Deck 53: Animal Development

Question 1

What factor has the strongest influence on the cleavage pattern of an embryo?

A)viscosity of albumin
B)amount of yolk
C)maturity of cytoplasm
D)oxygen in air

Answer 1

B

Question 2

The developing embryo of reptiles, birds, and mammals is encased in the fluid-filled ________ membrane.

A)amniotic
B)embryonic
C)chorionic
D)yolk sac

Answer 2

A

Question 3

What event initiates development?

A)fertilization
B)cleavage
C)gastrulation
D)organogenesis

Answer 3

A

Question 4

What pattern of cleavage is characteristic of mammals?

A)holoblastic cleavage with eggs containing little or no yolk
B)some yolk, and cleavage resulting in vegetal and animal poles
C)meroblastic cleavage with eggs containing almost entirely yolk
D)holoblastic cleavage with eggs containing very little yolk, but with the inner cell mass concentrated at one pole

Question 5

In mammals, embryonic cells form an inner cell mass that will become the body of the embryo and a layer of surrounding cells that will become the chorionic membrane and placenta.What are these surrounding cells called?

A)blastocoel
B)yolk
C)blastodisc
D)trophoblast

Question 6

What is the period of rapid cell division in which the embryo does not increase in overall size?

A)syngamy
B)cleavage
C)neurulation
D)meiosis

Question 7

A couple conceives at the beginning of January.During which month will their child be undergoing organogenesis?

A)January
B)February
C)March
D)April

Question 8

A couple conceives a child on January 1st.Which day falls within the period of somitogenesis?

A)January 3^rd
B)January 7^th
C)January 17^th
D)January 31^st

Question 9

The placenta protects the developing fetus from harmful substances like alcohol or drugs.

Question 10

What is the main role of human chorionic gonadotropin?

A)It stimulates the release of oxytocin from the mother's pituitary.
B)It allows the mother to realize she is pregnant, via pregnancy tests.
C)It is similar to FSH in stimulating follicle development.
D)It maintains the corpus luteum.

Question 11

What structure is formed from both fetal and maternal tissue?

A)chorion
B)placenta
C)yolk sac
D)amnion

Question 12

The human placenta is formed by the interaction of uterine tissue and what extraembryonic tissue?

A)amnion
B)embrion
C)chorion
D)yolk sac

Question 13

What factors stimulate uterine contractions and birth?

A)FSH and prostaglandins
B)LH and prostaglandins
C)oxytocin and prostaglandins
D)prolactin and prostaglandins

Question 14

When the placenta is delivered, what event allows secretion of prolactin and milk production?

A)a surge of adrenaline and endorphins
B)sudden drop in progesterone and estradiol
C)gradual drop in oxytocin
D)sudden rise in FSH and LH

Question 15

The hollow crater formed during gastrulation is known as

A)acrosome
B)archenteron
C)morula
D)cleavage furrow

Question 16

What would be the result of a mutation that reduces the amount of acrosomal enzymes?

A)Male infertility due to inability of the sperm to tunnel through the blastula.
B)Male infertility due to inability of the sperm to tunnel through the zona pellucida.
C)Female infertility due to blockage of sperm from tunneling through the allantois.
D)Female infertility due to blockage of sperm from tunneling through the archenteron.

Question 17

New mothers may benefit from the aid of lactation consultants when learning to breastfeed.These consultants give advice on technique, and help the mother to feel relaxed and confident.What hormone is associated with calm, warm emotions and is also critical for the milk let-down reflex?

A)prolactin
B)estradiol
C)oxytocin
D)mammotropin

Question 18

What is the term for segmented blocks of tissue that form on either side of the notochord and are added sequentially?

A)blastopores
B)gastropores
C)somites
D)amniotic cells

Question 19

Which of the following leads to the occurrence of vertebrate sense organs?

