wk5?+Mutation, Genetic Variation, Gametogenesis, ERRORS IN CELL CYCLE Flashcards
- are the original source of genetic diversity
- create different versions of genes called alleles
- reshuffling of alleles during sexual reproduction produces genetic variation
MUTATION
True or false? hays pagod na ba kau? same p
Homologous pairs of chromosomes orient randomly at metaphase I of meiosis kaya may genetic variation
TRUE SO MUCH!!!
in ___________ __________, each pair of chromosomes sorts maternal and paternal homologs into daughter cells INDEPENDENTLY(clue toh) of the othe pairs
INDEPENDENT ASSORTMENT
the number of combinations possible when chromosomes assort independently into gametes is 2^n (n is the haploid number)
so for humans 2^?
2^23!! so more than 8 million possible combinations of chromosomes
- produces recombinant chromosomes which combine genes inherited from each parent
- begins every early in prophase I as homologous chromosomes pair up gene by gene
CROSSING OVER
contributes to genetic variation by combining DNA from two parents into a single chromosome
CROSSING OVER
homologous portions of two nonsister chromatids trade places
CROSSING OVER
adds to genetic variation because any sperm can fuse any ovum
RANDOM FERTILIZATION
_______ _________ results in the accumulation of genetic variations favored by the environment
NATURAL SELECTION
means formation of gametes (sperm and ova)
GAMETOGENESIS
the process of development of spermatids from the male primordial germ cells and their differentiation into spermatozoa
SPERMATOGENESIS
- formation of female gametes
- differentiation of female primordial germ cell (oogonium) into mature ovum
OOGENESIS
3 MAIN PHASES OF SPERMATOGENESIS AND OOGENESIS
- Period of MULTIPLICATION
- Period of GROWTH
- Period of MATURATION
the primordial germ cells multiply by mitotic cell division giving rise to OOGONIA(females) and SPERMATOGONIA(males)
PERIOD OF MULTIPLICATION
During these phase, both oogonia and spermatogonia grow into primary oocyte or primary spermatocyte
PERIOD OF GROWTH
in females, the primary oocyte undergoes two meiotic cell divisions:
1. gives rise to secondary oocyte + polar body
2. gives rise to mature ova and secondary polar body
PERIOD OF MATURATION
- male sex gland, located in scrotum
- produces sperm and androgens
TESTIS
sperm storage, complete of sperm maturation
EPIDIDYMIS
duct that transports the sperm from the scrotum to the prostate gland
VAS DEFERENS
secretes fluid rich in fructose to semen
SEMINAL VESICLE
contributes milky alkaline fluid that assists sperm activation
PROSTATE GLAND
contributes mucus to semen
COWPERS GLAND (BILBOURETHRAL GLAND)
organ of copulation in males
URETHRA (PENIS)
serve a number of functions during spermatogenesis like providing the cells with nourishment and molecular signals
SERTOLI CELLS
a normal baby girl had about 2 million primary oocytes in her ovaries but by 7 years old about how many remain?
300,000
during the reproductive years of a woman, only about how many are released?
400 to 500
basahin niyo lang to HQHAHHA d q magets
penetration of the sperm includes the secondary oocyte and the first polar body to complete meiosis II
kaya pa ba
may mali ba or wala?
MEIOSIS I
prophase I = 4n
metaphase I = 4n
anaphase I = 2n
telophase I = 2
MEIOSIS II
prophase II = 2n
metaphase II = 2n
anaphase II = n
telophase II = n
syempre wala, lilituhin ko pa ba kau, love u p balik ka na <33
all cancers starts with a?
GENE MUTATION
- positive cell cycle regulators
- a gene involved in normal cell growth
- mutations (changes) in this may cause it to become an oncogene, which can cause the growth of cancer cells
PROTO-ONCOGENES
when activated, can prevent the cell from undergoing uncontrolled division
TUMOR-SUPRESSOR GENE
- the procress of programmed cell death
- used to rid of the body of cells that have been damaged beyond repair awts
APOPTOSIS
changes in chromosome structure or number
CHROMOSOMAL ABERRATIONS
presence of additional chromosome SETS
EUPLOIDY
is the presence of a VARIABLE number of chromosomes
ANEUPLOIDY
inability of the spindle fiber to attract the chromosomes
NONDISJUNCTION
homologous chromosomes or sister chromatid fails to separate
NONDISJUNCTION
extra no.21 chromosome
TRISOMY 21 or DOWN SYNDROME
single line across the palm [seen with ppl with down syndrome]
*pakifamiliarize characs ng mga taong may gantong syndrome kineme kasi baka may pic pakita paidentify]
Palmar crease
characteristics of a person with down syndrome
small ears
short neck
almond-shaped eyes that slant up
tounge that tends to stick out
has 3 copies of chromosome number 18
TRISOMY 18 or EDWARDS SYNDROME
characteristics of a person with edwards syndrome
boxer fist - ung joke ni miss lawls bato bato pick
abnormally shaped physical characteristic
low set ears
internal organs forming and functioning differently
extra copy of chromosome no.13
TRISOMY 13 or PATAU SYNDROME
characteristics of a person with patau syndrome
poldactyly - extra toes
holoprosencephally - forebrain fail to divide
HYPOTELORISM - problems with the development of the NASAL passages (pinaka halata kaya nakacaps)
anophthalmia - reduced distance between the eyes
microphthalmia - absence of 1 or both eyes
only 1 sex chromosome
only occurs in girls
MONOSOMY or TURNER SYNDROME
bali [XO]
characs ng monosomy or turner syndrome
shorter than most girls
dont go thru normal puberty
webbed neck
3 sex chromosome na XXY
KLINEFELTER SYNDROME
characs klinefelter
taller than average stature
men with female characteristics (boobs/hips)
3 sex chromosome na XYY
JACOBS SYNDROME
characs jacobs syndrome
might be taller than boys
problems with spoken language
coordination problems
hand tremors
behavioral problems
