Genetics and Developmental Biology

Fertilization normally

Fertilization normally

Fertilization normally     
A) follows gastrulation.
B) is required for parthenogenesis.
C) precedes ovulation.
D) merges two diploid cells into one haploid cell.
E) reinstates diploidy.

ppk   5316   1 Reply

bio_man

In mammalian eggs, the receptors for sperm are found in the

In mammalian eggs, the receptors for sperm are found in the

In mammalian eggs, the receptors for sperm are found in the

A) cytosol of the egg.
B) nucleus of the egg.
C) zona pellucida.
D) fertilization membrane.
E) mitochondria of the egg.

ppk   4475   1 Reply

bio_man

At the moment of sperm penetration, human eggs

At the moment of sperm penetration, human eggs

At the moment of sperm penetration, human eggs     
A) have used flagellar propulsion to move from the ovary to the oviduct.
B) have a paper-thin cell of calcium carbonate that prevents desiccation.
C) are still located

ppk   2231   2 Replies

bio_man

As cleavage continues during frog development, the size of the blastomeres

As cleavage continues during frog development, the size of the blastomeres

As cleavage continues during frog development, the size of the blastomeres     
A) decreases as the number of the blastomeres decreases.
B) increases as the number of the blastomeres stays the same.
C) increases as the

ppk   2167   1 Reply

bio_man

A human blastomere is

A human blastomere is

A human blastomere is     
A) an embryonic structure that includes a fluid-filled cavity.
B) that part of the acrosome that opens the egg's membrane.
C) a cell that contains a (degenerating) second polar body.

ppk   2227   1 Reply

bio_man

Compared to sea urchin eggs, those of mammals

Compared to sea urchin eggs, those of mammals

Compared to sea urchin eggs, those of mammals     
A) have not already completed meiosis at the time of ovulation.
B) have no requirement for the cortical reaction.
C) complete the fertilization process more rapidly.
D)

ppk   1388   1 Reply

bio_man

If gastrulation was blocked by an environmental toxin, then

If gastrulation was blocked by an environmental toxin, then

If gastrulation was blocked by an environmental toxin, then   
A) the blastula would not be formed.
B) the blastopore would form above the gray crescent in the animal pole.
C) cleavage would not occur in the zygote.
D) fertil

ppk   2739   2 Replies

ppk

In sea urchins, the "fast block" and the longer lasting "slow block" to polyspe

In sea urchins, the "fast block" and the longer lasting "slow block" to polyspe

 In sea urchins, the "fast block" and the longer lasting "slow block" to polyspermy, respectively, are     
A) the jelly coat of the egg and the vitelline membrane.
B) inactivation of the sperm acrosome.

ppk   2817   1 Reply

bio_man

From earliest to latest, the overall sequence of early development proceeds in w

From earliest to latest, the overall sequence of early development proceeds in w

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

A) acrosomal reaction ? cortical reaction ? synthesis of embryo's DNA begins ? first cell division

ppk   3015   1 Reply

bio_man

During the early part of the cleavage stage in frog development, the rapidly dev

During the early part of the cleavage stage in frog development, the rapidly dev

During the early part of the cleavage stage in frog development, the rapidly developing cells     
A) skip the mitosis phase of the cell cycle.
B) skip the cytokinesis phase of the cell cycle.
C) rapidly increase the volume a

ppk   2231   1 Reply

bio_man

The outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate e

The outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate e

The outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate embryo is   
A) ectoderm ? mesoderm ? endoderm.
B) endoderm ? mesoderm ? ectoderm.
C) mesoderm ? endoderm ? ectoderm.
D) endoderm ? ectoderm

ppk   3550   1 Reply

bio_man

In frog embryos, the blastopore becomes the

In frog embryos, the blastopore becomes the

In frog embryos, the blastopore becomes the     
A) anus.      B) ears.      C) nose.      D) mouth.      E) eyes.

ppk   2454   1 Reply

bio_man

An open space within the gastrula is the

An open space within the gastrula is the

An open space within the gastrula is the   
A) endoderm.
B) mesoderm.
C) ectoderm.
D) neural crest cells.
E) archenteron.

ppk   2875   1 Reply

bio_man

Although it contributes no cells to the embryo, the formation of the primitive s

Although it contributes no cells to the embryo, the formation of the primitive s

Although it contributes no cells to the embryo, the formation of the primitive streak is guided by the structure known as the   

