3. Leaf coloration in the four-o’clock plant, Mirabilis jalapa, was one of the first examples of cytoplasmic inheritance. Leaves may be green, white or variegated, depending on the phenotype of the ovule. If ovules from a white-leafed branch are pollinated with pollen from a green-leafed branch, what phenotypes will be observed in the progeny? (3 pts)

a. all green-leafed progeny

b. progeny with leaves that have green and white patches

c. all white-leafed progeny

d. progeny with a mixture of leaf types, all green and all white

e. progeny with leaves that green and white patches, green leaves and white leaves

6. Genotype BCD/dcb (inversion heterozygote) is backcrossed to a dcb/dcb homozygote. Locus B is 20 cM from locus C and locus C is 20cM from locus D. NOTE that locus C is between loci B and D. List the expected number of genotypes found in 1000 healthy offspring of this test cross. Show work. 8 pts.

9. Distinguish triploidy and trisomy ( 3 pts)

You do a complementation test with five mutants and find the following: (+) = growth, (-) = no growth

How many genes were identified in this analysis? (2 pts) ______

Which mutants belong to the same complementation groups? (2 pts)_________________

Are mutants in the same complementation group mutations of the same gene? (2 pts)_____

Place the letter for each label in the appropriate blank on the diagram of translation below (6 pts):

(a) Amino acid (b) Polypeptide (c) Ribosome (or ribosomal subunits) (d) tRNA

(e) mRNA (f) Anticodon

(True/False) In eukaryotes, the primary transcript contains introns. _________ (3 pts)

Use the following terms to fill in the blanks below (1 word & 1 pt / blank)

Suppression Splicing Electrophoresis Plasmid PCR Hybridization Translation Nonsense Sticky Cloning Palindromic Digestion Subliminal

· Most restriction enzymes cut at ______________ sequences, which frequently creates ___________ ends to the DNA.

· Binding a labeled oligonucleotide DNA probe to your DNA of interest is called ___________.

· The process that eukaryotic cells use to remove introns from their mRNA is known as ____________.

· ____________ is a means of amplifying portions of DNA in vitro using primers, DNA polymerase, and free nucleotides. (Some would say it is a sort of chain reaction.)

What is a Barr body?

Genes are expressed in:

A. Euchromatin

B. Heterochromatin

C. ONLY constitutive heterochromatin

D. None of the above

If telomerase did not exist, chromosomes would:

A. not be able to recombine

B. not be able to assort independently

C. be very fragile

D. get shorter in every round of replication

Duplications in a chromosome:

A. increase expression of genes

B. increase organismal growth

C. are always next to each other on the chromosome

D. may result in new functions for a gene

What is the difference between trisomy and triploidy?

Draw the 4 chromosomes that will result from this recombination within an inversion loop. (2pts)

Name________________________________________ Section _______________________

Part I. Fill in the blank (5 points)

1. PCR reaction is used to _____________ specific DNA fragments using _________, an enzyme that was obtained bacteria that lives in hot springs.

2. Restriction enzymes are ___________ made by bacteria that recognize _________ sequences in DNA and cut at those sites.

3. _____________ is the enzyme that allows to obtain cDNA sequences starting with mRNA transcripts.

Word bank: sequence, proteins, reverse transcriptase, TAQ polymerase, ligase, RNA ase, amplify, trepanation, palyndromic, receptors.

Part II. Short answer (15 pts)

1. If there were 68 amino acids instead of twenty in living organisms, what would be the MINIMUM number of nucleotide bases required to form a codon (assume: a codon specifies only one amino acid, the genetic code is degenerate, DNA is composed of four different bases)? (1 pt)

2. What effects (none, mild, severe ) would be expected if the following mutations occurred? EXPLAIN! 4pts.

a. A frameshift mutation near the N terminus of a protein’s coding sequence.

b. A nonsense mutation near the C terminus of a protein’s coding sequence.

3. You find five T4rII mutants that will not grow on E. coli K. You cross all mutants and score their ability to grow on E. coli (indicated as + or -) in chart below. 4pts

	1	2	3	4	5	6
1	-	+	+	-	+	+
2		-	-	+	-	+
3			-	+	-	+
4				-	+	+
5					-	+
6						-

a) How many genes were identified in this analysis?

b) Which mutants belong to the same complementation groups?

3. From the following word bank, label all the parts and enzymes corresponding to the diagramed translational units (A: aminoacid, B: small subunit of ribosome, C: complete polypeptyde D: anticodon, E: transfer RNA, F: 5’ UTR). .

