Marking Period 3 Quarterly Review Units 4-6 (Meiosis, Genetics, DNA/RNA/Protein Synthesis, Mutations, Biotech.)

1. What exactly happens in mitosis (use detail such as how many times the DNA is copied, how many rounds of division there are, how many daughter cells are produced, whether the cells are unique or identical, etc.)? DNA is copied once, cell divides once to make two identical daughter cells each with a full set of DNA/chromosomes.

2. What exactly happens in meiosis (use detail such as how many times the DNA is copied, how many rounds of division there are, how many daughter cells are produced, whether the cells are unique or identical, is there a full set or half set of chromosomes, etc.)? DNA is copied once, cell divides twice to make 4 unique daughter cells (gametes/sex cells) each with a half set of DNA/chromosomes.

3. How are the 2 processes similar? Both involve nuclear division.

4. How are the 2 processes different? (include the words haploid and diploid) Mitosis creates 2 identical diploid somatic cells (body cells), meiosis create 4 unique haploid gametes (sex cells).

5. Draw and explain the process of crossing over. Genetic material is exchanged between homologous chromosomes, increasing genetic variation by making new allele combinations.

6. What is the difference between a somatic cell and a gamete? Somatic cell is a body cell and contains a full set of DNA (produced by mitosis), gamete is a sex cell (sperm or egg) and contains a half set of DNA (produced by meiosis).

7. If a giraffe body cell has 62 chromosomes in it, how many chromosomes would be in a cell created through mitosis? Through meiosis? Mitosis: 62(Full set)Meiosis: 31 (Half set)

Metaphase II: Homologous chromosomes are already in different cells, sister chromatids are lined up in the middle to be separated Metaphase I: Homologous chromosomes are lined up in the middle to be separated

Prophase I: Homologous chromosomes have paired up and are undergoing crossing over. Nuclear envelope is disappearing. Anaphase II: Sister chromatids are being pulled apart to opposite sides of the cell.

Define the following: gene, polygenic, homozygous, heterozygous. Gene: A segment of DNA that contains instructions to build a protein Polygenic: Poly=more than one. Polygenic traits are controlled by more than one pair of genes/alleles. Homozygous: Two of the same allele (Ex.: 2 dominant OR 2 recessive) Heterozygous: Two different alleles (Ex.: 1 dominant, 1 recessive)

Explain the difference between normal dominant and recessive crosses (Mendelian) and incomplete and co dominant crosses (Non-Mendelian). Provide examples. Mendelian: Trait is controlled by one gene with two alleles with one being dominant and the other being recessive. Ex.: Yellow peas are dominant over green peas. Or, In blood type, allele A is dominant over allele O. Non-Mendelian: Trait is controlled by more than one gene and/or the gene has multiple alleles and/or neither allele is dominant over the other (codominance or incomplete dominance). Ex.: Alleles A & B are codominant in blood type, leading to type A.

Create a blood type cross in which one parent has the co-dominant blood type (remember: co-dominant=expression of both alleles) and explain the genotype and phenotype. Include ratios. Codominant blood type= Type AB (both alleles are separately but equally expressed in phenotype)

Create a problem involving a normal dominant and recessive cross and show phenotype and genotype. Include ratios. Homozygous dominant: RR Homozygous recessive: rr Heterozygous: Rr

Create a problem involving an incomplete dominance trait. Include ratios. Incomplete dominance = a BLEND in phenotype of heterozygous individuals. Ex.: RW = Pink

If a cross is performed and 25% of the offspring are homozygous recessive, 50% are heterozygous, and 25% were homozygous dominant, what were the parents genotypes? RRRr rr Parent Genotypes: Rr x Rr

7. Hemophilia is a sex-linked recessive allele carried on the X chromosome. A woman with hemophilia and a normal man have children. Do the cross and explain why only their sons would have hemophilia. X H Y Males only get one copy of X and therefore are more likely to suffer from X-linked genetic disorders compared with females. XHXhXHXh XHXhXHXh XhYXhYXhYXhY XhXhXhXh

1. Define mutation: Any change in the DNA of an organism. Random changes in genetic code lead to GENETIC variation

2. What is the difference between a point mutation and a frameshift mutation? Include the different types of each mutation. A point mutation substitutes one nucleotide for another and changes ONE amino acid in the protein. includes substitution, silent, and nonsense. A frameshift mutation changes the number of nucleotides by adding or removing nucleotides. This throws off the reading frame of the codons changing ALL amino acids. It includes insertion and deletion mutations.

