As the minor and major grooves of the DNA wind around a DNA double helix, do they ever intersect each other, or do they always run parallel to each other?

Viruses can contain any of the following genetic material except _____.

Select one:

a. Single stranded RNA used to produce DNA

b. a DNA/RNA hybrid

c. Double stranded DNA

d. Single stranded mRNA used as a template for mRNA

The type of model building used by Pauling and Watson and Crick involved the use of ball-and-stick units. Now we can do model building on a computer screen. Even though you may not be familiar with this approach, discuss the potential advantages of using computers in molecular model building.

What are the building blocks of a nucleotide? With regard to the $5^{\prime}$ and $3^{\prime}$ positions on a sugar molecule, how are nucleotides linked together to form a strand of DNA?

In what ways are the structures of an $\alpha$ helix in proteins and the DNA double helix similar, and in what ways are they different?

Write out a sequence of an RNA molecule that could form a stemloop with 24 nucleotides in the stem and 16 nucleotides in the loop.

Look up the meaning of the word transformation in a dictionary and explain whether it is an appropriate word to describe the transfer of genetic material from one organism to another.

C1. What is the meaning of the term genetic material? C2. After the DNA from type S bacteria is exposed to type R bacteria, list all of the steps that you think must occur for the bacteria to start making a capsule.

C3. Look up the meaning of the word transformation in a dictionary and explain whether it is an appropriate word to describe the transfer of genetic material from one organism to another.

C4. What are the building blocks of a nucleotide? With regard to the $5^{\prime}$ and $3^{\prime}$ positions on a sugar molecule, how are nucleotides linked together to form a strand of DNA?

C5. Draw the structure of guanine, guanosine, and deoxyguanosine triphosphate. C6. Draw the structure of a phosphodiester linkage. C7. Describe how bases interact with each other in the double helix. This discussion should address the issues of complementarity, hydrogen bonding, and base stacking.

C8. If one DNA strand is $5^{\prime}$-GGCATTACACTAGGCCT- 3 ', what is the sequence of the complementary strand? C9. What is meant by the term DNA sequence? C10. Make a side-by-side drawing of two DNA helices, one with $10 \mathrm{bp}$ per $360^{\circ}$ turn and the other with 15 bp per $360^{\circ}$ turn. C11. Discuss the differences in the structural features of A DNA, B DNA, and Z DNA.

C12. What parts of a nucleotide (namely, phosphate, sugar, and/or bases) occupy the major and minor grooves of double-stranded DNA, and what parts are found in the DNA backbone? If a DNAbinding protein does not recognize a specific nucleotide sequence, do you expect that it recognizes the major groove, the minor groove, or the DNA backbone? Explain.

A double-stranded DNA molecule contains 560 nucleotides. How many complete turns would be found in this double helix?

In a large herd of 5468 sheep, 76 animals have yellow fat, compared with the rest of the members of the herd, which have white fat. Yellow fat is inherited as a recessive trait. This herd is assumed to be in Hardy-Weinberg equilibrium.
A. What are the frequencies of the white and yellow fat alleles in this population?
B. Approximately how many sheep with white fat are heterozygous carriers of the yellow allele?

Two students live next door to each other. One receives three times more yearly radiation than the other. Explain how this could be possible.

Within a protein, certain amino acids are positively charged (e.g., lysine and arginine), some are negatively charged (e.g., glutamate and aspartate), some are polar but uncharged, and some are nonpolar. If you knew that a DNA-binding protein was recognizing the DNA backbone rather than base sequences, which amino acids in the protein would be good candidates for interacting with the DNA?

A DNA-binding protein recognizes the following double-stranded sequence:

$$\begin{aligned} &\text { 5'-GCCCGGGC-3' } \\ &\text { 3'-CGGGCCCG-5' } \end{aligned}$$

This type of double-stranded structure could also occur within the stem region of an RNA stem-loop molecule. Discuss the structural differences between RNA and DNA that might prevent this DNA-binding protein from recognizing a double-stranded RNA molecule.

Meiotic nondisjunction usually occurs during meiosis I. What is not separating properly: bivalents or sister chromatids? What is not separating properly during mitotic nondisjunction?