Cytogenetics Flashcards
Complex multi-step process that is complete in 24 hours
The sperm from a male meets an ovum from a female and forms a zygote
Fertilization
Fertilized ovum
Zygote
The point in which pregnancy begins and leads to a 280-day journey for a female
Fertilization
Where the sperm and oocytes are manufactured
Gonads
The reproductive organs are organized similarly in the male and female. Each system has
Gonads
Tubular structure that transport these cells
Hormones and secretions that control reproduction
Originate in seminiferous tubules within the
testes
Also passes through the epididymis and ductus
deferentia, where they mature before exiting the
body through the urethra during sexual
intercourse
Male gametes
Originate in the ovaries.
Each month after puberty, one ovary releases
an oocyte into a uterine tube.
Female Gametes
Also called eggs, are female gametes
Oocytes
Packed, paired, oval organs of seminiferous
tubules
Male gonads
Testes
Testes lie outside the abdomen with a sac caleed
Scrotum
A tightly coiled tube in which sperm cells mature
and are stored.
Epididymis
Epididymis continues to another tube
Bends behind the bladder and joins urethra
Ductus deferens
Tube that carries sperm and urine out of the
body through the penis.
Urethra
What happens during sexual arousal
Penis becomes erect, which enables it to penetrate and deposit sperm in the female reproductive tract.
A pleasurable sensation.
Orgasm
Accompanied by rhythmic muscular contractions that eject the sperm from each ductus deferens (through urethra and the penis.)
Peak of sexual stimulation
What happens at the peak of sexual stimulation
Orgasm
Ejaculation
Discharge of sperm from the penis (delivers 200 to 600 million sperm cells)
Ejaculation
3 Glands that add secretion along the sperm’s path
Prostate gland
Seminal vesicles
Bulbourethral gland
The ductus derentia/deferens pass through this
Produce a thin, milky, acidic fluid that activates the sperm to swim
Prostate gland
Opening into the ducturs deferens’ a duct
Secrete ____ ( an energy-rich sugar) and hormonelike _____(stimulate contractions in the female that help sperm and oocytes meet)
Seminal vesicle
Fructose
Prostaglandins
Each about the size of a pea
For alkalinity of pH mucus
Join the urethra where it passes through the body wall
Secrete an alkaline mucus that coats the urethra before sperm are released.
Bulbourethral Gland
Female sex cells develop in paired organs in the abdomen
Female gonads
Houses oocytes in different states of development
Ovaries
Muscular, cadlike organ
Th uterine tube carries the ooctye in this organ
Its lower end narrows and leads to the _____
Uterus or the womb
Cervix
Opens into a tubelike vagina
Cervix
Where the oocyte (released from the ovary) fmay encounter the sperm
If the sperm enters the oocye, and the DNA of the 2 gametes merges into a new nucleus
Uterine Tube
After a day, the first cell divides while moving through the uterine tube.
Settles into a lining of the uterus to continue divinding and developing into an ____
Fertilized Ovum
Embryo
If zygote is not fertilized, it will be expelled through
Menstuation
Fertilized Ovum
Zygote
Contains two copies of the genome (diploid)
Somatic Cells
____ coordinate the monthly menstrual cycle
Hormones
Contains one copy of the genome from each parent (haploid)
Germ cells (Sex cells / Gametes)
One set of chromosomes n=23
Non homologous chromosome
Haploid
_____ > _____
Haploid cell > Egg and sperm
____ > Zygote
Diploid cells
Two set of chromosomes
Pairs of homologous (n=36)
Diploid (2n)
Sculpts the distinctive characteristics of sperm and oocyte
Mturation
Mixes up trait combination
Occurs after Interphase
Type of cell division, halves the chromosomes number
Where gametes form special cells called Germline cells
Meiosis
Replication of DNA
Interphase
Contribute 23 different chromosomes constituting one copy of the genome, to a fertilized ovum
Gametes
Contain 23 pairs of chromosomes = 46 in total
One member of each pair comes from the father
Somatic CElls
Also called as homologs
Homologous pair
Chomorsome pairs have some genes in the same order bu tmay carry different alleles, or variants, of the same genes.
Homologous pair
First division of the gfenetic material in Meiosis
Reduces the number of replicated chromosomes from 46 to 23
Reduction Division or Meiosis I
46 to 23
The homologs align down the center of the cell
Each member of homologous pair attaches to a spindle fiber at an opposite pole
Metaphase I
Produces four cells from the two cells formed in the first division by splitting the replicated chromosoomes
Equational Division or MEIOSIS II
During synapsis, the homologs
exchange parts called cross over.
