UNIT 3 2B: The Genetic Code and Gene expression Flashcards
Genome
the collection of all of the genes contained with the DNA of an organism
Gene expression
Conversion of the code in DNA of a gene into a protein through protein synthesis
Transcription
The process through which DNA is converted to messenger RNA and the genetic code in the DNA is copied to the mRNA
Enzyme
A type of protein, also referred to as a biological catalyst, that speeds up reactions within an organism by lowering activation energy
Promoter
The region of a gene at which RNA polymeraze binds, to initiate transcription
Terminator
The region of a gene at which transcription stops and the RNA polymeraze dissociates from the strand.
Intron
A region of a gene that contains sequences that do not code for the protein to be expressed.
Exon
A region of a gene that contains genetic information that codes for the specific protein to be synthesized
Translation
The process through which the information in mRNA is converted into a sequence of amino acids to synthesize a protein
Codon
A set of three bases in mRNA that code for a specific amino acid
Anticodon
A set of three bases on tRNA that are complementary to codons in mRNA
Amino Acid
The monomer that forms polypeptide chains and proteins
Universal triplet code
The genetic coding system based on codons with three bases, shared by most organisms.
Degenerate
Describes a genetic code in which multiple codons code for the same amino acid; also referred to as redundant
Mutation
A permanent change in the nucleotide sequence of a section of DNA
Describe the steps involved in transcription
- RNA polymerase unwinds the two DNA strands and binds to the promoter, initiating transcription
- The RNA polymerase moves along the DNA template strand, adding free RNA Nucleotides which creates a strand of pre-mRNA(in eukaryotes) that is complementary to the template strand, and contains the nitrogenous base Uracil instead of Thymine
Describe the steps involved in RNA processing
- A 5’ methyl cap is added to help protect the pre-mRNA from being degraded by enzymes when it exits the nucleus
- A poly A tail is added to the 3’ end. this makes the strand stable and also prevents degradation
- The introns (non-coding regions) are removed from the pre-mRNA, so that all that is left in the final mRNA is a continuous stretch of exons (coding regions)
5 steps in translation
- mRNA binds to the ribosome
- tRNA anticodon binds to complementary mRNA codon
- tRNA delivers specific amino acid to the ribosome
- Amino acid joins to previous amino acids by peptide bonds
- Polypeptide chain (primary structure) is formed