GENETICS Genetics developed from curiosity about inheritance. SMP - 2013 1
Genetics The study of heredity (how traits are passed from one generation to the next (inherited) An inherited trait of an individual can be determined by one genes, but is usually determined by the interaction of many different genes 2
Trait A Specific characteristic of an organism Example: Flower color, eye color Cystic fibrosis, skin color, sickle cell disease SMP - 2013 3
Gregor Mendel Father of Genetics discovered that factors or alleles are passed from parent to offspring. breeding pea plants SMP - 2013 4
Mendel s Principles During meiosis (making gametes), the arms of the chromosomes cross-over and rejoin increasing the genetic possibilities of the offspring When egg and sperm unite to form a zygote, their alleles recombine and new combinations are formed genetic recombination SMP - 2013 5
Genes segments of DNA that contain instructions to make proteins Each gene carries a separate piece of information SMP - 2013 6
Hereditary information is contained in genes, which are composed of DNA, located in the chromosomes of each cell. Chromosomes are found in the nucleus of each cell. SMP - 2013 7
Gene Chromosome Theory Genes exist at definite loci in linear sequence on a chromosome and are found in homologous pairs. Chromosome GENES DNA alleles traits SMP - 2013 8
Regents Practice Question. Which chromosome pair best illustrates the gene-chromosome theory? SMP - 2013 9
4 - You Are Correct! The gene-chromosome theory states that genes are segments of DNA located on chromosomes and are found in homologous pairs. SMP - 2013 10
Mendel discovered that inheritance follows rules of chance. SMP - 2013 11
Allele Alternate forms or versions of a gene. Slightly different DNA codes and occur at the same location on homologous chromosomes SMP - 2013 12
Dominant allele The version of the gene that is expressed (observed) when both alleles are present. Symbolized with a capital letter: A Ex: SMP - 2013 13
Recessive allele The version of the gene that is not expressed (not observed) when both alleles are present. Symbolized with a lower case a letter: Ex: SMP - 2013 14
Genotype The genetic make-up of an individual. The combination of the 2 alleles an individual has for a particular trait. Ex: AA, Aa, aa SMP - 2013 15
1. Homozygous (SAME) dominant - both dominant genes are present. EX. AA 2. Homozygous (SAME) recessive both recessive genes are present EX. aa 3. Heterozygous (hybrid) one dominant gene and one recessive gene are present. EX. Aa SMP - 2013 16
Carrier Any individual who is heterozygous for a trait. They carry the recessive allele. SMP - 2013 17
Phenotype The observable aspects of a genotype the Physical characteristics The way a genotype is expressed/described. SMP - 2013 18
Mendel s Pea plants: Genotype -vs- Phenotype TT Tt tt tall pea plant (homozygous dominant) tall pea plant (heterozygous dominant) dwarf pea plant (homozygous recessive) SMP - 2013 19
A Punnett square is used to show the possible offspring combinations Complete the punnett square tall (TT) vs. dwarf (tt) pea plants T T t t Gentotype: Phenotype: SMP - 2013 20
tall (TT) vs. dwarf (tt) pea plants T T Gentotype: 100% Tt (heterozygous tall) Phenotype = tall t Tt Tt produces the F 1 generation t Tt Tt SMP - 2013 21
Bellwork turn to your table partner and discuss the questions below.. 1. What organelle is known as the control center of the cell? 2. What structures are found in the nucleus? 3. What are located on chromosomes? 4. What are genes composed of? SMP - 2013 25
All ABOUT DNA DNA: The Intro Clip SMP - 2013 26
I. DNA Structure A. Building Blocks 1. = Nucleic Acids! (NUCLEOTIDES) 2. also known as subunits B. Nitrogen bases (4 of them) SMP - 2013 27
C. DNA Shape 1. Each nucleic (acid) is made of 3 parts: a. Sugar (Deoxyribose) b. Phosphate c. 1 of 4 Nitrogenous Bases: 1. A = adenine 2. T = thymine 3. C = cytosine 4. G = guanine SMP - 2013 28
Label a nucleotide!
C. DNA Shape 1. DNA IS DOUBLE STRANDED 2. STRANDS TWIST TO FORM DOUBLE- HELIX 3. NITROGEN BASES BIND TOGETHER TO MAKE TWO STRANDS A always binds with T G always binds with C All Teachers Go Crazy THIS IS CALLED THE BASE-PAIR RULE! SMP - 2013 30
Base Pair Ruling SMP - 2013 31
DNA Structure Let s Practice! One strand of DNA has the sequence you see. What is the complimentary strand s sequence??? SMP - 2013 G -----C G -----C T -----A A -----T C -----G G -----C C -----G C -----G T -----A 32
Replication: The Video Clip http://www.youtube.com/watch?v=z685ff qmrpo
II. DNA Replication (copying) CLICK HERE FOR DEMO A. When does DNA need to be copied???? 1. BEFORE any cell division! (mitosis and meiosis) B. First, two strands are unzipped C. Second, enzymes bring new subunits to these strands (templates) D. Third, you end up with 2 identical double helices E. DNA acts as a PATTERN or TEMPLATE to make copies of itself! CLICK HERE FOR DEMO #2 34
DNA Replication Diagram Parent Strands New complimentary strands Free Floating Nucleotides
Replication Practice- Step 1 Unzip G -----C G C G -----C G C T -----A T A A -----T C -----G Enzymes UNZIP A C T G G -----C G C C -----G C G C -----G C G T -----A T A
Replication Practice- Step 2 Add Subunits using Base-Pair Rule G G T A C G C C T ----C ----C ----A ----T ----G ----C ----G ----G ----A G---- C G---- C T---- A A---- T C---- G G---- C C---- G C---- G T---- A
THE DNA RAP!!!! http://www.youtube.com/watch?v=d1up f7lxeo8