Label all the parts and enzymes corresponding to the following transcriptional unit (A: promoter, B: aminoacid, C: small subunit of ribosome, D: 3’ UTR, E: complete polypeptyde F: RNA polymerase, G: sigma factor, H: poly-A tail, I: DNA template strand, J: 5’ UTR).

BSCI 222 Quiz #8

Name________________________________________ Section _______________________

Part I. Fill in the blank (6 points). Word bank: single-stranded, conjugation, transformation, double stranded, transposons, prokaryotic, eukaryotic, nucleosomes, DNAse, plasmid.

1. ____________ are whole units of DNA that move from place to place within the genome without an RNA intermediary.

2. ___________ are complexes of DNA and protein found in the nucleus of ____________ organisms.

3. In addition to their chromosomes, most bacteria carry _____________, which are small circles of ______________DNA.

4. ______________ is the transfer of DNA that occurs when a bacterial cell comes into contact with another bacterial cell containing a plasmid.

Short Answer (14 pts)

1. Gesneria pedunculosa is a shrub with a haploid number of chromosomes of 13. What would be the somatic number of chromosomes of :

a. a monosomic variant of this species? _________________

b. an autotetraploid variant?____________

2. Consider the normal chromosome:

ABCD*EFG

List all the mutations that must have happened to obtain the following variants?

(a) ACBD*EFG ___________________________________________________________

(b) ABDC*DCEF ____________________________________________________________

3. The following is a drawing of the pairing of chromosomes at meiosis for a translocation heterozygote (reciprocal translocation, N=normal, T=translocated). What gametes are produced by this heterozygote when the meiosis segregation pattern is: (a) alternate, (b) adjacent-1?. Indicate which are viable and unviable gametes.

T1

N1

N2

T2

A

E D

Q R

Q R

O

P

P

O

C

E D

F

C

C

B

B

A

Alternate segregation Adjacent – 1 segregation

11. Rye is a diploid and has 7 chromosomes in its gametes. Triticale is an allopolyploid derived from the cross of Rye with Wheat. The F1 progeny of the Rye x Wheat cross were treated with colchicine to double the chromosome content of the germ (gamete) cells. The allopolyploid Triticale has 42 chromosomes in its somatic cells. (8 pts total).

a. How many chromosomes are found in the diploid somatic cells of Rye? (2 pts)

b. How many chromosomes are found in the gametes of Wheat? (2 pts)

c. How many chromosomes are found in the somatic tissue of Wheat? (2 pts)

d. How many chromosomes are found in the gametes of Triticale? (2 pts)

3. What protein(s) cut(s) DNA into smaller pieces (4 pts)

a. DNA ligase

b. Restriction enzyme

c. DNA helicase

d. DNA primase

e. Reverse transcriptase

8. Describe the unique property(ies) of the enzyme aminoacyl-tRNA synthetase (4 pts).

9. Where in the flow of information from DNA to protein synthesis is a stop codon expressed? (5 pts)

10. Two important experiments demonstrated that mutations are randomly produced. Name these experiments (2 pts) and describe one of them (3 pts). (Total = 5 pts)

12. Crick’s experiments with intragenic suppression confirmed the triplet nature of the codon and the wide-spread degeneracy of the code. Imagine if instead they had observed the following, where + and – indicates an insertion or deletion, respectively (Total = 5 pts):

+ or - = loss of function

+++ or --- = loss of function

++ or -- = reversion to wildtype

and ++ or -- mutations have to be very close to one another, otherwise there was still loss of function. What would have been their conclusion regarding a) the number of nucleotides corresponding to an amino acid (2 pts) and b) the number of different stop codons relative to codons coding for amino acids (3 pts).

13. Shown below are the results of a series of coinfections using T4 rII- strains similar to those employed by Benzer. Each strain contains a different deletion mutation. Ability to produce wild-type progeny phage is indicated by (+) and (o) indicates no wild-type progeny. (Total = 7 points)

A B C D E

A o + o + +

B + o + o o

C o + o + +

D o o + o +

E + o + + o

Indicate the order of the mutations within the cistron that is most consistent with the data, eg., ABCDE or BEDCA etc, (show work):

14. In a test cross between an individual that is heterozygote for 3 loci (Aa, Bb, Cc) and a homozygous recessive individual for the same 3 loci, list all gamete types produced by both parents. List the gamete types separately for each parent. Total = 5 pts.