Week 13 Flashcards
Principles of Genetics and Reproductive Physiology
Genetics is the study of? (3)
Genes, heredity, and variation in living organisms
A DNA segment on a chromosome that determines a specific trait is called a?
Gene
A gene is a basic unit of?
Heredity
What carry the instructions for producing proteins that influence traits like eye color, height, and blood type?
Genes
Each gene has its own specific location on a?
Chromosome
How many genes make up a chromosome?
Thousands
Human cells have how many chromosomes contained in
every cell in our bodies?
46 (23 pairs)
Every cell except gametes
What are located on either side of
centromere?
“Chromosome arms” (long and a short arm)
What is the spot where the chromosome arms are connected called?
Centromeres
What helps to keep chromosomes properly aligned during the complex
process of cell division?
Centromeres
What protects the ends of the chromosomes?
Telomeres
What are the (2) main categories of
chromosomes?
- Autosomes
- Sex Chromosomes
How many pairs of chromosomes are autosomes?
22 pairs
If 22 pairs of chromosome are autosomes, then what is the last pair of chromosomes?
Sex chromosomes
What are the (2) sex chromosomes?
X and Y
What are the chromosomes in females?
XX
What are the chromosomes in males?
XY
What is the asexual reproduction that leads to the division of the cell nucleus?
Mitosis
Mitosis results in how many daughter cells?
2 identical daughter cells
The reduction division that leads to two
successive divisions of the nucleus to form gametes is known as?
Meiosis
Meiosis results in how many daughter cells?
Results in 4 daughter cells, with half the
number of chromosomes (23)
In meiosis, are the daughter cells identical or different
Different
What is a person’s genetic information inherited from the parents called?
Genotype (the genetic code in their cells)
What is a person’s recognizable traits associated with the genotype?
Phenotype (the physical expression /
observed properties)
If two people’s genotypes are different, will their phenotypes be different also?
Not necessarily, expression of the trait
will depend on whether the version
coded for is dominant or recessive
What is an allele?
Different versions of a gene
What is a dominant allele?
Expressed even if only one copy
of the allele is present
What is a recessive allele?
Two copies of the recessive allele
need to be present in order for
trait to be expressed.
If both your copies of a gene are the same, you are?
Homozygous
If both your copies of a gene are different, you are?
Heterozygous
If you are heterozygous for a recessive trait and do not show it, you are a?
Carrier
What is the result from changes to genes of chromosomes?
Genetic mutation
Most hereditary disorders are
caused by what kind of defects?
Autosomal defects
Disease phenotype arises when
both alleles are?
Recessive
What are the primary sex organs?
Gonads (the glands that produce
reproductive cells)
What are gonads in males?
Testes
What are the gonads in females?
Ovaries
Gonads produce and secrete? (2)
Gametes and hormones
What are male gametes?
Sperm
What are female gametes?
Ova - Eggs
What is the term for the process of making sperm cells?
Spermatogenesis
What type of cells undergo rapid mitosis to produce more stem cells before puberty?
Spermatogonia (stem cells)
During puberty, what hormone is secreted in increasing amounts?
Follicle-stimulating hormone (FSH)
What kind of hormone is FSH?
Tropic hormone (a hormone that stimulates other glands to release their own hormone)
FSH is a tropic hormone that in males targets what gonad to stimulates
sperm production?
The testes
Sperm are formed were in the testes?
Seminiferous tubules
Meiosis + Spermiogenesis =
Spermatogenesis
Spermatids come from?
Daughter cell B in meiosis
Spermiogenesis formula is?
Spermatids → Sperm
Primary spermatocyte undergoes meiosis I to form?
2 secondary spermatocytes
Both secondary spermatocytes undergo meiosis II and form?
To form a total of 4 spermatids (n)
Streamlining process that strips excess cytoplasm from a spermatid and modifies it into a sperm is referred to as?
Spermiogenesis
Mature sperm is compacted into what (3) regions?
- Head
- Midpiece
- Tail
The entire process of spermatogenesis, including spermiogenesis takes how many days?
