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 The Study of the transmission/inheritance of traits through generations
 Inherited genetic variation is studied at the level of
 Individuals and their offspring o Where genetic information resides(In the Genome)
 Eukaryotic cells store DNA
 In Bacteria: DNA of the nucleoid region
 In virus: DNA or RNA included in the head or capsid o What is a gene?
 Unit of genetics information
 Genes code for proteins(also tRNA & rRNA)(not every rna translated into proteins)
 In Bacteria 85-90% of the genome consists of coding sequence
 In human only 1% of the genome is coding sequence o What is a chromosome?
 IN eukaryotes is a long stretch of DNA associated with proteins
 Chromosomes contain genes and non-genic regions
 Chromosomes are visible during mitosis or meiosis
 Every gene is localized in a specific position along the chromosome called Locus o Genes and genomes sequences are available in public databases
 Most commonly used
 National Center for BIotechnolofy Information (NCBI)
 http://www.ncbi.nlm.nih.gov
o How many types of chromosomes
 Middle/Metacentric
 Between Middle and End/Submetacentric
 Close to end/ Acrocentric(parm=short/qarm=long)
 At end/Telocentric o Karyotype
 Decription of the complete set of the chromosomes of an organism
 Chromosome arranged in a standard format showing
 Number
 Size
 Shape o Homologous chromosomes
 In pairs in diploid organisms
 Same length
 Same centromere location
 Same genes in the same order
 Exception: Sex Chromosomes o How man chromosomes organisms have

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 Number of chromosomes varies between species o Humans have 46 chromosomes o Chromosomes are in pairs: 2x23 o Haploid #(n) 23 o Diploid #(2n) 46
 Ploidy: number of sets of chromosomes
 Humans are diploid(2n;2sets)
 Gemets are haploid(n;1set)
 Yeast is a haploid(n) most of its life cycle
 Many plats are polypoid; o Triploid(3n) o Tetraploid(4n) o What is an allele? o Pentaploid(5n)
 One of the alternative forms of a gene
 Diifrent alleles arise by DNA sequence mutation
 Alleles go in pais(diploid organism)
 For every Gene(locus there are 2 alleles, One of each homologous chromosome.
 The pair of alleles for a gene = genotype(AA,Aa,aa)
 The detectable appearance of a charater = Phenotype(ex. Seed color)
 Dominant allele A: determines the phenotype
 Recessive allele a: it does not show as phenotype if A present
 Homozygote = identical
 Heterozygote= different
 Wild type: the allele most frequently observed in nature o The wild-type allele can be indicate with + o The mutant allele with intials of the mutation o Characters determined by one gene = monogenic traits o Characters determined by more than one gene = polygenic traits
 # genes are known to control eye color in humans(more genes are involved but still unknown)
 Skin color
 Multiple genes(loci) contribute to skin color
 Genes encoding proteins involved in the biosynthesis of malanine
o Two type of cell divison processes in eukaryotic cells(Mitosis/Meiosis) o Mitosis(2 2n cells) o Meiosis(4 n cells)

o The Cell Cycle an extended period between cell division, DNA synthesis, and chromosome replication phase
 M phased (mitotic phase)
 Nuclear and cell division
 Phase checkpoints: key transition points
 G1/S checkpoint
 G2/M checkpoint
 Spindle assembly checkpoint
 Cytokinesis
 S phase/dna replication
 G0/ wont divide anymore
 Interphase cell wont grow anymore
 Apoptosis/ protection against cancerous cells; cell suicide o M Phase
 Mitosis: separation of sister chromatids
 Prophase
 Prometaphase
 Metaphase- line up
 Anaphase-pulled away opposite polls
 Telophase- cytoplasm is seprated
 Cytokinesis: separation of cytoplasm
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