Bio 10 Flashcards
(22 cards)
What is the primary function of the SRY gene in male mammals?
A) It directs the development of ovaries.
B) It triggers the development of testes.
C) It inhibits the development of Wolffian ducts.
D) It stimulates the production of estradiol.
Answer: B) It triggers the development of testes.
Explanation: The SRY gene, found on the Y chromosome, is responsible for initiating the development of the testes in male mammals by activating a cascade of processes that differentiate undifferentiated gonads into testes.
Which hormone is primarily responsible for the development of the Wolffian ducts in males?
A) Estrogen
B) Progesterone
C) Androgens
D) Müllerian-inhibiting hormone
Answer: C) Androgens
Explanation: Androgens, particularly testosterone, promote the development of the Wolffian ducts into male internal structures such as the seminal vesicles and vas deferens.
What is the role of Müllerian-inhibiting hormone (MIH) in male development?
A) It promotes the development of the Wolffian ducts.
B) It causes the Müllerian ducts to degenerate.
C) It stimulates the formation of ovaries.
D) It converts testosterone into estradiol.
Answer: B) It causes the Müllerian ducts to degenerate.
Explanation: MIH is produced by the testes and causes the Müllerian ducts (which would otherwise form female reproductive structures) to degenerate in males.
How do steroid hormones like androgens and estrogens exert their effects?
A) By directly binding to DNA and modifying gene expression.
B) By rapidly increasing neurotransmitter release.
C) By entering the bloodstream and altering immune function.
D) By binding to membrane receptors and acting as neurotransmitters.
Answer: A) By directly binding to DNA and modifying gene expression.
Explanation: Steroid hormones, such as androgens and estrogens, exert their effects by entering cells, binding to receptors that influence gene expression, and modifying cellular activities.
What discovery challenged the earlier belief that hormones are the sole drivers of sexual differentiation?
A) Hormones have no effect on brain development.
B) Genes on the X and Y chromosomes influence sexual differentiation independently of hormones.
C) Both X and Y chromosomes produce the same effect on brain structure.
D) All individuals are genetically identical, regardless of sex chromosomes.
Answer: B) Genes on the X and Y chromosomes influence sexual differentiation independently of hormones.
Explanation: Later research showed that certain genes on the X and Y chromosomes, particularly in the brain, contribute to sexual differentiation beyond the effects of hormones like androgens and estrogens.
Which of the following best describes the organizing effects of sex hormones?
A) Short-term, temporary changes in behavior
B) Long-lasting structural changes in the body and brain
C) Immediate activation of sexual behaviors
D) Regulation of day-to-day hormonal fluctuations
Answer: B) Long-lasting structural changes in the body and brain
Explanation: Organizing effects of sex hormones refer to the long-term changes they produce, such as brain development and genital differentiation during early life and puberty.
What is the primary role of testosterone during the early development of male genitals?
A) It directly promotes the growth of the clitoris.
B) It is converted to dihydrotestosterone to stimulate the development of the penis.
C) It inhibits the development of internal reproductive organs.
D) It produces estradiol for brain differentiation.
Answer: B) It is converted to dihydrotestosterone to stimulate the development of the penis.
Explanation: Testosterone is converted to dihydrotestosterone during early development, which is crucial for male external genital development, specifically the penis and scrotum
What is the effect of estradiol on a genetic male when injected during early life?
A) It induces the development of female external genitals.
B) It causes complete masculinization of the external genitals.
C) It has no effect on external anatomy but can alter the prostate gland.
D) It induces the development of male internal reproductive organs
Answer: C) It has no effect on external anatomy but can alter the prostate gland.
Explanation: Estradiol does not alter the male’s external genitalia but can produce abnormalities in the prostate gland, highlighting the potential vulnerability of male development to estrogen-like compounds.
How do differences in brain anatomy between males and females arise?
A) Brain differences are solely due to overall body size.
B) Differences arise from varying levels of testosterone and estradiol during early development.
C) The hypothalamus plays no role in brain differences.
D) Brain anatomy is identical between the sexes.
Answer: B) Differences arise from varying levels of testosterone and estradiol during early development.
Explanation: Hormones like testosterone and estradiol influence the development of different brain areas, creating male-typical or female-typical patterns, especially in the hypothalamus.
In humans, how does testosterone affect the hypothalamus during early development?
A) Testosterone acts directly on the hypothalamus without being converted.
B) Testosterone is converted to estradiol, which acts on the hypothalamus to promote masculinization.
C) Testosterone inhibits the action of estradiol in the hypothalamus.
D) Testosterone has no effect on the hypothalamus in humans.
Answer: B) Testosterone is converted to estradiol, which acts on the hypothalamus to promote masculinization.
Explanation: In humans, testosterone is converted to estradiol, which then masculinizes specific areas of the hypothalamus during early development.
Which statement about the mosaic nature of brain development is true?
A) Male and female brains are always completely distinct and separate.
B) Most people’s brains are a mixture of male-typical, female-typical, and neutral areas.
C) Brain development is solely determined by genetics without hormonal influence.
D) All individuals have a fully female-typical brain structure.
Answer: B) Most people’s brains are a mixture of male-typical, female-typical, and neutral areas.
Explanation: Brain development involves a mosaic of different male-typical and female-typical areas, making it common for an individual to have a combination of both patterns.
