Chapter 5 Flashcards
Central Dogma
The fundamental concept in molecule biology that describe the flow of genetic information; DNA -> RNA -> Protein.
Genetic Material
The substance that carries heritable information from one generation to the next. In all known cellular life, this material is DNA
Heredity
The passing of physical or mental characteristics genetically from one generation to another
Transformation (in bacteria)
A process by which external DNA is taken up by a cell, resulting in a change in the cells genetic characteristics
Pathogenic
Capable of causing disease
Non-pathogenic
Not capable of causing disease
Transforming principle
The substance responsible for the heritable change of a cell. Identified as DNA by Avery, Macleod, McCarty
Bacteriophage
a virus that infects bacteria
Protein coat (capsid)
The outer protective layer of a virus, typically composed of protein
Radioactive isotope
An unstable form of an element that emits radiation as it decays to more stable form. Used as a label to track molecules in biological experiments
supernatant
a liquid that remains above the solid pellet after centrifugation
Pellet
The solid material that settles at the bottom of a tube after centrifugation. In the Hershey-chase experiment, this contained the bacterial cells
polymer
A large molecule composed of repeating subunits (monomers). DNA is a polymer of nucleotides
Nucleotides
The monomer unit of a nucleic acid, consisting of a five carbon sugar, a phosphate group, and a nitrogenous base
Phosphodiester bond
The covalent bond that links the nucleotides together in a DNA or RNA strand, connecting the sugar of one nucleotide to the phosphate of the next
Nitrogenous Base
A molecule containing nitrogen atoms and having chemical properties of a base. In DNA, the bases are adenine (A) guanine (G), cytosine (C), Thymine (T)
Purine
a double-ringer nitrogenous base (adenine and guanine)
Pyrimidine
A single-ringer nitrogenous base (cytosine and thymine)
Base composition
The relative amount of each of the four nitrogenous bases in a DNA molecule
Chargaff’s Rules
The observation that in DNA, the amount of adenine id equal to the amount of Thymine (A=T), and the amount of guanine is equal to the amount of cytosine (G-C)
X-ray Crystallography
technique used to determine the three-dimensional structure of molecules by analyzing the diffraction patter produced when X-rays pass through a crystallized sample
Double Helix
The twisted ladder shape of a DNA molecule, consisting of two antiparallel strands wound around each other
Antiparrallel
The orientation of the two strands of a DNA double Helix, which run in opposite directions (one strand runs 5’ to 3’, and the other 3’ to 5’)
Complementary base pairing
The specific hydrogen bond interactions between nitrogenous bases in DNA; Adenine (A) pairs with Thymine (T), and guanine (G) pairs with cytosine (C)
Hydrogen Bonds
A weak electrostatic attraction between a hydrogen atom bonded to a highly electronegative atoms (such as oxygen or nitrogen) and another electronegative atom. Hydrogen bonds hold the two strands of DNA together
Semi conservative Replication
The process of DNA replication where each new DNA molecule consists of one original (parental) strand and one newly synthesized strand
Origin of Replication
A specific DNA sequence where DNA replication begins
DNA polymerase
An enzyme that catalyzes the synthesis of new DNA strands by adding nucleotides to the 3’end of a growing DNA molecule
DNA helicase
An enzyme that unwinds the DNA double helix by breaking hydrogen bonds between the bases
Phosphodiester Bond
The covalent bond that links nucleotides together in a DNA or RNA strand
Transcription
The process of synthesizing RNA using a DNA template
RNA polymerase
An enzyme that catalyzes the synthesis of RNA using a DNA template
Promoter
A specific DNA sequence where RNA polymerase binds and initiates transcription
Terminator
A specific DNA sequence that signals the end of transcription
Gene
A unit of hereditary information consisting of a specific sequence of nucleotides in DNA that can be transcribed to produce RNA
Pre-mRNA
The initial RNA transcript in eukaryote’s before it undergoes processing
Mature mRNA
The process RNA transcript in eukaryotes that is ready for translation
5’ cap
A modified guanine nucleotide added to the 5’ end of eukaryotic pre-mRNA, protecting it, and aiding ribosome binding
3’ poly-A tail
A sequence of adenine nucleotide added to the 3’ end of eukaryotic pre-mRNA, protecting it and aiding in export
Intron
A non-coding sequence within a eukaryotic pre-mRNA molecule that is removed during splicing
Exon
A coding sequence withing eukaryotic pre-mRNA molecule that remains after splicing and is translated into protein
Splicing
The process by which introns are removed from pre-mRNA and exons are joined together to form mature mRNA
Codon
A three-nucleotide sequence in mRNA that specifies a particular amino acid or acts as start or stop signal for translation
Reading frame
The specific way mRNA nucleotides are grouped into codons during translation
Start codon (AUG)
The codon that initiates translation and also codes for methionine
Stop codon (UAA, UAG, UGA)
Codons that signal the termination of translation
Translation
The process of synthesizing a polypeptide chain using the information encoded in mRNA
tRNA (transfer RNA)
A small RNA molecule that carries a specific amino acid to the ribosome during translation
Anticodon
A three-nucleotide sequence on a tRNA molecule that base-pairs with a complementary codon on the mRNA
Ribosome
A complex molecular machine composed of rRNA and proteins that is the site of proteins synthesis
rRNA (Ribosomal RNA)
RNA molecules that are structural and catalytic components of ribosomes
A site
The sire on the ribosome where a new tRNA molecule carrying an amino acids binds
P site
A site on the ribosome where a tRNA carrying a growing polypeptide chain is located
E xite (exit site)
The site on the ribosome where an empty tRNA molecule leaves the ribosome after its amino acid has been added to the growing polypeptide chain
Peptide bond
The covalent bond that link amino acids together in a polypeptide chain
Gene expression
The process by which the information encoded in a gene is used to direct the synthesis of functional products, usually a protein
