Deck 17: Developmental Genetics

Question 1

Cloning mammals has proven to be:

A) impossible
B) easy and straightforward
C) not technically feasible at the present time
D) a technique that produces many similar-looking, deformed progeny
E) a process with a low success rate and a high incidence of genetic defects

Answer 1

E

Question 2

The significance of totipotency is that:

A) genes are not regularly lost during development.
B) most organisms can be easily cloned.
C) differentiation leads to the loss of certain genes in each cell.
D) somatic cells are incapable of differentiation.
E) unexpressed genes are lost during development.

Answer 2

A

Question 3

Cells become progressively committed to specific patterns of gene activity and developmental fate through a process known as:

A) morphogenesis
B) determination
C) cell differentiation
D) pattern formation
E) growth

Answer 3

B

Question 4

Figure 17-4

In the accompanying figure, the purpose of electrical shock at the stage of the process labeled as A is to:

A) kill the egg cell nucleus
B) initiate fusion of the two cells
C) stimulate cell division
D) induce mutations
E) initiate apoptosis

Question 5

The only known source of human embryonic stem cells is:

A) placental tissue
B) umbilical cords
C) early human embryos
D) brain tissue
E) nerve tissue

Question 6

Differential gene expression is defined as the:

A) ability of some cells to arrest their development under varying environmental conditions.
B) progressive fixation of the fates of a cell's descendants.
C) genetic variation found in various somatic cells of the same individual.
D) regulation during development that varies the type and quantity of gene products among cells.
E) constitutive expression of all genes in the somatic cells.

Question 7

The process of ____ describes cell specialization structure and gene activity.

A) morphogenesis
B) determination
C) differentiation
D) maturation
E) growth

Question 8

The occurrence of human identical twins is evidence that:

A) all human cells are totipotent.
B) no human totipotent cells have been identified.
C) the only totipotent human cell is the one-cell embryo.
D) cells in a two-cell human embryo are totipotent.
E) cells in a two-cell human embryo are pluripotent.

Question 9

Embryonic stem cells cannot develop into ____ cells.

A) muscle
B) nerve
C) blood
D) placental
E) other stem

Question 10

Figure 17-4

In the accompanying figure, the purpose of growing the donor cells in nutrient-limited media is to:

A) have small cells that would be easier to manipulate
B) replicate a normal environment
C) force the donor cell nucleus into the G₀ cell stage
D) induce favorable mutations
E) initiate apoptosis

Question 11

Due to nuclear equivalence in different cell types, the presence of different cell types in any given organism is accomplished by:

A) differential gene expression
B) pattern formation
C) cloning
D) induction
E) nuclear transplantation

Question 12

The first cloned mammal, Dolly:

A) was stillborn
B) developed arthritis and a virus-induced lung cancer at a relatively young age
C) lived a short period of time before suffering advanced aging effects
D) lived to a normal age for sheep
E) lived longer than normal sheep

Question 13

Cells able to divide and form some types of cells in an organism are called:

A) pluripotent stem cells
B) terminally differentiated cells
C) germ line cells
D) morphogenic cells
E) developmental cells

Question 14

Cells become progressively organized into recognizable structures through a process known as:

A) morphogenesis
B) determination
C) cell differentiation
D) pattern formation
E) growth

Question 15

Induced pluripotent stem cells are:

A) pluripotent cells lacking transcription factors
B) totipotent cells resulting from reproductive cloning
C) pluripotent cells resulting from reprogramming of differentiated cells
D) totipotent cells resulting from reprogramming of differentiated cells
E) pluripotent cells resulting from therapeutic cloning

Question 16

The concept of nuclear equivalence states that:

A) all of the somatic cells in an adult organism have the same genes.
B) the genes of the individuals of the same species are exactly the same.
C) as cells mature, unneeded genes are lost.
D) the nuclei of all organisms are the same.
E) nuclei of individuals of the same species are the same size.

Question 17

Regulation of development takes place mostly at the level of:

A) replication
B) transcription
C) posttranscription
D) translation
E) posttranslation

Question 18

What is a goal of human therapeutic cloning?

A) to transfer cells from an unrelated individual into a patient needing a transplant
B) to create pluripotent cells for medical research only
C) to make a new individual, who is genetically identical to a patient needing a transplant
D) to create pluripotent stem cells using a patient's nucleus
E) to extract ES cells from an embryo

Question 19

What evidence supports the idea that some nuclei are totipotent?

