Unit 5 Maybe Flashcards
What groups are the 5’ end and 3’ end associated with respectively
The Phosphate group and OH group with the sugar
what structure is a purine
two rings (bases are Adenine and Guanine)
what structure is a pyrimidines
one ring (bases are Thymine and Cytosine)
Semiconservative model
DNA separates into two strands and acts as a template for the synthesis of a new strand (parent strand || new strand)
Conservative model
DNAs two strands synthesize another two strands (both parental strands || & both new strands ||)
Dispersive model
The genetic material of the parent strands and new strands are mixed (both strands are a mix ||)
Helicase function
Enzymes that untwist the double helix
Single-strand binding protein function
Binds to the unpaired DNA strands keeping them from repairing
Primase function
initiates replication by adding primers to the DNA strand (think primase primary step)
What is a Primer
a short segment of RNA that’s added to a DNA strand
Mismatch repair
When enzymes remove and replace incorrectly paired nucleotides
Plasmids
Small circular DNA molecules that replicate separately from bacterial chromosome
Formation of a chromosome
DNA->Wraps around Histone(protein)->Wraps around to form a chromatin->Wraps more to form chromosome
Topoisomerase
Enzyme that helps to prevent strain/tension that’s ahead of the replication fork
What direction is DNA read in
3’ -> 5’
What direction is DNA synthesized in
5’ -> 3’
DNA Polymerase 3 (DNAP 3) function
Attaches to the primers and adds the nucleotides onto the new strand of DNA
Leading Strand
Characterized by DNAP 3 following helicase and requires only one primer
Lagging Strand
Characterized by DNAP 3 moving away from helicase and requires many primers
Okazaki Fragments
The chunks of the lagging strand (formed because DNAP 3 moves away from Replication Fork)
DNA ligase function
Merges the Okazaki fragments to each other
Telomerase function
Enzyme that adds telomeres to DNA
Telomeres
Repeating units of short nucleotide sequences (DONT CODE FOR A GENE)
Transcription
Synthesis of RNA using information from DNA (occurs in nucleus)
Translation
Synthesis of a Protein using information from RNA (occurs in ribosome)
mRNA function
Carries information from DNA to ribosomes (nucleus->cytoplasm)
tRNA function
Translates nucleotide sequence into an amino acid sequence
rRNA function
Helps to form ribosomes
What are the three steps of transcription
Initiation, Elongation, and Termination
What is the promotor region called in a eukaryotic cell
TATA box (always upstream of gene)
When is transcription initiated (initiation)
When RNA polymerase binds to a promoter region (TATA)
What does elongation do (transcription)
RNA polymerase opens the DNA and reads the triplet code then pairs the complimentary RNA nucleotides
How does transcription end (termination)
RNA polymerase must transcribe DNA sequence polyadenylation signal sequence (AAUAAA)
Intron
an intervening sequence of pre-mRNA (DOESNT CODE FOR AMINO ACID)
Exon
an expressed section in pre-mRNA (DOES CODE FOR AMINO ACID)
DNA Polymerase (DNAP 1) function
Removes RNA primers and replaces them with the Okazaki fragments
