7. Knowing that the segregation ratios for a set of loci are all 1/2 : 1/2, we c

Question

7. Knowing that the segregation ratios for a set of loci are all 1/2 : 1/2, we can predict the frequencies of all possible gametic types by multiplying, if the loci are on different chromosomes and independent. For an AaBbCcDd four locus heterozygote there are ______ possible gametes of equal
frequency. a. 2 b. 4 c. 8 d. 16 e. 32
8. Ten years after the Avery et al experiment was reported (50 ago)
Watson and Crick used model building and the data of other workers to propose a double helical model for DNA. In their model a. phosphodiester linkages between sugars are covalent b. purine content = pyrimidine c. the two chains are held by hydrogen bonds d. the DNA molecule is a double helix and bases face each other in the molecules interior e. a,b,c,& d are true
9. The DNA structure proposed by Watson and Crick suggested a replication model which was tested by Meselson and Stahl. They used nitrogen isotopes to label replicating DNA which was then separated into bands on a density gradient. The three possible
models of replication predicted different numbers of bands after one and then two DNA replications. For the conservative model of DNA replication two bands were expected after the first round of replication. The semiconservative model predicted the presence of _______ band after the first replication. a. 2 b. 4
c. 3 d. 1 e. 8

Explanation / Answer

7. For each gene (Aa eg), there will be 3 possible gametes formed. 1 AA: 2 Aa: 1 aa. So each has 2 that occur in equal frequency, AA and aa. Multiply 2 x 2 x 2 x 2 = 16. Multiply instead of adding because AAbbCCdd could occur, as could aabbCCdd, ect. May want to refer to the multiplication rule or "and" rule of basic statistics. 8. a, b, c, and d are true. Each of these statements describe DNA structure according to their proposed model. 9. The semiconservative model would only expect one band after 1 round of replication. One strand would be labeled with the heavy N, and it would split and each heavy strand would be replicated and result in a 2 new helixes, each with a heavy and light strand of DNA.

Related Questions

Navigate

• Browse (All)
• Browse 7
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.