Reptilian embryos are protected from desiccation by a leathery shell. Similarly, which pair of structures protects seed plantsʹ embryos and male gametophytes, respectively, from desiccation? 

#Question id: 2818

#Unit 2. Cellular Organization

Human mitochondrial DNA

#Question id: 2819

#Unit 2. Cellular Organization

A typical eukaryotic gene consists of which of the following elements?

a. internal ribosome binding sites       b. introns         c. exons            d. enhancers

#Question id: 2820

#Unit 2. Cellular Organization

Multiple mRNAs can arise from a primary transcript by use of alternative

a. splicing.      b. poly(A) sites.                      c. promoters.               d. ribosome binding sites.

#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