EOCT Review Day 2: Genetics

SB2. Students will analyze how biological traits are passed on to successive generations a. Distinguish between DNA and RNA. b. Explain the role of DNA in storing and transmitting cellular information. c. Using Mendel’s laws, explain the role of meiosis in reproductive variability. d. Describe the relationships between changes in DNA and potential appearance of new traits including e. Compare the advantages of sexual reproduction and asexual reproduction in different situations f. Examine the use of DNA technology in forensics, medicine, and agriculture

SB2a. Distinguish between DNA and RNA. DNA and RNA are both nucleic acids (made up of nucleotides) Nucleotides have 3 parts: sugar, phosphate, nitrogen base DNA nitrogen bases: A, T, C, and G RNA:U instead of T DNA has deoxyribose, RNA has ribose DNA is double stranded, RNA is single stranded

SB2b. Explain the role of DNA in storing and transmitting cellular information. DNA is copied during replication DNA is used as a template to make mRNA (transcription) mRNA is read by the ribosome to make a protein (translation) DNA -> mRNA -> Protein

SB2c. Using Mendel’s laws, explain the role of meiosis in reproductive variability. Gene: sections of DNA that code for protein Allele: different versions of a gene Dominant: allele that is always expressed if it is present Recessive: allele that is expressed only if two are present Homozygous: two of the same allele Heterozygous: two different alleles Genotype: genetic makeup (alleles) Phenotype: physical characteristics

SB2c. Using Mendel’s laws, explain the role of meiosis in reproductive variability. Meiosis: process by which gametes are formed. Number of chromosomes cut in half (haploid) Mendel’s Laws Law of segregation: each gamete only has one of the parent’s two alleles because they separate during meiosis Law of independent assortment: gene pairs separate independently of one another during meiosis

SB2c. Using Mendel’s laws, explain the role of meiosis in reproductive variability.

SB2d. Describe the relationships between changes in DNA and potential appearance of new traits Alterations during replication Insertions: base pair added (causes frameshift) Deletions: base pair deleted (causes frameshift) Substitutions: one amino acid substituted for another Mutagenic factors Radiation: X-Rays, UV Rays Chemicals: Carcinogens Nondisjunction: Extra chromosome Ex. Extra copy of chromosome 21 in Down Syndrome

SB2e. Compare the advantages of sexual reproduction and asexual reproduction in different situations Mitosis: cell divison that produces two identical cells (clones) Binary Fission: Asexual reproduction of Bacteria Asexual reproduction Advantage: only one parent needed Disadvantage: offspring are genetically identical Sexual reproduction Advantage: Offspring are genetically unique Disadvantage: spend time and energy finding a mate

SB2f. Examine the use of DNA technology in forensics, medicine, and agriculture DNA Fingerprinting: DNA is analyzed, used to identify suspects, relatives, or bodies Genetic Engineering: DNA from one species is inserted into the genome of another species (recombinant DNA) Ex. Human insulin gene in bacteria Ex. Pest resistance genes in crops