Chapter 2 Reproduction Flashcards
1
Q
What is a Diploid and haploid
A
Diploid (2n) cells have two copies of each chromosome;
Haploid (n) cells have one copy.
2
Q
What is interphase?
A
The cell cycle contains five stages.
The G1, S, and G2 stages are
collectively called interphase, during which the DNA is uncoiled in the
form of chromatin.
3
Q
What is chromatin?
A
Chromatin is a complex structure made up of DNA tightly wound around protein complexes called histones
4
Q
What is G1?
A
In the G1
stage (presynthetic gap), cells create organelles for energy and protein production, and increase their size. The restriction
point, during which the DNA is checked for quality, must be passed for the cell to move into the S stage.
5
Q
What is S stage?
A
In the S stage (synthesis), DNA is replicated. The strands of DNA,
called chromatids, are held together at the centromere.
6
Q
What is G2?
A
In the G2
stage (postsynthetic gap), there is further cell growth and replication of organelles in preparation for mitosis. Another quality checkpoint must be passed for the cell to enter into mitosis.
7
Q
What is M stage
A
In the M stage (mitosis), mitosis and cytokinesis occur
8
Q
What is G0?
A
In the G0 stage, the cell performs its functions without preparing for
division.
9
Q
What is P53 and it’s importance?
A
p53 plays a role in the two major checkpoints of the cell cycle (G1 to S, and G2 to M).
p53 primarily functions as a transcription factor. A protein that regulates the activity of other genes. Part of the reason that p53 can do so many things is that it controls the expression of many other genes.
10
Q
What is Cyclins and CDK?
A
Cyclins and cyclin-dependent kinases (CDK) rise and fall during the
cell cycle. Cyclins bind to CDKs, phosphorylating and activating transcription factors for the next stage of the cell cycle
11
Q
What is transcription factors?
A
Transcription factors are proteins that help turn specific genes “on” or “off” by binding to nearby DNA.
Transcription factors that are activators boost a gene’s transcription. Repressors decrease transcription.
Groups of transcription factor binding sites called enhancers and silencers can turn a gene on/off in specific parts of the body.
Transcription factors allow cells to perform logic operations and combine different sources of information to “decide” whether to express a gene.
12
Q
What is Cancer?
A
Cancer occurs when cell cycle control becomes deranged, allowing
damaged cells to undergo mitosis without regard to quality or quantity
of the new cells produced. Cancerous cells may begin to produce
factors that allow them to delocalize and invade adjacent tissues or
metastasize ((of a cancer) spread to other sites in the body by metastasis.
“cancers that metastasize to the brain) elsewhere
13
Q
What does mitosis produce?
A
Mitosis produces two genetically identical diploid daughter cells from a
single cell and occurs in somatic cells.
14
Q
4 phases of Mitosis
PMAT
A
Prophase Anaphase Metaphase Telophase
15
Q
What is prophase?
A
Condensation of Chromatin, Breakdown of the nuclear envelope, Assembly of mitotic Spindles
16
Q
What is metaphase?
A
In metaphase, chromosomes line up along the metaphase plate
(equatorial plate).
17
Q
What is Telphase?
A
In telophase, the nuclear membrane reforms, spindle apparatus
disappears, and cytosol and organelles are split between the two
daughter cells through cytokinesis.
17
Q
what is anaphase?
A
In anaphase, sister chromatids are separated and pulled to opposite
poles.
Cleavage Furrow (cell begins to elongate and a shallow groove called the cleavage furrow forms at the cell surface near the original location of the metaphase plate.)
18
Q
What is Meiosis?
A
Meiosis occurs in gametocytes (germ cells) and produces up to four
nonidentical haploid sex cells (gametes).
Meiosis has one round of replication and two rounds of division (the
reductional and equational divisions).
19
Q
Explain meisosis I and Homologues?
A
In meiosis I, homologous pairs of chromosomes (homologues) are
separated from each other.
Homologues are chromosomes that are
given the same number, but are of opposite parental origin
20
Q
What is prophase I
A
In prophase I, the same events occur as in prophase of mitosis, except that homologues come together and intertwine in a process
called synapsis. e four chromatids are referred to as a tetrad, and crossing over exchanges genetic material between one chromatid and material from a chromatid in the homologous chromosome. This accounts for Mendel’s second law (of independent assortment).
