CAMPBELL BIOLOGY,VOL.II >CUSTOM<
17th Edition
ISBN: 9781323803677
Author: Urry
Publisher: PEARSON
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Chapter 47, Problem 13TYU
SYNTHESIZE YOUR KNOWLEDGE
Occasionally, two-headed animals such as this turtle are born. Thinking about the occurrence of identical twins and the property of totipotency, explain how this might happen.
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A:
Why do sea urchins have external fertilization? [Discuss the life style of the developing sea urchin embryo in the water column compared to a very different ecological niche of the adults on the ocean floor. Besides, would you want to give live birth to a sea urchin! ouch!]
2:
Then why don't the parents take care of the young? [In fact the adults do in a way. After the embryo has grown large enough and metamorphosed into a young urchin they hide in the spines of the adults, living off of the scraps of food produced from the messy eating of the adults]
3:
Because the urchin life involves two or more ecological niches, they are more susceptible to predation and exposure to environmental toxins. What environmental conditions, predators and toxins might they be exposed to at each stage?
Ken Doll isn't very smart. He and Barbie are not trying to have a baby. Ken is confused about a few details and asked his friend GI Joe why Barbie became pregnant. "Look, we did the deed on Monday and she didn't ovulate until Thursday. I should have been safe and my 'little swimmers' should have been out of there by then." How should GI Joe explain the necessary information to Ken?
The slow block to polyspermy involves a permanent modification of the egg surface, usually through exocytosis of the cortical granules. In the 1970s, Dave Epel carried out experiments that led to the conclusion that a Ca2+ rise in the egg is both necessary and sufficient to trigger cortical granule exoctyosis (CGE). For the experiment below, describe it as correlation, loss-of-function or gain-of function. Then, indicate the predicted result.
Experiment (a) – Dr. Epel injects the egg with an indicator dye that fluoresces when Ca2+ binds to it. In unfertilized eggs, there is no fluorescence and no CGE. However, when sperm are added to the eggs, he observes fluorescence and then CGE.
Chapter 47 Solutions
CAMPBELL BIOLOGY,VOL.II >CUSTOM<
Ch. 47.1 - How does the fertilization envelope form in sea...Ch. 47.1 - Prob. 2CCCh. 47.1 - MAKE CONNECTIONS Review Figure 12.16 on cell...Ch. 47.2 - In the frog embryo, convergent extension elongates...Ch. 47.2 - WHAT IF? Predict what would happen if Ca2+ was...Ch. 47.2 - MAKE CONNECTIONS Unlike some other types of birth...Ch. 47.3 - Prob. 1CCCh. 47.3 - Prob. 2CCCh. 47.3 - Prob. 3CCCh. 47.3 - Prob. 4CC
Ch. 47 - What cell-surface event would likely fail if a...Ch. 47 - What are some functions of apoptosis in...Ch. 47 - Suppose you found two classes of mouse mutations,...Ch. 47 - Prob. 1TYUCh. 47 - Which of the following is common to the...Ch. 47 - The archenteron develops into a. the mesoderm. b....Ch. 47 - What structural adaptation in chickens allows them...Ch. 47 - Prob. 5TYUCh. 47 - In humans, identical twins are possible because a....Ch. 47 - Cells transplanted from the neural tube of a frog...Ch. 47 - DRAW IT Each blue circle in the figure below...Ch. 47 - EVOLUTION CONNECTION Evolution in insects and...Ch. 47 - Prob. 10TYUCh. 47 - Prob. 11TYUCh. 47 - Prob. 12TYUCh. 47 - SYNTHESIZE YOUR KNOWLEDGE Occasionally, two-headed...
