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genetics_study_guide The first half of the study guide is basically all the AB stuff. Bio (2021-22):
Typology: Study notes
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How is this all one unitโฆ
โ Purine Bases (Ag for Silver) โ Adenine & Guanine โ Two-Ring โ Pyrimidine Bases โ Thymine (Uracil) & Cytosine โ Single-Ring โ DNA Denaturation โ Separating the strands by the H bonds โ NOT harmful & reversible โ Directionality โ 5โ end is top of nucleotide (where the Phosphate sticks up) โ Five = phosphate โ Organized in tightly wounded chromosomes โ Circular in prokaryotes โ Linear in eukaryotes
โ In both strands: ยฝ is new DNA and ยฝ is the parent template strand โ Semi-conservative process
โ The one and only enzyme that does all: RNA Polymerase (RNAP) โ NO EDITING: unnecessary โ Transcription bubble contained in RNAP โ RNAP binds to the promoter region โ TATA Box in any direction โ Enhancer region โ Transcription factors โ Initiation complex binds to promoter region and triggers transcription โ Terminator Region POST-TRANSCRIPTIONAL PROCESSING โ Splicing: cut out the introns to make mature mRNA transcripts โ Eukaryotic genes are not continuous โ Exons = the โreal geneโ โ expressed/coding โ Introns = the โjunkโ โ In between โ Alternative splicing โ One gene can code for more than one protein โ Di erent introns within the same gene โ Protecting the ends of the mRNA as it travels from the nucleus through the cytoplasm โ Add 5โ GTP cap โ Add poly-A tail on 3โ end โ mRNA will last longer and produce more protein
โ Codon: each group of consecutive 3 nucleotides that code for 1 amino acid โ Directionality โ โ N-AA 1 -AA 2 -AA 3 -AAi-C
โ Highly conserved genetic code: a 3 base combination will code for the same amino acid across ALL species โ Defense against mutation: more than 1 codon for the same Amino Acid โ Start Codon: 5โ AUG 3โ (methionine) โ Stop Codons (5โ โ 3โ): UAA, UAG, UGA โ Stop translation as there is no tRNA to bind to here โ Transfer RNA Structure (tRNA): โ โClover leafโ โ Anticodon determines amino acid โ Ribosomes facilitate coupling of tRNA anticodon to mRNA codon
โ Virus: Genetic material within a protein capsid/envelope/capsule
โ No nucleus (or other organelles) โ No post transcriptional processing โ Direct translation โ As mRNA gets made, it is fed into a ribosome
โ Phenotype: Version of a trait โ Allele: Version of a Gene โ Genotype: Combination of Alleles โ 2 Chromosomes = 2 Copies of each gene = 2 alleles for each trait โ Dominant allele renders 2nd^ allele irrelevant (will be expressed no matter what) โ Functioning Protein โ Recessive Allele typically makes a malfunctioning allele โ True-Breeding: Homozygous โ Carrier: Heterozygous โ Punnett Squares โ Dihybrid Cross: Maintain Gene Order and FOIL for gametes โ Polyhybrid Cross: figure out probability of each trait and then x โem all โ Autosomal Chromosomes (Regular, 2 of each #) & Sex Chromosomes (X, Y) โ Pedigree โ Square = Genetically Male โ Circle = Genetically Female โ Shaded = Has Phenotype โ Skipped Generation: when children have the trait, but the parents donโt โ Can use? or _ for second allele when dominant and indertiminable โ Determining Inheritance Patterns โ Skipped Generation? = Autosomal Recessive, X-Linked Recessive โ Sex Distribution? โ Only Males (all dads with sons) = Y-linked โ All moms with sons = X-linked recessive โ All females with dads = X-linked dominant
a. During meiosis, alleles segregate i. Homologous chromosomes separate b. Each allele for a trait is packaged into a separate gamete i. Can only give 1 allele per gene to your kiddo
โ Incomplete Dominance: 2 Dominant Alleles โ Heterozygote shows a novel, intermediate, blended phenotype โ Ex. RR = Red, WW = White, RW = Pink โ Codominance: 2 Dominant Alleles โ New Phenotype that is BOTH simultaneously (SEPARATE BUT EQUAL) โ Multiallelic Trait: has more than 2 alleles coding for 1 gene โ Ex. Blood Type Phenotype Genotype Antigens Antibodies Donation Status To From A AA, AO A Anti-B A, AB A, O B BB, BO B Anti-A B, AB B, O AB AB A & B None AB A, B, O, AB O OO None Anti-A, Anti-B A, B, O, AB O โ Pleiotropy: 1 Gene a ects many traits โ Most genes! โ Lethality โ Presence of 2 specific alleles is LETHAL even if the phenotype is possible โ Polygenic Inheritance: Many genes a ect 1 trait โ Epistasis: One gene can completely mask another gene