21
Q
What is metaphase I
A
In metaphase I, homologous chromosomes line up on opposite sides
of the metaphase plate.
22
Q
What is anaphase I
A
In anaphase I, homologous chromosomes are pulled to opposite poles of the cell. is accounts for Mendel’s first law (of segregation)
[Mendel’s first law, also known as the “Law of Segregation,” states that during the formation of gametes (sex cells), the two alleles for a given trait separate from each other, so that each gamete only receives one allele, ensuring genetic diversity in offspring; essentially, each parent contributes only one copy of each gene to their offspring. ]
23
Q
What is telephase I
A
In telophase I, the chromosomes may or may not fully decondense,
and the cell may enter interkinesis after cytokinesis.
24
What is interkinesis?
a period of rest that cells of some species enter during meiosis, between meiosis I and meiosis II. No DNA replication occurs.
25
What is meiosis II
In meiosis II, sister chromatids are separated from each other in a
process that is functionally identical to mitosis
26
What are sister chromatids?
Sister chromatids are
copies of the same DNA held together at the centromere.
27
How is chromosomal sex determined?
Chromosomal sex is determined by the 23rd pair of chromosomes in
humans, with XX being female and XY being male.
28
What is the X chromosome?
The X chromosome carries a sizeable amount of genetic information;
mutations of X-linked genes can cause sex-linked disorders.
Males are hemizygous with respect to the unpaired genes on the X chromosome, so they will express sex-linked disorders, even if they
only have one recessive disease-carrying allele.
Females with only one
copy of the affected allele are called carriers.
29
What is the Y chromosome
The Y chromosome carries little genetic information, but does contain the SRY (sex-determining region Y) gene, which causes the
gonads to differentiate into testes.
30
Where does sperm develop?
Sperm develop in the seminiferous tubules in the testes. They are
nourished by Sertoli cells.
31
What is the Interstitial cells of Leydig?
Interstitial cells of Leydig, in the testes, secrete testosterone and other male sex hormones (androgens).
32
Where are the testes and what does it do.
The testes are located in the scrotum, which hangs outside of the
abdominal cavity and has a temperature 2°C to 4°C lower than the
rest of the body.
33
Where does spem gain motility?
Once formed, sperm gain motility in the epididymis and are stored
there until ejaculation.
34
During ejaculation, sperm travel through the _____ ________ to the
ejaculatory duct, and then to the _______ and out through the penis.
During ejaculation, sperm travel through the vas deferens to the
ejaculatory duct, and then to the urethra and out through the penis.
35
What is The seminal vesicles?
The seminal vesicles contribute fructose to nourish sperm and
produce alkaline fluid
36
what is The prostate gland
The prostate gland also produces alkaline fluid.
37
What is the bulbourethral glands?
The bulbourethral glands produce a clear viscous fluid that cleans out any remnants of urine and lubricates the urethra during sexual
arousal.
38
What is semen composed of?
Semen is composed of sperm and seminal fluid from the glands
above.
39
What happens in spermatogenesis?
In spermatogenesis, four haploid sperm are produced from a spermatogonium.
40
After S stage, the germ cells are called ________ ___________
After S stage, the germ cells are called primary spermatocytes
41
After meiosis I, the germ cells are called secondary spermatocytes.
After meiosis I, the germ cells are called ________ ____________
42
After meiosis II, the germ cells are called _________
After meiosis II, the germ cells are called spermatids
43
After maturation, the germ cells are called _________.
After maturation, the germ cells are called spermatozoa.
44
Anatomy of a sperm:
Sperm contain a head, midpiece, and flagellum.
45
The head of a sperm contains:
The head contains the genetic material and is covered with an
acrosome—a modified Golgi apparatus that contains enzymes that
help the sperm fuse with and penetrate the ovum
46
The midpiece of sperm does what?
The midpiece generates ATP from fructose and contains many mitochondria.
47
The flagellum promotes _________
The flagellum promotes motility
48
The Ova (eggs) are produced in ________ in the ________.
The Ova (eggs) are produced in follicles in the ovaries.
49
When an egg is ovulated what happens?
