Chapter 3: Nucleic Acids + Transcription Flashcards
4 Functions of Nucleic Acids
- Forms LONG LINEAR polymers for encoding, transmitting and expressing genetic information
- Energy exchange: ATP + GTP
- Metabolic regulation
- Catalytic
What is the Central Dogma of Biology/DNA?
DNA is translated into RNA which is transcribed into proteins
Where does translation occur in a eukaryotic cell? Transcription? prokaryotes?
Euk: Translation: nucleus
Transcription: Cytoplasm by ribosomes
Prok: both cytoplasm
Transformation
the conversion of cells from one state to another
ex) nonvirulent to virulent
mutation
any change in genetic material to the nucleotide sequence of a gene
What are nucleotides 3 components?
5-carbon sugar, base (AGTC), one or more phosphate group (Ionized)
Difference between a nucleoside and nucleotide
Nucleoside: sugar and base w/o phosphate group
Nucleotide: has one of more phosphate groups
What are the prime numbers on a strand of nucleotides?
5 prime, top phosphate end
3 prime, bottom hydroxyl on sugar
Who were the scientists that discovered the structure of DNA?
Charles Watson and Crick
What does complementary mean?
Base pairs line up equally. Equal number of opposite bases
How does DNA coil itself and what helps it?
DNA is wrapped around proteins called histones which are them supercoiled to create chromatin. Only happens during cell division. Helped by enzyme topoisomerase
RNA World Hypothesis
RNA was probably the original storage molecule for cell info before DNA
3 Functions of RNA
catalyst, DNA replication, transcription and translation
Difference in DNA and RNA sugar
DNA: deoxyribose
RNA: ribose (has 2 hydroxyl groups on bottom of sugar)
RNA bases
A, U (uracil), G, C
Anti parallel
DNA strands run opposite each other from 5’-3’ and 3’-5’
5’ end of DNA and RNA
DNA: monophosphate
RNA: triphosphate (ATP)
How is transcription initiated?
Promoter (TATA box) TATAAA
RNA Transcript
RNA sequence synthesized from DNA template
Where does the first nucleotide to be transcribed? Why?
25 bases away from promoter; to make room for RNA polymerase (Pol II) and Transcript factors
When does transcription end?
When it hits the terminator sequence
Housekeeping gene
Continually transcribed gene because the cell always needs the protein
What carries out promoter recognition on Prokaryotes? Eukaryotes?
Pro: sigma factor
Euk: transcript factor
4 parts of Transcription bubble
Pol II, Transcript factors, Mediator complex, Transcriptional activator proteins bonded to enhancer sequence
What happens when 2 RNA base pairs bond together?
2 phosphates pop pff creating pyrophosphate group (PPi). PPi gets cleaved into two separate phosphates Pi and Pi.
What is the function of transcript factors?
help guide the Pol II to the binding site
RNA-DNA dulex
where DNA and RNA attach
Elongation
process in translation where AA’s are added one by one to a growing peptide chain
Monosystronic, Polysystronic
Euk: mono: codes for one protein
Pro: poly: codes for more than one protein
What must RNA go through after transcription?
Chemical modifications; pass through the nuclear membrane
Introns and Exons
Introns: pieces of data that code for nothing
Eons: data that codes for something
Nuclease
enzyme that degrades loose nucleotides
What two things help stabilize mRNA?
polyadenylation on 3’ end (repeating A bases) and the 5’ cap (upside down 7-methylguanosine)
RNA splicing
cutting out of introns and reconnection of exons by splicosome
Alternate splicing
One strand of RNA being spiced into two different ones that code for 2 different proteins. More efficient for the body
Ribosomal RNA (rRNA)
found in all ribosomes that aid translation
Transfer RNA (tRNA)
carries individualized amino acids for use in translation
Small Nuclear RNA (snRNA)
found in eukaryotes; used for splicing, polyadenylation, and and other things in nucleus
Small regulatory RNA (srRNA)
2 of them!
microRNA: cleave, disable, inhibit translation
small interfering RNA: double stranded RNA that destroys single stranded RNA