● All four chromatids that comprise each
homologous chromosome pair align as
exchanges occur.
● After crossing over, each homolog bears
some genes from each parent.
● Prior to cross over, all of the genes on a
homolog were derived from one parent.
● Generates genetic diversity by
recombining genes, mixing parental
traits.
● The capital and lowercase forms of the
same letter represent different variants (alleles) of the
same gene.
Cross over
Homologs move to opposite poles
TElophase I
Determines the combination of maternally and paternally derived chromosomes in the daughter cells.
Random alignment of chromosome during METAPHASE I
Homologs Separate
ANAHPHASE I
Chromosomes unfold into thin threads
Protein are manufactures, but DNA is not replicated a second time
Interphase II
The replicated chromosome align fown the center of the Cell
MEtaphase II
The centromeres part
The newly formed chromosomes (unreplicated form), move to opposite poles
Anaphase II
Marks the start of the second meiotic division
Chromosomes are again condensed and visible
Prophase II
Used for sexual reproduction, producing new gene combinatiuon
Meiosis
one division
Two daughter cells per cycle
Daughter cells genetically identical
Mitosis
Nuclear envelopes form around th four nuclei, which then separate into individual cells
Telophase II
Two divisions
Four daughter cells per cycle
Daughter cells genetically different
1n
germline cells
Sexual Maturity
Meiosis
Used for groth, repair, and asexual reproduction
Mitosis
The forming gametes of the maturing male and female
proceed through similar stages, but with sex-specific
terminology and vastly different timetables.
A male begins manufacturing sperm at puberty and
continues throughout life.
Gametes Mature
Two types of gametes mature
Spermatogenesis
Oogenesis
Must travel about 18
centimeters (7 inches)
to reach an oocyte.
Consists: Tail, body or
midpiece, and a head
region
Sperm
Formation of sperm cells
Also called sperm formation
Spermatogenesis
Has distinct regions that assist in delivering DNA to an oocyte
0.006 centimeter (0.0023 inch) long
Sperm
Within the
___, DNA
wraps around
proteins (but
genetically
inactive)
head
Membrane-covered
area on the front end of the sperm
Contains enzymes that help the sperm cell
penetrate the protective layers around the
oocyte.
Acrosome
Where spermatogenesis begin
A diploid stem cell
Spermatogonium
One cell: continues to specializes into a ____
Mature Sperm
Other cells: remain a ____ (able to self-renew and continually produce more sperm)
Stem cell
As spermatogonia mature, they accumulate cytoplasm
and replicate their DNA, becoming ____
Primary Spermatocytes
Meiosis I: Each primary spermatocyte divides >
forms two equal-sized haploid cells called
Secondary Spermatocytes
Each secondary spermatocytes
divides to two equal-sized spermatids > each
develops _____ or flagellum (has many
mitochondria to propel the sperm by splitting
ATP to release energy)
Sperm tail
Concentrates most of the cytoplasm into a one
large cell called an ___ (or egg)
Oocyte
Other products called polar bodies contain the
other ____ sets of chromosomes and normally
degenerate.
three
Also called Ovum formation
Primary oocytes have the diploid number of 23
chromosome pairs.
Spermatid Differentiation
An event after puberty where in the most mature
oocyte in one ovary bursts out each month
Ovulation
A cell where most of the cytoplasm among the
four meiotic products in the female ends up in.
Ovum
A diploid cell where oogenesis begins
Unlike male cells, oogonia are not attached to each other
Surrounded by follicle cells each
As it grows, cytoplasm accumulates, DNA replicates, the
cell becomes a primary oocyte.
Oogonium
Produces cells of different sizes to ensue meiotic division
Oogonium
Primary oocyte divides into two cells > (1) small cell with very little cytoplasm called first ____ ___, (2) a larger cell called secondary oocyte
Polar body
Tiny first polar body divide to yield two polar bodies of equal size (with unreplicated chromosomes) or decompose > secondary oocyte divides unequally to produce another small polar body (with unreplicated chromosomes)
MEIOSIS II
Type of miscarriage
A rare case of when the sperm fertilizes a polar body.
In this case, the woman’s hormones respond as if she is
pregnant, but a disorganized clump of cells that is not an embryo grows for a few weeks (but also leaves the woman’s body)
Blighted Ovum
A female ovulates about 400 oocytes between puberty
and menopause.