Once each month, an egg is ovulated into the peritoneal sac and is drawn into the fallopian tube or oviduct.
50
Where are the fallopian tubes are connected?
The fallopian tubes are connected to the uterus,
the lower end of
which is the cervix.
51
What is the vaginal canal?
The vaginal canal lies below the cervix and is the site where sperm are deposited during intercourse.
The vaginal canal also can be the site of childbirth.
52
What is oogenesis?
In oogenesis, one haploid ovum and a variable number of polar bodies
are formed from an oogonium.
53
Whats the vulva?
The external parts of the female genital organs are collectively known
as the vulva.
54
What is primary oocytes?
(part of oogenesis)
At birth, all oogonia have already undergone replication and are
considered primary oocytes. They are arrested in prophase I.
55
What is secondary oocytes?
(part of oogenesis)
The ovulated egg each month is a secondary oocyte, which is
arrested in metaphase II.
If the oocyte is fertilized, it will complete meiosis II to become a true
ovum.
56
What is a polar body in Oogenesis?
Cytokinesis is uneven in oogenesis. The cell receiving very little cytoplasm and organelles is called a polar body.
57
Oocytes are surrounded by the ____ _________, an acellular mixture
of glycoproteins that protects the oocyte and contains the
compounds necessary for sperm binding;
And the _______ _______,
which is a layer of cells that adheres to the oocyte during ovulation.
Oocytes are surrounded by the zona pellucida, an acellular mixture
of glycoproteins that protects the oocyte and contains the
compounds necessary for sperm binding;
And the corona radiata,
which is a layer of cells that adheres to the oocyte during ovulation.
58
Where do Gonadotropin releasing hormone (GnRH) happen? And What do they do?
Gonadotropin-releasing hormone (GnRH) from the hypothalamus
causes the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), the functions of which depend on the sex
of the individual.
59
Explain follicle-stimulating hormone (FSH) in Men?
In males, FSH stimulates the Sertoli cells and triggers
spermatogenesis, while LH causes the interstitial cells to produce testosterone.
Testosterone is responsible for the maintenance and
development of the male reproductive system and male secondary
sex characteristics (facial and axillary hair, deepening of the voice,
and increased bone and muscle mass)
60
Explain follicle-stimulating hormone (FSH) in females?
In females, FSH stimulates development of the ovarian follicles, while LH causes ovulation. These hormones also stimulate production of
estrogens and progesterone.
61
Name the phases of menstural cycle:
Follicular phase, Ovulation, Luteal phase, Ovulation, Menstruation
62
Describe the Follicular phase:
In the follicular phase, GnRH secretion stimulates FSH and LH secretion, which promotes follicle development. Estrogen is released, stimulating vascularization and glandularization of the decidua.
[The decidua is the modified uterine lining during pregnancy that supports the embryo and placenta. Glandularization of the decidua refers to the growth of glands that secrete nutrients for the developing embryo.]
63
What is the Ovulation phase?
Ovulation is stimulated by a sudden surge in LH. is surge is triggered when estrogen levels reach a threshold and switch from
negative to positive feedback effects.
64
What is Luteal phase?
In the luteal phase, LH causes the ruptured follicle to become the. corpus luteum, which secretes progesterone that maintains the uterine lining. High estrogen and progesterone levels cause negative
feedback on GnRH, LH, and FSH.
65
What is menstruation?
Menstruation occurs if there is no fertilization. As the estrogen and progesterone levels drop, the endometrial lining is sloughed off, and
the block on GnRH production is removed.
66
If fertilization does occur, the blastula produces _______ _________ ________ (___)
which, as an LH analog, can maintain the corpus luteum. Near the end of the first trimester, hCG levels drop as the placenta takes over progesterone production.
If fertilization does occur, the blastula produces human chorionic
gonadotropin (hCG)
which, as an LH analog, can maintain the corpus luteum. Near the end of the first trimester, hCG levels drop as the placenta takes over progesterone production.
67
What is Menopause?
Menopause occurs when the ovaries stop producing estrogen and progesterone, usually between ages 45 and 55. Menstruation stops and FSH and LH levels rise. Physical and physiological changes accompanying menopause include flushing, hot flashes, bloating, headaches, and irritability.
