chap 2- glossary Flashcards
a-helix
a type of secondary protein structure in which the polypeptide chain folds into a tight coil
Allele
a different version of the same gene (at the same locus) determined by small differences in the DNA sequence of the gene
Alternative Splicing
a process in which one or more exons are removed with the introns to produce mRNA molecules of different length and sequence
Amino Acid
a nitrogen-containing compound that is the monomer from which proteins are built
Anticodon
the 3 nucleotides in tRNA that bind to the complementary codon in mRNA according to base-pairing rules, resulting in the addition of a specific amino acid to the polypeptide chain
Antiparallel
parallel but orientated in the opposite direction.
B-pleated sheet
a type of secondary protein structure in which segments of the polypeptide chain bond side by side into a flattened assembly
Base Pair
2 complementary nitrogen bases linked by hydrogen bonding
Biological Functionality
the function of a protein
Catalyse
to speed up a biochemical reaction using an enzyme
Chromosome
a thread-like structure made of nucleic acids and proteins that encode genetic information
Cisterna
a flattened membrane disc that makes up the Golgi apparatus and ER
Codon
a group of 3 nucleotides in mRNA that specifies an amino acid
Complementary Base Pairing
the linking together of complementary nitrogen bases by hydrogen bonding. A pairs with T (or U in RNA) and C pairs with G
Condensation Polymerisation
a reaction in which monomers are linked together into a polymer with the release of a small molecule, such as water, as a by-product
Conformation
the proper functional shape of a protein
Degenerate
a property of the genetic code in which most amino acids are encoded by two or more codons
Denature
to permanently change the molecular structure of a protein or DNA
DNA
the information molecule that is the basis of an organisms genetic material
DNA polymerase
the enzyme that catalyses the bonding of nucleotides to form new strands of DNA
Endoplasmic Reticulum
an organelle made up of a network of membranous tubules involved in protein synthesis and folding for secretion
Enzyme
a specific protein catalyst that increases the rate of a biochemical reaction within the cell by lowering the amount of energy required for the reaction to proceed
Exon
a segment of DNA or RNA containing information that codes for a polypeptide or part of a polypeptide
Functional Proteomics
the study of how proteins work together in different cells or tissues, or under different circumstances
Gene
a segment of DNA in a chromosome that codes for a polypeptide, comprises the promoter, exons and introns
Gene expression
the process by which the information in a gene is turned into a polypeptide
Gene regulation
the process by which gene expression is switched on or off
Genetic Code
the complete set of mRNA codons and he corresponding amino acids they specify
Genome
the complete sequence of DNA in a single (haploid) mitochondrial and chloroplast DNA
Golgi Apparatus
a collection of membranes that package and store substances into vesicles in preparation for their release from the cell
Histone
a protein that binds and packages DNA in eukaryotic chromosomes
Hydrogen Bond
a weak chemical bond between a hydrogen atom on one molecule and a more electronegative element, usually an oxygen or nitrogen atom, or another molecule
Hydrophillic
describes the substances such as polar molecules and ionic compounds that dissolve readily in water
Hydrophobic
describes substances such as non-polar molecules that are insoluble in water
Inducer
a signaling molecule that switches on expression of a gene
Intron
a segment of DNA within a gene or pre-mRNA that conveys the instructions needed for polypeptide synthesis from the nucleus to the cytoplasm
mRNA
RNA copied from DNA that conveys the instructions needed for polypeptide synthesis from the nucleus to the cytoplasm
Non-coding region
DNA that does not encode a protein sequence
Non-template strand
the DNA strand that has the same sequence of nucleotides as the mRNA (except that it has a T instead of U)
Nucleic Acid
a large, linear polymer built from nucleotide monomers bonded together; includes DNA and RNA
Operator
a segment of DNA to which a protein binds, usually to switch off gene expression.
Operon
a group of genes that are expressed as a single unit
Peptide Bond
a chemical bond that links two amino acids in a chain
Phosphodiester Bond
a chemical bond that links 2 nucleotides in a growing chain
Plasmid
a small, circular DNA structure independent of the chromosome in prokaryotic cells
Poly-A-Tail
a chain of 100-200 adenine nucleotides added at the 3’ end of an mRNA strand
Polypeptide
a linear polymer built from amino acid monomers
Polyribosome
a chain of ribosomes formed by attaching and translating from a single mRNA strand
Pre-mRNA
an unprocessed RNA strand that is transcribed directly from the DNA
Primary Structure
the linear sequence of amino acids that makes up a polypeptide chain
product
the outputs of a chemical reaction that are formed from the reactants or inputs
Promoter Region
a segment of DNA to which RNA polymerase binds to begin transcription
protein
a polymer made up of amino acid monomers; may consist of a single polymer chain or many polymers bonded together into a functional molecule
Protein Secretory Pathway
the pathway through which cells package proteins into vesicles for release into the extracellular environment
Proteome
the complete set of proteins produced by a cell, a tissue or organism
Proteomics
the study of proteomes
Quaternary Structure
the structure formed when 2 or more polypeptides associate into a mature protein
Random Coil
a secondary protein structure in which the polypeptide chain does not fold into a specified arrangement
Regulatory Gene
a gene whose product switches on or switches off expression of one or more other genes
Repressor Protein
a protein that binds DNA to prevent RNA polymerase attaching or transcribing; essentially shuts off gene expression
RNA
a type of nucleic acid consisting of a single strand of nucleotides, has essential roles in protein synthesis
rRNA
an RNA strand that serves as a structural component of a ribosome.
Ribosome
a small structure consisting of RNA and proteins where amino acids are joined to form polypeptides
RNA polymerase
the enzyme that catalyzes the synthesis of RNA
Rough ER
ER with ribosomes attached
Secondary Structure
the localised folding of a polypeptide chain when neighbouring amino acids bond to each other to form a-helices, B-pleated sheets or random loops
Semi-conservative Replication
the replication of DNA in which the product contains on original and one newly made strand
Structural Gene
the replication of DNA in which the product contains on original and one newly made strand.
Substrate
the substance that an enzyme acts on
Subunit
a distinct component of a biological particle; in proteins, it refers to each polypeptide that contributes to the quaternary structure
Template
a pattern that can be used for making many more copies
Template Strand
a strand of DNA that is copied during DNA or RNA synthesis
Tertiary Structure
the overall 3D shape of a completely folded polypeptide
Transcribe
to copy DNA into mRNA
Transcription
the process by which DNA is copied into mRNA
Transcription Factor
a protein that binds to DNA to control the rate of transcription from a gene
tRNA
an RNA molecule that transports an amino acid to the ribosome for assembly into a polypeptide
Translation
the process of turning the nucleotide sequence of mRNA into the amino acid sequence of a polypeptide
Transport Vesicle
a small membrane-bound sac containing protein that is transported from the Golgi to the plasma membrane into the extracellular environment
Triplet
a set of 3 nucleotide codes
