Somatic cells are body cells with 2N amount of chromosomes
Gametes are sex cells (eggs/sperm) produced through meiosis with 1N chromosomes
Homologous chromosomes are chromosomes that are very similar to each other, carrying the same type of genetic information that contain the same genes
diploid cells have 2 copies of each chromosome
haploid cells only have 1 copy of each chromosome
fertilization is the uniting of a sperm and an egg resulting in a diploid zygote (fertilized egg)
gametes of offspring do not have the same traits as teh parents due to crossing over and independent assortment (prophase + metaphase I)
during prophase I, each pair of chromosomes lines up next to its homologue, producing tetrads
a tetrad consists of four chromatids, where portions of the chromatids twist around each other and break off, attaching to the adjacent chromosomes (crossing over)
crossing over is the exchange of genetic information between segments of homologous chromosomes, and the offspring receives a new genetic information combination
independent assortment: homologous pairs line up opposite of each other at the equator (random paternal + maternal locations) and they are separated
variation leads to offspring to be able to survive, be better suited to their environment, and pass more variations to their offspring
crossing over leads to evolution
gametogenesis: meiosis produces 4 haploid cells that are different;
in males, meiosis results in four sperm cells
in females, four cells are produced but only one will become a functional egg, whilst the other 3 become Polar bodies.
all of the cytoplasm and organelles are put into the egg cell
Oogenesis: polar bodies form because eggs do not divide equally, resulting in cells with the same DNA but the other 3 are much smaller
spermatogenesis: produces 4 functioning sperm
sexual reproduction: gametes fusing to create a zygote
meiosis: the process that produces gametes
Nondisjunction: when chromosomes fail to separate evenly (occurs during anaphase)
contributes to genetic disorders, determined through karyotyping
autosomes: chromosomes that carry traits (chromosomes 1-22)
sex chromosomes - chromosomes with genes related to biological sex (XX - female, XY - male)
Karyotyping: the image of all 23 pairs of chromosomes, arranged by size (largest to smallest), with sex chromosomes being the last
Monosomy: the absence of one member of a pair of chromosomes; only one copy of a chromosome instead of the normal 2
Trisomy: the presence of an extra chromosome, with 3 copies of a chromosome instead of the normal 2 (ex: down syndrome)
cytokinesis: the division of the cytoplasm
mitosis: the division of the nucleus
in mitosis, each daughter cell will get a complete set of chromososmes
in mitosis, the 2 daughter cells will be identical to the mother cell.
S (synthesis) phase: the replication of DNA occurs
G2 phase: prepares the special cell structures necessary for cell division
Interphase: time between cell divisions and the chromosomes are replicated (90%. of the cell cycle)
centrioles: organelles that create the spindle fibers used to separate sister chromatids
prophase: chromosomes condense and become visible, nuclear envelope breaks down (IN MITOSIS)
Metaphase: the double stranded chromosomes become attached to the spindle fibers and move to the equator of the cell
Anaphase: centromeres replicate then separate and the spindle fibers begin to shorten, pulling the chromatids apart
Telophase: nuclear membrane begins to form around the new set of chromosomes (cleavage furrow occurs only in animal cells. plant cells have a cell plate.)
multicellular organisms: mitosis is used for growth and repair
unicellular organisms: mitosis results in new offspring
G0 phase: the non-dividing state of the cell cycle
uncontrolled cell growth: cells divide uncontrollably and form tumors, causing cancer