68
Name the Cell Cycle stages and features
G: 1Cell grows and performs its normal functions. DNA is examined and
repaired
S: DNA is replicated.
G2: Cell continues to grow and replicates organelles in preparation for
mitosis. Cell continues to perform its normal functions.
M: Mitosis (cell division) occurs.
G0: The cell performs its normal functions and is not preparing to divide.
69
What is the Mitotic phases and features
Prophase:
Chromosomes condense, nuclear membrane dissolves, nucleoli disappear, centrioles migrate to opposite poles and begin forming the
spindle apparatus
Metaphase:
Chromosomes gather along the metaphase plate in the center of the cell under the guidance of the spindle apparatus
Anaphase:
Sister chromatids separate, and a copy of each chromosome migrates
to opposite poles
Telophase and Cytokenseis:
Chromosomes decondense, nuclear membrane reforms, nucleoli reappear, spindle apparatus breaks down, cell divides into two
identical daughter cells
70
What is the number and ploidy of the daughter cells produced from meiosis I? From meiosis II?
After meiosis I, there are two haploid daughter cells.
After meiosis II, there are up to four haploid gametes.
71
What is the difference between homologous chromosomes and sister
chromatids?
Homologous chromosomes are related chromosomes of opposite parental origin (such as maternal chromosome 15 and paternal chromosome 15, or—in males—the X and Y chromosomes)
Sister chromatids are identical copies of the same DNA that are held together at the centromere. Aer S phase, a cell contains 92 chromatids, 46 chromosomes, and 23 homologous pairs.
72
What is the Meiotic I phases and features
what are the differences from the analogous phase of mitosis?
Prophase I:
Homologous chromosomes come together as tetrads during synapsis; crossing over
Metaphase I:
Homologous chromosomes line up on opposite sides of the metaphase plate, rather than individual chromosomes lining up on the metaphase plate
Anaphase I:
Homologous chromosomes separate from each other; centromeres do not break
Telophase I: Chromatin may or may not decondense; interkinesis occurs as the cell prepares for meiosis II
73
What are the functions of interstitial cells of Leydig and Sertoli cells?
The interstitial cells of Leydig secrete testosterone and other male sex
hormones (androgens). Sertoli cells nourish sperm during their development
74
During which phase of meiosis is a primary oocyte arrested?
VS
During which phase of meiosis is a secondary oocyte arrested?
A primary oocyte is arrested in prophase I, while a secondary oocyte is
arrested in metaphase II.
75
What is the acrosome? What organelle forms the acrosome?
The acrosome contains enzymes that are capable of penetrating the corona radiata and zona pellucida of the ovum, permitting fertilization to occur.
It is a modified Golgi apparatus.
76
Which hormones are key to sexual differentiation in a fetus with XY genotype? Describe the expected phenotype if receptors to these hormones are absent.
Androgens, such as testosterone, lead to male sexual differentiation.
Absence of androgen receptors, a condition known as androgen
insensitivity syndrome, leads to an XY genotype with phenotypically female characteristics.
77
Name the phases and how it effects hormones
Follicular:
Egg develops, endometrial
lining becomes vascularized
and glandularized
(FSH =↑) (LH remained =) (Estrogen ↓ then ↑) (Progesterone = ↓)
Ovulation:
Egg is released from follicle
into peritoneal cavity
(FSH =↑) (LH =↑) (Estrogen =↑) (Progesterone = ↓)
Luteal:
Luteal Corpus luteum produces progesterone to maintain endometrium
(FSH =↑) (LH remained =) (Estrogen = ↑) (Progesterone = ↑)
Menses:
Shedding of endometrial
lining
(FSH =↑) (LH =↑) (Estrogen =↑) (Progesterone = ↓)
78
Which of the following is the correct sequence of the development of a
mature sperm cell?
A. Spermatid→ 1° spermatocyte→spermatogonium→2°
spermatocyte→spermatozoan
B. Spermatogonium→1° spermatocyte→2°
spermatocyte→spermatid→spermatozoan
C. Spermatozoan→1° spermatocyte→2°
spermatocyte→spermatogonium→spermatid
D. Spermatogonium→1° spermatocyte→2°
spermatocyte→spermatozoan→spermatid
B
Diploid cells called spermatogonia differentiate into primary spermatocytes, which undergo the first meiotic division to yield two haploid secondary spermatocytes.
