Deck 19: Cellular Mechanisms of Development

Question 1

There are cases, particularly in fruit flies, in which a normal body part grows in the wrong spot.For instance, legs on the head growing instead of antennae, or a second set of wings behind the normal pair.What can explain this?

A)These are due to the reappearance of stem cells, which are totipotent.
B)These are due to misregulation of hormones from environmental contamination with pesticides.
C)These occur as a result of mutations in homeotic genes, which normally act to direct development along the anterior-posterior axis.
D)These naturally occur sometimes in animals that have metamorphic development, due to different organization of homeotic gene expression in larvae versus adults.

Answer 1

C

Question 2

In general, the blastomeres of this region form the endodermal tissues.

A)animal pole
B)vegetal pole
C)equator region
D)membrane

Answer 2

B

Question 3

In Drosophila, the cells created by cleavage contain different developmental signals from the egg called cytoplasmic

A)stem cells.
B)signals.
C)determinants.
D)junctions.

Answer 3

C

Question 4

Plants have special groups of self-renewing cells called

A)root cells.
B)chloroplasts.
C)cast cells.
D)meristems.

Question 5

A zygote is a fertilized egg formed by an egg and a sperm.The zygote undergoes many mitotic events as it develops into a solid ball of cells (ie, blastomeres) called a blastula.What changes occur in this early cleavage?

A)During the initial stages of cleavage, there is a tremendous increase in the number and size of blastomeres.
B)During the initial stages of cleavage, there is a tremendous decrease in the number and size of blastomeres.
C)During the initial stages of cleavage, there is a tremendous increase in the number of cells coupled with a decrease in the size of the cells composing the developing organism.
D)During the initial stages of cleavage, there is no increase in the number of cells of the developing organism, but the size of the cells increases.

Question 6

How did Briggs and King move the nuclei between cells?

A)with a glass pipet
B)with a dissecting needle
C)with a scalpel
D)with forceps

Question 7

A zygote initially divides into smaller cells, each called a

A)blastomere.
B)gastrula.
C)neurula.
D)cleavage cell.

Question 8

In general, the blastomeres of this region form the ectodermal tissues.

A)animal pole
B)vegetal pole
C)equator region
D)membrane

Question 9

Plants do not utilize the process of cell migration in their development.Instead plants utilize

A)the process of building themselves inwardly via the meristems present in the developing plant tissues.
B)the process of building themselves outwardly via the meristems present in the developing plant tissues.
C)the process of building themselves with epidermal tissues, which eventually become ground tissues, which can then begin the process of photosynthesis.
D)the process of building themselves by using their vascular tissues to form meristems, which promotes normal development in the plant.

Question 10

Which proteins are encoded by genes that code for the first mRNAs transcribed in Drosophila embryos?

A)gap and pair-rule proteins
B)dorsal proteins
C)bicoid and nanos proteins
D)caudal and hunchback proteins

Question 11

During this initial period of division in a zygote, there is no increase in the overall size of the embryo.

A)Mitosis
B)Cleavage
C)Meiosis
D)Fertilization

Question 12

Drosophila eggs acquire an initial asymmetry before fertilization as a result of

A)production of bicoid proteins in one end of the egg.
B)maternal DNA molecules being deposited in one end of the egg.
C)nurse cell migration to one end of the egg.
D)maternal mRNA being deposited in one end of the egg.

Question 13

Scientists attempted for many years to conduct nuclear transplants but failed.However, geneticists had success in cloning a sheep.They were successful because they

A)picked a cell very early in development.
B)replicated the blastomeres before insertion.
C)delayed transcription in the blastomeres.
D)treated the nucleus with sheep plasma before nuclear insertion.

Question 14

Very early in development, each cell is capable of expressing all its genes.This is referred to as

A)determination.
B)specification.
C)bipotential induction.
D)totipotency.

Question 15

In insects, the passage from one body form to another is called

A)pupation.
B)ecdysis.
C)metamorphosis.
D)transference.

