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DNA, Chromosomes and the Genomes

Probability in drosophila mutation experiment

In a mutation experiment in drosophila, 45 mutations were detected amongst 543 males that received 2500 Roentgens (R) and 67 mutations in 649 males that received 4000R. What is the number of progeny expected in 1000 progeny of males exposed to 6000R?

Predicting triplets in laboratory conditions

Under laboratory conditions, a synthetic polyribonucleiotide was produced using a mixture of A and G with a relative frequency of 5:1 respectively. How would a scientist predict the relative frequencies in which the triplets are expected to form when the ribonucleotides form in a random linear array? Indicate which amino acid(s)

Triplet codons and probability

Find the number of triplet codons feasible from 4 ribonucleotides A, U, G and C containing a) no uracil, b) one or more uracils.

Chromosome number in different body cells

An animal cell has 46 post-mitotic chromosomes in each of its somatic cells. How many chromosomes should be present in the following cells- a) Mature egg, b) 1st polar body, c) Sperm, d) Spermatid, e) Primary spermatocyte, f) Brain cell, g) Secondary oocyte, h) Spermatogonium.

Chi-square testing

Cross between pure red tomato and yellow tomato produced all red F1 progeny. From the F2 progeny of 400 plants, 90 were yellow. Hypothesize that a single pair of allele is involved such that Y- = Red and yy = Yellow. Test this hypothesis using Chi square test.

F2 progeny ratio

In squash, disc shaped fruit is dependent on dominant gene D and elongated fruit on recessive allele d. Yellow color is controlled by dominant gene R and green color by recessive allele r. Draw a cross between the homozygous squash fruits and summarize the expected results of F2.

Crosses in garden pea

Garden pea producing round seeds were crossed with those producing wrinkled seeds. The result was the production of 5474 round seeds and 1850 wrinkled seeds. a) What is the original parental cross? b) Indicate the gamete types c) F1 progeny? d) What result do you expect when F1 is selfed? e) Indicate F1 selfed ga

Understanding chromosome mapping techniques.

(a) By using the map function, calculate how many real map units are indicated by a recombinant frequency of 20 percent. Remember that a mean of 1 equals 50 real map units. (b) If you obtain an RF value of 45 percent in one experiment, what can you say about linkage? (The actual figures are 58, 52, 47, and 43 out of 200 pro

Understanding the DNA structure.

In the harlequin-chromosome technique, you allow THREE rounds of replication in bromodeoxyuridine and then stain the chromosomes. What result do you expect to obtain?

Understanding the DNA structure is achieved.

If you extract the DNA of the coliphate thetaX174, you will find that its composition is 25 percent A, 33 percent T, 24 percent G, and 18 percent C. Does this make sense in terms of Chargaff's rules? How would you interpret this result? How might such a phage replicate its DNA? Ideas are expressed.

Mendelian heredity is summarized.

Consider two-child families in which the parents have been identified as carriers of an autosomal recessive gene by virtue of having at least one child with the phenotype. When the children of many such two-child families are totaled, what proportion of children in these families will show the phenotype? (Hint: The answer is N

Understanding Mendelian genetic heredity.

When a pea plant of genotype Aa Bb produces gametes, what proportion will be Ab? (Assume that the two genes are independent) (a) 3/4 (b) 1/2 (c) 9/16 (d) none (e) 1/4

Understanding Mendelian heredity.

Maple syrup urine disease is a rare inborn error of metabolism. It derives its name from the odor of the urine of affected individuals. If untreated, affected children die soon after birth. The disease tends to recur in the same family, but the parents of the affected individuals are always normal. What does this information

Understanding Mendelian analysis and heredity.

Holstein cattle are normally black and white. A superb black and white bull, Nick, was purchased by a farmer for $100 000. The progeny sired by Nick were all normal in appearance. However, certain pairs of his progeny, when interbred, produced red and white progeny at a frequency of about 25 percent. Nick was soon removed fr

Some characteristics of mRNA.

Name 5 features of mRNA that can regulate its stability or translation. Indicate whether the feature regulates stability or translation.

Analyzing Western Blots, etc.

I took photographs of 3 stains: SDS-PAGE analysis of C. elegans protein extract (Coomassie Blue Staining), Western Blot of C. Elegans protein, and Indirect Immunofluorescence Staining. There are 3 photos attached .How do you analyze these stains? I need help discussing these results.

Cell Biology Homework

1. Digestion of the oligonucleotide, AGUACAA, by pancreatic RNase would yield what products? 2. A 5.5 kb, circular plasmid is cut with the following restriction endonucleases, producing the fragments listed. Construct a restriction map for this plasmid. Endonuclease DNA fragments (kb) Eco RI 5.5 Pst I 5.5

Cell Biology Homework

1. When DNA samples A and B were separated by buoyant density centrifugation the two samples migrated 23 and 15 cm, respectively. If DNA B had a GC content of 34%, what was the GC content of DNA A? 2. If Meselson and Stahl found that the ratio of 15N-labeled single-strands to 14N-labeled single-strands was 2:6 in the secon

Cell Biology: DNA and Viruses

1. Bacteriophage M13 infects E. coli differently from the way bacteriophage T2 does. The M13 coat is removed in the inner membrane of the bacterial cell, where it is sequestered during phage replication. It is subsequently used to package the newly replicated phage DNA to create progeny phage. Why would this make M13 less su

More questions--but easy.

For the first question, I thought PCR might have something to do with it, but it seems to restrictive. I can't think of any other descriptive techniques. can anyone suggest any? For question 2, it look simple but when a deletion occurs does it happen to the top and bottom strand? I was just wondering because that changes the