Activation (maturation) of frog oocytes is signaled through a MAP kinase signaling module. An increase in the hormone progesterone triggers the module by stimulating the translation of Mos mRNA,...

1. G. Johnson and colleagues have analyzed the MAP kinase cascade in which MEKK2 participates in mammalian cells. By a yeast two-hybrid screen (see Chapter 7), MEKK2 was found to bind MEK5, which can...

Imagine that you are evaluating the early steps in translocation and processing of the secretory protein prolactin. By using an experimental approach similar to that shown in Figure 13-7, you can use...

You have just gotten back the results from an RNAseq analysis of mRNAs from liver. You had anticipated counting the number of reads of each mRNA to determine the relative abundance of different...

Protein synthesis in eukaryotes normally begins at the first AUG codon in the mRNA. Sometimes, however, the ribo-somes do not begin protein synthesis at this first AUG but scan past it (leaky...

The phosphorylation of a protein can influence its ability to interact with other proteins. These protein-protein interactions play a fundamental role in signal transduction pathways, and these...

In eukaryotes, the three RNA polymerases, Pol I, II, and III, each transcribes unique genes required for the synthesis of ribosomes: 25S and 18S rRNAs (Pol 1), 55 rRNA (Pol III), and mRNAs for...

You are investigating DNA synthesis in tissue-culture cells, using 3H-thymidine to radioactively label the replication forks. By breaking open the cells in a way that allows some of the DNA strands...

Antibody labeling of proteins like that used in immune-fluorescence analysis can be applied to electron microscopy, but instead of using fluorescent labels attached to antibodies, investigators use...

A proton gradient can be analyzed with fluorescent dyes whose emission-intensity profiles depend on pH. One of the most useful dyes for measuring the pH gradient across mitochondrial membranes is the...

The automated DNA sequencing machines utilize fluorescent dyes to detect the nascent DNA chains synthesized in the presence of the four dideoxy (ddX) chain terminators, each labeled with a different...

Cyclopamine is a known antagonist of Smo. Describe how cyclopamine reduces the number of BCCs in UV-irradiated mice.

A vapor mixture of equal volumes NH 3 and N 2 is contacted at 20 C and 1 atm (760 torr) with water to absorb some of the NH 3 . If 14 m 3 of this mixture is contacted with 10 m 3 of water, calculate...

You have genetically engineered green fluorescent protein (GFP) containing a KDEL sequence. When the construct is transfected into normal human fibroblasts and examined using fluorescence microscopy,...

Which of the trees based on molecular sequence data shown in Figure 4.10 supports hypothesis A in tree B? Explain. 125 rDNA k-casein

Using either the iodine test or the Benedicts test, design an experiment to examine other factors in the action of amylase on starch. Your experiment should test only one of the following variables:...

Satellite DNA is a known component of our genome and can be found in both coding and noncoding DNA. When it is found in coding DNA, the number of repeats can result in altered proteins. Bur the...

Tree thinking is a term biologists use to describe the process of approaching biological problem solving by considering the role of descent with modification based on phylogenetic evidence. This can...

Most humans are infected with herpes simplex virus-1 (HSV-1), the causative agent of cold sores. The HSV-1 genome comprises about I 00 genes, most of which are expressed in infected host cells at the...

Do you think molecular sequence data are helpful characters to use to infer phylogenetic relationships? What concerns might you have if a tree were based on a single molecule?

A polypeptide consists of three separate segments of amino acids, ABC. Another polypeptide contains segments A and C but not segment B. How might you determine if these two polypeptides are produced...

The thymine analog 5-bromouracil is a chemical mutagen that induces single base-pair substitutions in DNA called transitions (substitutions of one purine for another purine and one pyrimidine for...

cAMP is a second messenger that regulates many diverse cellular functions. In the intestinal lumen, cAMP is responsible for maintaining electrolyte and water balance. Certain bacterial toxins,...

