Chapter 12 and 13 Flashcards
Fredrick Griffith experiment
So that something a lethal strain of bacteria could transform a harmless strain into a lethal strain. Later it was discovered the DNA was transmitted between lethal and harmless bacteria.
Transformation
The process by which exogenous DNA is transferred into a host cell.
Oswald Avery experiment
Separated the contents of S cells into lipids, proteins, polysaccharides, and nucleic acids. Only nucleic acids cause transformation. This was the first demonstration that DNA is genetic material.
Hershey Chase experiment
Worked with bacterial phages. Phages reproduce inside of bacterial cell, causing it to break open to release large numbers of new viruses.
Bacteriophages (phages)
Type of virus that infects bacteria
Double helix
Physical structure of DNA. Each strand has backbone made of alternating sugar (deoxyribose) and phosphate groups.
X-ray diffraction
Phenomenon in which the atoms of a crystal, by virtue of their uniform spacing, cause an interference pattern of waves present in an incident beam of x-rays.
Nucleotide
DNA building block
Deoxyribose
Pentose sugar found in nucleotide.
Nitrogenous base
Found in nucleotides. Attached to 1’ carbon of the sugar.
Adenine (A)
Nitrogenous base
Guanine (G)
Nitrogenous base
Thymine (T)
Nitrogenous base
Cytosine (C)
Nitrogenous base.
Chargaff’s rules
Complimentary base pairing.
A pairs with T
G pairs with C
Complimentary base pairing
A pairs with T
G pairs with C
Antiparallel
Opposite directions
Purine
Used to make building blocks of DNA and RNA.
Includes adenine and guanine.
Pyrimidine
Used to make DNA and RNA.
Includes cytosine, thymine, and uracil.
Template strand
The DNA sequence that can duplicate itself during mRNA synthesis.
Complimentary base pairing
The manor in which the nitrogenous bases of the DNA molecules align with each other.
3’ end
End of the molecule that terminates in a 3’ phosphate group.
5’ end
End of the molecule which terminates in a 5’ phosphate group
Semiconservative replication
Two identical DNA double helices are produced, each consisting of one original strand from the parent molecule and one newly synthesized complementary strand.
Conservative replication
Both parent (old strands) might remain together, and the two newly synthesized strands would form a second double helix.
Dispersive replication
Parental and newly synthesized strands become randomly mixed during the replication process.
Origins of replication
Where DNA replication begins and double helix unwinds.
DNA helicase
Travels along the helix, opening the double helix like a zipper, forming a replication fork.
Replication fork
The point at which the two strands of DNA are separated to allow replication of each strand.
Single strand binding proteins (SSB)
Prevent helix from reforming until strand is replicated.
Topoisomerases
Produce breaks in the DNA molecules and the rejoin the strands, preventing knot formation during replication.
RNA primer
(15-24) nucleotides are made where replication begins, starts process
DNA primase
Synthesizes RNA primer
DNA polymerase
Links nucleotide subunits. Adds nucleotides only to the 3’ end (hydroxyl group) of an existing polynucleotide strand.
Leading strand
Adds nucleotides continuously to the 3’ end of the new strand that is always growing toward the replication fork
Lagging strand
Adds nucleotides discontinuously to the 3’ end of the new strand that is growing away from the replication fork.
Okazaki fragments
100-2000 nucleotide fragments. Synthesized on the lagging strand since the lagging strand is growing away from the spot that is being unzipped (replication fork)
DNA ligase
Joins Okazaki fragments.
Replication bubble
Unwound and open region in a DNA helix where DNA replication occurs.
Telomere
The end of a chromosome. Made of repetitive sequences of non-coding DNA that protect the chromosome from damage.
RNA
Acid in the chromosomes of the cells of living things which plays an important part in passing information about protein structure between different cells
Uracil (U)
Nucleotide base in RNA
Genotype
An organisms DNA
Phenotype
An organism’s physical features
Transcription
The transfer of genetic material from DNA into an RNA molecule
Translation
The transfer of information from RNA into a protein
mRNA
Carry the genetic information needed to make proteins.
RNA polymerase
Links nucleotide subunits to form a new DNA strand complimentary to a DNA template
Promoter region
A region of DNA where RNA polymerase begins to transcribe a gene.
Initiation of transcription
RNA polymerase unwinds DNA double helix and initiates RNA synthesis
Elongation of transcription
Additional nucleotides are added to 3’ end of RNA molecule. DNA double helix re-forms following transcription.
Termination of transcription
RNA polymerase recognizes termination sequence. RNA transcript and RNA polymerase are released.
Initiation of translation
Ribosome gets together with the mRNA and the first tRNA so translation can begin.
Elongation of translation
Amino acids are brought to the ribosome by tRNAs and linked together to form a chain.
Termination of translation
The ribosome reaches a stop codon (UAA), UAG, and UGA.)
Leader sequence
A sequence of nucleotides at the 5’ end of mRNA (and on DNA), upstream of the start codon for translation. Regulation of gene expression in eukaryotes and prokaryotes.
Codon
A sequence of three consecutive nucleotides in a DNA or RNA molecule that codes for a specific amino acid.
Start codon
Follows the leader sequence and signals the beginning of the coding sequence for the protein.
Stop codon
At the end of each coding sequence (UAA, UGA, UAG), signals the end of a protein.
5’ (7-methylguanosine) cap
Protects the transcript from being broken down. Helps the ribosome attach to the mRNA and start reading it to make a protein.
Poly-A tail (polyadwnation signal)
Long chain of adenine nucleotides that is added to a mRNA molecule during RNA processing to increase the stability of the molecule
Pre-mRNA
The first form of RNA created through transcription in protein synthesis.
Intron
Intervening sequences
Exon
Expressed sequenced which are parts of the protein-coding sequence
Small nuclear ribonucleoprotein complex
Protein RNA complex composed of specific snRNP-associated proteins along with snRNAs. Non coding RNA molecules abundant in the nucleus
Transfer RNA (tRNA)
Adaptor molecules that translate genetic information into protein sequence by delivering amino acids to the protein synthesis machinery during translation.
Anticodon
Trinucleotide sequence located at one end of a tRNA molecule, which is complementary to a corresponding codon in a mRNA sequence.
Small ribosomal subunit
Programs protein synthesis. Binds with mRNA and mediates the interaction between mRNA codons and tRNA anticodons.
Large ribosomal subunit
Composed of two RNA strands: a long one colored orange and a shorter one colored yellow. Catalyses the key chemical event in protein synthesis, peptide bond formation.
P site
(Peptidyl) binds the tRNA, holds the growing protein.
A site
(Aminoacyl) site of entry for next RNA
E site
Exit
Release factor
A type of translation factor that triggers translation termination.
Gene mutation
A change in one or more genes resulting in genetic disorders or illnesses.
Base substation
The simplest type of gene-level mutation, involve the swapping of one nucleotide for another during DNA replication
Frameshift mutation
An insertion or deletion involving a number of base pairs that is not a multiple of three, which consequently disrupts the triplet reading frame of a DNA sequence.