A)both adrenal medullary cells and sympathetic neurons derive from the neural crest
B)neural crest cells form both neurons that carry messages and cartilaginous bars
C)the neural crest and associated sensory ganglia
D)formation of the endoderm

Question 20

Certain groups of cells move inward from the surface of the blastula in a carefully orchestrated migration called

A)blastulation
B)archenteron formation
C)morula formation
D)gastrulation

Question 21

The head of a sperm is capped with an organelle that contains glycoprotein-digesting enzymes.What is this organelle called?

A)zona pellucida
B)acrosome
C)granulosa
D)blastula

Question 22

Which of the following activates the egg?

A)entrance of sperm into the zona pellucida
B)contact of sperm with the outside of the zona pellucida
C)contact of sperm with the vitelline envelope
D)fusion of sperm and egg membranes

Question 23

What stimulates milk production in mammary alveoli?

A)oxytocin
B)prolactin
C)chorionic gonadotropin
D)progesterone

Question 24

Which of the following animals undergoes true holoblastic cleavage?

A)butterfly
B)ant
C)snail
D)tuna

Question 25

In 1999, researchers found that they could create hybrid embryos between two species of sea urchin that had been separated for 10 million years.By treating eggs to remove the jelly coat, the sperm of the other species was able to fertilize.What step of the fertilization process is normally blocked, preventing hybridization between these species?

A)Sperm penetration
B)Membrane fusion
C)Egg activation
D)Nuclear fusion

Question 26

Your research project involves sea cucumbers, a poorly-understood group of echinoderms.You are trying to determine whether they block polyspermy by changing membrane potential like sea urchins do.In the chart below, you have counted the number of embryos that complete normal development after fertilization in either normal or low-sodium artificial sea water (ASW), for each of three sets of experiments.Looking over your data, what do you conclude?

A)Sea cucumbers appear not to block polyspermy the same way as sea urchins, which use an influx of Na⁺ that changes the membrane potential.
B)Sea cucumbers appear not to block polyspermy the same way as sea urchins, which use an outflow of Na⁺ that changes the membrane potential.
C)Sea cucumbers appear to block polyspermy the same way as sea urchins, via an influx of Na⁺ that changes the membrane potential.
D)Sea cucumbers appear to block polyspermy the same way as sea urchins, via an outflow of Na⁺ that changes the membrane potential.

Question 27

What are the two components of the human placenta?

A)chorionic frondosum and chorionic villus
B)chorionic frondosum and decidua basalis
C)decidua basalis and chorionic villus
D)chorionic villus and endometrium

Question 28

Removing some fluid from directly around a developing human fetus is performed by inserting a long needle into the belly of the female patient.What extraembryonic membrane will be punctured in this process?

A)chorion
B)amnion
C)chorionic villi
D)external epithelium of mother

Question 29

In human females, what process causes milk production?

A)Stimulation of the alveoli of the mammary glands by prolactin from the anterior pituitary gland.
B)Stimulation of the alveoli of the mammary glands by oxytocin from the anterior pituitary gland.
C)Stimulation of the alveoli of the mammary glands by prolactin from the posterior pituitary gland.
D)Stimulation of the alveoli of the mammary glands by oxytocin from the posterior pituitary gland.

Question 30

What actually begins the uterine contractions which leads to giving birth?

A)oxytocin
B)prolactin
C)estrogen
D)prostaglandins

Question 31

What is the role of cleavage in the early embryo?

A)produce bigger cells
B)produce many cells
C)extrude polar bodies
D)make the embryo larger

Question 32

How is brain growth in humans different from other mammals?

A)In humans brain growth is complete by the third trimester.
B)In humans brain growth stops at birth.
C)Human growth is not allometric.
D)In humans brain growth continues after birth.

Question 33

In this diagram, which of the following numbers represents the actual event of egg activation?

A)I
B)II
C)III
D)IV

Question 34

Egg activation by sperm entry is associated with a sudden increase in protein synthesis.What must be true of these proteins?

A)They are histone proteins.
B)They are small peptides.
C)They are from maternal mRNAs.
D)They are from paternal mRNAs.

