Chap 10 (I think) DNA->RNA->Protein

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

1. alternative splicing

2. poly-A tail

3. 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