Question 1

What is the primary mechanism by which eukaryotes control transcription during cellular differentiation?

Accepted Answer

A)  regulatory transcription factors that influence chromatin structure and bind to regulatory regions 
B)  production of microRNAs to disable mRNAs that should not be expressed 
C)  post-translational control of proteins through ubiquitination and phosphorylation 
D)  alternative splicing of genes in different tissue types 
E)  inhibition of RNA polymerase through the expression of inhibitory enzymes

Question 2

The duplication of homeotic (Hox) genes has been significant in the evolution of animals because it ________.

Accepted Answer

A)  permitted the evolution of novel forms 
B)  caused the extinction of major groups 
C)  reduced morphological diversity into simpler forms of life 
D)  allowed animals to survive on significantly fewer calories

Question 3

During metamorphosis, a tadpole's tail is reduced in size by the process of ________.

Accepted Answer

A)  regeneration 
B)  apoptosis 
C)  meiosis 
D)  oxidative phosphorylation 
E)  re-differentiation

Question 4

Muscle cells differ from nerve cells mainly because they ________.

Accepted Answer

A)  express different genes 
B)  contain different genes 
C)  use different genetic codes 
D)  have unique ribosomes 
E)  have different chromosomes

Question 5

Which of the following statements about the DNA in one of your brain cells is TRUE?

Accepted Answer

A)  Most of the DNA codes for protein. 
B)  All of the genes of the genome are likely to be transcribed. 
C)  Each gene lies immediately adjacent to an enhancer. 
D)  Many genes are grouped into operon-like clusters. 
E)  It is the same as the DNA in one of your heart cells.

Question 6

The bicoid gene product is normally localized to the anterior end of the embryo. If large amounts of the product were injected into the posterior end as well, which of the following would occur?

Accepted Answer

A)  The embryo would grow to an unusually large size. 
B)  The embryo would grow extra wings and legs. 
C)  The embryo would probably show no anterior development and die. 
D)  Anterior structures would form in both ends of the embryo. 
E)  The embryo would develop normally.

Question 7

Scientists have found that the lifetimes of mRNAs coding for pair-rule regulatory elements in Drosophila embryos may last only a few minutes. What does this suggest about the overall developmental plan of an animal body?

Accepted Answer

A)  The role of mRNAs is less important than the position of genes in chromosomes. 
B)  Homeotic genes have greater impact in forming an embryo than mRNA from pair-rule genes. 
C)  Building an animal body requires a sequence of precisely timed steps. 
D)  Timing of pair-rule sequence determination is not as important as spatial signaling.

Question 8

Gastrulation is an important event in early embryonic development. Which of the following is NOT a result of gastrulation?

Accepted Answer

A)  formation of three embryonic cell layers 
B)  movement and alignment of many embryonic cells 
C)  the formation of a gastrula 
D)  the formation of specialized adult tissues

Question 9

Suppose you have identified a type of lizard that seems to have acquired a mutation in which hindlimbs are absent. Which gene, also responsible for the loss of limbs in snakes, may be mutated in this animal?

Accepted Answer

A)  bicoid 
B)  MONOPTEROS 
C)  PHANTASTICA 
D)  cytoplasmic determinants 
E)  Sonic hedgehog

Question 10

Which of the following are maternal effect genes that control the orientation of the egg and thus the Drosophila embryo?

Accepted Answer

A)  homeotic genes 
B)  segmentation genes 
C)  egg-polarity genes 
D)  morphogens 
E)  inducers

Question 11

Meristematic tissue cells in plants are most similar to which kind of cells in animals?

Accepted Answer

A)  somite cells 
B)  ectodermal cells 
C)  embryonic stem cells 
D)  mesodermal cells

Question 12

Mutations in which of the following genes lead to transformations in the identity of entire body parts?

Accepted Answer

A)  morphogens 
B)  segmentation genes 
C)  egg-polarity genes 
D)  homeotic genes 
E)  inducers

Question 13

Suppose the protein specified by bicoid was injected into Drosophila embryos so that a high concentration was present everywhere in the embryo. What might be the result of such an experiment?

Accepted Answer

A)  The embryos would grow larger than normal. 
B)  The embryos would show no development of posterior regions. 
C)  The embryos would show no development of anterior regions. 
D)  The embryos would halt their development.

Question 14

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences?

Accepted Answer

A)  gastrulation → organogenesis → cleavage 
B)  ovulation → gastrulation → fertilization 
C)  cleavage → gastrulation → organogenesis 
D)  gastrulation → blastulation → neurulation 
E)  preformation → morphogenesis → neurulation

Question 15

Within a cell, the amount of protein made using a given mRNA molecule depends partly on ________.

Accepted Answer

A)  the degree of DNA methylation 
B)  the rate at which the mRNA is degraded 
C)  the presence of certain transcription factors 
D)  the number of introns present in the mRNA 
E)  the types of ribosomes present in the cytoplasm

Question 16

Plant embryos do NOT undergo the process of ________.

Accepted Answer

A)  gene expression 
B)  mitosis 
C)  embryogenesis 
D)  gastrulation

Question 17

When the Bicoid protein is expressed in Drosophila, the embryo is still syncytial (divisions between cells are not yet fully developed). This information helps to explain which observation by Nüsslein-Volhard and Wieschaus?

Accepted Answer

A)  mRNA from the egg is translated into the Bicoid protein. 
B)  Bicoid protein diffuses throughout the embryo in a concentration gradient. 
C)  Bicoid protein serves as a transcription regulator. 
D)  Bicoid protein determines the dorsoventral axis of the embryo.

Question 18

The product of the bicoid gene in Drosophila provides essential information about ________.

Accepted Answer

A)  lethal genes 
B)  the dorsal-ventral axis 
C)  the left-right axis 
D)  segmentation 
E)  the anterior-posterior axis

Exam 21: Genes, Development, and Evolution