Question 35

Working in an experimental fertility clinic, a researcher removes one cell from an 8-cell stage chimpanzee embryo.What is the likely result?

A)Both the cell and the blastula will die.
B)All the cells are already committed and therefore are not viable.
C)The embryo from which the cell was removed still remains viable and can form a normal chimp.

Question 36

In the diagram, which of the following is true?

A)Both diagrams show developmental sequences occurring in the same animal.
B)Both diagrams show blastulae.
C)Diagram II shows gastrulation in a bird.
D)Diagram I shows gastrulation in a frog.

Question 37

Which of the following animals undergoes rotational cleavage?

A)echinoderms
B)annelids
C)amphibians
D)mammals

Question 38

What is the first milk that is produced after birth called?

A)prolactase
B)colostrum
C)hCG
D)chorionic lactase

Question 39

You are studying the development of a poorly-understood species at the 8-cell stage.You use a laser to zap away a certain one of the eight cells, and discover that part of the gut is missing once the embryos finish development.Your colleague, who is working on a different species, uses the laser to blast away one of the cells in her embryos, zapping each of the possible cells in a set of eight experiments.However, when the embryos finish development, every one is perfectly normal! What can you conclude about the two species?

A)The first species has regulative development, the second has non-regulative development.
B)The first species has non-regulative development, the second has regulative development.
C)Both species have regulative development.
D)Both species have non-regulative development.

Question 40

A research group claims that they have discovered microscopic fossilized embryos, including some at the blastula stage, but other researchers are skeptical.Finally, one student develops a technique for splitting the embryos in half to reveal the substructure.Cutting open the first blastocyst embryo, the student is very excited."It is a blastula!" she shouts,"Look, you can see the ____________________ inside!"

A)granulosa cells
B)hollow blastocoel
C)archenteron
D)neural tube

Question 41

In the famous Spemann-Mangold experiment, what detail was crucial to understanding the result?

A)transplanting the new dorsal lip cells to the same dorsal lip location in the second embryo
B)using genetically different donor and host frogs
C)placing the dorsal lip cells deep inside the archenteron
D)treating the dorsal lip cells with morphogens before transplanting them

Question 42

In 1998, researchers found that genes similar to the Drosophila gene tinman are necessary for heart development in vertebrates.What can you conclude about the ancient bilaterian ancestor of insects and vertebrates over 500 million years ago?

A)The fly species that eventually gave rise to vertebrates used tinman to make a heart.
B)Something about heart development requires a gene to have a tinman-like sequence, but the vertebrate and invertebrate genes arose by convergent evolution -- so the ancestor had a similar but not homologous gene.
C)The ancient ancestor lacked a heart, but already had a tinman-like gene.
D)The ancestor had a heart-like structure that was specified by a tinman-like gene.

Question 43

In a normal mammalian birth, how does the body guarantee that birth proceeds to completion?

A)Via positive feedback -- stretching of the uterus by the descending fetus induces release of oxytocin from the posterior pituitary causing even stronger uterine contractions.
B)Via negative feedback -- stretching of the uterus by the descending fetus induces release of FSH and LH from the posterior pituitary causing even stronger uterine contractions.
C)Via positive feedback -- stretching of the uterus by the descending fetus induces release of prolactin from the posterior pituitary causing even stronger uterine contractions.
D)Via negative feedback -- stretching of the uterus by the descending fetus induces release of prostaglandins from the posterior pituitary causing weaker uterine contractions.

Question 44

What problem would result from disrupted development of the allantois in both birds and mammals?

A)Inability to retain the fluid that surrounds the embryo
B)Inability to form the placenta
C)Problems with gas exchange
D)Loss of nutritional stores

Question 45

What is critical to the development of neural crest cell derivatives?

A)close contact with the notochord
B)regulation of N-cadherin
C)muscle development genes like muscle myosin
D)strong cellular adhesions that lock the cells in the place of their origin

Question 46

What would result if too many cells left the surface of the embryo to move inside during gastruation?