A) neural crest.      B) endoderm.      C) hypoblast.    &n

ppk   1540   1 Reply

bio_man

Thalidomide, now banned for use as a sedative in pregnancy, was used in the earl

Thalidomide, now banned for use as a sedative in pregnancy, was used in the earl

Thalidomide, now banned for use as a sedative in pregnancy, was used in the early 1960s by many women in their first trimester of pregnancy. Some of these women gave birth to children with arm and leg deformities, suggesting that the drug most likely

ppk   1983   1 Reply

bio_man

Animal development compares to plant development in that

Animal development compares to plant development in that

Animal development compares to plant development in that   
A) plant cells, but not animal cells, undergo convergent extension.
B) animal cells, but not plant cells, migrate during morphogenesis.
C) plant cells and animal cells mi

ppk   2189   1 Reply

bio_man

In a frog embryo, gastrulation

In a frog embryo, gastrulation

In a frog embryo, gastrulation     
A) occurs along the primitive streak in the animal hemisphere.
B) is impossible because of the large amount of yolk in the ovum.
C) proceeds by involution as cells roll over the lip o

ppk   2868   1 Reply

duddy

In a developing frog embryo, most of the yolk is

In a developing frog embryo, most of the yolk is

In a developing frog embryo, most of the yolk is     
A) located near the vegetal pole.
B) distributed equally throughout the embryo.
C) found within the blastocoels.
D) found within the cleavage furrow.
E) lo

ppk   2230   1 Reply

duddy

Cells move to new positions as an embryo establishes its three germ tissue laye

Cells move to new positions as an embryo establishes its three germ tissue laye

Cells move to new positions as an embryo establishes its three germ tissue layers during     
A) cleavage.
B) determination.
C) fertilization.
D) gastrulation.
E) induction.

ppk   2896   1 Reply

duddy

Which of the following correctly displays the sequence of developmental mileston

Which of the following correctly displays the sequence of developmental mileston

 Which of the following correctly displays the sequence of developmental milestones?     
A) morula ? cleavage ? gastrula ? blastula
B) cleavage ? morula ? blastula ? gastrula
C) cleavage ? gastrula ? morula ? blastula
D

ppk   3067   1 Reply

duddy

Meroblastic cleavage occurs in

Meroblastic cleavage occurs in

 Meroblastic cleavage occurs in   
A) humans, but not sea urchins or birds.
B) birds, but not sea urchins or humans.
C) both sea urchins and birds, but not humans.
D) sea urchins, but not humans or birds.
E) both h

ppk   2950   1 Reply

duddy

An embryo with meroblastic cleavage, extraembryonic membranes, and a primitive s

An embryo with meroblastic cleavage, extraembryonic membranes, and a primitive s

An embryo with meroblastic cleavage, extraembryonic membranes, and a primitive streak must be that of   
A) an insect.
B) a sea urchin.
C) an amphibian.
D) a bird.
E) a fish.

ppk   2316   1 Reply

duddy

The vegetal pole of the zygote differs from the animal pole in that

The vegetal pole of the zygote differs from the animal pole in that

The vegetal pole of the zygote differs from the animal pole in that     
A) the blastomeres originate only in the vegetal pole.
B) the polar bodies bud from this region.
C) the vegetal pole cells undergo mitosis but not cytok

ppk   2332   1 Reply

duddy

The pattern of embryonic development in which only the cells lacking yolk subseq

The pattern of embryonic development in which only the cells lacking yolk subseq

The pattern of embryonic development in which only the cells lacking yolk subsequently undergo cleavage is called     

A) holoblastic development, which is typical of amphibians.
B) arcadian development, which is typic

ppk   2042   1 Reply

duddy

The small portion of the embryo that will become its dorsal side develops from t

The small portion of the embryo that will become its dorsal side develops from t

The small portion of the embryo that will become its dorsal side develops from the     
A) gray crescent.
B) morula.
C) blastocoel.
D) primitive streak.
E) archenteron.

