18-20 Flashcards
what is DNA and RNA
dna- nucleic avid molecule that governs the process of hereditary
rna- nucleic acid that plays a role in gene expression and protein synthesis
structure of a nucleotide
five carbon sugar, phosphate and nitrogen base
dna and rna bases
dna - adenine, guanine, cytosine, thymine
rna - same but instead of thy. it’s uracil
are the nitrogen based bound on the sugar or phosphate group
sugar
what is chargaffs rule
nucleotides aren’t present in equal amounts. adenine is present with thymine, cytosine with guanine
what are the nitrogen bases held together by
hydrogen bonds
what are complimentary base pairs
A-T and C-G pairs
what are the differences between RNA and DNA
- sugar is ribose instead of deoxyribose
- has uracil
- is single stranded
what is a genome
sum of all the DNA that’s carried in each cell
what is semi conservative replication
Each new DNA molecule contains one new strand of the original and one new parent strand
steps of initiation
- helicases attach to replication origin and unwind double helix
- replication bubbles form and move towards opposite directions
- grow until they meet and contains the parent and new complimentary strand
steps of elongation in the leading strand
- helicase opens up double helix
- RNA primase used as a starting point
- DNA polymerase adding new nuecleotides along 5’-3’
steps of elongation in lagging strand
- helicase opens
- copied in sections, RNA primase starts at one section (okazaki fragments)
- DNA polymerase adds nucleotides
- DNA poly. goes back and replaces the primase
- DNA ligase brings together the okazaki fragments
what are the functions of DNA polymerase
- adds nucleotides
- proof reads mistakes when replication occurs
what is gene expression
genetic info flows from DNA, RNA, proteins
what is transcription
DNA copied into RNA molecule
what is a codon
each set of 3 bases
what is the start codon
AUG
what is the stop codon
UAA UAG UGA
steps of transcription
- RNA polymerase binds with DNA molecule
- dna copied into mRNA
- only one strand is copied (sense strand)
- mRNA strand synthesized to form complimentary strand
- mRNA detaches and DNA rewinds
steps of translation
- mRNA strand binds to a ribosome
- AUG is most likely the start codon
- tRNA with the anticodon UAC base pairs with AUG
- another anti codon on tRNA pairs with the next codon on mRNA
- first amino acid (from UAC) transfers to the second tRNA amino acid
- creates a polypeptide chain
- stops until it reaches a stop codon
what is a transgenic organism
organism whose genetic material includes DNA from other species
bioremediation and give example
use of living cells for environmental remediation, using bacteria to clean up oil spill
