MasteringMicrobiology (Ch 4) & Genomics (Ch 6)

Why DNA polymerase cannot initiate a new DNA strand

DNA polymerase requires a free 3′-hydroxyl group to add nucleotides.

When comparing genes from Archaea, Bacteria, and Eukarya, which statement is TRUE?

Genes in Archaea involved in DNA replication, transcription, and translation are more similar to those of Eukarya, while those encoding metabolic functions other than information processing are more similar to those of Bacteria.

Horizontal gene transfer refers to the transfer of genes from one organism to another, as occurs during conjugation between bacteria. How does this differ from vertical gene transfer?

In horizontal gene transfer, genes are transferred from one mature adult organism to another. In vertical gene transfer, genes are transferred from adults to offspring.

What statement is TRUE regarding protein synthesis?

The 23S rRNA catalyzes peptide bond formation in the growing polypeptide chain.

An open reading frame (ORF) encodes for

a polypeptide

What is TRUE concerning mRNA?

mRNA has a very short half-life

DNA-binding proteins interact predominantly within which portion of a double-stranded DNA helix?

major groove

Match the bacterial genetic element with the correct characteristic. a. chromosome -- nonessential genes b. chromosome -- linear, double-stranded DNA c. plasmid -- linear, single-stranded DNA d. plasmid -- nonessential genes

plasmid -- nonessential genes

Which of the following is NOT included in the genome? a. noncoding regions of DNA b. genes that encode RNAs c. coding regions of DNA d. proteins

proteins

A plasmid differs from the bacterial chromosome in that it is ________

significantly smaller

Researchers discover a new species of bacterium that has an unusual metabolism. However, it has biochemical and morphological similarities to other species. What is the most comprehensive and effective approach to determine how to classify these bacteria?

the bacteria should be classified by using genomic analyses to construct phylogenies.

You are studying a protein in Salmonella typhimurium that you believe is a toxin. Whenever you attempt to purify the protein from lysed cell cultures, you get two forms of the protein. One form is smaller than the other and is missing 15 amino acids from the N-terminus compared to the larger form. This leads you to hypothesize that

the protein is secreted and folds outside of the cell

A surprising finding of environmental metagenomic studies is that a majority of genes in the environment are

viral in origin

Which of these organisms is likely to have the largest genome? a. a chloroplast b. a yeast cell c. an extremophile Archaean due to the demands of surviving in harsh environments d. an autotrophic bacterium

yeast cell