Only one in three of the oocytes that do meet and merge
with a sperm cell will continue to grow, divide, and specialize to eventually form a new individual.
blighted ovum
A prenatal human for the first 8 weeks, when rudiments of all body parts form.
Embryo
To be considered an embryo if it begins to develop tissue layers at about ___ weeks.
2
In the first week, the embryo is in a “______” stage because it has not yet settled into the uterine lining
Preimplantation
Occurs after the eighth week of prenatal
development.
Where structures grow and specialize
From the start of the ninth week until birth, the prenatal human organism is the fetus.
Fetal Period
Also called as conception.
Fertilization
A sperm cell can survive in a woman’s body for up to __ days
3
A process where the woman’s body helps sperm reach an oocyte.
Chemically activates sperm, and the oocyte secretes a chemical that attracts sperm
Capacitation
A covering of follicle cells that the sperm first contacts
Guards a secondary oocyte
Corona Radiata
Begins when the outer membranes of the sperm and
secondary oocyte meet and a protein on the sperm head
contacts a different type of protein on the oocyte.
Induces the oocyte (arrested in metaphase II) to complete meiosis
Fertilization
When the sperm’s acrosome then bursts, it releases enzymes that bore through a protective layer of _____ (the zona pellucida) beneath the corona radiata
Glycoprotein
Within 12 hours of sperm penetration, the ovum’s nuclear
membrane disassembles, and the two sets of chromosomes (called ____) approach one another
Pronuclei
From ovulation to implantation
A beginning period of frequent cell division that occurs a day after fertilization where the zygote is divided by mitosis
Cleavage
It completes when the two genetic packages meet and merge, forming the genetic instructions for a new individual.
Fertilization
During this period, organelles and molecules from the secondary oocyte’s cytoplasm still control cellular activities, but some of the embryo’s genes begin to function
Creates Blastocyst
Cleavage
Resulting early cells
Forms a solid ball of sicteen or more cells, the embryo is called a ____
Blastomeres
Morula
Morula came from Latin form “_____”, which it resembles
Mulberry
The outermost cells of the blastocyst
Secretes human Chorionic gonadotropin, a hormone that prevents menstruation
Trophoblast
A formed clump on the inside lining of some cells.
Its formation is the first event that distinguishes cells from each other by their relative positions.
When it continues developing, it forms the embryo.
Inner cell mass
Occurs after a week after fertilization where the blastocyst nestles into the uterine lining.
Takes about a week
Implantation
What is hCG
Human Chorionic Gonadotropin
This hormone is detected in a
woman’s urine or blood as
one sign of pregnancy
Human Chorionic gonadotropin (hCG)
Mother tends to have 2 mature oocytes, this is called ___
Heteropaternal Superdecundation
Fraternal occurs about ___
2.4%
During the second week of prenatal development, a space called the amniotic cavity forms between the inner cell mass and the outer cells anchored to the uterine lining.
Then the inner cell mass flattens into a two-layered embryonic disc.
Embryo Formation
Germ layers of Embryonic Development
Ectoderm
Mesoderm
Endoderm
Layer neearest the amniotic cavity
Ectoderm
Ectoderm forms the ff organs:
Nervous system
Skin
Third layer
Forms in the middle
Mesodorm
Mesodorm forms the ff organs:
Muscle
Skeleton
Kidneys
Reproductive system
Inner layer, closer to the blastocyst cavity.
Endoderm
Endoderm forms the ff. organ:
Endocrine glands
Lungs
Digestive tract
Liver
Three-layered, curved, sandwich-like structure
Also called the primordial embryo
Gastrula
Epidermis of skin and epidermal derivatives, hair, nails, glands of the skin, lining of cavities
Ectoderm
Dermis of skin: dentin of teeth
Epithelium of blood vessels, lumphatic vessels, cavities
Mesoderm
Epithelium of pharynx, auditory canal, tonsils, thyroid, parathyroid, thymus, larynx, trachea, lungs, digestive tract
Endoderm
Stages and Events of early human prenatal development
Fertilized ovum
cleavage
Morula
Blastocyst
Gastrula
12 to 24 hours following ovulation
Oocyte fertilized; zygote has 23 pairs of chromosomes and is genetically distinct
Fertilized ovum
30 hours to third day
Mitosis increase cell number
Cleavage
Third to fourth day
Solid ball of cells
Morula
Formed from the chorionic villi by 10 weeks.
