nucleic acids and transcription Flashcards
What is the central dogma
theory of how genetic info flows in cells from DNA to RNA to proetin
What is transcription
generation of RNA from DNA to RNA; emphasizing that they use the same “language” of nucleic acids
T/F DNA is the template for RNA
True
what is the second step in the readout of genetic information
translation; synthesis of proteins according to the “code” carried in the molecule of RNA
T/F DNA is a polymer of nucleotides
True
what did griffith’s experiment demonstrate
molecules can transfer genetic information from one organism to another
- bacteria in mice
what did griffith’s experiment demonstrate
molecules can transfer genetic information from one organism to another
- dna rna and protein extracted from heat-killed virulent and purified to make a solution
what are the components of nucleotides
1.) five-carbon sugar
2.) base
3.) phosphate groups
in DNA, the sugar is deoxyribose
what are the four DNA bases
purines:
1.) adenine
2.) guanine
pyrimidines:
1.) thymine
2.) cytosine
T/F nucleotide sequences are read from 3’-5’
false: 5’-3’
Which end of a DNA nucleotide sequence has a phosphate
5’.
3’ is a hydroxyl group
what are the base pairs and their hydrogen bonds
Adenine and Thymine
A - T = two hydrogen bonds
Guanine and Cytosine
G - C = three hydrogen bonds
what contributes to the stability of DNA
hydrogen bonds
base stacking (nonpolar, flat surfaces the bases stacking as tightly as possible to group together away from water molecules)
In the DNA of certain bacterial cells, 16% of the nucleotides are adenine. What are the percentages of the other nucleotides in the bacterial DNA?
16% thymidine, 34% guanine, 34% cytosine
A - T are = to each other
therefore
G - C must be =
why is complementary base pairing important
incoming nucleotides are accepted if they correctly base pair with the template
the 3 OH- of the growing strand attacks the high energy phosphate bond of the incoming nucleotide to initiate the synthesis reaction
what end of a DNA strand is the growing strand
3’ (hydroxyl group)
Unwinding of the DNA duplex results in
a replication fork
replication always occurs in the _ to _ order
5 - 3
during replication, the daughter cell on top will elongate from _ to _ while the bottom will elongate from _ to _
top = left to right
bottom = right to left
replication of the top strand is
discontinuous (fragmented)
replication of the bottom strand is
continuous
the discontinuous pieces in replication are called
okazaki fragments
what does helicase do in replication
unwinds the parental DNA strands
what does DNA polymerase do in replication
extends and RNA primer
reads the nucleotides and removed incorrect ones
what does topoisomerase II do in replication
relieves the stress of unwinding
each point where DNA replication is initiated is called
origin or replication
T/F eukaryotes have multiple origins in replication
True
T/F prokaryotes have multiple origins of replication
False: circular replication. starts at one spot on the circle and peels away turning into own circle
what does a telomere do for eukaryotes
at each end of a eukaryote chromosome is capped with a repeating sequence called a telomere.
5’-TTAGGG-3’
it acts as a buffer between each round of replication since replication shortens the chromosome
what does telomerase do
differs from one cell to another.
fully active in germ cells or stem cells
it is the enzyme that makes up a telomere
PCR, gel electrophoresis, restriction digests, southern blots and sanger sequencing are all methods of
dna manipulation
during this process, the donor dna and vector dna are both cleaved with the same restriction enzyme
recombinant dna
genetically engineered organisms are known as
transgenic organisms/genetically modified organisms (GMOs)
how does dna editing work
1.) guide rna combines with protein
2.) guide rna brings protein to the target dna and the target is cleaved
3.) an EXONUCLEASE widens the gap iin the target dna
4.) the editing template is used to repair the gap in the target dna
5.) result is an edited dna with an altered sequence
