Biology Chapter 2: Reproduction (3 Stars) Flashcards
Diploid (2n) cells have ____ copies of each chromosome; ______ cells have one copy.
Two
haploid (n)
The cell cycle contains five stages. The G1, S, and G2 stages are collectively called _____, during which the DNA is uncoiled in the form of chromatin.
Interphase
In the _____ stage, cells create organelles for energy and protein production, while also increasing their size.
G1 stage (presynthetic gap), The restriction point, during which the DNA is checked for quality, must be passed for the cell to move into the S stage.
In the S stage (synthesis), DNA is _______.
DNA is replicated. The strands of DNA, called chromatids, are held together at the centromere.
In the G2 stage (postsynthetic gap), there is further ____ and replication of ______ in preparation for mitosis. Another quality checkpoint must be passed for the cell to enter into mitosis.
cell growth and replication of organelles
Checkpoint must be passed for the cell to enter into mitosis.
In the ____ stage , mitosis and cytokinesis occur.
M stage (mitosis)
In the ____ stage, the cell performs its function without any preparation for division.
G0 stage
p53 plays a role in the ____ major checkpoints of the cell cycle A & B
2v major checkpoints of the cell cycle
(G1 to S, and G2 to M).
Cyclins bind to _____, phosphorylating and activating transcription factors for the next stage of the cell cycle.
CDKs
Cancer occurs when cell cycle control becomes deranged, allowing damaged cells to undergo _____ without regard to quality or quantity of the new cells produced. Cancerous cells may begin to produce ______ that allow them to escape their site and invade or metastasize elsewhere.
mitosis
factors
Mitosis produces two genetically identical haploid or diploid ______ cells from a single cell and occurs in somatic cells.
identical diploid daughter
In _______, (CNNCS)
chromosomes condense
nuclear membrane dissolves
nucleoli disappear,
centrioles migrate to opposite sides of the cell,
spindle apparatus begins to form.
prophase
The kinetochore of each chromosome is contacted by a spindle fiber.
What happens in metaphase?
In metaphase, chromosomes line up along the metaphase plate (equatorial plate).
In _______, sister chromatids are separated and pulled to opposite poles.
Anaphase
What happens in telophase? NSC
In telophase,
the nuclear membrane reforms,
spindle apparatus disappears,
cytosol and organelles are split between the two daughter cells through cytokinesis.
Meiosis occurs in _______ and produces up to_____ nonidentical haploid sex cells (gametes).
gametocytes (germ cells)
4
Meiosis has ____# round of replication and____ # rounds of division
1 round of replication
2 rounds of division (the reductional and equational divisions)
In meiosis I, ______ pairs of chromosomes are separated from each other.
Homologous: are chromosomes that are given the same number, but are of opposite parental origin.
In prophase I, the same events occur as in prophase of mitosis, except _______.
The # chromatids are referred to as a tetrad
This accounts for Mendel’s _____ law (of independent assortment).
that homologues come together and intertwine in a process called synapsis.
4 chromatids are referred to as a tetrad
Mendel’s second law (of independent assortment).
In metaphase I, _______ chromosomes line up on opposite sides of the metaphase plate.
homologous
In ______ I, homologous chromosomes are segregated to opposite poles of the cell.
Mendel’s ____ law (of segregation).
anaphase I
Mendel’s first law (of segregation).
In ________ I, the chromosomes may or may not fully decondense, and the cell may enter interkinesis after ______.
telophase I
cytokinesis.
In meiosis II, _______ are separated from each other in a process that is functionally identical to mitosis. Sister chromatids are copies of the same DNA held together at the centromere.
sister chromatids
Sister chromatids are copies of the same DNA held together at the centromere.
Biological sex is determined by the _____ pair of chromosomes in humans, with XX being female and XY being male.
23rd pair
The _ chromosome carries a sizeable amount of genetic information
X chromosome
The __ chromosome carries little genetic information, but contains the SRY gene
The Y chromosome
(sex-determining region Y) gene, which causes the gonads to differentiate into testes.
Sperm develop in the ________ in the testes. They are nourished by Sertoli cells.
Seminiferous tubules
Interstitial cells (of Leydig) secrete _______ and other male sex hormones (androgens).
testosterone
The testes are located in the _____, which hangs outside of the abdominal cavity and has a temperature 2° to 4°C lower than the rest of the body.
Scrotum
Once formed, sperm gain motility in the ______and are stored there until ejaculation.
Epididymis
During ejaculation, sperm travel through the ________to the ejaculatory duct to the ______ and out through the penis.
vas deferens
urethra
The seminal vesicles contribute _____ to nourish sperm and produce alkaline fluid.
fructose
The ______ gland also produces alkaline fluid.
