Your bone cells, muscle cells, and skin cells look different becausea. each cell contains different kinds of genes.b. they are present in different organs.c. different genes are active in each kind of cell.d. they contain different numbers of genes.

A friend is interested in isolating genes that are expressed solely in liver cells but only has access to skin cells. She asks you for advice on whether to start her studies. What will you say?

What did Linnaeus' system of naming organisms ensure?a. Two different organisms never end up with the same genus and species name.b. Two different organisms have the same genus and species name if they are closely related.c. The genus name is different for closely related species.d. The species name is the same for each organism in a genus.

Scientists have recently developed a process by which a skin cell from a human can be triggered to develop into a human heart muscle cell. This is possible because .a. most cells in the human body contain the genetic instructions for making all types of human cells;b. a skin cell is produced when all genes in the cell are expressed; turning off some genes in the cell results in a heart cell;c. scientists can add new genes to old cells to make them take different forms;d. a skin cell expresses only recessive alleles, so it can be triggered to produce dominant heart cell alleles;e. it is easy to mutate the genes in skin cells to produce the alleles required for other cell types

A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative ofa. the influence of environment on development.b. paedomorphosis.c. a change in a developmental gene or in its regulation that altered the spatial organization of body parts.d. heterochrony.

The following predictions ask you to consider how genetic regulatory cascades provide positional information. Select True or False for each statement.T/F Mutation of a gene at one level of a regulatory cascade will affect the expression of genes at all levels of the cascade.T/F Mutation of a gene that is expressed later in a regulatory cascade will affect a smaller region of the body than mutation of gene that is expressed early in the cascade.T/F In the regulatory cascade used by Drosophila, a gene at one level of the cascade will be controlled only by genes at the level immediately above it.T/F Genes that control the largest regions of the Drosophila embryo are not transcribed in the embryo.

Locate fluorine (F) on the partial periodic table provided in Figure 2.2. Predict its relative electronegativity compared to hydrogen, sodium, and oxygen. State the number and type of bond(s) you expect it would form if it reacted with sodium (Na).

Absence of bicoid mRNA from a Drosophila egg leads to the absence of anterior larval body parts and mirror-image duplication of posterior parts. This is evidence that the product of the bicoid genea. normally leads to formation of head structures.b. normally leads to formation of tail structures.c. is transcribed in the early embryo.d. is a protein present in all head structures.

What is the connection between genetic regulatory cascades and the observation that differentiation is a step-by-step process?