Takes 64 to 72 days
What is the role of gonadotropin-releasing hormone (GnRH)?
Stimulates anterior pituitary to release FSH and LH
What is the role of FSH?
Stimulates spermatogenic cells to produce sperm
What is the role of LH?
Stimulates interstitial cells in seminiferous tubules to release testosterone
What is the final trigger for
spermatogenesis?
Testosterone
What stimulates growth spurt,
primary sex characteristics
and secondary characteristics in males?
Testosterone
Where is GnRH released?
Hypothalamus
FSH and LH are released by?
Anterior pituitary
Testosterone is released by?
Testes
When testosterone levels increase, they send a signal to the brain’s hypothalamus and the anterior pituitary gland to do what?
To slow down the production of hormones that stimulate testosterone. This is the body’s way of keeping testosterone levels balanced.
In females, what contains an immature oocyte?
Primary follicle
In females, a growing follicle with a maturing oocyte is a?
Vesicular (Graafian) follicle
When ____________ occurs, the follicle
ruptures when the egg is mature and ready to be ejected from the ovary
Ovulation
Ovulation occurs every how many days?
28 days
During ovulation, the ruptured follicle is transformed into what?
A corpus luteum
What is the process of producing ova (eggs) in a female called?
Oogenesis
What are female stem cells found in a developing fetus?
oogonia
Oogonia undergo mitosis to produce?
Primary oocytes
Primary oocytes are surrounded by a single layer of cells that form what in the ovary?
Primary follicles
What kind of stem cells will no longer exist at birth (females)?
Oogonia
At birth, what is there a lifetime supply of that is already in place in ovarian follicles?
Primary oocytes
Are primary oocytes inactive until puberty?
Yes
At puberty, what gets released that causes some primary follicles to mature each month in preparation for ovulation?
Follicle stimulating hormone (FSH)
Cyclic monthly changes in the ovary constitute what cycle?
The ovarian cycle
There is a spike in FSH and LH around what day of the ovarian cycle to cause
ovulation?
Day 14
Meiosis II is completed after ovulation only if what happens?
Sperm penetrates the oocyte
In meiosis II, what is produced? (2)
- Ovum
- 2 additional polar bodies
In meiosis, males produce how many functional sperms?
4
In meiosis, females produce how many ovum and polar bodies?
Produces 1 functional ovum and 3
tiny polar bodies
What is is large, non-motile, and has nutrient reserves to nourish the embryo until implantation?
The egg
What are tiny, motile, and equipped with nutrients in seminal fluid?
Sperm
What (2) things regulate the production of estrogens and progesterone by the
ovaries?
FSH and LH - from the anterior pituitary
How many days is the menstrual phase?
1-5 days
In what phase of the uterine cycle is the endometrium sloughed off and hormones are at their lowest levels?
Menstrual phase
By day 5 of the menstrual phase, the
growing follicles will produce more?
Estrogen
How many days is the proliferative phase?
Days 6-14
In what phase of the uterine cycle has the estrogen levels rise and the regeneration of endometrium?
Proliferative phase
At what phase of the uterine cycle does ovulation end?
Proliferative phase
How many days is the secretory phase?
15-28 days
In what phase of the uterine cycle is there a rise in progesterone and endometrium is more vascular and ready for implantation?
Secretory phase
What are the (3) phases of the uterine cycle?
- Menstrual
- Proliferative
- Secretory
When does the secretory phase begin?
Immediately after ovulation
Does FSH or LH cause ovulation?
LH
What hormone stimulates a small number of primary follicles to grow and mature each month?
FSH
Estrogen is produced by?
Primary follicle cells
What hormone is responsible for the regeneration of endometrium during
proliferative phase?
Estrogen
What hormone causes female secondary sex characteristics?
Estrogen
Progesterone is produced by?
Corpus luteum
What hormone maintains the endometrium during the secretory phase?
Progesterone
What are the (4) female secondary sex characteristics?
- Breasts
- Axillary and pubic hair
- Widening of the pelvis
- Onset of menses
(menstrual cycle)