A) Nuclei taken from the cells of an embryonic frog can direct a frog egg to develop into a tadpole.
B) Nuclei taken from the cells of a frog embryo can direct any amphibian egg to develop into a tadpole.
C) Nuclei taken from a different species can direct a tadpole egg to develop into a normal tadpole.
D) Some cells are capable of undergoing unlimited cell cycles.
E) Some cells are capable of arresting their cell cycle at will.

Question 20

Undifferentiated cells that can divide and specialize to form a variety of different cells are called:

A) differential cells
B) mother cells
C) somatic cells
D) stem cells
E) morphogens

Question 21

For about ____ of mouse genes, there is a similar gene in the human genome.

A) 10%
B) 25%
C) 50%
D) 90%
E) 99%

Question 22

RNA interference is used to:

A) interfere with specific transcription factors.
B) knock out the expression of a specific gene.
C) prevent the duplication of DNA.
D) cause a mutation in a specific gene.
E) stimulate apoptosis.

Question 23

Instances in which cells die shortly after they are produced in development illustrate:

A) morphogenesis
B) mosaic development
C) apoptosis
D) non-specific differentiation
E) caspases

Question 24

The ABC genes in the model of Arabidopsis flower development are organ-identity genes that are also:

A) segmentation genes
B) homeotic genes
C) gap genes
D) translation factors genes
E) growth factor genes

Question 25

Imaginal discs are:

A) found in mammalian cells and control gene activation in mature somatic cells
B) paired groups of undifferentiated cells that are precursors of adult structures in Drosophila
C) found in plant cells and assist in the development of the flower
D) part of the salivary gland of Drosophila
E) found in Drosophila ovary cells and represent inactivated X chromosomes

Question 26

What is an advantage for using Arabidopsis to study plant development and genetics?

A) The Arabidopsis genome is largely unstudied, and therefore there is a lot that scientists can learn.
B) Arabidopsis mutants can be easily induced with chemicals.
C) There are no developmental mutants in Arabidopsis , therefore, normal development can be studied easily.
D) This plant completes its life cycle in just a few months.
E) This plant is a weed of no economic importance.

Question 27

Maternal effect genes of Drosophila are genes active in ____ cells, whose products establish ____ in developing embryos.

A) maternal; gender
B) maternal; polarity
C) embryonic; polarity
D) embryonic; gender
E) egg; gender

Question 28

One of the main obstacles to successful cloning of sheep, apparently overcome by Wilmut et al., was:

A) to find an adult nucleus that was likely to work.
B) to synchronize the cell cycles of the donor cell and the egg cell.
C) to enucleate the donor cell.
D) the ability to culture cells in the laboratory.
E) to recognize that the nucleus from one sheep cell may contain different genetic information than the nucleus of another cell from the same animal.

Question 29

The results of the experiment outlined in the accompanying figure clearly demonstrate:

A) gene amplification
B) founder cell development pattern
C) mosaic development
D) apoptosis
E) totipotency

Question 30

How does the early development of the mouse differ from that of Caenorhabditis ?

A) Embryonic mouse cells commit to their ultimate fate earlier than do the cells of Caenorhabditis .
B) Early development of a mouse is regulative, while early development of Caenorhabditis is not.
C) Mouse cells require higher concentrations of nutrients than do the cells of Caenorhabditis .
D) Embryonic mouse cells differentiate much later than the cells of Caenorhabditis .
E) Embryonic development in the mouse is controlled by transcription factors, while Caenorhabditis is not.

Question 31

Capases are ____ that are active in the first stages of ____.

A) genes; polarity establishment
B) genes; cancer
C) transcription factors; cancer
D) hormones; apoptosis
E) proteolytic enzymes; apoptosis

Question 32

In early Drosophila development, which of the following forms first?

