Chapter 1 - Genetics

Nucleotide

The building block of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base.

Phosphodiester bond

The bond that links nucleotides in DNA and RNA through a phosphate group connecting the 3' carbon of one sugar to the 5' carbon of another.

3’ hydroxyl

The hydroxyl group located at the 3' end of a nucleotide, crucial for DNA and RNA synthesis.

Primer

A short nucleic acid sequence that serves as a starting point for DNA synthesis.

Complementarity

The specific base pairing between adenine and thymine, and guanine and cytosine in DNA, and adenine and uracil, and guanine and cytosine in RNA.

Hybridization

The process of forming a double-stranded nucleic acid by combining complementary strands.

Denaturation

The separation of double-stranded nucleic acids into single strands through the disruption of hydrogen bonds.

Colinearity

The correspondence between the order of nucleotides in a gene and the order of amino acids in the resulting protein.

ncRNA = noncoding RNA

RNA molecules that are not translated into proteins but have various regulatory functions.

Exon

The coding region of a gene that is expressed.

Intron

The non-coding region of a gene that is removed during RNA processing.

Enhancer

A DNA sequence that can increase transcription of a gene.

Promoter

A region of DNA where RNA polymerase binds to initiate transcription.

Terminator

A sequence that signals the end of transcription.

Operon

A unit of genetic regulation in bacteria consisting of a promoter, operator, and genes.

Polycistronic

mRNA that encodes multiple proteins in prokaryotes.

5’ cap = 5-methylguanosine(5 Me-G)

A modified nucleotide added to the 5' end of eukaryotic mRNA.

polyA tail = polyadenosine tail

A sequence of adenine nucleotides added to the 3' end of eukaryotic mRNA.

5’ UTR = 5’ untranslated region

The region of mRNA upstream of the start codon that is not translated.

3’ UTR = 3’ untranslated region

The region of mRNA downstream of the stop codon that is not translated.

Consensus sequence

A sequence of DNA or RNA with high similarity among different genes or species.

Spliceosome

A complex of RNA and protein that removes introns from pre-mRNA.

Degeneracy

The redundancy in the genetic code where multiple codons can code for the same amino acid.

Open reading frame (ORF)

A sequence of DNA or RNA that can be translated into a protein.

Reading frame

The way in which a series of nucleotides is read in groups of three during translation.

Locus (plural loci)

The specific physical location of a gene on a chromosome.

Element

A specific DNA sequence that regulates gene expression.

Peptidyl transferase reaction

The enzymatic reaction that forms peptide bonds between amino acids during translation.

Residue

An amino acid in a protein sequence.

Template/non-coding/antisense strand

The DNA strand that is used as a template for RNA synthesis.

Non-template/coding/sense strand

The DNA strand that has the same sequence as the RNA transcript, except with thymine instead of uracil.