BIO 1305 Final Review Powerpoint PDF

FINAL REVIEW This PowerPoint quickly goes over some of the major concepts that you will need to know for the Final Exam. Use this as reference but not as your sole source of study.  ASEXUAL VS SEXUAL REPRODUCTION Asexual – daughter cell is identical (clone) to parent Sexu...

FINAL REVIEW This PowerPoint quickly goes over some of the major concepts that you will need to know for the Final Exam. Use this as reference but not as your sole source of study.  ASEXUAL VS SEXUAL REPRODUCTION Asexual – daughter cell is identical (clone) to parent Sexual – 2 parents make a daughter cell that is genetically unique GAMETES VS SOMATIC CELLS (IN HUMANS) Somatic – normal cells, 46 chromosomes (2n) Gametes – reproductive cells, 23 chromosomes (n)  KARYOTYPE 23 pairs for 46 total chromosomes pairs 1-22 = autosomes pair 23 = sex linked Tetrad = 1 pair (4 sister chromatids) Each pair is homologous Same size Same genes (loci) SISTER CHROMATIDS ARE IDENTICAL - HOMOLOGOUS CHROMOSOMES ARE PARALLEL Male or female?  MEIOSIS I Prophase I – homologs pair, CROSSING OVER and chiasmata Metaphase I – homologs line up at metaphase plate , INDEPENDENT ASSORTMENT Anaphase I – homologs separate Telophase I / Cytokinesis I – 2 haploid daughter cells with sister chromatids still in each chromosome  MEIOSIS II * * SUP E R SI MI L AR TO MI TOSI S Prophase II – spindles form & attach Metaphase II – chromosomes line up at metaphase plate (chromatids not identical anymore bc crossing over) Anaphase II – sister chromatid separate Telophase II / Cytokinesis II – ends with 4 genetically distinct haploid daughter cells  Independent assortment – homologous pairs assort independent of each other during metaphase I Each daughter cell will get a random proportion of maternal / paternal Crossing over - Non sister chromatids exchange GENETIC segments of DNA during prophase I at the site of VARIATION the chiasmata Results in unique recombinant chromosomes Random fertilization – any sperm can fuse with any ovum with equal probability Nothing is favored over another Only genetic variation factor that is not seen in meiosis I  NONDISJUNCTION Incorrect separation of chromosomes Can happen in I or II ANEUPLOIDY when a gamete that went through nondisjunction is fertilized, it will be trisomic (3 copies) or monosomic (1 copies) Trisomy 21 (down syndrome) Polyploidy – 2+ sets of chromosomes Plants!!  CHROMOSOME ALTERATIONS Deletion Duplication Inversion Translocation  Alleles = versions of a gene Traits = versions of a character For each gene an organism gets 2 alleles INHERITANCE Homozygote – organism has 2 of VOC AB the same allele BB or bb Heterozygote – organism has 2 different versions of the allele Bb  MENDEL! Law of segregation – these 2 alleles segregate during gamete formation (meiosis) and end up in different gametes Homologous chromosomes have the different alleles – so this law is evident in Anaphase I Law of independent assortment – each pair of alleles (homologs) separate independently of any other pair (homologous) Just because pair 1 happens to line up mom, dad doesn't mean anything for pair 2 Metaphase I  DOMINANCE Complete – if there is a dominant allele present, it will be exclusively expressed RR and Rr both mean red flower Only rr means white Incomplete – both alleles are present, both are expressed but each to a lesser degree Rr means pink flower Codominance – both alleles are completely expressed Rr means red flower with white speckles Blood type!!!! Pleiotropy One gene affects multiple traits Polygenic inheritance multiple genes affect one trait Epistasis multiple genes affect each other’s expression Have a gene for hair color and a gene for keratin (hair growth protein)  SEX-LINKED INHERITANCE Female sex chromosomes are XX Males are XY Vast majority of genes are on the X, so if there is an X allele with a disorder, males are much more likely to express it In embryo, the second female X condenses into a Barr Body, some of its genes can still be expressed and mix with the remaining X (ex/ calico cats) but its mostly inactive Sex-linked disorders: Hypertrichosis, Color-blindness  GENETIC DISEASES Sickle cell Cystic fibrosis Down Syndrome Substitution of a Build up of Trisomy 21 single amino acid mucus because in hemoglobin Cl ions are not (RBCs) transported into Heterozygotes the cell less susceptible to malaria GENE EXPRESSION Proteins are the link between genotype and phenotype Genetic code is realllllllllly similar in all living things (bacteria and animals) Genes can be transported into different species  TRANSCRIPTION Transcription Unit – stretch of DNA being transcribed RNA polymerase - pulls DNA strands apart and synthesizes the primary transcript based on the DNA Attaches at the promoter – a DNA sequence that starts with TATA TATA box No primer! DNA template is the 3’ → 5’ RNA is made 5’ → 3’ This means the non-template and mRNA strand will be identical except sub T for U IN THE NUCLEUS  INITIATION RNA polymerase binds to promoter Transcription factors help it bind RNA Polymerase + transcription factors + promoter = transcription initiation complex  ELONGATION RNA polymerase adds ONLY to the 3’ end 5’ → 3’ No lagging strand!!! TERMINATION RNA polymerase reads polyadenylation sequence on DNA (AAAAAAA) and knows to release the RNA it just made PROCESSING Add 5’ cap and 3’ poly-A tail RNA splicing Spliceosomes (with many ribozymes) remove intron and join exons so final mRNA is coding only Alternative RNA splicing - # of proteins an organism can make exceeds its # of genes  TRANSLATION **Must match amino acid to anticodon and anticodon to codon aminoacyl-tRNA synthetase tRNA brings amino acids to the peptide chain – knows which amino acid based on its anticodon that matches codons of the mRNA mRNA codons determined from DNA Amino acid attaches to 3’ end of tRNA aminoacyl-tRNA synthetase Matches amino acid to tRNA IN THE CYTOPLASM  IN THE RIBOSOME rRNA – makes up ribosomal subunits (small and large) Initiation: small (bottom) subunit binds to mRNA and reads it until it finds the start codon, then tRNA with Met amino acid comes straight into P site, then large subunit attaches and we’re ready to start If there's no one in line when you first walk up, you go straight to the front Elongation: move from A → P → E site A site – tRNA first comes in with attached amino acid P site – tRNA adds its amino acid to the peptide chain E site – tRNA exits without its amino acid READS THE MRNA 5’ → 3’ Termination: when ribosome reaches stop codon on mRNA the stop amino acid comes into A site, accepts a release factor which adds a water to the peptide chain, thus releasing it from the ribosome  TRACE ELEMENTS