Question

QUESTION 15

1. Viruses lack abilities cellular life forms have including

   		a. Heredity
   		b. Protein binding
   		c. Evolution
   		d. A metabolism

2 points   

QUESTION 16

1. For this stretch of DNA: 5’ G C G T C A 3’

   The complementary DNA strand is

   		a. 5’ G C G T C A 3’
   		b. 3’ C G C U G T 5’
   		c. 5’ C G C A C U 3’
   		d. 3’ C G C A G T 5’

2 points   

QUESTION 17

1. This is the pedigree of a family with dry earwax syndrome, a single gene trait. Individuals with dry earwax often need professional flushing of the ear canals to avoid blockage. Individuals with dry earwax also have less body odor, and are less likely to get breast cancer. Affected individuals are colored circles and squares. Open circles and squares indicate those with normal wet earwax. What is the genotype of individual number 3 in generation II?

   		a. Homozygous dominant: normal earwax
   		b. Homozygous recessive: dry earwax
   		c. Heterozygous: normal carrier with wet earwax
   		d. Heterozygous: they are affected with dry earwax

2 points   

QUESTION 18

1. Transcription in eukaryotes requires which of the following in addition to RNA polymerase?

   		a. the protein product of the promoter
   		b. ribosomes and tRNA
   		c. start and stop codons
   		d. several transcription factors (TFs)

2 points   

QUESTION 19

1. What is the energy source for the DNA synthesis reaction?

   		a. ATP
   		b. GTP
   		c. Hydrolysis of amino acids
   		d. The dNTPs: dATP, dGTP, dCTP, and dTTP

2 points   

QUESTION 20

1. Which of the following represents a difference between viruses and prions?

   		a. Viruses infect many types of cells, whereas prions infect only prokaryotic cells.
   		b. Viruses have nucleic acids and protein, whereas prions are only protein.
   		c. Viruses contain introns, whereas prions have only exons.
   		d. Viruses always have genomes composed of DNA, whereas prions always have genomes composed of RNA.

2 points   

QUESTION 21

1. How do females compensate for having a double dose of all the genes on the X chromosome?

   		a. All the genes are down-regulated
   		b. One X chromosome is digested by nucleases
   		c. One X is inactivated in each female cell
   		d. Males duplicate their one X, so their cells actually have two X’s

2 points   

QUESTION 22

Hemophilia A is a recessive sex-linked disease characterized by the inability to form normal blood clots. Without medical treatment this disease is fatal. The “H” is a normal allele for blood clotting factor VIII, the “h” is the hemophilia allele for abnormal clotting factor. This Punnett square is from a family with the allele for Hemophilia A. What percentage of the daughters of this couple will suffer from Hemophilia?

		a. 0%
		b. 25%
		c. 50%
		d. 100%

2 points   

QUESTION 23

1. Which two alleles a person has for a particular gene is their:

   		a. Appearance
   		b. Phenotype
   		c. Genotype
   		d. Karyotype

2 points   

QUESTION 24

1. Sickle-cell anemia is a recessive genetic disease that is fatal in childhood without medical treatment. The frequency of carriers of the sickle-cell anemia allele is extremely high in sub-Saharan Africa, presumably because heterozygotes are less likely to die from childhood malaria infections. Such a relationship is probably due to:

   		a. Mendel's law of independent assortment
   		b. Mendel's law of segregation
   		c. Darwin's explanation of natural selection
   		d. the malarial parasite directly changing the allele

2 points   

QUESTION 25

1. People have always noticed there are traits in humans, plants, and animals that disappear and reappear over the generations. We now know these traits are due to:

   		a. Dominant alleles
   		b. Sex-linked traits
   		c. Incomplete dominance
   		d. Recessive alleles

2 points   

QUESTION 26

1. Most cold viruses are unaffected by alcohol-based hand sanitizers like Purell. Flu viruses are inactivated by hand-sanitizer. What might account for this difference?

   		a. Cold viruses don’t have receptors for alcohol
   		b. Flu viruses are alive, cold viruses aren’t
   		c. Cold viruses contain alcohol dehydrogenase
   		d. Flu viruses have a membranous capsule which is damaged by alcohol

2 points   

QUESTION 27

1. When an mRNA molecule is made from DNA, this process is called:

   		a. Translation
   		b. Transcription
   		c. Transposition
   		d. Teleportation

2 points   

Answer 1

16. Answer: d. 3’ C G C A G T 5’

Explanation: According to chargaff's rule, A always pairs with T or vice versa and G pairs with C or vice versa for DNA in a complementary strand. Here the template strand is 5’ G C G T C A 3’ and so the complementary bases as pair the rule is C G C A G T and the ends are 3' to 5'. So the answer is d. 3’ C G C A G T 5’.

A pairs with U in RNA and not in DNA so the option b and c is wrong. Option A is wrong because it is same template DNA.

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27. Answer: (b) Transcription

Explanation: In molecular biology, the central dogma of life is three major process. DNA replication (DNA copies itself), Transcription (DNA is converted in to mRNA) and Translation (mRNA is converted in to protein to perform the function).

So option b is right and a is wrong.

Transposition is nothing but the shifting of DNA sequence from one place to another site. Teleportation is not related to DNA biology. So c and d is also wrong.

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