What aspect of male sexual behavior is influenced by testosterone?
A) Testosterone decreases the sensitivity of the penis to touch.
B) Testosterone has no effect on sexual motivation in males.
C) Testosterone stimulates dopamine release in the MPOA during sexual arousal.
D) Testosterone increases serotonin levels, which inhibits sexual behavior.
Answer: C) Testosterone stimulates dopamine release in the MPOA during sexual arousal.
Explanation: Testosterone plays a significant role in sexual arousal in males by priming the brain, especially the medial preoptic area (MPOA), to release dopamine. Dopamine release is strongly correlated with sexual motivation and behavior, particularly in terms of initiating and maintaining sexual activity. This effect is central to male sexual behavior.
What is the role of estradiol in the female menstrual cycle?
A) It decreases the release of follicle-stimulating hormone (FSH).
B) It increases the release of luteinizing hormone (LH).
C) It prevents the ovum from being released from the follicle.
D) It decreases the sensitivity of the pudendal nerve.
Answer: B) It increases the release of luteinizing hormone (LH).
Explanation: Estradiol, released from the follicle, not only promotes the release of FSH but also causes a surge in LH, which is necessary for ovulation.
Which of the following statements is true about the function of birth control pills?
A) Birth control pills primarily prevent pregnancy by thickening the cervical mucus.
B) Birth control pills prevent the release of estradiol from the ovaries.
C) Birth control pills cause a surge in FSH and LH to release an ovum.
D) Birth control pills protect against sexually transmitted diseases.
Answer: A) Birth control pills primarily prevent pregnancy by thickening the cervical mucus.
Explanation: Birth control pills work in several ways, including thickening cervical mucus to prevent sperm from reaching the egg. However, they do not protect against sexually transmitted diseases.
What is the primary reason for sexual interest peaks during the periovulatory period in women?
A) A decrease in estradiol levels.
B) A surge in testosterone levels.
C) A decrease in progesterone levels.
D) An increase in estradiol levels.
Answer: D) An increase in estradiol levels.
Explanation: During the periovulatory period, estradiol levels peak, which has been linked to heightened sexual interest and behavior, even without conscious recognition.
Which of the following brain areas is most associated with maternal behavior and attention to young during pregnancy in female mammals?
A) Prefrontal cortex
B) Medial preoptic area
C) Hippocampus
D) Parietal lobe
Answer: B) Medial preoptic area
Explanation: The medial preoptic area (POA) is highlighted as a key brain region involved in maternal behavior and attention to young, particularly during pregnancy, in female mammals.
Which of the following hormones is primarily responsible for enhancing social behavior in many species, including forming pair bonds in voles?
A) Oxytocin
B) Prolactin
C) Vasopressin
D) Estradiol
Answer: C) Vasopressin
Explanation: Vasopressin plays a central role in social behavior, such as promoting pair bonding in voles and facilitating olfactory recognition.
What is a primary factor in human parental behavior, according to recent studies?
A) Hormonal changes alone
B) Experience-dependent behavior
C) The physical size of the offspring
D) Genetics alone
Answer: B) Experience-dependent behavior
Explanation: In humans, parental behavior is more influenced by experience rather than just hormonal changes, as brain scans show increased activity in areas related to reward and motivation as a result of experience with the child.
Which of the following findings is true regarding fathers’ hormone levels and their behavior toward infants?
A) Testosterone levels increase significantly after childbirth.
B) Fathers with higher prolactin levels spend less time with their children.
C) Fathers with higher prolactin levels and lower testosterone levels tend to be more involved with their children.
D) Fathers’ hormone levels have no significant impact on their behavior.
Answer: C) Fathers with higher prolactin levels and lower testosterone levels tend to be more involved with their children.
Explanation: Studies show that fathers with higher prolactin and lower testosterone levels engage more with their infants, especially in societies where men participate in infant care.
Which concept did Charles Darwin propose that involves genes increasing the likelihood of reproduction by making an individual more appealing to the opposite sex?
A) Natural selection
B) Kin selection
C) Sexual selection
D) Genetic drift
Answer: C) Sexual selection
Explanation: Sexual selection refers to traits that evolve because they make an individual more attractive to potential mates, increasing the likelihood of reproduction.
Which of the following is true about intersex individuals?
a) They are infertile by default
b) They may have ambiguous genitalia, making their sex unclear at birth
c) They always identify as a gender opposite to their biological sex
d) They do not require medical intervention or surgery
Answer: b) They may have ambiguous genitalia, making their sex unclear at birth
Explanation: Intersex individuals may have a mix of male and female anatomical traits, leading to ambiguity regarding their sex at birth. Medical treatments are often used to manage their conditions, including surgery to adjust genital appearance.
What is the primary factor influencing the toy preferences of girls with CAH (Congenital Adrenal Hyperplasia)?
A) Parental encouragement of tomboyish behavior
B) Exposure to higher levels of prenatal testosterone
C) Gender reassignment surgeries
D) Cultural expectations of femininity
Explanation: Studies show that higher prenatal testosterone levels correlate with a greater preference for toys typically associated with boys, such as toy cars and tool sets, despite parents encouraging the children to engage with toys of any type (Pasterski et al., 2005; Berenbaum, 2000).
