Biochemical Basis of Heredity

Vocabulary flashcards based on lecture notes about the biochemical basis of heredity.

Adenine (A)

A nitrogenous base found in DNA; pairs with Thymine.

Guanine (G)

A nitrogenous base found in DNA; pairs with Cytosine.

Thymine (T)

A nitrogenous base found in DNA; pairs with Adenine.

Cytosine (C)

A nitrogenous base found in DNA; pairs with Guanine.

Uracil (U)

A nitrogenous base found in RNA; pairs with Adenine.

Nucleoside

Molecule containing a nitrogenous base and a pentose sugar.

Nucleotide

Molecule containing a nitrogenous base, a pentose sugar, and a phosphate group.

Phosphodiester bond

Bond formed between two mononucleotides by linking the phosphate groups.

Oligonucleotide

A short chain of nucleotides, typically less than 20.

Polynucleotide

A long chain of nucleotides, typically more than 20.

Deoxyribonucleic Acid (DNA)

Molecule that carries the genetic information of an organism; packaged in chromatin using histones and organized into chromosomes.

Ribonucleic Acid (RNA)

Single-stranded molecule containing a ribose sugar, which is susceptible to alkaline hydrolysis.

DNA Ligase

Enzyme that joins DNA fragments formed by discontinuous synthesis.

Nuclease

Enzyme that 'digests' nucleic acid molecules by breaking phosphodiester bonds.

Endonucleases

Enzymes that digest nucleic acids from the middle of the molecule.

Exonucleases

Enzymes that digest nucleic acids from a free end.

Continuous Synthesis

Synthesis done in the 5' to 3' direction.

Discontinuous synthesis

Synthesis done in the 3' to 5' direction.

5’ end (cap)

Addition of 7-methyl guanosine residues which aids in binding of ribosome to mRNA.

3’ end (tail)

Addition of poly-A tail for stability and transport.

Point Mutation

Single base pair substitution.

Mismatch repair

Checks for errors made when DNA is replicated.

Electrophoretic Separation

Physical method of separation of DNA and RNA based on molecular weight and length of the molecule.

Polymerases

Enzymes that join DNA or RNA nucleotides together to form a single-stranded daughter molecule.

Reverse Transcriptase

Enzyme that synthesizes DNA from either an RNA or DNA template.

Spliceosome

Identifies and splices boundaries of introns

Leading strand

Template for continuous DNA synthesis

Lagging strand

Template for discontinuous DNA synthesis

Deletion/insertion

Subtracted/addition of amino acid codons in multiples of three. Reading frame is retained.

Deletion/insertion with frameshift

Subtraction/addition of amino acid codons in non-multiples of three. Results in a shift of the reading frame

Amplification/ trinucleotide repeat

Increase in the number of repeat sequences in microsatellite DNA. Results in distruption of gene expression.

Translocation

Interchromosomal exchange of large chromosome segments. Results in a new protein with different function.

Mismatch Repair

Checks for errors made when DNA is replicated

Base excision repair

Repairs small, nonhelix-deforming adducts

Nucleotide excision repair

Removes bulky DNA adducts

Double-strand break repair

Repairs double-strand breaks that result from physiologic processes or from ionizing radiation.

Nucleoid

Region in prokaryotes where DNA is located.

Transcription

The process of creating RNA from a DNA template.

Translation

The process of creating proteins from an mRNA template.

Codon

A sequence of three nucleotides that codes for a specific amino acid during translation.

Genome

The set of all the genes in an organism.

DNA Polymerase

The enzyme responsible for synthesizing DNA during replication.

RNA Primer

A short sequence of RNA that is used to start DNA synthesis; synthesized by Primase.

Okazaki fragments

A replication mechanism where DNA is synthesized in short fragments.

Topoisomerase

Enzyme that relieves strain ahead of the replication fork during DNA replication.

Helicase

An enzyme that unwinds the DNA double helix at the replication fork during DNA replication.

Frameshift Mutation

A type of mutation that results from the insertion or deletion of nucleotides in a DNA sequence, causing a shift in the reading frame.

DNA Replication

The process of copying a DNA molecule to produce two identical DNA molecules.

Gene Expression

The process by which information from a gene is used in the synthesis of a functional gene product.

Messenger RNA (mRNA)

The molecule that carries genetic information from DNA to ribosomes for protein synthesis.

Ribosomal RNA (rRNA)

A component of ribosomes, essential for protein synthesis.

Transfer RNA (tRNA)

The molecule that carries amino acids to the ribosome during protein synthesis.

Ribosome

Cellular structure responsible for protein synthesis.

Histones

Proteins that package and organize DNA within the nucleus of eukaryotic cells.

Chromatin

The complex of DNA and proteins that make up chromosomes.

Gene

A segment of DNA that contains the instructions for making a specific protein or RNA molecule.

Point Mutation

A type of mutation where one nucleotide is replaced by another.

Semiconservative replication

The form of DNA replication in which each new molecule consists of one original strand and one newly synthesized strand.

Ribosome

A structural component of ribosomes that facilitates the binding of mRNA and tRNA during protein synthesis.

Frameshift

A mutation where the reading frame of the genetic code is disrupted due to insertion or deletion of nucleotides.

Translation

The process of converting the information encoded in mRNA into a sequence of amino acids to form a protein.

Transcription factors

Small proteins that bind to DNA and play a crucial role in regulating gene expression.