These undergo a second meiotic division to become immature spermatids. e
spermatids then undergo a series of changes leading to the production of mature
sperm, or spermatozoa.
79
Which of the following correctly pairs the stage of development of an egg cell
with the relevant point in a woman’s life cycle?
A. From birth to menarche—prophase II
B. At ovulation—metaphase I
C. At ovulation—metaphase II
D. At fertilization—prophase II
C
From the time of birth until shortly before ovulation, all egg cells are arrested at the
prophase stage of meiosis I. ese cells are referred to as primary oocytes. At
ovulation, the egg cell has completed meiosis I and is now arrested in metaphase II as a haploid cell called a secondary oocyte. When a sperm penetrates the outer layers of the secondary oocyte, it completes meiosis II to become a mature ovum.
80
Some studies suggest that in patients with Alzheimer’s disease, there is a
defect in the way the spindle apparatus attaches to the kinetochore fibers. At
which stage of mitotic division would one first expect to be able to visualize
this problem?
A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
A
The spindle apparatus first interacts with the kinetochore fibers near the end of prophase. While the spindle apparatus aligns the chromosomes at the equatorial plate
during metaphase, (B), the initial connection of the microtubule to the kinetochore
occurs in prophase.
81
A researcher wishes to incorporate a radiolabeled deoxyadenine into the
genome of one of the two daughter cells that would arise as a result of
mitosis. What is the latest stage of cellular development during which the
radiolabeled deoxyadenine could be added to achieve this result?
A. G1
B. G2
C. M
D. S
D
To ensure that the labeled deoxyadenine will be incorporated into the DNA of one of
the daughter cells, we have to insert the nucleotide before DNA replication has been
completed. Because replication occurs during S stage, we could introduce the
deoxyadenine during G1 or S stage. Because G1 precedes S, the latest point at which
the deoxyadenine could be added is the S stage.
82
Certain ovarian tumors called granulosa cell tumors are known to produce
excessive levels of estrogen. A physician who diagnoses a granulosa cell
tumor should look for a secondary cancer in which of the following parts of
the reproductive tract?
A. Fallopian tube
B. Cervix
C. Endometrium
D. Vagina
C
Estrogen is known to cause growth of the endometrial lining during the follicular
phase of the menstrual cycle, and its levels stay high during the luteal phase to
promote vascularization and glandularization of this tissue. Excessive levels of
estrogen may provide a strong enough signal for cell growth to promote tumor
formation or even cancer.
The other tissues listed in this question require estrogen for development, but are not strongly dependent on estrogen for growth.
83
Upon ovulation, the oocyte is released into the:
A. fallopian tube.
B. follicle.
C. abdominal cavity.
D. uterus.
C
This subtle point about ovulation is missed by most students and remains hard to believe until the organs are examined in anatomy class in medical school. e
ruptured ovarian follicle releases an oocyte into the abdominal cavity, close to the entrance of the fallopian tube. With the aid of beating cilia, the oocyte is drawn into the fallopian tube, through which it travels until it reaches the uterus. If it is fertilized in the fallopian tube, it will implant in the uterine wall. If fertilization does not occur, it will be expelled along with the uterine lining during menstruation.
84
Cancer cells are cells in which mitosis occurs continuously, without regard to quality or quantity of the cells produced. For this reason, most chemotherapies attack rapidly dividing cells. At which point(s) in the cell cycle could chemotherapy effectively prevent cancer cell division?
I. S stage
II. Prophase
III. Metaphase
A. I only
B. I and II only
C. II and III only
D. I, II, and III
D
The question is asking us to determine at which points in the cell cycle we can prevent
or at least lower the number of cells undergoing mitosis. One idea would be to
prevent DNA synthesis during the S stage of the cell cycle. Without the DNA being replicated, two viable daughter cells could not be formed. Other ideas would be preventing the mitotic cycle from forming altogether in prophase by preventing spindle apparatus formation, preventing the nuclear membrane from dissolving, or interfering with other processes during this phase. Similarly, a treatment that would act on cells in the metaphase stage of the cell cycle would also interfere with the mitotic cycle. Therefore, any of the three solutions presented would be a viable option
85
Which of the following INCORRECTLY pairs a structure of the male
reproductive system with a feature of the structure?
