BIO post-lectures Development

• Which of the following types of inheritance is defined as when neither member of an allelic pair is dominant over the other and the resulting heterozygotic offspring express a phenotype that is intermediate between the two homozygotes?

  incomplete dominance
• Monozygotic twins develop from a single fertilized ovum.

  true
• The fetal portion of the placenta is formed by the ____ of the blastocyst.

  trophoblasts
• The most common site of fertilization of an ovum by a sperm is in the uterine cavity.

  false
• Of the sperm cells introduced into the vagina during sexual intercourse, what percentage actually reach the secondary oocyte?

  less than 1 percent
• All of the following are pregnancy-induced changes observed in the mother EXCEPT
• All of the following are pregnancy-induced changes observed in the mother EXCEPT

  decreased urine production
• Alcohol in maternal blood does not cross the placenta into the fetal circulation.

  false
• Some types of sudden movements during exercise are difficult for pregnant women because the hormone called _____ causes certain joints, like the pubic symphysis, to become less stable.

  relaxin
• Down syndrome is a genetic disorder that results from

  the presence of an extra 21st chromosome
• Birth typically occurs ___ weeks after fertilization.

  38
• Unspecialized cells that have the ability to continue dividing for long periods of time and eventually become specialized cells are called

  stem cells
• Because of the risks of dehydration, decreased blood flow to the placenta, and decreased stability of pubic symphysis, pregnant women should avoid all types of exercise.

  false
• Deoxygenated blood carrying fetal waste products exits the body of the fetus through the

  umbilical arteries
• Embryology refers to the study of development from the fertilized egg through the _____ week of pregnancy.

  eighth
• The developmental process that occurs at about 3 weeks of development in which the bilaminar embryonic disc transforms into the trilaminar embryonic disc containing the three primary germ layers is called

  gastrulation
• By the beginning of the _____, the placenta consists of two distinct parts including a fetal portion of chorionic villi and a maternal portion formed by the endometrium.

  twelfth week
• The regulatory chemical found in high quantities in breast milk that helps inhibit GI tract inflammation in the newborn is

  interleukin - 10
• Which of the following placental hormones helps ease delivery of a baby through the birth canal by stimulating the loosening of pubis symphysis, along with the sacroiliac and sacrococcygeal joints?

  relaxin
• Uterine contractions during labor are stimulated by a positive feedback loop involving a pituitary hormone called

  oxytocin
• Which of the following is the correct order of developmental stages?

  zygote - morula - blastocyst - embryo - fetus - neonate
• Which of the following anatomical structures develop from the mesoderm of the embryo?

  muscle
• The term neonatal period refers to the first ___ days after birth.

  28
• Amniocentesis involves withdrawing amniotic fluid to analyze fetal cells.

  true
• Which of the following structures serves as an early site of formation of blood and blood vessels, and is associated with the development of the urinary bladder?

  allantois
• Pluripotent stem cells, like inner mass cells, have the unique ability to develop into all the cells of an organism.

  false
• The principal hormone involved in promoting milk production by the mammary glands is

  prolactin
• Which of the following is NOT an existing fertility-expanding technique?

  fetal ultrasonography
• Which of the following hormones is secreted by the chorion of the placenta as a signal to the corpus luteum to continue secreting progesterone?

  chorionic gonadotropin
• The process of implantation of the blastocyst into the endometrium begins to occur approximately ___ days after fertilization.

  6
• Successive cleavages of the zygote produce a solid sphere of small cells called the

  morula
• The series of rapid mitotic cell divisions that convert a zygote into a morula are called

  cleavage
• The hormone that stimulates contraction of smooth-muscle-like cells in the mammary gland resulting in milk being made available to the suckling newborn is called

  oxytocin
• The zona pellucida is a clear layer of glycoprotein surrounding the ovulated oocyte.

  true
• A chart that uses the possible paternal and maternal allele combinations to determine the probability of expression of each genotype in offspring is called a

  Punnett square
• Phenylketonuria (PKU) is a sex-linked inherited disorder.

  false
• Substances in breast milk enhance both nonspecific resistance and immunity in the baby.

  true
• The term used to describe the actual genetic makeup of an organism is

  genotype
• The fetal period refers to the time of development extending from the end of the ___ month after fertilization until birth.

  2nd
• Before a sperm cell can fertilize an ovum, it has to undergo _____, which is a process involving a series of functional changes that occur inside the female reproductive tract.

  capacitation