Question 16

Many insects, like moths and flies, undergo complete metamorphosis.What would you predict about gene expression in these two kinds of insects?

A)The basic organization of homeotic genes is the same in both larvae and adult, but the expression of some other genes must be different.
B)Completely different sets of genes must be used in the development of larvae and the adult.
C)The order of homeotic genes along the body axis must be different in larvae and adult.
D)The same genes are expressed at each stage, but the age and number of cells accounts for the minor morphological differences.

Question 17

These are cell adhesion proteins that some cells use in the process of differentiation during development.

A)Cadherins
B)Glycospheres
C)Receptors
D)Phospholipids

Question 18

A fertilized egg is called a

A)zygote
B)ovule
C)oocyte
D)blastocyst

Question 19

What can be said about Drosophila development?

A)Paternal genes determine the initial course of development after fertilization.
B)Zygotic genes determine the initial course of development after fertilization.
C)Maternal genes determine the initial course of development after fertilization.
D)Syncytial blastoderm genes determine the initial course of development after fertilization.

Question 20

Briggs and King demonstrated nuclear transplantation in

A)sheep.
B)frogs.
C)pigs.
D)lizards.

Question 21

A muscle precursor cell expressing the MyoD1 gene would be considered to be

A)pluripotent.
B)determined.
C)differentiated.
D)totipotent.

Question 22

In contrast to the cell cycle of adult somatic cells, the dividing cells of an early embryo lack which cell cycle stage(s)?

A)M
B)S
C)G₁ and G₂
D)interphase

Question 23

Adult stem cells are usually

A)differentiated.
B)totipotent.
C)pluripotent.
D)multipotent.

Question 24

The Drosophila homeotic genes typically contain the homeobox.The homeobox is a sequence of 180 nucleotides.The number of amino acids coded for by this sequence is

A)30.
B)60.
C)90.
D)120

Question 25

In a 32-cell stage tunicate embryo, vegetal marginal cells that lack functional genes for both macho-1 and the FGF receptor would develop as what cell type?

A)mesenchyme
B)muscle
C)notochord
D)nerve cord

Question 26

The low success rate and age-related diseases associated with reproductive cloning is thought to be due to

A)genetic imprinting.
B)the age of the donor cell.
C)cell cycle problems.
D)large offspring syndrome (LOS).

Question 27

What was the most significant research finding that resulted from the successful cloning of Dolly?

A)The key to cloning success is to pick a donor cell from very early in development.
B)Cloned animals are capable of producing normal offspring.
C)The nucleus of a fully-differentiated cell can be reprogrammed to be totipotent.
D)Genetic imprinting, which occurs in adult reproductive tissue, can take months for sperm and years for eggs.

Question 28

Caenorhabditis elegans is an organism with exactly 959 somatic cells.This organism is a(n)

A)fruit fly.
B)earthworm.
C)nematode.
D)angiosperm.

Question 29

The finding that homeotic genes are present in both mammals and insects indicates that these genes must

A)control the same traits.
B)be on the same chromosomes.
C)have arisen very early in the evolutionary history of animals.
D)have developed independently and simultaneously.

Question 30

Overexpression of caudal in the early Drosophila embryo, at a level high enough to overcome inhibition by Bicoid protein, would

A)interfere with the development of anterior structures.
B)interfere with the development of posterior structures.
C)interfere with the development of both anterior and posterior structures.
D)have no effect since the cytoplasm has already been determined.

Question 31

Cells that are programmed to die, shrivel and shrink in a process called

A)apoptosis.
B)necrosis.
C)totipotency.
D)induction.

Question 32

A fly embryo that expresses the bicoid mutant phenotype

A)is genetically wild-type, but has a bicoid mutant mother.
B)is mutant for bicoid and has a bicoid mutant mother.
C)may be either genetically wild-type or mutant for bicoid, but definitely has a bicoid mutant mother.
D)can be either genetically wild-type or mutant for bicoid.The genotype of the mother cannot be determined from the information provided.

