Genetics = the study of all aspects of genes and transmission of DNA genes being the fundamental units of biological information composed of DNA molecules (deoxyribonucleic acid) * * 1. classical the study of chromosomal theory began with Mendel’s observation of pea plant (Pisum sativum) discontinuous/qualitative characters the “either/or” traits * * 2. molecular study of genetic materials (DNA & RNA) including structure, replication, mutation, & expression molecular structure discovered by Watson & Crick in 1950s * linear series of nucleotides (4 kinds) sequence constitutes language of code * architectural blueprint for life is DNA * * 3. evolutionary study of evolution mechanisms on a genetic level quantitative genetics and the interaction of genes + environment to produce a phenotype population genetics, how factors change allele frequency * genomics = study of complete gene sets… ‘genomes’ allele = 1 of the different forms of a gene that can exist at a locus dominant, masks expression of another at locus recessive, is masked by another at same locus genotype = allelic composition of an organism for a gene/gene set phenotype = detectable outward manifestation of a genotype morph = form AND polymorphism = many different forms wild type vs. mutant = naturally occurring vs. mutation
Molecular Genetics = study of genetic materials (DNA/RNA) & processes
Physical structure = 2 strands of nucleotides in a double helix form * NUCLEOTIDES have 1. dexyribose (sugar) always SAME 2. phosphate group 3. nitrogen base VARIES!!
* Adenine double hydrogen bonds * Thymine * Guanine triple hydrogen bonds * Cytosine
DNA is organized into genes and chromosomes * genome = complete set of genetic info for an organism prokaryotes single, circular chromosome * lacking proteins or other molecules eukaryotes multiple, linear chromosomes * found mostly in nuclei * # of chromosomes specific to species haploid = one chromosome (n) * extra chromosomes = plasmids * viruses have single, linear genome diploid = 2 identical chromosomes (2n) * (humans are n = 23 so… 2n = 46) * * chromosome pairs are called ‘homologs’ * * extranuclear genome: although mostly found in nucleus, small fraction of DNA found in MITOCHONDRIA as “mother” DNA plants have extra DNA in chloroplasts * cytogenics = study of physical properties of chromosomes * each chromosomal DNA molecule contains * many functional regions known as genes also noncoding inserts called ‘introns’ gne pairs exist because of ‘homologs’ *
DNA is coiled very efficiently (human is 1 meter to microns * – double helix coiled around ‘spools’ called nucleosomes composed of proteins called histones
DNA + nucleosomes = chromatin centromere area of attachment during division telomere tip of chromosome prevent chromosomal ‘fraying *
How does life take form from DNA? DNA RNA protein main elements of an organism are proteins * 3 TYPES: 1) structural build the physical structure * 2) enzymatic catalyze cell reactions * 3) regulatory turn gene activity on/off primary, secondary, tertiary, & quaternary structure * * main task of living system is to convert DNA info into proteins
* DNA is transcribed into RNA * RNA is translated into protein
TRANSCRIPTION --- synthesis of RNA from DNA template * RNA (ribonucleic acid) composed of nucleotides with *
