![Page 1: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/1.jpg)
DNA, Genes, and cell divisionWeek 4(Ch 3)
1
![Page 2: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/2.jpg)
DNA StructureStructureDNA is made of complementary chains of stacked nucleotides
Nucleotides structure: composed of a sugar plusa phosphate (sides), and a nitrogenous base (rungs)
Bases: form complementary bonds
Adenine bonds with Thymine
Guanine bonds with Cytosine
2
![Page 3: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/3.jpg)
DNA Replication
Process of DNA replication1. Enzymes 'unzip' bases2. Exposed bases attract complementary free-floating nucleotides3. Two parental nucleotide chains are models for growing replicated strands
-the new DNA molecules consist of an original and new strand3
![Page 4: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/4.jpg)
Chapter 3: Biological basis of lifeProteins: perform functions like binding with other molecules
Structural proteins: e.g., collagen
Functional proteins: e.g., hormones, enzymes
Protein composition: amino acid chains
Amino acids: building blocks of proteins-protein function is determined by order and number of amino acids
4
![Page 5: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/5.jpg)
Protein synthesis
5
Step 1: Transcription (in nucleus)-complementary messenger RNA (mRNA) is produced from DNA strands
mRNA: single-stranded and has Uracil base instead of thymine
Step 2: Translation (at ribosomes)-ribosomes reads mRNA 3-bases at a time (triplets = codons)
Transfer RNA (tRNA) binds codons with one amino acid
![Page 6: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/6.jpg)
GenesGenes: segments of DNA bases coding for specific traits
Human Genome-25,000 genes-90,000 proteins
6
![Page 7: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/7.jpg)
Cell divisionChromosomes DNA condenses into sausage-shaped packages visible during cell division
Full complement of genetic material for humans = 46 chromosomes (varies from species to species)
Two types of chromosomesAutosomes: carry genetic information that governs all physical characteristics
Sex chromosomes: governs primary sexX chromosome = femaleY chromosome = male
7
![Page 8: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/8.jpg)
Cell division: mitosisMitosis: cell division in somatic cellsOne division:-46 double-stranded chromosomes align at the cell's center -pulled apart at the centromere
Result -two genetically identical daughter cells -46 single-stranded chromosomes
8
![Page 9: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/9.jpg)
Cell division: meiosisMeiosis: gamete division
1st division: -46 reduced to 23 double-stranded chromosomes
Recombination: parent genetic material is exchanged
2nd division: -similar to mitosis (pairs are separated)
Result-23 single-stranded chromosomes in each genetically distinct daughter cell
![Page 10: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/10.jpg)
Cell division and evolutionEvolutionary significance of meiosis
Recombination: shuffling of maternal/paternal chromosomes during meiosis
10
![Page 11: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/11.jpg)
Cell division and evolutionMutations: change in DNA that creates new genetic material
-necessary fuel for evolutionary change
11
![Page 12: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/12.jpg)
Ch 4: Mendel and Modern evolutionary theory
Week 4(Ch 3/4)
12
![Page 13: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/13.jpg)
Mendelian principles of inheritanceMendel's principles explains transmission of traits generation to generation
Background: decades of experiments with pea plant hybrids.
13
![Page 14: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/14.jpg)
Mendelian principles of inheritance
14
Experiments: crossbred pure-bred pea plants
Parent generation:-tall pea plants x short pea plants
F1 generation:
F2 generation:
![Page 15: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/15.jpg)
Mendel's first principle of inheritancePrinciple of segregation: traits are controlled by discrete units which come in pairs and separate into sex cells.
Alleles: variations of a gene at a locus, i.e., allele pairs control trait expression
E.g., pea plant height is controlled by two alleles at one locus
15
![Page 16: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/16.jpg)
Mendel's first principle of inheritanceRecessive alleles are masked by the expression of dominant alleles
Homozygous: two copies of an allele
Heterozygous: two different alleles
Genotype: organism's entire genetic makeup
Phenotype: observed physical expression of genotype/genes
16
![Page 17: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/17.jpg)
Mendel's second principle of inheritancePrinciple of independent assortment: traits are inherited separately
E.g., pea plant height and seed color are not inherited together
-genes that code for different traits sort out individually during gamete formation
17
![Page 18: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/18.jpg)
Punnett square problems1. Identify the different phenotypic and genotypic ratios in F2 generations for a cross of two heterozygous tall plants (tall = dominant trait).
18
![Page 19: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/19.jpg)
Punnett square problems2. Hypothetically, B is the allele that causes brachydactyly. If a man with two normal alleles (bb) has average length fingers/toes has kids with a woman with brachydactyly (Bb).
What proportion of their kids will have average length fingers/toes?
19
![Page 20: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/20.jpg)
Mendelian geneticsMendelian traits-discrete traits-one gene determines one trait-rarely influenced by environment
Polygenic traits-continuous-multiple genes determine one trait-relationship between genetics/environment heavily influential
20
![Page 21: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/21.jpg)
Mitochondrial DNA briefly...Mitochondrial inheritance: mtDNA is transmitted matrilineally-meiosis (and so recombination) doesn't occur because inherited from one parent-only variations between individuals in mtDNA is due to mutations-studying mutation rates to learn more about ancestry, evolutionary relationship between species, etc.
21
![Page 22: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/22.jpg)
Synthetic theory of evolutionSynthetic theory of evolution
-modern synthesis of Darwin's theory and genetics now:
Evolution defined: change in allele frequencies of a population from one generation to the next.
Gene pool: the genetic material (alleles) making up a population of organisms
22
![Page 23: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/23.jpg)
Synthetic theory of evolutionTwo-stages of evolution involve variation and natural selection
Stage 1: Factors produce and redistribute variation
Stage 2: Natural selection acts on variation
Microevolution: changes from generation to generation
Macroevolution: speciation, changes over time evident in the fossil record
23
![Page 24: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/24.jpg)
Factors producing and redistributing variationMutations: any change in alleles-produces new alleles (only source of new genetic material)-only passed on if occurs in gametes
Recombination: chromosome pairs exchange DNA during meiosis shuffling variation for natural selection to act on
24
![Page 25: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/25.jpg)
Factors producing and redistributing variationGenetic drift: changes in allele frequencies due to chance
Founder effect: small subpopulation leaves to find new populationE.g., Amish polydactyly
Bottleneck: population shrinks and recoversE.g., Pingelap islanders today are mostly colorblind
25
![Page 26: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/26.jpg)
Factors producing and redistributing variationGene flow: (migration) exchange of genes between populationsE.g., significant gene flow between human populations explains the low occurrence of hominin speciation in the past million years
26
![Page 27: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/27.jpg)
Variation and natural selectionNatural selection
-directional change relative to environment
-acts on variation
27
![Page 28: DNA, Genes, and cell division (Ch 3) Week 4...Week 4 (Ch 3/4) 12 Mendelian principles of inheritance Mendel's principles explains transmission of traits generation to generation Background:](https://reader034.vdocuments.us/reader034/viewer/2022051909/5ffe7571f5d81503ec5e7e24/html5/thumbnails/28.jpg)
Mendel - 1860s Monk experimenting with peasRecall: Cross-breeding - artificial selection, farmers...metaphor for natural selection
Missing in Darwin's theory of NS: a mechanism governing how traits were inherited
Background
-Mendel cross-bred pea plants-Observed the traits individual plants possessed over thousands of generations
Inferred the Principles of Inheritance
28