Question 33

What can be said about animal and vegetal poles?

A)When animal pole cells are cultured with vegetal pole cells, some of the animal pole cells become mesoderm.
B)When animal pole cells are cultured with vegetal pole cells, some of the vegetal pole cells become mesoderm.
C)Isolated animal cells develop as endoderm.
D)Isolated vegetal cells develop as ectoderm.

Question 34

Egg cells were combined with this cell type to form the cloned sheep named Dolly.

A)skin cells
B)sperm cells
C)mucous membrane cells
D)mammary cells

Question 35

The main difference between therapeutic cloning and reproductive cloning is that

A)in therapeutic cloning, embryonic stem cells are extracted from the blastocyst, while in reproductive cloning, the blastocyst is kept intact and implanted into a surrogate mother.
B)somatic cell nuclear transfer is used for therapeutic cloning, while gametic cell nuclear transfer is used in reproductive cloning.
C)unlike cells used for reproductive cloning, cells grown for therapeutic purposes do not display genetic imprinting problems.
D)unlike cells used for reproductive cloning, cells grown for therapeutic purposes do not require the destruction of embryos.

Question 36

What is the correct order of gene expression in the early Drosophila embryo?

A)pair-rule genes, gap genes, segment polarity genes
B)gap genes, pair-rule genes, segment polarity genes
C)gap genes, segment polarity genes, pair-rule genes
D)segment polarity genes, pair-rule genes, gap genes

Question 37

If one were to inject cytoplasm containing Bicoid into the middle of a Drosophila egg immediately prior to fertilization, the embryo would

A)try to form anterior structures in the middle of its body.
B)try to form posterior structures in the middle of its body.
C)not develop at all.
D)develop normally.

Question 38

Cells that die of injury usually swell and then burst.Their contents are released into the extracellular fluid.This form of cell death is referred to as

A)apoptosis.
B)necrosis.
C)toti-latency.
D)induction.

Question 39

If cells from a wing are transplanted to the leg prior to their determination, into what will they likely develop?

A)wing cells
B)leg cells
C)a mixture of wing and leg cells
D)cannot be determined

Question 40

If a Drosophila mother is mutant for dorsal, her embryos would

A)develop normally.
B)have a delay in the development of dorsal/ventral polarity.
C)lack dorsal structures.
D)lack ventral structures.

Question 41

The term neoplasia refers to cell accumulation.Neoplasia can be caused by

A)increased apoptosis.
B)decreased apoptosis.
C)blood clots.
D)cell membrane interactions.

Question 42

You have discovered a new gene similar to an integrin.If you misexpress this gene in the wrong tissue early in development, what is a likely phenotype?

A)migration into the wrong area
B)apoptosis
C)homeotic transformation
D)defects in anterior-posterior patterning

Question 43

Describe the apoptotic pathway in mammalian cells.

A)Apaf1 inhibits Bcl2, Caspase-8 or 9 is activated, caspases degrade cell components
B)Bcl2 activates Apaf1, Caspase-8 or 9 is inhibited, caspases degrade cell components
C)Apaf1 activates Bcl2, Caspase-8 or 9 is activated, caspases degrade cell components

Question 44

You created a worm that expresses a human Bcl-2 transgene, and you are crossing the transgene into a homozygous ced-9 mutant background.However, you inadvertantly used a clone of Bcl-2 with a mutation in the BH domain, which is essential for function.What results do you expect for the ced-9 mutants with the mutant Bcl-2 transgene?

A)131 cells will die.
B)All 1090 cells will die.
C)All 1090 cells will live.
D)959 cells will die.

Question 45

A mutation in a Hox gene typically results in

A)development of normal body parts in abnormal places.
B)faulty development of the cellular blastoderm.
C)cleavage disruption.
D)legs growing out of the head of a fly.

Question 46

In

A)131 cells always die.
B)all 1090 cells die.
C)all 1090 cells live.
C)elegans ced-9/ced-3 double mutants