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

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)...

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

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

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

The pattern of embryonic development in which only the cells lacking yolk subsequently undergo cleavage is called  A) arcadian development,...

Among these choices, the largest cell involved in frog reproduction is

Among these choices, the largest cell involved in frog reproduction is A) the spermatozoon. B) the ovum. C) a blastomere in the vegetal pole. D)...

In a developing frog embryo, most of the yolk is

In a developing frog embryo, most of the yolk is  A) located near the animal pole. B) located near the vegetal pole. C) found within the cleavage...

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) accept as many...

A human blastomere is

A human blastomere is  A) an embryonic cell that is much smaller than the ovum. B) an embryonic structure that includes a fluid-filled cavity. C)...

Compared to sea urchin eggs, those of mammals

Compared to sea urchin eggs, those of mammals  A) complete the fertilization process more rapidly. B) have not already completed meiosis at...

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

In mammalian eggs, the receptors for sperm are found in the  A) fertilization membrane. B) zona pellucida. C) cytosol of the egg. D) nucleus...

Fertilization normally

Fertilization normally  A) reinstates diploidy. B) follows gastrulation. C) is required for parthenogenesis. D) merges two diploid cells into...

In mammals, the nuclei resulting from the union of the sperm and the egg are first truly diploid at the end of the

In mammals, the nuclei resulting from the union of the sperm and the egg are first truly diploid at the end of the  A) acrosomal reaction. B)...

In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions, the

In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions, the  A) acrosomal reaction would be blocked. B) fusion...

In sea urchins, the "fast block" and the longer lasting "slow block" to polyspermy, respectively, are

In sea urchins, the "fast block" and the longer lasting "slow block" to polyspermy, respectively, are  A) the acrosomal reaction and the formation...

The cortical reaction functions directly in the

The cortical reaction functions directly in the  A) formation of a fertilization envelope. B) production of a fast block to polyspermy. C)...

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

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences?  A) first cell division ?...

In a newly fertilized egg, the vitelline layer

In a newly fertilized egg, the vitelline layer  A) opens the egg's nuclear membrane to allow haploid sperm DNA to enter. B) hardens to form...

The vitelline layer of the sea urchin egg

The vitelline layer of the sea urchin egg  A) is outside of the fertilization membrane. B) releases calcium, which initiates the cortical...

During fertilization, the acrosomal contents

During fertilization, the acrosomal contents  A) block polyspermy. B) help propel more sperm toward the egg. C) digest the protective jelly...

Contact of a sea urchin egg with signal molecules on sperm causes the egg to undergo a brief

Contact of a sea urchin egg with signal molecules on sperm causes the egg to undergo a brief  A) mitosis. B) membrane depolarization. C)...

A reproductive difference between sea urchins and humans is

A reproductive difference between sea urchins and humans is  A) the sea urchin egg completes meiosis prior to fertilization, but meiosis in...

A human zygote undergoes its first cell division

A human zygote undergoes its first cell division  A) 5 seconds after fertilization. B) 30 minutes after fertilization. C) 90 minutes after...

A sea urchin zygote undergoes its first cell division

A sea urchin zygote undergoes its first cell division  A) 5 seconds after fertilization. B) 30 minutes after fertilization. C) 90 minutes after...

The formation of the fertilization membrane requires an increase in the availability of

The formation of the fertilization membrane requires an increase in the availability of  A) bicarbonate ions. B) calcium ions. C) hydrogen...

Even in the absence of sperm, metabolic activity in an egg can be artificially activated by

Even in the absence of sperm, metabolic activity in an egg can be artificially activated by  A) abnormally high levels of carbonic acid in...

Contact of a sperm with signal molecules in the coat of an egg causes the sperm to undergo

Contact of a sperm with signal molecules in the coat of an egg causes the sperm to undergo  A) mitosis. B) depolarization. C) apoptosis. D)...

Fertilization of an egg without activation is most like

Fertilization of an egg without activation is most like  A) placing the key in the ignition of a car but not starting the engine. B) resting...

As an embryo develops, new cells are produced as the result of

As an embryo develops, new cells are produced as the result of  A) differentiation. B) preformation. C) cell division. D) morphogenesis. E)...