A. Seminal vesicles—produce alkaline fructose-containing secretions
B. Prostrate gland—surrounded by muscle to raise and lower the testes
C. Vas deferens—tube connecting the epididymis to the ejaculatory duct
D. Cowper’s glands—produce a fluid to clear traces of urine in the urethra
B
The prostrate gland, along with the seminal vesicles and the bulbourethral gland, secretes seminal fluid that combines with sperm to produce semen. It is the cremaster muscle which surrounds the testes that raises and lowers the testes in response to changes in temperature
86
What is the last point in the meiotic cycle in which the cell has a diploid
number of chromosomes?
A. During interphase
B. During telophase I
C. During interkinesis
D. During telophase II
B
the first meiotic division (reductional division) pulls homologous chromosomes to opposite poles of the cell during anaphase I. Near the end of telophase I, cytokinesis occurs, resulting in two haploid (n) daughter cells.
Thus, during interkinesis and anaphase II, the daughter cells are already haploid, eliminating (C) and (D). The cell
is diploid during interphase, (A), but remains diploid up until the end of telophase I.
87
Which of the following does NOT likely contribute to genetic variability?
A. Random fertilization of an egg by a sperm
B. Random segregation of homologous chromosomes
C. Crossing over between homologous chromosomes during meiosis
D. Replication of the DNA during S stage
D
The safest way to answer this question correctly is to go through each answer choice and eliminate the ones that contribute to genetic variability. e random fertilization
of an egg by a sperm, the random segregation of homologous chromosomes during anaphase I, and crossing over between homologous chromosomes during prophase I all contribute to genetic variability during sexual reproduction because they result in novel combinations of genetic material, eliminating (A), (B), and (C). S stage, (D), should not cause increased genetic variability; the DNA should be copied precisely,
without error, meaning that both strands of DNA should be identical.
88
Which of the following statements correctly identifies a key difference
between mitosis and meiosis?
A. In metaphase of mitosis, replicated chromosomes line up in single file; in
metaphase II of meiosis, replicated chromosomes line up on opposite
sides of the metaphase plate.
B. During anaphase of mitosis, homologous chromosomes separate; during anaphase of meiosis I, sister chromatids separate.
C. At the end of telophase of mitosis, the daughter cells are identical to each
other; at the end of meiosis I, the daughter cells are identical to the parent
cell.
D. During metaphase of mitosis, centromeres are present directly on the
metaphase plate; during metaphase of meiosis I, there are no
centromeres on the metaphase plate.
D
e key differences between mitosis and meiosis primarily appear during meiosis I.
Of note, synapsis and crossing over occur during prophase I, and homologous
chromosomes are separated during meiosis I (rather than sister chromatids, as in
mitosis). While the location of the centromeres relative to the metaphase plate may
seem trivial, it is representative of the fact that homologous chromosomes line up on
opposite sides of the equatorial plate in meiosis, in contrast to the positioning of each
chromosome directly upon the metaphase plate in mitosis.
89
Which of the following is true regarding prophase?
A. The chromosomes separate and move to opposite poles of the cell.
B. The spindle apparatus disappears.
C. The chromosomes uncoil.
D. The nucleoli disappear
D
In prophase, the chromatin condenses into chromosomes, the spindle apparatus forms, and the nucleoli and nuclear membrane disappear. (A) describes anaphase,
whereas (B) and (C) describe telophase.
90
An individual who is phenotypically female is found to have only one copy of
a disease-carrying recessive allele on the X chromosome, yet demonstrates
all of the classic symptoms of the disease. Geneticists determine that the
individual has a genotype that likely arose from nondisjunction in one parent.
What is the likely genotype of this individual?
A. 46,XX (46 chromosomes, with XX for sex chromosomes)
B. 46,XY
C. 45,X
D. 47,XXY
C
Nondisjunction refers to the incorrect segregation of homologous chromosomes
during anaphase I, or of sister chromatids during anaphase II. In either case, one daughter cell ends up with two copies of related genetic material, while the other
receives zero. Immediately, this should eliminate (A) and (B), which show a normal
complement of chromosomes (46). An individual who has only one recessive diseasecarrying allele, and yet still expresses the disease, likely does not have a dominant
allele for the given trait. is is seen in males, who are hemizygous for many X-linked
genes, and can also be seen in females who have Turner syndrome (45,X) and only
one X chromosome. us, (C) is the answer.
