Mitosis and Meiosis Flashcards
cell division
the process by which a cell divides into two daughter cells (mitosis and meiosis)
M-phase
The phase where cellular division (mitosis) happens
S-phase
When DNA is copied to prepare for division
Interphase
Stage during which a cell grows and develops into a functional cell, and prepares to divide by duplicating DNA
What stages is Interphase divided into?
Gap 1, synthesis, and Gap 2
Centromere
The part of a chromosome that attaches two sister chromatids and that spindles attach to
sister chromatids
structures that contain identical copies of DNA
1 chromatid comes from ____ and 1 from _____ in meiosis
mom and dad
Prophase
The first and longest stage of mitosis
What happens in prophase?
The nuclear membrane temporarily disappear
Chromatins condenses into visible chromosomes
The spindle fibers attach to the centromere and move to opposite poles
Kinetochores appear (tracks)
Chromosomes begin to move toward the center
Metaphase
The 2nd stage of mitosis
What happens in metaphase?
Sister chromatids are pulled along the spindle toward the center cell and line up.
The chromosomes in the MIDDLE are visible
Anaphase
The 3rd stage of mitosis
What happens in anaphase?
Chromosomes are split in the middle and are pulled by the spindles to opposite poles.
Telophase
Chromosomes arrive at poles and 2 new nucleuses reappear
Cytokinesis
By which a cell’s cytoplasm divides, also dividing organelles, resulting in 2 cells with identical nuclei
spindle fibers
The ropes that will attach to the centromere and help separate the chromosomes
Cell plate
The structure that forms between the 2 daughter nuclei in plant cells (occurs in cytokinesis)
tumors
masses of cells that form when there is uncontrolled growth and division of cells (form cancer)
differentiation
The process in which an unspecialized cell develops into a specialized cell with a defined structure and functions
Does differentiation occur in unicellular organisms?
No
True or false: all cells are the same during early development and differentiate as the organism develops
True!!!
Stem cell
A type of cell that can be directed to become a specialized cell (they don’t have a job yet)
What happens in Prophase I that doesn’t happen in mitosis’s prophase?
Homologous chromosomes pair, then cross over to exchange genetic info (the genes randomly swap places)
Does genetic variation occur in meiosis?
YES!!
nondisjunction
cell division during which sister chromatids fail to separate properly
What can nondisjunction lead to?
Genetic disorders
apoptosis
programmed cell death
How does apoptosis happen?
The lysosomes open, allowing the acid to escape and destroy the cell
As a cell becomes larger, what happens to the volume and its surface area?
its volume increases and the ratio of surface area to volume decreases
What is an advantage of sexual reproduction over asexual reproduction?
Genetic variation
When during the cell cycle are chromosomes visible?
Prophase, Metaphase, Anaphase
What happens in Gap 1?
growing, doing normal functions, preparing to replicate DNA
What happens in synthesis?
DNA is replicated
What happens in Gap 2?
Preparing to divide nucleus
What are the two main stages of cell division called?
Mitosis and cytokinesis
Does cancer affect unicellular or multicellular organisms?
Multicellular because the tumors attack multiple cells.
What has cancer lost the ability to control?
The amount of times the cell replicates without stopping.
What is the end product of Meiosis I?
2 diploid (46 chromosomes) non-homologous cells
What is the end product of Meiosis II?
4 non-homologous haploid (23 chromosome) cells are produced
What cells does meiosis form?
Gametes (egg and sperm)
When does quality control happen?
After each phase
