mutation

Answer 31

new triplet code still codes for same amino acid

Question 32

base subs - transitions

Answer 32

pyrimidine replaces pyrimidine or purine replaces purine

Question 33

base subs - transversions

Answer 33

purine and pyrimidine are interchanged

Question 34

frameshift mutations

Answer 34

- result from insertions or deletions of base pairs - loss or addition of nucleotide causes shift in reading frame - frame of triplet reading during translation is altered ex) UAG AAA GAA

Question 35

loss of function mutation

Answer 35

reduces/eliminates function of gene product

Question 36

null mutation

Answer 36

results in complete loss of function

Question 37

dominant mutation

Answer 37

results in mutant phenotype in diploid organism

Question 38

dominant gain of function mutation

Answer 38

results in gene with enhanced negative, or new function

Question 39

haploinsufficiency

Answer 39

a situation where the total level of a gene product produced by the cell is about half of the normal level, which is not sufficient for the cell to function normally

Question 40

dominant-negative

Answer 40

a mutation resulting in a gene product that can interfere with the function of the normal gene product in heterozygotes

Question 41

spontaneous mutations

Answer 41

changes on nucleotide sequence that occur naturally

Question 42

how do spontaneous mutations arise

Answer 42

from normal biological or chemical processes that alter nitrogenous bases

Question 43

spontaneous mutation rates

Answer 43

vary, but are exceedingly low for all organisms

Question 44

induced mutations result from...

Answer 44

- extraneous factors (natural or artificial) - radiation - UV light - natural and synthetic chemicals

Question 45

what do mutations arise from

Answer 45

replication

Question 46

why do mutations arise from replication

Answer 46

- replication is imperfect - DNA polymerase occasionally - misincorporated nucleotides persist after proofreading - errors due to mispairing predominantly lead to point mutations

Question 47

mutagens

Answer 47

-natural or artificial agents that induce mutations

Question 48

examples of mutagens

Answer 48

- fungal toxins - cosmic rays - ultraviolet light - industrial pollutants - medical x-rays - chemicals in tobacco smoke

Question 49

what do repair systems counteract

Answer 49

spontaneous and induced DNA damage counteract genetic damage that would result in genetic diseases and cancer

Question 50

DNA repair system

Answer 50

maintains the integrity of genetic material

Question 51

mutations in what gene cause cystic fibrosis

Answer 51

CFTR

Question 52

what mutation class does the CFTR mutation belong to

Answer 52

loss of function

Question 53

what gene codes for the lactase enzyme

Answer 53

LCT

Question 54

individuals who can digest lactose have...

Answer 54

a mutation in the LCT regulatory element that leads to sustained lactose production in the small intestine and the ability to digest lactose throughout life

Question 55

mutations in what gene cause sickle cell disease

Answer 55

HBB gene

Question 56

loss of function

Answer 56

the altered gene product lacks the molecular function of the normally functioning gene

Question 57

reduction of function

Answer 57

reduces the normal function

Question 58

dominant negative

Answer 58

a mutation whose product negatively effects the normal wild type gene product within the same cell

Question 59

gain of function

Answer 59

more function to the wild type

Question 60

dominant gain of function

Answer 60

mutation in which the altered gene product has a new molecular function or new pattern of gene ecpression