The structure of the Drosophila gene called Tinman is similar to a gene in humans that also

The structure of the Drosophila gene called Tinman is similar to a gene in humans that also  A) promotes ear development. B) specifies the...

Which statement about human reproduction is false?

Which statement about human reproduction is false?  A) Fertilization occurs in the oviduct. B) Effective hormonal contraceptives are currently...

For which of the following is the number the same in spermatogenesis and oogenesis?

For which of the following is the number the same in spermatogenesis and oogenesis?  A) interruptions in meiotic divisions B) functional gametes...

Which of the following is a true statement?

Which of the following is a true statement?  A) All mammals have menstrual cycles. B) The endometrial lining is shed in menstrual cycles but...

During human gestation, rudiments of all organs develop

During human gestation, rudiments of all organs develop  A) in the first trimester. B) in the second trimester. C) in the third trimester. D)...

Peaks of LH and FSH production occur during

Peaks of LH and FSH production occur during  A) the menstrual flow phase of the uterine cycle. B) the beginning of the follicular phase of...

Which of the following is not properly paired?

Which of the following is not properly paired?  A) seminiferous tubule?cervix B) Sertoli cells?follicle cells C) testosterone?estradiol D) scrotum?labia...

In male mammals, excretory and reproductive systems share

In male mammals, excretory and reproductive systems share  A) the testes. B) the urethra. C) the seminal vesicle. D) the vas deferens. E)...

Which of the following characterizes parthenogenesis?

Which of the following characterizes parthenogenesis?  A) An individual may change its sex during its lifetime. B) Specialized groups of...

Imagine that a woman is in the final week of her pregnancy. Her doctor gives her an injection of oxytocin. The likely result of this is that the pregnant woman would

Imagine that a woman is in the final week of her pregnancy. Her doctor gives her an injection of oxytocin. The likely result of this is that the pregnant...

You observe vertebrate organisms with parthenogenetic reproduction, internal development of embryos, and the lack of parental care for its young. Based on this information, you should categorize these organisms as

You observe vertebrate organisms with parthenogenetic reproduction, internal development of embryos, and the lack of parental care for its young. Based...

So-called "combination" birth control pills function in contraception by

So-called "combination" birth control pills function in contraception by  A) inhibiting the release of GnRH, FSH, and LH. B) irritating the...

For lactation to take place, the synthesis of breast milk and its release from the mammary gland, respectively, are caused by

For lactation to take place, the synthesis of breast milk and its release from the mammary gland, respectively, are caused by  A) testosterone...

Time-release progesterone implants function in contraception by

Time-release progesterone implants function in contraception by  A) increasing the frequency of ovulation. B) thickening the cervical and uterine...

A vasectomy

A vasectomy  A) eliminates spermatogenesis. B) eliminates testosterone synthesis. C) prevents implantation of an embryo. D) prevents sperm...

Tubal ligation

Tubal ligation  A) reduces the incidence of ovulation. B) prevents fertilization by preventing sperm from entering the uterus. C) prevents implantation...

Two contraceptive methods that are generally irreversible and which block the gametes from moving to a site where fertilization can occur are

Two contraceptive methods that are generally irreversible and which block the gametes from moving to a site where fertilization can occur are  A)...

The use of birth control pills (oral contraceptives)

The use of birth control pills (oral contraceptives)  A) reduces the incidence of ovulation. B) prevents fertilization by keeping the sperm...

Among these contraception methods, the highest risk of accidental pregnancy accompanies

Among these contraception methods, the highest risk of accidental pregnancy accompanies  A) the use of a diaphragm. B) the use of a condom. C)...

The "immunotolerance" of a pregnant woman toward her unborn child is the result of

The "immunotolerance" of a pregnant woman toward her unborn child is the result of  A) the tenacity with which the unborn child's immune system...

In excreted urine, a reliable "marker" that a pregnancy has initiated is

In excreted urine, a reliable "marker" that a pregnancy has initiated is A) progesterone. B) estrogen. C) follicle-stimulating hormone. D) chorionic...

The thin layer of the developing embryo which secretes a hormone that keeps the corpus luteum functioning is the

The thin layer of the developing embryo which secretes a hormone that keeps the corpus luteum functioning is the  A) cervix. B) endometrium. C)...