Prostate gland
The bulbourethral glands produce a clear _____ fluid that cleans out any remnants of urine and lubricates the urethra during sexual arousal.
clear viscous fluid
Semen is composed of sperm and _______ from the glands above.
seminal fluid
In spermatogenesis, ____ haploid sperm are produced from a spermatogonium.
4
After S stage, the germ cells are called ______ spermatocytes.
primary
After ______, the germ cells are called secondary spermatocytes.
meiosis I
After meiosis II, the germ cells are called _____
spermatids.
After _______, the germ cells are called spermatozoa.
maturation
Sperm contain a head, ______, and flagellum.
midpiece
The_____ contains the genetic material and is covered with an acrosome— a modified Golgi apparatus that contains enzymes that help the sperm fuse to and penetrate the ovum.
head
The midpiece generates _____ from fructose and contains many mitochondria.
ATP
The flagellum promotes ______.
motility
The female reproductive system only contains ______structures.
internal
Ova (eggs) are produced in ______ in the ovaries.
follicles
Once each month, an egg is ovulated into the _______ and is drawn into the fallopian tube or oviduct.
peritoneal sac
The fallopian tubes are connected to the _____, the lower end of which is called the cervix.
uterus.
The vaginal canal lies below the ______ and is the site where sperm are deposited during intercourse. Birth also occurs here.
cervix
The external female anatomy is known as the _____.
vulva
In oogenesis, one _____ ovum and a variable number of polar bodies are formed from an oogonium.
haploid
At birth, all oogonia have already undergone replication and are considered _____ oocytes. They are arrested in ______ I.
primary oocytes
prophase I.
The ovulated egg each month is a secondary oocyte, which is arrested in ________ II.
metaphase II.
If the oocyte is fertilized, it will complete meiosis II to become a _______.
true ovum.
Cytokinesis is uneven in oogenesis. The cell receiving very little cytoplasm and organelles is called a _____
polar body.
Oocytes are surrounded by the _______, an acellular mixture of glycoproteins that protect the oocyte and contain the compounds necessary for sperm binding, and the corona radiata, which is a layer of cells that adhered to the oocyte during ovulation.
zona pellucida
Gonadotropin-releasing hormone (GnRH) from the hypothalamus causes the release of follicle-stimulating hormone (FSH) and __________, the functions of which depend on the sex of the individual.
luteinizing hormone (LH)
In males, _____ stimulates the Sertoli cells and triggers spermatogenesis, while ____ causes the interstitial cells to produce testosterone.
FSH
LH
In females, _____ stimulates development of the ovarian follicles, while LH causes ovulation. These hormones also stimulate production of ____ and _____
FSH
estrogens and progesterone.
The menstrual cycle is a periodic growth and _____ of the endometrial lining.
shedding
GnRH secretion stimulates FSH and LH secretion, which promotes ______ development.
follicle development. Estrogen is released, stimulating vascularization and glandularization of the decidua.
Ovulation is stimulated by a sudden surge in _____. This surge occurs because estrogen stops having negative feedback effects at a certain threshold and begins to have positive feedback effects.
LH.
In the luteal phase, ____ promotes the ruptured follicle to become the corpus luteum, which secretes progesterone that maintains the uterine lining. High estrogen and progesterone levels cause ______ feedback on GnRH, LH, and FSH.
LH
negative feedback
Menstruation occurs if there is no fertilization. As the estrogen and progesterone levels drop, the endometrial lining is sloughed off, and the block on _____ production is removed.
GnRH
If fertilization does occur, the _____ produces______which, as an LH analog, can maintain the corpus luteum.
blastula
human chorionic gonadotropin (hCG)
Near the end of the first trimester, hCG levels drop as the placenta takes over progesterone production.
Menopause occurs when the ovaries stop producing ____ and ______, usually between ages 45 and 55. Menstruation stops and ____ and _____ levels rise. Physical and physiological changes accompanying menopause include flushing, hot flashes, bloating, headaches, and irritability.
estrogen and progesterone,
FSH and LH levels rise.
Mutations of ____-linked genes can cause sex-linked disorders.
X-linked
_____ 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.
Males
_____ with one copy of the affected allele are called carriers.
Women
What is Testosterone responsible for?
Maintenance and development of the male reproductive system
male secondary sex characteristics (facial and axillary hair, deepening of the voice, and changes in growth patterns).
Difference between Mitosis & Meosis:
How is Metaphase I different from Metaphase (Mitosis)?
Homologous chromosomes line up on opposite sides of the metaphase plate, rather than individual chromosomes lining up on the metaphase plate
