You have sequenced the genome of the bacterium Salmonella typhimurium, and you are using BLAST analysis to identify similarities within the S. typhimurium genome to known proteins. You find a protein that is 100 percent identical in the bacterium Escherichia coli. When you compare nucleotide sequences of the S. typhimurium and E. coli genes, you find that their nucleotide sequences are only 87 percent identical. a. Explain this observation. b. What do these observations tell you about the merits of nucleotide- versus protein-similarity searches in identifying related genes?

Two diploid species of closely related frogs, which we will call species A and species B, were analyzed with regard to genes that encode an enzyme called hexokinase. Species A has two distinct copies of this gene: $A 1$ and $A 2$. In other words, this diploid species is A1A1 A2A2. The other species has three copies of the hexokinase gene, which we will call $B 1, B 2$, and $B 3$. A diploid individual of species $\mathrm{B}$ would be $B 1 B 1 B 2 B 2 B 3 B 3$. These hexokinase genes from the two species were subjected to DNA sequencing, and the percentage of sequence identity was compared among these genes. The results are shown here:

$$\begin{aligned} &\text { Percentage of DNA Sequence Identity }\\ &\begin{array}{rrrrrr} & A 1 & A 2 & B 1 & B 2 & B 3 \\ \hline A 1 & 100 & 62 & 54 & 94 & 53 \\ \text { A2 } & 62 & 100 & 91 & 49 & 92 \\ \text { B1 } & 54 & 91 & 100 & 67 & 90 \\ \text { B2 } & 94 & 49 & 67 & 100 & 64 \\ \text { B3 } & 53 & 92 & 90 & 64 & 100 \end{array} \end{aligned}$$

If we assume that hexokinase genes were never lost in the evolution of these frog species, how many distinct hexokinase genes do you think there were in the most recent ancestor that preceded the divergence of these two species? Explain your answer. Also explain why species $B$ has three distinct copies of this gene, whereas species A has only two.

Poky is a slow-growing mutant strain of the pink bread mold (Neurospora crassa). If poky is crossed to the normal wild-type mold, all the offspring are poky. But if the reciprocal cross is done, all the offspring are wild type. Why does poky display this type of inheritance, and why is it slow growing?

Work the following applied problem.

Bill Poole wants to have $20,000 available in 5 years for a down payment on a house. He has inherited$16,000. How much of the inheritance should he invest now to accumulate the $20,000 if he can get an interest rate of 5.5% compounded quarterly?

Which of the following is true of innate behaviors?

(A) Their expression is only weakly influenced by genes.

(B) They occur with or without environmental stimuli.

(C) They are expressed in most individuals in a population.

(D) They occur in invertebrates and some vertebrates but not mammals.

Quorum sensing controls the expression of virulence in many pathogenic bacteria. Usually, pathogens express toxins in response to receptor activation by ligand binding at high cell density. V. cholerae (the causative agent of cholera) does the opposite; its virulence genes are expressed only at low cell density because its quorum-sensing receptor is repressed by Iigand binding. The unusual "reversed'' mechanism for activating virulence genes in V. cholerae has suggested to scientists a simple idea for generating a new kind of antibiotic for the treatment of cholera. Explain.

a. codicil

b. estate

c. estate tax

d. gift tax

e. inheritance $\operatorname{tax}$

f. power of attorney

g. probate

h. reverse mortgage

i. trust

j. will

__ A legal document in which an individual gives someone else control of property, for ultimate distribution to another person

The model of globin gene evolution suggests that an ancestral gene duplicated and mutated to become $\alpha$ - and $\beta$-globin genes, and then each one was further duplicated and mutated. What features of the data set support the model?

To find genes that are turned on or off in response to changes in osmolarity (the total concentration of solutes in solution), you grow a culture of E. coli in a medium with high osmolarity and another culture in a medium with low osmolarity. You now perform RNA-Seq analysis on each culture. It is possible that osmotic changes may induce a general stress response that may be seen with other stresses as well (for example, heat shock). How could you distinguish the genes that might be involved in a general stress response from those that are specific for the osmolarity change?

Match the terms with the definitions. Some terms may not be used.

a. codicil

b. estate

c. estate tax

d. gift tax

e. inheritance $\operatorname{tax}$

f. power of attorney

g. probate

h. reverse mortgage

i. trust

j. will

___ A legal document authorizing someone to act on your behalf

You’re probably wearing on your wrist one of the world’s most common types of objects— a watch. Discuss how each of the following terms and concepts applies to the notion of a watch: object, attributes, behaviors, class, inheritance (consider, for example, an alarm clock), abstraction, modeling, messages, encapsulation, interface and information hiding.

With two pairs of genes involved ( $P / p$ and $Z / z)$, a testcross (ppzz) with an organism of unknown genotype indicated that the gametes produced were in the following proportions:

$$P Z, 42.4 \% ; P_z, 6.9 \% ; p Z, 7.1 \% ; p z, 43.6 \%$$

Draw all possible conclusions from these data.

A spadefoot toad tadpole that develops in a rapidly drying pond is likely to eat many of its brothers and sisters. How can eating its siblings, which share half of an individual's genes, be favored by natural selection?

Match the terms with the definitions. Some terms may not be used.

a. codicil

b. estate

c. estate tax

d. gift tax

e. heir

f. inheritance tax

g. power of attorney

h. reverse mortgage

i. trust

j. will

__ A federal tax on property transferred from an estate to its heirs