BIOSCI150 Review sheet for EXAM III Fall 2022 This is only a guide Refer to class notes and textbook for complete material Covers material in chapters 7 11 chapter 12 pages 296 297 and Appendix D 1 How does Mendel s Law of Segregation explain meiosis 2 Are Dominant traits always the most common phenotype in a population 3 Distinguish how does the Law of Independent Assortment explains gametic combinations when two genes are close together on the same chromosome vs genes that occur on different chromosomes 4 a b 2 should know how to expand and apply this for simple dihybrid cross problems Hint Remember that in a heterozygous monohybrid cross it is 3 4 for dominant and 1 4 for recessive traits But look at the problem carefully and watch out for crosses that involve homozygous and sex linked traits 5 How does blood types A B AB and O codominance and what is the probability of two parents who are heterozygous for A and B blood group having a child who will have O blood group How many genes control the ABO blood type What kinds of antibodies will be present for a person with hh genotype 6 What is the probability of a color blind father or mother the gene is on the X chromosome passing on the traits to their son or daughter 7 What is the probability of two parents who are heterozygous for Huntington s disease it is a dominant trait having a child who will not have the disease What are the implications of chromosome segments duplicating for evolution What causes Huntington disease 8 How does epistasis explain coat color in Labrador dogs 9 Why does the Laws of Mendel also apply to genes that affect continuous variation such as height 10 Why are most calico cats female 11 Why are there more examples of trisomy 21 and sex chromosomes than other chromosome aneuploidies in humans Why are most aneuploids fatal in most birds and mammals 12 How is one of two X chromosomes silenced in mammals Xist gene and by methylation adding CH3 to DNA 13 Can an organism genotypically be XY but phenotypically resemble a female 14 Are males always the heterogametic sex Were the offspring of parthenogenetic Komodo dragons males or females 15 Where or what influences the initial signal for cell division in prokaryotes and in eukaryotes 16 What the essential factors that determine the four stages of the cell cycle G1 S G2 and mitosis 17 What is the significance of the cell fusion experiments 18 What is the role of cyclins and CDKs in the cell cycle 19 How does phosphorylation of RB retinoblastoma regulate cell division 20 What is the normal role of BRCA1 21 Are elephants with their substantial cancer number of cells less or more prone to 22 How does HPV stimulate induce cancer RB blocks the cell cycle at R HPV causes synthesis of E7 protein which fits into the protein binding site of RB thereby inactivating it 23 How does HER2 cause cancer Overexpression of HER2 24 How does meiosis differ from mitosis Where does meiosis occur 25 When do the chromosomes separate during meiosis and when do these chromosomes split at the centromere during mitosis and meiosis When does crossing over occur in meiosis Does crossing over happen during mitosis When does DNA replication occur during meiosis 26 Distinguish between a tetrad chromatid and chromosome 27 What happened when Griffith the heat treated S strain was mixed with the non virulent Rough stain bacteria during the transformation experiment 28 How did Avery Macleod and McCarthy experiment 1944 show that the transforming principle is DNA What did they mix with the heat treated S and R strain of bacteria 29 How did Hershey and Chase Experiment show that the genetic material was made up of DNA They used 35S to tag protein coat and 32P for DNA to show that DNA was the genetic material 30 Why was Chargaff s ratios A T and C G and Franklin s X ray photo crucial to Watson Crick to decipher the DNA double helix structure What does 3 and 5 refer to Why are the two strands considered antiparallel Are the bases attached to the sugar or phosphate of the helix What is the chemical composition of DNA 31 Four roles of DNA Replication carry genetic material instruct cellular functions mutate 32 How did Meselson and Stahl s experiment show that DNA replication was semiconservative Where were the DNA bands after bacteria were transferred from 15N media to 14N media and grown for two generations 33 What role do primase DNA polymerase and DNA ligase do during DNA replication Why is replication always in both strands in the 5 to 3 direction What are Okazaki fragments and are they present in the leading or lagging strand Which strand would need multiple primers for a given stretch of DNA What is the significance of Telomerase in chromosomes Are they expressed more or less in cancer cells 34 How is DNA amplified by PCR Explain basic steps denature anneal extend then repeat 30 times 35 What are the differences between DNA and RNA double vs single stranded RNA has uracil instead of thymine pentose sugar in DNA lacks a sugar DNA is found is present the nucleus and is much larger than RNA and not present in the cytoplasm RNA is very short lived 36 What are the roles of mRNA tRNA and rRNA during protein synthesis Central dogma in molecular Biology Transcription Translation DNA RNA Protein 37 Which RNA is translated What is a codon Know how to read the Genetic code table Where does RNA polymerase bind during transcription to the Promoter sequence 38 How does one conduct a positive test for Covid 19 RT PCR 39 Are all the transcribed sequences translated 40 Why are eukaryotic genes segmented into introns and exons Identify the mRNA stand and DNA strand in this classic figure shown here What is the significance of this experiment 41 How many mutations are said to occur in a cell every day 10 000 16 000 of which 80 is repaired 42 How do mutations arise deamination methylation adding CH3 chemicals can also introduce spaces for random insertion of genes 43 What are different types of base pair point mutations Substitutions silent frameshift and nonsense mutations What would happen if mutations occur at the splice site 44 What causes sickle cell anemia How many polypeptide chains make up the hemoglobin molecule and how many genes code for it On which chromosome are these genes located 45 Chromosomal mutations Inversions deletions nonhomologous pairing addition or deletion of chromosomes during meiosis 46 How does the Lac operon work inducer 47 Where and what is the role of enhancer sites Sites where