3. Using the below DNA sequence, show the following types of gene mutations: insertion, deletion, substitution, silent, and nonsense. Original: TAC TTA GGC TTT ATC Substitution: TAC TTT GGC TTT ATC Insertion: TAT CTT AGG CTT TAT C Deletion: T_CT TAG GCT TTA TC Silent: TAC TTG GGC TTT ATC Nonsense: TAC ACT GGC TTT ATC

4. Redraw the below chromosome to show the following chromosome mutations: duplication/insertion, deletion, translocation, inversion. Original chromosome: [ABCDEFG] Duplication/insertion: [ABBCDEFG] Deletion: [ACDEFG] Translocation: [ABCDLMNO] Inversion:[ADCBEFG]

5. Explain what happens during nondisjunction and what it results in. When chromosomes fail to separate during meiosis. This leads to gametes that have either an extra copy of a chromosome or a missing copy of a chromosome.

Describe the shape of DNA. What is in the backbone? What is in the middle? What are the base pairing rules? Shape: Double Helix Backbone: Sugar-phosphate portion of nucleotide Middle: Nitrogenous base portion of nucleotide Rule: A-T, C-G

What is DNA Replication? Briefly describe the steps, including the role of DNA polymerase. DNA Replication copies all of the DNA so each new cell produced by cell division gets a copy of the DNA. Strands unzip, nucleotides pair up using base pairing rules, DNA polymerase proofreads and binds nucleotides in new strand, at the end there are two molecules of DNA each with one old strand and one new strand.

DNA replication is said to be semiconservative because: A new double helix contains one old and one new strand (CONSERVES the old strands)

4. The sequence of one strand of DNA is TCGATC. The sequence of the complementary strand would be AGCTAG DNA Base-pairing rules: A-T, C-G

5. Draw a picture of a homologous set of chromosomes and explain why they are considered to be homologous. Have same genes in same places, but possibly different alleles for genes.

6. What is the relationship between a chromosome, a gene, and a nucleus?

. How is the nucleus involved in making proteins in eukaryotic organisms? Nucleus holds DNA which contains the instructions for building proteins.

8. What is the role of ribosomes in protein synthesis? Ribosomes bond the amino acids together (a protein is a chain of amino acids) as the tRNA molecules bring them.

9. Explain what is meant by the universal code/common language of genetics. All organisms use the same bases in the same codons for the same amino acids.

10. What molecule is made at the end of replication? At the end of transcription? At the end of translation? Replication makes DNA Transcription makes RNA Translation makes Protein

11. Cloning involves making a genetically identical copy of an original. Which of the following would be identical between the clone and the original: A. Number of chromosomes B. Types of genes C. Nucleotide sequence D. All of the above

Transcription (unwound DNA and single stranded RNA being made, RNA polymerase present)

Replication (DNA unwound, two new strands forming using old strands as templates)

Translation (tRNA molecules bringing amino acids coded for by mRNA to ribosome)

13. True or false: Environment can affect the expression of genes (i.e. gender in sea turtles) True! Think of height.

14. How many different amino acids will be in the protein coded for by this gene in these 2 different species? Species 1: AAA TTT GGG CCC CGC Species 2: AAA TTT TAT CCC TTT # of different amino acids: TWO

15. What are the benefits of genetically engineering crops (GMOs)? What are the downfalls? Pros: Crops now have genes that give them resistance to frost, disease, pests. Also, genes can be inserted to increase nutrient content of crops. Cons: Decrease genetic variation, cross- pollination (mating) between GMO’s and wild plants (transfers genetically engineered gene into wild plant genome)

16. What are the benefits of genetic engineering in medicine (production of human proteins, cloning, gene therapy)? What are the downfalls? Benefits: Treatment of disease, organs for transplant, steady inexpensive supply of human proteins Downfalls: Cloning not always successful, clones “imperfect,” gene therapy is still experimental