A)Too little endoderm, resulting in missing gut and organs
B)Too little ectoderm, resulting in missing nervous system or skin
C)Problems in muscle development
D)Too little protoderm, resulting in missing organs

Question 47

What basic developmental challenge is solved by the organizer?

A)enhancing migration of cells into the interior of the blastula
B)assigning developmental fates to cells along the anterior-posterior axis
C)creating an anterior-posterior axis by responding to maternally-deposited protein factors
D)creating a dorsal-ventral axis from a spherical ball of cells

Question 48

In blind cave fish, eyes do not form.However, transplantation of the lens from a closely-related aboveground fish into the optic cup of the cave fish induces eye development.What does this suggest about the loss of vision in the cave fish?

A)Primary induction of the eye fails in the cave fish because the lens lacks some critical signal.
B)Secondary induction of the eye fails in the cave fish because the lens lacks some critical signal.
C)Primary induction of the eye fails in the cave fish because the optic cup lacks the ability to receive some critical signal.
D)Secondary induction of the eye fails in the cave fish because the optic cup lacks the ability to receive some critical signal.

Question 49

What would result if an error inside gastrulation caused too few cells inside the archenteron?

A)Too little endoderm, resulting in missing gut and organs
B)Too little ectoderm, resulting in missing nervous system or skin
C)Problems in muscle development
D)Too little protoderm, resulting in missing organs

Question 50

The snakes include some rather short and some incredibly long species, with a variation from about 100 to over 300 vertebrae.What developmental mechanism is the best candidate for changing the number of vertebrae in evolution?

A)Changes in genes that lay down extracellular matrix in bone
B)Changes in genes necessary for neural crest development
C)Changes in genes that control mitosis
D)Changes in the somitogenesis clock

Question 51

To your chagrin, you and your labmate have discovered that you both labeled your petri dishes "A", "B", and "C".How can you distinguish your sea urchin gastrula embryos from her frog gastrula embryos?

A)Unlike frogs, sea urchins are deuterostomes which form the anus first and the mouth second.
B)Sea urchin cells migrate inside to form the archenteron, whereas in frogs proliferation of dividing cells from the dorsal lip populate the inside of the embryo.
C)Sea urchins have relatively yolk-poor eggs with similar animal and vegetal poles, whereas frogs have large amounts of yolk distinguishing the vegetal pole from the animal pole.
D)Frogs have an animal pole and vegetal pole, whereas urchins have only a vegetal pole.

Question 52

What human organ is formed from two genetically-different tissues?

A)neural crest
B)neural tube
C)placenta
D)uterus

Question 53

What would result if a defect in gastrulation caused too little mesoderm inside the embryo?

A)Too little endoderm, resulting in missing gut and organs
B)Too little ectoderm, resulting in missing nervous system or skin
C)Problems in muscle development
D)Too little protoderm, resulting in missing organs

Question 54

400 micrograms a day of folic acid are recommended for all women of child-bearing age.Folic acid helps prevent neural tube defects in the first weeks of pregnancy, before most women even realize they are pregnant (and almost half of pregnancies in the U.S.are unintended).Knowing that folic acid promotes proper neural tube closure, which disease can be prevented by this supplement?

A)Spina bifida -- the vertebrae are unfused and may allow the spinal cord to protrude outside the body
B)Horseshoe kidney -- the two kidneys are fused together across the midline
C)Esophageal atresia -- the esophagous ends in a pouch, unconnected to the stomach
D)Chronic otitis media -- frequent ear infections that can result from blocked eustachian tubes

Question 55

What prevents menstruation from occurring in the 10^th week when the corpus luteum regresses?

A)The follicle takes over secretion of hCG.
B)The follicle takes over secretion of estradiol and progesterone.
C)The placenta takes over secretion of estradiol and progesterone.
D)The cervix takes over secretion of oxytocin and prostaglandins.