The resistance of the pulmonary tree is so low that a 1 cm of water pressure gradient is sufficient to cause normal air flow during resting conditions. Which of the following often has a substantial resistance during pulmonary disease states that can limit alveolar ventilation?

#Question id: 2821

#Unit 2. Cellular Organization

Which of the following is (are) encoded by multiple genes present in the human genome?

a. ribosomal RNA       b. transfer RNA                       c. histone            d. lysozyme

#Question id: 2822

#Unit 2. Cellular Organization

Transposition by a bacterial insertion element

a. occurs at a frequency of approximately 1 in 10^3 cells per generation.

b. can inactivate an essential gene.    

c. is mediated through a RNA intermediate.

d. requires the enzyme transposase

#Question id: 2823

#Unit 2. Cellular Organization

Transposition by a retrotransposon requires activity of which of the following enzymes?

a. RNA polymerase                b. reverse transcriptase

c. DNA methylase                  d. DNA polymerase

#Question id: 2824

#Unit 2. Cellular Organization

Plant mitochondrial DNA

a. is the same size as human mitochondrial DNA.

b. encodes a 5S mitochondrial rRNA.

c. contains multiple copies that recombine with each other.

d. uses the standard genetic code.

#Question id: 2825

#Unit 2. Cellular Organization

Metaphase chromosomes can be identified

a. by shape.                 

b. by the size and number of introns.

c. by banding patterns with Giemsa reagent.

d. by chromosome painting.

#Question id: 2826

#Unit 2. Cellular Organization

An open reading frame (ORF) is defined as a DNA sequence that

a. begins with a start codon.               

b. ends with a stop codon.

c. contains 50 codons.   

d. contains approximately an equal frequency of A, T, G, and C.