Why do mitochondria need a special translocator to import proteins across the outer membrane, when the membrane already has large pores formed by porins?

Mutations in .trimcric G proteins can cause many diseases in humans. Patients with acromegaly often have pituitary tumors that oversecrete growth hormone (GH). GH-releasing hormone (GHRH) stimulates...

Describe the effects of the ECB infestations you used. Were all corn varieties equally effective at controlling the ECB? How do you know?

In the following illustration, the upper line shows a gene composed of segments AD. The lower circle shows a mutant version of this gene, consisting of two fused pieces (A-B, C-D), carried on a...

At 45C, 1,000 kg/h of a mixture of 0.80 mass fraction docosane and 0.20 mass fraction diphenylhexane is extracted with pure furfural to remove some diphenylhexane from the feed. Phaseequilibrium data...

In order to examine the specificity of membrane fusion conferred by specific v-SNAREs and t-SNAREs, researchers reconstituted liposomes (artificial lipid membranes) with specific t-SNARE complexes or...

Plants use the proton electrochemical gradient across the vacuole membrane to power the accumulation of salts and sugars in the organelle. This creates a hypertonic situation. Why does this not...

A dilute aqueous slurry of viscosity 0.001 N-s/m 2 and density 1,000 kg/m 3 is to be separated from the solid particles, which have a density of 3,000 kg/m 3 , by centrifugal sedimentation....

A mixture of 60 mol% propylene and 40 mol% propane at a flow rate of 100 lbmol/h and at 25C and 300 psia is to be separated with a polyvinyltrimethylsilane polymer (see Table 14.10 for...

Suggest reasons why the information represented in the pyramid of numbers of animals of one of the ecosystems you studied may not truly represent that ecosystem?

How might the concentration of glucose in the medium in which an E. coli cell is growing regulate the intracellular level of cyclic AMP?

Use the updated following figure to calculate the death rate due to bird flu for Indonesia, Vietnam, China, and Egypt. Death rate = (number dead/total cases) Ã 100%. Round to nearest 0.1%....

Make a chart that compares systemic arteries, capillaries, and systemic veins. Consider the following properties: structure; amount of smooth muscle; presence of valves; cross-sectional area; blood...

Rose-comb chickens mated with walnut-comb chickens produced 15 walnut-, 14 rose-, 5 pea-, and 6 single-comb chicks. Determine the genotypes of the parents.

The three-stage extractor shown in Figure 8.46 is used to extract the amine from a fluid consisting of 40 wt% benzene (B) and 60 wt% trimethylamine (T). The solvent (water) flow to stage 3 is 5,185...

The system docosanediphenylhexane (DPH)furfural is representative of complex systems encountered in the solvent refining of lubricating oils. Five hundred kg/h of a 40 wt% mixture of DPH in docosane...

Recently, researchers discovered that treating mammalian cells with juniferdin, a plant-derived compound, affects protein secretion, and have reported that the target of this drug is protein...

A farmer planted a field of Bt 123 corn and wants to estimate the yield in terms of bushels per acre. He counts 22 ears in 1/1000 of an acre. He determines that each ear has about 700 kernels on...

Suppose you are an ecologist studying the effects of acid precipitation on plant life. Describe an experiment you would perform in order to determine which plant species would be a useful indicator...

Describe the offspring phenotype and genotype ratios that resulted from crossing the parents that you chose on the Punnett squares. Using these ratios, what percentage of offspring are white-eyed?...

Why is the presence of a larger than normal number of neutrophils indicative of an infection? Explain your answer.

Why is the O c mutation in the E. coli lac operon epistatic to the I s mutation?

Write the partial diploid genotype for a strain that will (a) Produce -galactosidase constitutively and permease inducibly and (b) Produce -galactosidase constitutively but not permease either...

In the following pedigrees, determine whether the trait is more likely to be due to a dominant or a recessive allele. Assume the trait is rare in the population. a. b. IV 5 8. IV

A slight change in a plant species flower structure might favor a different pollinator. How might such a change in flower structure lead to a new plant species? How does coevolution between flowering...