A) segmented larva
B) pupa
C) syncytial blastoderm
D) blastocyst
E) cellular blastoderm

Question 33

Totipotent nuclei are capable of:

A) controlling the expression of other genes in the nucleus
B) directing normal development of an organism
C) causing cells to lose the ability to differentiate
D) undergoing unlimited nuclear divisions
E) stopping the cell cycle at will

Question 34

The role of maternal effect genes in Drosophila is to:

A) code for the production of yolk proteins
B) prepare the female fly for reproduction
C) control the early stages of Drosophila development
D) control the development of the pupa
E) control the shape and size of the eggs produced

Question 35

Drosophila melanogaster is a suitable research subject for developmental genetics studies because:

A) the fly is large enough for many surgical procedures.
B) many developmental control genes observed in the fly are also present in humans.
C) flies are not subject to genetic mutations.
D) while flies are small and easy to house, they require specialized and expensive dietary requirements.
E) the control of fly development is unique and unrelated to human development.

Question 36

____ are organisms that contain two or more kinds of genetically dissimilar cells from different zygotes.

A) Heterozygotes
B) Chimeras
C) Recombinants
D) Transgenics
E) Polyploids

Question 37

The fact that most segmentation genes code for ____ indicates that these protein products are ____ that regulate the expression of other genes.

A) homeobox genes; genetic switches
B) transcription factors; genetic switches
C) transcription factors; inducers
D) maternal effect genes; protein switches
E) hormones; signaling molecules

Question 38

When the human gene coding for insulin is introduced into a mouse embryo, the gene is correctly expressed in the appropriate tissue. This shows that:

A) tissue-specific gene expression is highly conserved during evolution.
B) the introduced gene was edited by the mouse embryo for proper function.
C) the introduced gene was exactly the same as the mouse gene for insulin.
D) mice and humans are not closely related.
E) mouse genes are not tissue specific.

Question 39

One characteristic that makes Caenorhabditis elegans attractive for developmental studies is:

A) its small, transparent body
B) the extensive number of genes shared with humans
C) the developmental defects that occur in this organism
D) the close evolutionary relationship between this mammal and humans
E) the presence of zygotic segmentation genes, similar to those found in humans

Question 40

____ are known as master genes of development, and may hold clues to the field of evolutionary developmental biology known as Evo Devo.

A) Nuclear equivalent genes
B) Stem cell genes
C) Prokaryotic transcription factors
D) Segmentation genes
E) Homeobox genes

Question 41

Genes that normally block cell division are called:

A) growth factor genes
B) oncogenes
C) tumor suppressor genes
D) proto-oncogenes
E) growth inhibiting genes

Question 42

Maternal effect genes form ____ gradients in the developing egg.

A) maternal Hox protein
B) segment
C) polarity gene
D) morphogen
E) maternal growth factor

Question 43

Metastatic tumors:

A) are examples of neoplasms
B) contain cells tightly controlled by the cell cycle
C) contain nondividing cells
D) are caused by the normal expression of homeotic genes
E) are localized in one part of the body

Question 44

The _____ oncogene, the ____ in human cancer, causes cells to become cancerous due to abnormal cell signaling.

A) BRCA1; most common
B) Ras; most common
C) BRCA1; least common
D) Ras; least common
E) BRCA2; most common

Question 45

Drosophila developmental mutants of ____ genes produce larvae with mirror image segments.

A) gap
B) pair-rule
C) segmentation
D) paternal effect
E) segment polarity

Question 46

Homeotic genes of Drosophila :

A) cause cells of the same type to produce differing amounts of gene products
B) specify the developmental plan(s) for each segment
C) are expressed in only one sex in any particular species
D) are always the sites of lethal mutations
E) control developmental timing

Question 47

Malignant tumors are characterized by:

A) metastasis
B) abnormal cell growth
C) the formation of cell masses
D) specific mutations
E) proto-oncogenes

Question 48

Figure 17-12

The mutation labeled as 1 to the far right in the accompanying figure represents:

A) legs developing where antenna should be
B) appendages of the eyes
C) enlarged antennae
D) newly formed structures to remove pollen or dust from the eyes
E) a revision of the fly body so that legs and antenna have switched places

Question 49

The first active Drosophila segmentation genes are the ____, which begin organization of the body into regions.

A) pair-rule genes
B) segment polarity genes
C) gap genes
D) homeotic genes
E) maternal effect genes

Question 50

Figure 17-12

The mutant fly in the accompanying figure illustrates:

A) the existence of homeotic genes in Drosophila
B) the concept of totipotency
C) the normal functions of genes affecting segment identity
D) genetic diversity in the fly
E) a structure containing many nuclei residing in a common cytoplasm

Question 51

Gap genes of Drosophila embryos:

A) organize the embryo into broad regions and influence the activity of pair-rule genes.
B) are missing from the chromosomes of mutant flies.
C) are genes that have moved to gaps on other chromosome during meiosis.
D) cause gaps in the cell cycle.
E) cause the death of embryos before they hatch.

