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what are the enzymes involved in DNA rep. (in order)
Helicase
Topoisomerase
DNA Polymerase
Ligase
Primase
(I think of Helen Took Diana’s Little Puppy)
what does helicase do
separating the DNA by breaking the H bonds
what does topoisomerase do
holds the DNA open, prevents coiling
what does DNA Polymerase do
creates new DNA, read the template DNA and puts in the correct base, makes new H bonds
what is the only way DNA Polymerase will work
5’→3’
what does ligase do
link Okazaki fragments (like a glue stick) connects backbones
what does primase do
places RNA (primer) to help DNA polymerase start
why can’t DNA rep be done when DNA is in chromosome form (tightly wrapped)
too tight to access
what does the DNA wrap around when in chromosome form a nd where do they go when DNA rep starts
histone proteins
move out of the way
what are the 4 different bases and which other do they match with
Adenine - Thymine
Guanine - Cytosine
how many bonds are between each AT and CG
AT - 2 bonds
CG - 3 bonds
what does 5’ or 3’ translate to
five prime or three prime
is DNA parallel or antiparallel
antiparallel
how is DNA antiparallel
it is two strands that run the opposite way
→
←
one starts of 5’ and ends on 3’ (the leading strand)
one starts on 3’ and ends of 5’ (the lagging strand)
what is different about the leading and lagging strand
leading- makes one continuous strand of new DNA
lagging- works on sections
is primase in both the leading and lagging strands
yes but only one in the leading at the beginning to get it start and in the lagging it needs one every fragment (but there are a few that just “jump” to where they are needed next once they’re done)
what is a mutation
permanent change in the DNA sequence
what enzyme is most likely to make a mutation
DNA polymerase
why is DNA polymerase most likely to make a mutation
reads letter/base and puts in correct letter/base (usually)
it will double check but sometimes misses things
what is a silent mutation
no change in amino acid
what is a missense mutation
a change in amino acid (sometimes and issue/ it depends)
nonsense mutation
protein is cut short (stops early)
what is transcription
Transcription is the process of copying a segment of DNA into RNA
what is the RNA strand called right after transcription until it leaves the nucleus
pre-mRNA
what are the 3 steps/parts of post-transcriptional modifications
alternative splicing
poly-A tail
methyl cap
what is alternative splicing
when there are parts of the pre-mRNA that get remove or flipped around
introns and exons
all the different versions will make different proteins but they are all from the same original DNA
although it may seem it this is not random (transcription factors influence it)
what are introns
parts of the pre-mRNA that are cut out
what are exons
parts of the pre-mRNA that stay
what is a poly-A tail
when the strand leaves the nucleus exonucleases immediatlely starting “eating” it so in the nucleus a poly-A tail is put on the 3’ end so it doesn’t “eat” the important information
longer poly a tail - more time and vise versa
what is the methyl cap
goes on the 5’ end and it helps lead the strand out of the nucleus and throhg the nuclear pore
back to transcription where does it happen
nuclueus
what is used to construct the pre-mRNA made during transcription
bases/free RNA nucleotides
what enzyme is required for transcription
RNA polymerase
which strand of DNA contains the blueprint for pre-mRNA
the template/reading strand
in what direction is the DNA molecule read in transcription
3’→5’
and it is constructed in the opposite way
what makes up the transcription initiation process
transcription factor protein and RNA polymerase
where on the DNA strand does the transcription initiation complex form (start of transcription)
promoter
what is it called where transcription ends and then the pre-mRNA is released into the nucleoplasm
terminator
why is messenger RNA have that name
it carries the message from DNA to the ribosomes
what are the 3 steps of translation
initiation, elongation, and termination
when is pre-mRNA regular mRNA
after being spliced capped and tailed and when it is leaving the nucleus
which moves the mRNA or the ribosome in translaton
the mRNA moves
what is mRNA
messanger RNA takes the message of DNA from translation to the ribosome for transcription
what is tRNA
brings the amino acid to the ribosome and has an anticodon on the bottom of it and if the anticodon matches the codon on the mRNA then it will release the amino acid into the ribosome to be bonded with the previous amino acid to make a polypeptide chain
what is rRNA
what a ribosome is made of
during elongation how many tRNA can the ribosome hold
2
what 2 things happen during termination
an H2O is added and a release factor binds
what is a mutation in dna in which only 1 condon is wrong
substitution/ point mutation
what is are the 2 mutations in which every codon after it would be wrong
deletion or insertion
what are deletion and insertion mutations also called
frameshift mutations
what are the differences between DNA and rna
sugar (deoxyribose or ribose), base (u and t), structure (double helix or single helix)
where is DNA in the cell
nucleus
where is RNA in the cell
nucleus and cytoplasm
what is a codon
3 bases
what is an amino acid
a part of a polypeptide chain that tRNA brings and it codes to one codon
what is the bond between the amino acids
peptide bond
when doing/writing transcription and then translation where do you start and end
at the start codon (AUG) and end at one of the 3 end codons
where does translation happen
cytoplasm
every amino acid has its own
trna
what is a promoter in transcription
a special sequence of base pairs on the DNA template strand thast signals the beginning of a gene
Note 
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