Cell division, genetics and molecular biology Flashcards
Interphase
Spermatogenesis
Production of sperm begins at puperty
Uses the process of meiosis1 and meiosis 2 - haploid
Oogenesis
Production of eggs begins at birth
Use the process of meiosis 1 and meiosis 2 - haploid
Monthly cycle - out of the 4, 1 survives and 3 die
Meiosis = unidentical cells
Haploid; n=23
Gametes
Cell division in sexual reproductive strategies
Stages of mitosis = identical cells
PMAT
Prophase - DNA - chromosomes, nuclear membrane brakes down, centriollies provide attachments for spindle fibers that help move chromosomes
Metaphase - chromosomes line up on equatorial plate
Anaphase - spindle fibers shorten, 2 sister chromosomes are seperated
Telophase - chromosomes reach destination, clevage furrow forms, nuclear membrane reforms, spindle fibers disintegrate
Conjugation (Prokaryotes)
Transfere of genetic material from 1 cell to another by cell to cell contact.
Binary Fiusion (Prokaryotes)
Cell dividing method used by bacteria; used when bacteria have only 1 circular chromosome and no nucleus.
Sexual reproduction
Involves the production of gametes by meiosis followed by fertilization between genetically distinct parental gametes to produce genetically distinct offspring, meiosis to create haploid gametes
Asexual reproduction
The reproductive in which a parent organism produces genetically identical offspring
Mitosis to create identical offspring
Faternal twins
2 oocytes are released instead of one
Identical twins
Single zygotes splits into 2 seperate bodies in the first few days
Nondisjunction
When homologous chromosomes/chromatids do not seperate
Monosomy - 1 less chroosome 45 chromosomes
Turner syndrome-female with 1x chromosome
Kinifler syndrome 2x and 1y chromosome
Trisomy - 1 more chromosome 47 chromosomes 21=down syndrome 18=edward syndrome
Symptoms - ceased tounge, big forhead and mental disabilities
Independent assortment
During metaphase 1, chromosomes are arranged in homologus pairs along the equator plate of the cell. In each pair the chromosomes of the maternal origin is oriented toward one pole of the cell while the chromosome of parental origin is oriented towards the other pole.
Crossing over
As paris of chromosomes come together the chromatids will interwine
Karyotype
The set of chromosomes that an individual possess
Sex - linked traits
Sex-linked traits are traits determined by genes
located on sex chromosomes (usually the X
chromosome)
The symbols for sex linked traits are written with a
capital X and a superscript of the letter
representing the allele i.e. hemophilia - Xh
X - Chromosomes
It has been estimated that the human X chromosome
carries between 100 and 200 different genes
Sex linked traits include: color blindness, hemophilia,
night blindness, near sightedness, male pattern
baldness and Duchenne Muscular Dystrophy
Many recessive lethal X-linked disorders occur more
often in males
Sex-linked traits
More males will express the trait than females
Females will be carriers but will not express the trait
– are able to pass it onto their children
i.e. hemophilia, color blindness, Duchenne muscular
dystrophy
Crossing over
Crossing over - occurs during prophase I when
homologous pairs sometimes have sections that flip
This results in more diversity than expected
The farther apart the genes the more likely crossing
over is going to occur compared to those genes that
are closer to the centromere