The loz (lethal on Z) mutants of bacteriophage X are conditional lethal mutants that can grow on E. coli strain Y but cannot grow on E. coli strain Z. The results shown in the following table were...

Explain at least three functions that lipids serve in plants and/or animals.

In contrast to their similar brain abnormalities, newborn mice deficient in Apaf1 or caspase-9 have distinctive abnormalities in their paws. Apaf1-deficient mice fail to eliminate the webs between...

Describe the main functions of the different components of ATP synthase enzyme in the mitochondrion. A structurally similar enzyme is responsible for the acidification of lysosomes and endosomes....

Treatment of cells with the drug brefeldin A (BfA) has the effect of decoating Golgi apparatus membranes, resulting in a cell in which the vast majority of Golgi proteins arc found in the ER. What...

Discuss possible benefits and drawbacks of a transgenic organism such as Bt corn?

The behavior of receptor X (XR), a transmembrane protein present in the plasma membrane of mammalian cells, is being investigated. The protein has been engineered as a fusion protein containing the...

Geneticists have used mutations that cause altered phenotypes such as white eyes in Drosophila, white flowers and wrinkled seeds in peas, and altered coat color in rabbits to determine the locations...

What are the digestive products of carbohydrates, proteins, and fats? Where in the digestive system is each macromolecule digested?

At 45C, 5,000 kg/h of a mixture of 65 wt% docosane, 7 wt% furfural, and 28 wt% diphenylhexane is to be extracted with pure furfural to obtain a raffinate with 12 wt% diphenylhexane in a continuous,...

Continuous exposure of a G,., protein-coupled receptor to its ligand leads to a phenomenon known as desemitization. Describe several molecular mechanisms for receptor desensitization. How can a...

The Rb protein has been called the "master brake" of the cell cycle. Describe how the Rb protein acts as a cell cycle brake. How is the brake released in mid- to late G 1 to allow the cell to proceed...

A child appears to be suffering from I-cell disease, but when a sample of his proteins (lane 3* below), isolated from skin fibroblasts, is compared to protein samples from fibroblasts of his healthy...

Two methods for functionally inactivating a gene without altering the gene sequence are by dominant-negative mutations and RNA interference (RNAi). Describe how each method can inhibit expression of...

You observe samples from two coal balls collected in different places. Sample 1 contains roots and stems of tree-size lycophytes and horsetails. Sample 2 contains evidence of sphagnummoss leaves,...

Kinesin-1 contains two identical heavy chains and therefore has two identical motor domains. In contrast, kinesin-5 contains four identical heavy chains. Electron microscopic analysis of...

Many of the proteins that regulate transit through the cell cycle have been characterized. Xnf7, identified in extracts of Xenopus eggs, binds to the anaphase-promoting complex/ cyclosome (A PC/C)....

How might the prosecuting attorney answer this argument?

If there was no ECB infestation in a certain year, would a farmer gain or lose financially by planting Bt corn?

When a lipid bilayer is torn, why does it not seal itself by forming a hemi micelle cap at the edges, as shown in Figure Q101? Figure Q10-1 tear in bilayer seal with hemi-micelle cap

1. Recognize potential issues and major topics in the case. What is this case about? Underline terms or phrases that seem to be important to understanding this case. Then list 34 biology related...

List and describe five mechanisms of evolution.

The following table presents chromosome data on four species of plants and their F 1 hybrids: (a) Deduce the chromosomal origin of species A. (b) How many bivalents and univalents would you expect to...

List and describe six types of connective tissue.

Cre recombinase is a site-specific enzyme that catalyzes recombination between two LoxP DNA sites. Cre recombinase pairs two LoxP sites in the same orientation, breaks both duplexes at the same point...

