Chapter 17 Flashcards
Synthesis of RNA using information in the DNA
Transcription
DNA direct the synthesis of proteins
Gene expression
Synthesis of a polypeptide using the information and mRNA
Translation
The central dogma of molecular genetics
DNS, RNA, protein
Coding strand to make an M RNA transcript
Template strand
What is the start codon
AUG
Triplet grouping of ribonucleotide used by the translation machinery during polypeptide synthesis
Reading frame
The enzyme that uses the DNA template strand to transcribe a new M RNA strand
RNA polymerase
Stretch of DNA transcribed in an RNA molecules
Transcription unit
Nucleotide sequence containing TATA
TATA box
What makes up a transcription initiation complex
Transcription factors, RNA polymerase bound to a promoter
What are the three important functions of the 5’ cap and poly-A tail?
Facilitate the export of mature mRNA from the nucleus, help protect mRNA from degradation by hydrologic enzymes, help ribosomes attached to 5’ end of mRNA
Non-coding segments of nucleic acid
Introns
Coding DNA segments
Exons
Small nucleoproteins made up of RNA and protein molecules
snRNP
Interact with certain sites along the intron, releasing it and it rapidly degrades, joining 2 exons that flanked the intron
Spliceosomes
RNA molecule that functions as an enzyme
Ribozymes
Carries genetic material to protein synthesis site
mRNA
Carries amino acids to growing polypeptide
tRNA
Makes up ribosomes
rRNA
Nucleotide triplet at one end of a tRNA molecule that base pairs with a complementary codon
Anticodon
How many different aminoacyl-tRNA are there?
20
Aminoacyl-tRNA binding site
A site
Peptidyl-tRNA binding site
P site
Exit site
E site
What are the 3 stages of translation?
Initiation, elongation, termination
Protein shaped like aminoacyl-tRNA, binds directly to stop codon hydrolyzation
Release factor
Group of ribosomes attached to and translating mRNA
Polyribosomes
What are some of the things that will result in a final form functional protein?
Modifications of proteins, amino acids, removal or rearrangement of amino acids
Change in a nucleotide sequence of DNA
Mutation
Change in a single nucleotide
Point mutation
Nucleotides are inserted or deleted from a gene
Frameshift mutation
Amino acid changes into a codon resulting in a shorter and nonfunctional protein
Nonsense mutation
Nucleotide pair substitution that results in a codon that codes for a different amino acid
Missense mutation
What are the 2 categories of mutagens?
Physical, chemical
What are the actions of chemical mutagens?
Can change base pairs, interfere with DNA, pair incorrectly during replication
RNA polymerase binds to DNA at promoter
Initiation
RNA chain grows in the 5’ to 3’ direction
Elongation
Transcription proceeds until RNA polymerase so reaches a terminator site; RNA molecule is released
Termination
Strings of ribosomes can work on the same mRNA site at the same time
Polysomes
Help wrap DNA into a 3D shape
Chaparonin
Type of mRNA first produced in the nucleus of a eukaryotic cell
pre mRNA
Combines with proteins to make protein synthesis machinery (ribosomes)
rRNA
Contains the codon sequence that is edited in eukaryotes before translation
mRNA
Contains the anticodon sequence that brings the correct amino acid into the ribosome
tRNA
Charges up tRNA’s by adding the correct amino acid
aminoacyl tRNA synthetase
Amino acid polymer by ribosomes during translation
Polypeptide
Genetic code has more than one sequence that could code for the same amino acid
Redundant, not ambiguous