91
During which phase of the menstrual cycle does progesterone concentration
peak?
A. Follicular phase
B. Ovulation
C. Luteal phase
D. Menses
C
Progesterone peaks during the luteal phase, as it supports the endometrium for potential implantation of a blastula. Progesterone levels are relatively low during the follicular phase and ovulation, eliminating (A) and (B). Withdrawal of progesterone
actually causes menses, eliminating (D).
92
Which of the following would NOT be seen during pregnancy?
A. High levels of hCG in the first trimester
B. High levels of progesterone throughout the pregnancy
C. Low levels of FSH in the first trimester
D. High levels of GnRH throughout the pregnancy
D
During the first trimester of pregnancy, the corpus luteum is preserved by human chorionic gonadotropin (hCG); hence, progesterone secretion by the corpus luteum is
maintained during the first trimester. is eliminates (A). During the second
trimester, hCG levels decline, but progesterone levels rise because the hormone is
now secreted by the placenta itself, eliminating (B). High levels of progesterone and
estrogen inhibit GnRH secretion, thus preventing FSH and LH secretion and the
onset of a new menstrual cycle. This eliminates (C) and validates (D).
93
Female chromosome pairs are [XX or XY]
Female chromosome pairs are XX
94
In [mitosis phase], chromosomes meet in middle of the cell
In metaphase, chromosomes meet in middle of the cell
Metaphase = "meet in middle" at the metaphase plate
95
A/an [... protein] is any protein that acts as an agent to bind two or more molecules together
A/an binding protein is any protein that acts as an agent to bind two or more molecules together
Examples include:
DNA-binding protein
Single-strand binding protein
Telomere-binding protein
96
[Hormone] develops the female reproductive tract and thickens the uterine wall
Estrogen develops the female reproductive tract and thickens the uterine wall
“Estrogen establishes and progesterone protects the endometrium”
Estrogen responds to FSH
97
In males with an X-linked recessive mutation, the mutation [will or will not] be expressed
In males with an X-linked recessive mutation, the mutation will be expressed
This is because males only have one X chromosome
98
The phases of meiosis:
The phases of meiosis:
Prophase I
Metaphase I
Anaphase I
Telophase I
Prophase II
Metaphase II
Anaphase II
Telophase II
PMAT x 2
99
Male chromosome pairs are [XX or XY]
Male chromosome pairs are XY
100
[...] is when two chromosomes of a homologous pair exchange segments with each other
Crossing over is when two chromosomes of a homologous pair exchange segments with each other
101
The [...] have follicles that produce ova
The ovaries have follicles that produce ova
102
In females with an X-linked recessive mutation, the mutation [will or will not] be expressed
In females with an X-linked recessive mutation, the mutation will not be expressed
Females have two X chromosomes, so the mutation is carried but not expressed. The normal X chromosome will be expressed because this is a recessive trait
103
[Organs] are controlled by FSH and LH
Ovaries are controlled by FSH and LH
104
[...] and the [...] make alkaline fluid to help sperm survive the acidic environment of the female reproductive tract
Seminal vesicles and the prostate gland make alkaline fluid to help sperm survive the acidic environment of the female reproductive tract
105
The number of complete sets of chromosomes in a cell is referred to as the [...] of a cell
The number of complete sets of chromosomes in a cell is referred to as the ploidy of a cell
Haploid (N) Diploid (2N)
106
The process of fertilization involves the following 4 steps:
1. [...]
2. [...]
3. [...]
4. [...]
The process of fertilization involves the following 4 steps:
1. Sperm binding
2. Acrosome reaction
3. Cortical reaction
4. Genetic transfer
107
In [mitosis phase], chromosomes decondense, the nuclear membrane forms, and cytokinesis occurs
In telophase, chromosomes decondense, the nuclear membrane forms, and cytokinesis occurs
108
Female egg pathway:
[...]
