Unit 6.1-6.3 Flashcards
Prokaryotic have
-Circular chromosomes
-no nucleus
-single loop of DNA
Eukaryotic have
-multiple linear chromosomes
-a nucleus with DNA
-non looped chromosomes
Plasmids
small extra chromosomal, double-stranded circular DNA molecules in prokaryotes and some eukaryotes
Pyrimidines
single ringed bases
ex. cytosine, thymine and uracil
Purines
double ringed bases
ex. Adenine and Guanine
helicase
enzyme that untwists the double helix of DNA at replication forks separating the 2 strands and making them available as template strands
topoisomerase
breaks, swivels, and a rejoins the parental DNA of the replication fork relieving the strain caused by unwinding
DNA polymerase
enzyme that adds nucleotides to new strand, also cuts out primary and adds DNA
semi conservative replication
new molecules built have one of the original and one new in a DNA structure
leading strand
moves toward the 5’ end and replication fork
built continuously
lagging strand
moves away from replication fork
built fragmented or discontinuously
DNA Ligase
seals the free end of the new DNA to the old DNA, making the strand complete
replication fork
religion on a replicating DNA molecule where the parental strands are being unwound and new strands are being synthesized
the flow of genetic info goes:
DNA –> RNA –> Protein (only retroviruses don’t follow this)
Proteins are the links between ____ and _____
genotype and phenotype
transcription
-RNA polymerase attaches to promoter on the TATA box using transcription factors
-RNA polymerase reads the DNA and puts the corresponding nucleotide on the mRNA
-leaving you with a “complete” mRNA
template strand can be known as
-non coding strand
-minus strand
-antisense strand
transcription factors are
specific for every gene
RNA polymerase always reads DNA from
the 3’ to 5’ so that the RNA is 5’ to 3’
RNA processing only occurs in ___ and mRNA is ____ until after it undergoes processing
eukaryotic cells, NOT FUNCTIONAL
What do introns do?
midigate mutations
Alternative RNA splicing
cutting the pre-mRNA differently which creates different proteins from one gene (such as cutting out an exon)
RNA processing
-cuts the introns out of the pre-mRNA leaving just the exons
-add on the 5’ cap and poly-A tail which keep it stable and make the mRNA reusable
a ribosome is made up of
rRNA
Translation
-tRNA brings in start codon to the ribosome into the P site starting the process
-tRNA brings in more amino acids building a polypeptide chain going from the p site to A site to combine with the new amino acids
-the tRNA bumps down a site each time till it gets to the e site where it gets pushed out the ribosome to go find a new amino acids
-this continues till a stop codon is reached and a release factor comes and breaks everything apart
elongation
polypeptide chain goes from the P site to combine with the amino acid in the a site
translocation
tRNA bumping down a site till it gets to e site and gets booted out the ribosome
If the ribosome is on the endoplasmic reticulum what will be likely transported out of the cell
the protein
reverse transcriptase
an enzyme encoded by certain viruses (retroviruses) that uses RNA as a template for DNA synthesis
Why do RNA viruses change so much?
reverse transcriptase always makes a mistake an causes mutations