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- Birth control pills are oral contraceptives taken by women to prevent pregnancies. The most effective forms of birth control pills contain estrogen and a small amount of progestin (a synthetic hormone that mimics the effects of progesterone). Although the most effective forms of oral contraceptive for women contain estrogen and progestin, some birth control pills contain a small dose of progestin only. This is because there are many risks and side effects associated with estrogen.Which of the following statements is NOT a reason for using a progestin-only oral contraceptive? Select one: a. Progesterone suppresses the maturation of follicles, thereby preventing ovulation of a mature ovum. b. Progesterone maintains the corpus luteum as corpus luteum releases a large amount of progesterone and some estrogen. c. Progestin-only oral contraceptives prevent the production of FSH and LH in the anterior pituitary. d. Progesterone suppresses the production of GnRH in the hypothalamus.arrow_forwardThere are 6 major events in fertilization. Discuss the process of fertilization or conception, with emphasis on the sperm-egg interaction. Proteins on the sperm plasma membrane bind to ZP3 molecules within the zona pellucida of the egg. Why is this event important? Zona binding triggers the acrosome reaction, in which the sperm plasma membrane fuses with the outer acrosomal membrane, causing exocytosis of acrosomal contents. What is in the "acrosomal content"? Acrosomal enzymes begin to dissolve a hole in the zona pellucida. This enzymatic degradation, accompanied by rapid sperm tail beating, moves the sperm through the zona. Where does the sperm intend to reach?arrow_forwardWhich of the following events does not occur in the preparation for pregnancy?arrow_forward
- Some couple practice natural family planning (also known as the rhythm method of birth control), which involves abstaining from sexual intercourse during the time that a woman can become pregnant in her menstrual cycle. The egg only survives in the fallopian tube from 24 hours after ovulation, so conception can only happen during a 24-hour period each month. However, this form of contraceptive is very unreliable and is not recommended for couples who are actively trying to avoid pregnancy. Which of the following is NOT a reason why this form of birth control is unreliable? A. Sperm can survive in the fallopian tubes for 3 to 5 days. B. Ovulation can be affected by stress or illness. C. Women always ovulate on the same day of their menstrual cycle every month. D. It is difficult to predict exactly when in her cycle a woman ovulates.arrow_forwardSome couples practice natural family planning (also known as the rhythm method of birth control), which involves abstaining from sexual intercourse during the time that a woman can become pregnant in her menstrual cycle. The egg only survives in the Fallopian tube for 24 hours after ovulation, so conception can only happen during a 24-hour period each month. However, this form of contraception is very unreliable and is not recommended for couples who are actively trying to avoid pregnancy. Which of the following is NOT a reason why this form of birth control is unreliable? Select one: a. Women always ovulate on the same day of their menstrual cycle every month. b. Ovulation can be affected by stress or illness. c. Sperm can survive in the Fallopian tubes for 3 to 5 days. d. It is difficult to predict exactly when in her cycle a woman ovulates.arrow_forwardThe change of successful fertilization is approximately 18% in every cycle. Why does this statistic seem so low? All of the following statements provide a reason as to why the chance of fertilization is 18% every ovarian cycle EXEPT Select one: A. Some Sperm cells are not very motile, while others are formed without a tail. B. If more than one sperm fertilizes an egg, multiple embryos can result. C. Vagina is very acidic, killing many sperm. D. There two fallopian tubes and two ovaries, but only one of them releases an ovum every cycle.arrow_forward
- Which of the following statements does NOT correctly describe the events following fertilization? Select one: a. Only the inner cell mass cells in a blastocyst are pluripotent. b. The trophoblast has an important role in maintaining the pregnancy, as it prevents the endometrium from shedding. c. As hCG takes over maintaining the endometrium immediately after implantation, the corpus luteum degenerates into the corpus albican. d. All 16 cells in a morula are truly totipotent, meaning that they can become any cells in the human body.arrow_forwardExplain why breastfeeding can have lifelong, favorable consequences for the development of infants in poverty-stricken regions of the world?arrow_forwardIf an embryo was lacking HOX genes many problems might happen including this... neural crest would not undergo EMT neural progenitors would never form neurons would not form axons The rhombomeres would not form | If a fetus was exposed to a teratogen during week 16, this type of birth defect could be the most likely to occur. congenital heart defect cleft lip and palate limb defects central nervous system defectarrow_forward
- When the fetus is fully developed and takes up the maximum amount of space in the uterus, the pressure that it inflicts upon the cervix activates stretch receptors to send a signal to the hypothalamus (a structure within the brain). The brain responds by producing oxytocin, which is then released by the pituitary gland (an endocrine organ in the brain). Oxytocin travels through the bloodstream; when it reaches the uterus, it signals through myometrial (uterine smooth muscle) oxytocin receptors. Activation of the oxytocin receptors on myometrial tissue causes a signaling cascade that results in the cell producing prostaglandins that facilitate myometrial contraction (Figure 2).. Contraction of myometrial tissue then reduces the intrauterine space, causing the fully developed fetus to inflict more pressure on the cervix, thus repeating this process until the fetus is delivered. a) Fetal delivery is an example of which type of feedback loop? b) What type of sensory receptor is the…arrow_forwardIt is no mystery how harmful a lot of environmental factors can be on a fetus nor is it misunderstood how important proper prenatal care is during pregnancy. Despite this, we have seen that many people do not receive the recommended care and children are still born with birth defects due to preventable teratogens. explain how you could reduce or eliminate these negative consequences.arrow_forwardWhich of the following events does NOT occur in preparation for pregnancy? * After fertilization progesterone & estrogen begin to decline. Without fertilization menstruation occurs. The Secretory phase is due to the growth of endometrial glans & secretion of glycogen. Progesterone & Estrogen cause thickening of the endometrium. The preparatory phase peaks at 1 week after ovulation.arrow_forward
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