Deck 21 (MR): Human Development and Genetics

Question 1

Which of the following statements are true of the placenta and fetal circulation (Select all that apply)?

A)The umbilical arteries carry oxygen and nutrients to the fetus.
B)The foramen ovale permits blood to flow from the left atrium to the right atrium.
C)The ductus venosus takes blood to the superior vena cava after bypassing the lungs.
D)The ductus arteriosus takes blood from the aorta to the pulmonary artery.
E)The placenta is made of both fetal and maternal tissue.
F) Fetal carbon dioxide is brought to the placenta by the umbilical vein.

Answer 1

The placenta is made of both fetal and maternal tissue.

Question 2

Which of the following statements are true of the placental hormones (Select all that apply)?

A)The chorion of the embryo produces hCG to maintain the corpus luteum during early pregnancy.
B)Contractions of the myometrium are inhibited by the estrogen produced by the placenta.
C)Estrogen and progesterone begin to stimulate milk production toward the end of pregnancy.
D)Progesterone is first produced by the corpus luteum,then by the placenta.
E)The secretion of FSH and LH by the anterior pituitary is inhibited by estrogen and progesterone.f.Relaxin increases the stretchiness of the ligaments of the pubic symphysis.

Answer 2

A,D,E,F

Question 3

Which of the following statements are true of dominant-recessive inheritance (Select all that apply)?

A)A heterozygous offspring will have the dominant characteristic in the phenotype.
B)A homozygous offspring will have the recessive characteristic in the phenotype.
C)If a recessive trait does not appear in a family for two generations,the gene for it is no longer present.
D)If Mom and Dad both have blue eyes,the chance for a child of theirs to have brown eyes is only 50%.
E)If Mom and Dad both have brown eyes,the chance for a child of theirs to have blue eyes is 50%.
F)A trait is considered dominant when it is more common (frequent)in a population than its recessive counterpart.

Answer 3

A

Question 4

Which of the following statements are true of the embryonic membranes (Select all that apply)?

A)The amniotic sac surrounds the fetus and contains fluid.
B)The yolk sac provides the first nutrients for the embryo.
C)The chorion will form the maternal part of the placenta.
D)The first fetal blood cells are made by the amnion.
E)The embryonic membranes are not part of the fetus,but are made of fetal tissue.f.The yolk sac becomes a cushion for the embryo.

Question 5

Which of the following statements are true of genes and chromosomes (Select all that apply)?

A)Chromosomes are made of DNA and protein; genes are made of DNA.
B)A homologous pair of chromosomes consists of maternal and paternal chromosomes with genes for the same traits.
C)A human diploid body cell has 23 pairs of autosomes.
D)The sex chromosomes are XX for women and YY for men.
E)The DNA for a gene is the sequence of bases in the triplets for the amino acids that make up the protein that the gene is the code for.
F)The genome of a species is the number of chromosomes in one cell.

Question 6

Which of the following statements are true of the primary germ layers of the embryo (Select all that apply)?

A)The ectoderm gives rise to the nervous system.
B)Mesoderm forms most of the liver and pancreas.
C)Bones come primarily from endoderm.
D)The lungs are epithelial tissue from the ectoderm.
E)The stomach lining is an inside surface,and is of endodermal origin.
F)Most organs have tissues from all three germ layers.

Question 7

Which of the following statements are true of sex-linked inheritance (Select all that apply)?

A)The Y chromosome has more genes than does the X chromosome,and they are all dominant.
B)A woman with one gene for a sex-linked trait is a carrier of the trait.
C)The dominant gene on the Y chromosome is expressed when the corresponding gene on the X chromosome is missing.
D)The dominant gene on the Y chromosome is expressed when the corresponding gene on the X chromosome is recessive.
E)Men can be carriers only if the gene for the trait on the Y chromosome is recessive.f.A daughter acquires a sex-linked trait from both parents,but a son acquires such a trait only from his mother.

Question 8

Which of the following statements are true of fertilization and embryonic development (Select all that apply)?

A)Fertilization usually takes place within the body of the uterus.
B)Implantation usually occurs 5 to 8 hours after fertilization.
C)The zygote has the diploid number of chromosomes and begins to divide by mitosis.
D)The first 18 weeks of human development are the embryonic phase.
E)In fertilization,the tail of the sperm cell creates an opening in the egg cell membrane. f.The cells of an 8-cell embryo are still very similar to one another.
G)The outer layer of the blastocyst will become the embryo.
H)Cell divisions of the zygote are collectively called cleavage.

Question 9

Which of the following statements are true of labor and delivery (Select all that apply)?

A)The hormone oxytocin from the anterior pituitary promotes strong contractions of the myometrium.
B)The uterine cervix dilates during the first stage of labor.
C)The amniotic sac ruptures during the second stage of labor.
D)If the fetus is positioned sideways,the third stage of labor will be prolonged.
E)The placenta is delivered soon after the delivery of the infant.
F)Decreasing progesterone at the end of gestation increases the contractility of the myometrium.

Question 10

Which of the following statements are true of the infant at birth (Select all that apply)?

A)The lungs are expanded by the first breaths and pulmonary circulation increases.
B)The foramen ovale between the ventricles is closed.
C)The ductus arteriosus dilates to help establish pulmonary circulation.
D)After the umbilical cord is cut,the ductus venosus constricts.
E)An Apgar score is an assessment only of the newborn's breathing.
F)A newborn may have slight jaundice,because the liver is not fully mature.

Question 11

Which of the following statements are true of genetics (Select all that apply)?

A)Genotype is the assortment of alleles (genes)that are actually present in a person.
B)The same phenotype may be possible with two different genotypes.
C)The same genotype may be possible with two different phenotypes.
D)In a homozygous pair of alleles,both are the same.
E)In a heterozygous pair of alleles,both are either maternal or paternal.
F)The homozygous phenotype for a trait is always different from the heterozygous phenotype.

Question 12

Which of the following statements are true of multiple allele inheritance (Select all that apply)?

A)More than two alleles for the trait exist,but an individual will have only two of them.
B)At least one of the alleles will be dominant over another.
C)A child may have a phenotype that is different from that of both parents.
D)A child may have a genotype that is different from that of both parents.
E)The human ABO blood group has three alleles and four possible blood types.
F)In the ABO group,the recessive phenotype is the most frequent in the human population.