MITOSIS AND MEIOSIS Flashcards
what are the cells formed in cell division called
daughter cells
what are some controls on the cell division
G1 - has the cell grown to a suitable size ?
G2 - did DNA replicate correctly
M - did cell divide properly
these checkpoints are controlled by protein
Describe cell growth as it relates to a cut or scrape
the skin cells will go mitosis in order to divide and make exact copies of themselves.
Describe the events of the three phases of interphase
G1: Stands for time gap following cell division and preceding DNA replication.
Offspring grow to mature size
Perform all “cellular duties”
Make molecules and organelles
S: Cell’s DNA is copied (synthesized)
G2: Stands for time gap following DNA synthesis and preceding cell division.
Growth and preparation for cell division
Distinguish between chromosomes and chromatin.
chromatin is loosely coiled and not condensed. Chromosomes are a rod shaped structure made of DNA
describe the structure of chromatin
two identical halves that form as the DNA replicate.
One arm of a chromosome. Identical to its sister
phases of the cell cycle
G1, S, G2, PROPHASE, METAPHASE, ANAPHASE, TLEOPHASE, CYTOKINESIS
what takes place during prophase
tight coiling and condensing of DNA into chromosomes
centrosomes migrate to opposite poles of the cell
spindle fibers form
what takes place during metaphase
“M” for middle. the chromosomes line up in the middle of the cell. The spindle fibers move the chromosomes to the middle of the cell
what takes place during anaphase
“A” for apart. the spindle fibers pull the opposite poles of the chromosomes apart at the centromere. Once each chromatic is separated from its “sister”, they are now each separate chromosomes
what takes place during telophase
the spindle fibers disassemble and the chromosomes convert back to chromatin
what takes place during cytokinesis
the cell officially divides into two new IDENTICAL cells
cytoplasm begins pinching and forms a cleavage furrow
when does the nuclear membrane go away?
prometaphase
what is apoptosis and when does it occur
apoptosis is when a cell self-destructs and it occurs when there is an issue with the cell that can not be repaired
what is MEIOSIS
a process of nuclear division that reduces the number of chromosomes in new cells to half the number of the original cell
difference between MEIOSIS and MITOSIS
what are the cells produced by meiosis called
gametes
what are gametes
sex cells (sperm + egg)
what are homologous chromosomes
Every cell in organisms produced by sexual reproduction has 2 of each autosome
Have information for the same traits but not the exact same information
what is the goal of meiosis
to produce four unique daughter cells
what is a cleavage furrow
indentation that appears on a cell’s surface when the cell is preparing to divide
What types of cells are haploid?
when cells have only one set of chromosomes (23), they are a haploid (n)
Describe what happens in meiosis I and what happens in meiosis II.
MEIOSIS 1 - reduces chromosome numbers from diploid to haploid in prep for gamete formation
MEIOSIS 2 - further divide haploid cells produced in meiosis 1
what happens in telophase 1
chromosomes reach opposite ends of the cell
cytokinesis 1 begins
the resulting new cell contains a haploid number of chromosomes