Female egg pathway:
Ovary → Oviduct or fallopian tube → Uterus → Cervix → Vagina
Note: If unfertilized, the egg will leave through the cervix and vagina, otherwise it implants into the uterus as an embryo
109
The four phases of Mitosis:
[...]
[...]
[...]
[...]
The four phases of Mitosis:
Prophase
Metaphase
Anaphase
Telophase
Acronym: PMAT
Note: Interphase precedes mitosis, it is not part of mitosis
110
A cell will enter [cell cycle phase] if it does not need to divide
A cell will enter G0 phase if it does not need to divide
111
The [gene] is responsible for initiation of male sex determination and codes for testicles
The SRY gene is responsible for initiation of male sex determination and codes for testicles
"Sorry you're a male"
112
Crossing over occurs in [meiosis phase]
Crossing over occurs in prophase I
113
A/an [...] is one half of a chromosome
A/an chromatid is one half of a chromosome
One of the chromatids is an identical copy of the other
114
[...] is the production of female gametes
Oogenesis is the production of female gamete
115
[...] is when sister chromatids don’t separate properly during anaphase
Nondisjunction is when sister chromatids don’t separate properly during anaphase
Results in aneuploidy. (Aneuploidy is when a cell has too many or too few chromosomes. Instead of the normal number, it can have extra or missing ones, which can cause health problems.)
116
Mitosis and cytokinesis occur in the [cell cycle phase]
Mitosis and cytokinesis occur in the M phase
117
In the [cell cycle phase], cells grow and make organelles
In the G2 phase, cells grow and make organelles
118
Eukaryotes have [#] chromosome(s)
Prokaryotes have [#] chromosome(s)
Eukaryotes have multiple chromosome(s)
Prokaryotes have one chromosome(s)
Note:
1.The prokaryotic chromosome is circular
2. Plasmids are different from chromosomes and contain DNA that is not essential for survival
119
The [...] makes viscous fluid to clean out the urethra
The bulbourethral gland makes viscous fluid to clean out the urethra
120
Pathway of sperm during ejaculation:
[...]
Pathway of sperm during ejaculation:
SEVE(N) UP mnemonic
Seminiferous Tubules
Epididymis
Vas Defens
Ejaculatory ducts
(Nothing)
Urethra
Penis
120
[...] states that two alleles of each gene become separated and only one allele from each parent will be passed to the offspring
The law of segregation states that two alleles of each gene become separated and only one allele from each parent will be passed to the offspring
Parent Offspring
YY. →. Y or Y
Yy → Y or y
yy →. y or y
121
At the [...] checkpoint, cells choose whether or not to divide
At the G1 checkpoint, cells choose whether or not to divide
P53 is in charge
122
Eukaryotic cells reproduce via [...]
Eukaryotic cells reproduce via mitosis
123
Interphase includes [cell cycle phases]
Interphase includes G1, S, and G2 phases
Phase where the cell spends most of its life
124
In [mitosis phase], the DNA condenses, centrioles migrate to opposite poles, and microtubules form
In prophase, the DNA condenses, centrioles migrate to opposite poles, and microtubules form
125
Semen is a combination of [...] and [...]
Semen is a combination of sperm and seminal fluid
126
Humans have [#] pairs of chromosomes, for a total of [#] chromosomes
Humans have 23 pairs of chromosomes, for a total of 46 chromosomes
127
DNA is replicated in the [cell cycle phase]
DNA is replicated in the S phase
S = synthesis phase
128
Fertilization occurs in the [...]
Fertilization occurs in the fallopian tube
129
At the [...] checkpoint, the cell will check that the DNA has replicated correctly
At the G2 checkpoint, the cell will check that the DNA has replicated correctly
130
[...] refers to genetic conditions associated with mutations in genes on the X chromosome
X-linked recessive inheritance refers to genetic conditions associated with mutations in genes on the X chromosome
131
During the [cell cycle phase], cells synthesize mRNA and proteins
During the G1 phase, cells synthesize mRNA and proteins
This is to prepare for subsequent steps leading to mitosis
G1 stands for "Gap 1"
132
In [mitosis phase], sister chromatids separate and move to opposite poles
In anaphase, sister chromatids separate and move to opposite poles
Anaphase = "Apart"
133