ppk   1668   1 Reply

kellyk412

In all vertebrate animals, development requires

In all vertebrate animals, development requires

In all vertebrate animals, development requires     
A) an amnion.
B) a large supply of yolk.
C) a primitive streak.
D) an aqueous environment.
E) extraembryonic membranes

ppk   2812   1 Reply

bio_man

To meet a zygote's metabolic and developmental requirements,

To meet a zygote's metabolic and developmental requirements,

 To meet a zygote's metabolic and developmental requirements, 
A) the haploid DNA in the nucleus must be transcribed.
B) paternal RNA and maternal proteins must be present.
C) maternal RNA and maternal proteins must be prese

ppk   2628   1 Reply

bio_man

Select the choice that correctly associates the organ with its embryonic sources

Select the choice that correctly associates the organ with its embryonic sources

63) Select the choice that correctly associates the organ with its embryonic sources.     
A) skin?endoderm and mesoderm
B) anterior pituitary gland?mesoderm and endoderm
C) thyroid gland?mesoderm and ectoderm

ppk   1623   1 Reply

bio_man

The first cavity formed during sea urchin development is the

The first cavity formed during sea urchin development is the

The first cavity formed during sea urchin development is the     
A) anus.      B) blastopore.      C) blastocoel.      D) mouth.

ppk   1611   1 Reply

bio_man

Human trophoblasts

Human trophoblasts

Human trophoblasts     
A) form the inner cell mass.
B) are the precursors of the mesoderm.
C) form from ectoderm.
D) are of maternal origin and function in embryo gas exchange.
E) are of embryonic origin and

ppk   665   1 Reply

bio_man

Animal cells that are present only for a brief developmental phase will, follow

Animal cells that are present only for a brief developmental phase will, follow

Animal cells that are present only for a brief developmental phase will, following completion of that phase, undergo     

A) re-differentiation.
B) diapause.
C) meiosis.
D) apoptosis
E) oxidative phosphorylati

ppk   1962   1 Reply

bio_man

The developmental precursors to the gonadal tissues of C. elegans uniquely conta

The developmental precursors to the gonadal tissues of C. elegans uniquely conta

 The developmental precursors to the gonadal tissues of C. elegans uniquely contain
A) proteins of maternal origin.
B) P granules of mRNA and protein.
C) high concentrations of potassium ions.
D) haploid proteins.
E) T tubule

ppk   1138   1 Reply

bio_man

Two primary factors in shaping the polarity of the body axes in chick embryos ar

Two primary factors in shaping the polarity of the body axes in chick embryos ar

 Two primary factors in shaping the polarity of the body axes in chick embryos are   
A) gravity and pH.
B) location of sperm penetration and cortical reaction.
C) moisture and mucus.
D) salt gradients and membrane potentials

ppk   1733   1 Reply

bio_man

The least amount of yolk would be found in the egg of a

The least amount of yolk would be found in the egg of a

The least amount of yolk would be found in the egg of a   
A) eutherian (placental) mammal.
B) fish.
C) reptile.
D) bird.
E) frog.

ppk   1719   1 Reply

bio_man

At the time of implantation, the human embryo is called a

At the time of implantation, the human embryo is called a

At the time of implantation, the human embryo is called a     
A) blastocyst.      B) gastrula.      C) somite.      D) zygote.      E) fetus.

ppk   1755   1 Reply

bio_man

Uterine implantation due to enzymatic digestion of the endometrium is initiated

Uterine implantation due to enzymatic digestion of the endometrium is initiated

Uterine implantation due to enzymatic digestion of the endometrium is initiated by the     
A) chorion.
B) trophoblast.
C) endoderm.
D) mesoderm.
E) inner cell mass.

ppk   2998   1 Reply

bio_man

Changes in both cell shape and cell position occur extensively during

Changes in both cell shape and cell position occur extensively during

Changes in both cell shape and cell position occur extensively during     
A) gastrulation, organogenesis, and cleavage.
B) gastrulation, but not organogenesis or cleavage.
C) cleavage, but not gastrulation or organogen

ppk   3266   1 Reply

bio_man

The vertebrate ectoderm is the origin of the

The vertebrate ectoderm is the origin of the

The vertebrate ectoderm is the origin of the     
A) nervous system.
B) kidneys.
C) heart.
D) liver.
E) pancreas.

ppk   3166   1 Reply

bio_man

The arrangement of organs and tissues in their characteristic places in 3-D spac

The arrangement of organs and tissues in their characteristic places in 3-D spac

The arrangement of organs and tissues in their characteristic places in 3-D space defines     
A) determination.
B) induction.
C) pattern formation.
D) organogenesis.
E) differentiation.

ppk   2132   1 Reply

biolove

The nematode Caenorhabditis elegans

The nematode Caenorhabditis elegans

The nematode Caenorhabditis elegans   
A) has only a single chromosome, which has been fully sequenced.
B) has about 1,000 genes, each of which has been fully sequenced.
C) is composed of about 1,000 cells, in which the deve

ppk   867   1 Reply

biolove