Exam 11: DNA and Genes

In plants,transposons are often the cause of variegation (the formation of white stripes of cells on a green leaf).Which of the following explains why a transposon might have this effect?

Because of the Human Genome Project,scientists now know the function of all 21,000 human genes.

Which of the following is NOT true? Organisms turn genes on and off

The genome of a prokaryote rarely contains ________ DNA sequences that do not undergo transcription.

The sequence of DNA differs among individuals within a species.This is the basis for

A gene sequence is disrupted by a mobile segment of DNA such that the gene is no longer functional.The mobile segment of DNA is a ________.

Which of the following does NOT correctly state a difference between prokaryotic and eukaryotic DNA organization?

DNA is often damaged or may be replicated incorrectly.Which of the following is NOT true?

When Francis Collins described the Human Genome Database as a "shop manual," he meant that the human genome contains

A permanent change in the DNA base sequence due to an uncorrected mismatch error is called a ________.

Once a gene is turned on,it cannot be turned off.

If their food source changes from lactose to arabinose,bacteria turn off their genes for lactose enzymes and turn on their genes for arabinose enzymes.Why don't bacteria express the genes for both lactose and arabinose enzymes all the time?

How can a cell contain DNA molecules that are much longer than the cell?

This figure shows a short sequence of DNA.During DNA replication,the piece of DNA depicted below will produce

At any given time,most of the genes in the genome of an organism are actively undergoing gene expression.

The 220 different cell types in the human body each contain all of the same DNA found in every other cell type.

Housekeeping genes

DNA is tightly packed around protein spools known as ________.

The early hypothesis that protein was the genetic material was based in part on the

Replication of DNA CANNOT begin until