Gregor Mendel
"Father of Genetics"; described genetic traits
Johann Mescher
isolated nuclein in 1868
Thomas Hunt Morgan
showed units of heredity (genes) were located on chromosomes in 1911
Phoebus Levene
identified the chemical components of DNA in 1929
Erwin Chargaff
found that the number of purines is equal to the number of pyrimidines in 1950 (A+G)/(T+C)=1
Rosaline Franklin
generated original x-ray diffraction data leading to discover of structure of DNA
James Watson and Francis Crick
pieced together structure of DNA and built model in 1953
Restriction Enzymes
shown to cleave DNA into fragments
Southern Blot
allowed for detection of DNA fragments and sequences in 1975
polymerase chain reaction
described in 1985 which led to microarray technology in 1996
human genome project
began in 1990 to understand radiation effects leading to identifying 25,000 genes
prokaryote
has no nucleus, single copy of DNA (haploid), conjugation and DNA exchange; includes bacteria, viruses, spirochetes
eukaryote
nucleated with cytoplasmic organelles, double cope of DNA (diploid), exons and introns
autosome
non-sex chromosome
exon
translated portion of eukaryotic gene (coding portion of gene)
intron
non-translated intervening sequence of eukaryotic gene (junk DNA)
genome
complete set of genetic instructions for an organism; complete blueprint for reproduction
chromosome
nuclear "colored body"; nucleic acid polymers that encode genes
gene
unit of inheritance; one encodes one protein; sequence of DNA bases
histone
proteins around which chromosomes fold
diploid
DNA that has two copies or pairs of homologous chromosomes; humans: 46 chromosomes, 6 billion base pairs per cell
haploid
found in gametes which have 1 copy of each chromosomes; humans: 23 chromosomes, 3 billion base pairs per cell
locus
a gene or region of DNA
allele
alternate form of a gene at a locus on a chromosome; one copy from each parent: homozygous, heterozygous
phenotype
a trait or group of traits resulting from transcription and translation of these genes; observed expression of genotype
genotype
the DNA nucleotide sequence responsible for a phenotype; the alleles at a given locus for an individual
mutation
a DNA sequence change that is present in a relatively small proportion (<1%) of a population
polymorphism
a change in DNA sequence that is present in at least 1-2% of a population
Central Dogma
expresses transfer of information; includes replication, transcription, and translation
Francis Crick
proposed the central dogma in 1953
replication
reproduction of DNA into double-stranded nucleotides that provides a genetic code in the form of the bases: A, T, G, and C; where DNA produces daughter strands with DNA as the starting material and reproduces its own genetic code
transcription
...
translation
...
Deoxyribonucleic acid
double-stranded nucleotide polymers providing ATGC genetic codes
Ribonucleic acid
single-stranded nucleotide polymers providing AUGC template
molecular pathology
testing which is based upon the detection of nucleic acids (DNA and RNA) as opposed to protein (enzymes and antibodies)
nucleosides
comprised of a ribose sugar and a nitrogen base
nucleotides
polymers which DNA is made from; phosphorylated nucleosides
pyimidine or purine
makes up the base
ribose or deoxyribose
makes up the pentose sugar
pyrimidines
single ring nitrogenous bases with a hexagonal structure with nitrogen present at positions 1 and 3; includes thymine, cytosine, and uracil (cytidine, thymidine, uridine)
purines
hexagonal structure with a pentagon at positions 4 and 5 of hexagon and carbons at positions 2 and 6; adenine and guanine (adenosine and guanosine)
uracil
replaces thymine in RNA molecule
ribose
...
deoxyribose
...
pentoses
5-carbon sugars which are numbered clockwise starting with one on upper right
hydrogen bonds
how base pairs bind together
A:T
pair contains two hydrogen bonds
G:C
pair contains three hydrogen bonds
covalent bonds
binds phosphate to molecule
kcal
the amount of energy it would take to break the bonds
anealing
DNA is heated and separated, then recombined in the double-stranded form
polarity
describes the orientation of the DNA strand with reference to the 5'-phosphate and 3'phosphate groups
B-DNA
most common form of DNA; right-hand helix
A-DNA
compact form of right-hand DNA helix; produced in vitro
Z-DNA
left-hand helix 12 base pairs per turn; results from stressful conditions
double stranded DNA
consists of deoxyribose, phosphate, nitrogenous bases, pyrimidines (thymine and cytosine) and purines (adenine and guanine)
single stranded RNA
consists of ribose, phosphate, nitrogenous bases, pyrimidines (uracil and cytosine) and purines (adenine and guanine)
polymerase
catalyze formation of the phosphodiester bond
helicase
unwind and untangle to form replication forks
primase
synthesizes a short ribonucleic acid (RNA) to prime DNA synthesis
methylases
add methyl groups to nitrogen bases
deaminases
take amino groups from nitrogen bases
nucleases
cut DNA
ligases
catalyze formation of a single phosphodiester bond