BIO (CELL DIVISIONS) mitosis and meiosis Flashcards
In _______, _______is the MEANS OF REPRODUCTION
- unicellular organism
- cell divisions
during the cell divisions:
: cell grows
: prepares for division
: divides to form two daughter cells.
In __________ it is the means of TISSUE GROWTH AND MAINTENANCE
multicellular organisms
- It is the process by which a cell segregates its duplicated DNA, ultimately DIVIDING ITS NUCLEUS INTO TWO
- This is the cell division process for the somatic cells/ body cells.
mitosis
cells with NO NUCLEUS and MEMBRANE BOUND organelles
prokaryotic cells
cells that make up your ORGANS and TISSUES
mitosis (somatic cells)
cells WITH MEMBRANE BOUND and NUCLEUS and organelles
eukaryotic cells
the ONLY cells that are not somatic - sperm and egg
meiosis (gametes)
- is the period of growth that
occurs between cell divisions. - Cell spends most of its life in this phase.
interphase
- increases in size (cell
grows) - synthesizes new proteins
and organelles (cell
develops
during G1
- chromosomes are replicated
during S phase (DNA replication)
- Each ___ consists of two
identical “sister” chromatids. - Each pair of ____ is attached
at an area called the centromere.
chromosomes
- organelles and molecules required for
cell division are produced - Once __ is complete, the cell is ready to start
the M phase—Mitosis
the G2 phase
- First and longest phase of MITOSIS
- Chromosomes become visible
- Centrioles separate and move to
opposite poles (ends) - Spindle fibers appear
- Nucleolus and nuclear membrane
(envelope) disappear
summary of prophase
Centromeres split apart and chromatids separate from one another. Each
chromatid moves to opposite poles
summary of anaphase
- The fourth and final phase of mitosis.
- Chromosomes gather at opposite ends of
the cell and lose their distinct shape - A new nuclear envelope forms around
each cluster of chromosomes
telophase
why does interphase happens?
Cell must grow in order for
extra organelles and DNA
have room in cell
- The second phase of mitosis
- The chromosomes line up across the center of the cell.
- Microtubules connect the centromere of each chromosome to the poles of the spindle
metaphase
- Homologous chromosomes will
align at the middle of the cell. - Spindle fiber from centrioles will
attach to these chromosomes
metaphase 1
- It is the first phase of mitosis.
- The centrioles separate and take
up positions on opposite sides of
the nucleus. - The centrioles lie in a region called the
centrosome. - The centrosome helps to organize the
spindle, a fanlike microtubule structure that
helps separate the chromosomes.
prophase
- During ____, the cytoplasm
pinches in half. - Each daughter cell has an identical set
of duplicate chromosomes
cytokinesis
- Shortest Phase
- Chromosomes attach to spindle
fibers in center of the cell
summary of metaphase
- Chromosomes reach opposite
poles of cell - Chromatids unwind back into
chromatin - Nuclear envelope and nucleolus
reappear reforming the nucleus - Spindle fibers disappear
- New double membrane
- Animal cell – cleavage
summary of telophase
- The third phase of mitosis.
- The sister chromatids separate into individual
chromosomes. - The chromosomes continue to move until they have separated into two groups.
anaphase
- It is a specialized form of cell division that
occurs in organisms that
reproduce sexually. - It produces reproductive cells, such as
sperm cells, egg cells, (gametes) and
spores in plants and fungi. - One parent cell under ____ can
produce 4 daughter cells - reduction division
- theses produces haploid cells. (with 23 chromosomes)
- it has 2 divisions of PMAT
meiosis
- Chromosomes will condense and
thicken. - Spindle fibers will attach at the
chromosomes. - No more crossing over in this
part
prophase 2
- Chromosomes condense and
thicken - Line up homologous pairs
- Crossing over
- Recombinant chromosomes
prophase 1
Homologous chromosomes will be pulled away on both sides of the cell
anaphase 1
- Two newly formed nuclei with
nuclear envelope. - End the first part of meiosis
- This followed by the splitting of
cytoplasm known as cytokinesis
telophase 1
- The chromosomes will line up in
the middle. - Chromosomes will not be in
pairs.
metaphase 2
- Nuclei will be enclosed with
nuclear envelope. - Cytokinesis will follow to
completely separate the
cells
telophase 2
- Sister chromatids will be pulled away from each other
anaphase 2