Links the woman and her fetus for the rest of the pregnancy.
It secretes hormones that maintain pregnancy and sends nutrients to the fetus.
Placenta
Fifth day through second week
Hallowed fluid-filled ball forms trophoblast (outside) and inncer cell mass, which implants and flattens to form embryonic disc
Blastocyst
End of second
Primary germ layers form
Grastula
During the second week of prenatal development, a space called the amniotic cavity forms between the inner cell mass and the outer cells anchored to the uterine lining.
Then the inner cell mass flattens into a two-layered embryonic disc.
Chorionic villi
Project into pools of the woman’s blood.
Blood system and the embryo’s are separate, but nutrients and oxygen diffuse across the chorionic villi from circulation to the embryo.
Chorionic villi
A membrane surrounding the embryo that gives rise to the umbilical blood vessels
Allantois
Manufactures blood cells, as does the allantois
Yolk Sac
Forms around vessel and attaches to the center of the placenta
Umbilical cord
Swells with fluid toward the end of the embryonic period while the yolk sac shrinks.
Cushions the embryo and maintains a constant temperature and pressure
Amniotic sac
The ____ contains fetal urine and a few fetal cells.
Amniotic acid
Examines chromosomes from cells snipped off the chorionic villi at 10 weeks.
Chorionic villus sampling
Secreted from the stem cells that give rise to lung cells
Should be present in alveoli
Measure in which the baby for the baby to breathe
Surfactant
A sample of amniotic fluid is taken and fetal cells in it are examined for biochemical, genetic, and chromosomal anomalies.
Amniocentesis
Prenatal Tests
Chorionic villus sampling
Amniocentesis
Analysis of cell-free DNA
Types of Identical Twin
Fraternal; or dizygotic (DZ), twins
Identical, or monozygotic (MZ), twins
Twins, and other multiple arise early in development
This can happen if ovulation occurs in two ovaries in the
same month or if two oocytes leave the same ovary and are both fertilized.
Formation of Multiples
Descend from a single fertilized ovum and therefore are genetically identical. They are natural clones
Identical, or monozygotic (MZ), twins
Result when two sperm fertilize two secondary oocytes.
These twins develop their own amniotic sacs, yolk sacs, allantois, placentas, and umbilical cords.
Fraternal, or dizygotic (DZ), twins
Certain genetic abnormalities or toxic exposures can affect development in an embryo or fetus, causing birth defects.
Birth Defects
The time when genetic abnormalities, toxic substances, or viruses can alter a specific structure is its critical period.
Many birth defects are caused by toxic substances the pregnant woman encounters.
The critical period
Chemicals or other agents that cause birth defects are called ____
Teratogens
Teratogens came from the Greek word for ____
monster-causing
Most drugs are not teratogens. Whether or not exposure to a particular drug causes birth defects may depend upon a woman’s genes.
Teratogens
Gene Variant of Teratogens
MTHFR C677T
A malnourished fetus has intrauterine growth retardation
(IUGR), and though born on time, is quite small. Premature infants, in contrast, are small but are born
early, and are not predisposed to conditions resulting from IUGR.
Adult onset inherited disease
Means moving through the life cycle, despite advertisements for products that promise to reverse the process.
Aging
As we age, the limited life spans of cells are ___ in the waxing and waning of biological structures and functions.
Reflected
A component of red wine, dark chocolate, and raspberries.
Resveratrol
Protect against:
Hypertension, diabetes, cardiovascular disease
Apoliprotein C3 (APOC-3)
Type of enzyme called ___ that regulates energy use in cells by altering the expression of certain sets of genes
sirtuin
Types of genes that affect longetivity control:
Immune system functioning
Insulin secretion and glucose metabolism
Response to stress
The cell cycle
DNA repair
Lipid (including cholesterol) metabolism
Nutrient metabolism; and
Production of antioxidant enzymes
Seems to prevent or delay several
diseases that are more common in the aged, such as ____
heart disease and neurodegenerative conditions
Protects against:
Poisoning, digestive problems
Bitter taste recepror (TAW2R16)
Protects against:
Cardiovascular Disease
Cholesteryl ester transfer protein (CETP)
Protects against:
Cancer, cardiovascular disease
Forkhead box O3 (FOXO3)
Protects against:
Diabetes, cancer
Growth Hormone Receptor (GHR)
Protects against:
Oxidative damage, poor energy se
Uncoupling proteins (UCP 2,3,4)