Question 52

____ promote cancer development, while ____ prevent cancer development.

A) Oncogenes; tumor suppressor genes
B) Tumor suppressor genes; homeobox genes
C) Tumor suppressor genes; oncogenes
D) Oncogenes; homeobox genes
E) Homeobox genes; proto-oncogenes

Question 53

Some Drosophila developmental genes result in the loss of alternate segments in the larva when mutated. These genes are called:

A) embryonic segment genes
B) larval segmentation genes
C) segment polarity genes
D) pair-rule genes
E) gap genes

Question 54

Most segmentation genes code for:

A) transcription factors
B) genetic switches such as operators
C) repressors
D) insulin-like growth factors
E) morphogens

Question 55

In the process known as ____, the fate of a cell is influenced by interactions with neighboring cells.

A) determination
B) induction
C) apoptosis
D) differentiation
E) tumor suppression

Question 56

Proto-oncogenes can be converted to oncogenes by:

A) mutation
B) tumor suppressor genes
C) growth factors
D) transcription factors
E) infection by certain viruses

Question 57

You would not expect to find homeobox or homeobox-like genes in:

A) Drosophila
B) Arabidopsis
C) C. elegans
D) H. sapiens
E) E. coli

Question 58

What would be the consequence of removing a founder cell early in the development of Caenorhabditis ?

A) The organism would continue to develop normally.
B) The organism would develop normally but would be slightly smaller.
C) The organism would not develop at all.
D) The organism would be a hermaphrodite.
E) The structures that normally develop from that cell would be missing.

Question 59

Which of the following is characteristic of mosaic development?

A) The cells of the adult are very different from each other.
B) The fate of adult cells is predetermined in embryonic founder cells.
C) Adult cells are richly interspersed with proteins.
D) Embryonic cells have a wide range of possible developmental patterns.
E) Embryos have a wide range of morphologies, but all look identical as adults.

Question 60

The ____ is a functional region found in certain proteins that are important in development. It consists of 60 amino acids that form four helices.

A) homeobox
B) homeodomain
C) homeogene
D) homeochromosome
E) functional group

Question 61

Pattern formation includes signaling between cells, changes in cell shape, and cell apoptosis.

Question 62

Ras is a tumor suppressor gene that is mutated in cases of familial breast cancer.

Question 63

Describe how maternal effect genes and segmentation genes work together in the early embryonic stages of Drosophila .

Question 64

Mutations in segmentation genes cause one body part to be substituted for another body part.

Question 65

A morphogen is a chemical agent that affects the differentiation of cells and the development of form.

Question 66

Explain why apoptosis is a part of normal development.

Question 67

The Hox gene clusters in mouse are very similar to those identified in Drosophila .

Question 68

During the course of development, unspecialized cells become more committed to a specific fate.

Question 69

Briefly discuss how homeobox transcription factors and genes-containing homeodomains affect development.

Question 70

Scientists were able to produce induced pluripotent stem cells by introducing key homeotic factors into mature mouse fibroblasts and human skin cells.

Question 71

What characteristics of Drosophila melanogaster make it useful in molecular genetics studies?

Question 72

A chimera is an organism containing two or more kinds of genetically similar cells from different zygotes.

Question 73

Homeotic genes code for transcription factors.

Question 74

Adult stem cells are found only in adults.

Question 75

Each homeobox codes for a protein functional region that binds to a specific DNA sequence and thereby affects translation.

Question 76

Adult stem cells in the brain are totipotent and differentiate into neurons and glial cells.

Question 77

Describe the relationship between proto-oncogenes and oncogenes.

Question 78

What is the difference between a totipotent stem cell and a pluripotent stem cell? How would you distinguish between them?

Question 79

In animals, somatic cell lines are those that will undergo meiosis, differentiate into gametes, and be set aside early in development.

Question 80

One way RNA interference molecules work is by selectively cleaving DNA molecules that have sequences complementary to small RNA molecules.