The nuclear pore complex (NPC) creates a barrier to the free exchange of molecules between the nucleus and cytosol, but in a way that remains mysterious. In yeast, for example, the central pore of...

Refer to figure 25.15 and the chapter content to answer the following questions. 1. What features distinguish the four types of tissue? 2. Add skin to the concept map, making at least five...

Two feedsF at 7,500 kg/h containing 50 wt% acetone and 50 wt% water, and F0 at 7,500 kg/h containing 25 wt% acetone and 75 wt% waterare to be extracted in a system with 5,000 kg/h of...

For the conditions of Exercise 9.7, with bubble-point liquid feed at column pressure, compute the minimum external reflux and nonkey distribution at Rmin by the Class 2 Underwood equations. Data From...

Talc is to be filtered at a constant filtration rate under conditions listed below. The pressure drop is expected to rise from 2.0 psi to 100 psi. Generate a table of pressure versus time at 10, 20,...

The electron transport chain consists of a number of multiprotein complexes, which work in conjunction to pass electrons from an electron carrier, like NADH, to O 2 . What is the role of these...

The photosystems responsible for absorption of light energy are each composed of two linked components, the reaction center and an antenna complex. What is the pigment composition and role of each...

Discuss the role of par genes in generating A-P polarity in the C. elegans embryo.

How do lAPs (inhibitor of apoptosis proteins) interact with caspases to prevent apoptosis? How do mitochondrial proteins interact with lAPs to prevent inhibition of apoptosis?

A ligand binds two different receptors with a K d value of 10 -7 M for receptor l and a K d value of 10- 9 M for receptor 2. For which receptor does the ligand show the greater affinity? Calculate...

Consider the binding reaction L + R LR, where L is a ligand and R is its receptor. When 1 X 10 -3 M L is added to a solution containing 5 X 10 -2 M R, 90 percent of the L binds to form LR. What is...

While investigating the function of a specific growth factor receptor gene from humans, researchers found that two types of proteins are synthesized from this gene. A larger protein containing a...

You have learned about the events surrounding DNA replication and the central dogma. Identify the steps associated with these processes that will be adversely affected in the following scenarios. a....

Which of your three media choices would be the most useful for convincing your classmates that avian flu is a real biological concern? Explain.

Construct a graph with 1911 to 1919 on the x-axis and 0 to 60 years of age on the y axis. Show separate male and female life expectancy lines by connecting the points plotted for each year versus...

Which is more effective at quickly conveying the impact of the 1918 influenza pandemic, the table or your graph? Why?

The PI3K/AKT signaling pathway is aberrant in a wide variety of cancers. In soft-tissue sarcoma (STS) cells, AKT1 activation induces cell motility and invasiveness, which leads to aggressive...

Which age group had the highest number of influenza- and pneumonia-related deaths in 1917?

Another way of looking at the data is to consider the specific increase in the number of influenzaand pneumonia-related deaths in one age group between 1917 and 1918. You can calculate this by...

Scientists were puzzled why the 1918 flu resulted in increased deaths in specific age groups. What was so unexpected?

Explain why Rob did not have to worry that the amylase cleaning solution would damage the dress.

Review the following figure and note which of the reagents were used in each of the four test tubes. In the following table, check off the reagents found in each tube.

Test-tube results for the use of IKI. The color change in the contents of each test tube is also shown in the test-tube rack at the upper left corner of the figure. A dark shade indicates a positive...

What is the purpose of adding iodine to test tubes 1A and 3A?

Now examine the results for the Benedicts solution test. Color changes are shown in the rack containing tubes 14 at the middle right. A dark shade indicates a positive test (the actual color is...

Olfaction occurs when volatile compounds bind to specific odorant receptors. In mammals, each olfactory receptor neuron in the olfactory nasal epithelium expresses a single type of odorant receptor....

Proteomics involves the global analysis of protein expression. In one approach, all the proteins in control cells and treated cells are extracted and subsequently separated using two-dimensional gel...