1. Milestone Minutes Genetics Week 3 Write notes in your Milestone Journal and answer the practice questions.

2. Genetics DNA and RNA are molecules essential for the transmission of genetic information.  DNA is a double stranded helix, contains the sugar deoxyribose, A-T & G-C  RNA is single stranded, contains the sugar ribose, A-U & G-C, produces proteins  DNA replication (copying)occurs prior to mitosis during the cell cycle  Mitosis stages: prophase, metaphase, anaphase, telophase  Mitosis results in two genetically identical daughter cells, occurs in autosomal cells, diploid (asexual)  Meiosis results in four genetically different gametes (egg & sperm), haploid (sexual)  Recombination of genetic material (crossing over) occurs during anaphase 1 & 2 of meiosis

3. Mendel was the father of genetics and put forth laws concerning heredity.  Law of Dominance -dominate alleles (capital letter) suppress recessive alleles (lowercase letter)  Law of Segregation -during fertilization gametes randomly pair to produce four sets of alleles (monohyrid)  TT=homozygous dominant, Tt=heterozygous, tt=homozygous recessive  Genotype is the combination of alleles, Phenotype is the physical expression of alleles  Law of Independent Assortment -genes for traits are inherited independently of each other (dihybrid)  Segregation & Independent Assortment allow only one allele a gene to be present in the gametes

4. Alterations (mutations) can occur during meiosis and change the genetic code.  Some environmental factors are mutagenic (sunlight, chemical waste, radiation, toxins)  Insertion-addition of one or more nucleic bases in the genetic sequence, changes reading frame  Deletion-removal of one or more nucleic bases in the sequence, changes reading frame  Substitution-switch of one or more nucleic bases in the genetic sequence, no change to reading frame  Nondisjunction- failure of homologous chromosomes to separate during anaphase of meiosis  Trisomy- condition of having an extra chromosome (Down Syndrome)

5. DNA technology can change the genetic makeup of an organism. Recombination-moving genes from one organism to another (cross- pollination/Hybrids) Genetic Engineering- using organisms for beneficial purposes (insulin production, fighting viruses)

6. Complete the practice questions in your journal.