Genbio w3 (cell cycle and mitosis) Flashcards
An integral part of the cell cycle
Cell division
Key roles of cell division
-The ability of organisms to reproduce distinguishes living things from nonliving matter
-continuity of life is based on reproduction of cells or cell division
In unicellular organisms, division of one cell reproduces the entire organism. Multicellular organisms depend on cell division for:
-development from a fertilized cell
-growth
-repair
DNA molecules in a cell are packaged into what
chromosomes
Every eukaryotic species has a certain number of chromosomes in each nucleus. Humans have how many chromosomes
46 (23 pairs)
nonreproductive cells that have 2 sets of chromosomes.
i.e. body cells
Somatic cells
Reproductive cells (sperm and eggs) have half as many chromosomes as somatic cells
Gametes
Eukaryotic chromosomes consist of ______, a complex of DNA and protein that condenses during cell division
chromatin
Half a number of chromosomes
Haploid
Complete set of chromosomes
Diploid
Genetic information
DNA (Deoxyribonucleic Acid)
DNA + Histones (proteins)
chromatin
coiled chromatin fibers
chromosome
one of the duplicated chromosome
chromatid
most cell division results in daughter cells with identical genetic information. DNA
(basa lang)
-
-All the DNA in a cell constitutes the cell’s _______
-consist of a single DNA molecules (common in prokaryotic cells) or a number of DNA molecules (common in eukaryotic cells)
-entirety of DNA identity
Genome
The narrow “waist” of the duplicated chromosome, where the two chromatids are most closely attached
centromere
-The division of nucleus
-for cell regeneration, growth and development
Mitosis
The division of cytoplasm
Cytokinesis
Yields nonidentical daughter cells that have only one set of chromosomes, half as many as the parent cell (gametes, sperm cell and egg cell)
Meiosis
About 90% of the cell cycle
Interphase
Subphases of interphase
G1 phase (“first gap”)
S phase (synthesis)
G2 phase (second gap)
What happens in G1 phase
-RNA and protein synthesis
-cell size increases for the preparation for cell division
- other terms are post-mitotic phase or pre synthetic phase
-longest phase
What happens in S phase
DNA synthesis/duplication
What happens in g2 phase
Duplication of organelles for the duplicated cell to function
Cetain cells cannot reporduce like the nerve cells because they do not go through the normal interphase process (G0). What happens in gap 0 phase.
-also referred to as the Quiescent phase (meaning inactivity or dormancy)
-cells don’t grow or differentiate
-cell cycle arrest
cells can re-enter normal cell cycle if there’s stimulation of mitogens
Characteristics/events in interphase
-Formation of centrosomes (with centriole pairs)
-nuclear envelope is still present
-chromatin (duplicated) but not yet condensed
Characteristics/events in prophase
-appearance of early mitotic spindle fibers
-things start to move inside
-stretching of microtubules emerged from centrosome
-degration of nuclear envelope to give way for chromosome condensation
-condensation of chromatin into becoming a chromosome (and these duplicated chromosome appear as sister chromatids)
Characteristics/events of prometaphase
-microtubules elongate
-has kinetochore and nonkinetochore microtubules
-greated condensation of chromosomes (distinct x shape of chromosomes are observed)
-fragments of nuclear envelope are still left/almost completely dissolved
Difference of kinetochore and nonkinetochore
the kinetochore microtubules attach to chromosomes and move them towards poles.
nonkinetochore microtubules are responsible for elongating the cell during anaphase.
Characteristics/events of metaphase
-centrosome pairs moved to opposite poles of the side
-microtubules aligned your sister chromatids in the center of the cell after the tug-of-war situation (metaphase plate)
-full blown spindle fibers
Characteristics/events of anaphase
-shortest stage of mitosis
-sister chromatids separate (after separate, they are now called chromosomes)
-kinetochore microtubules pull chromosomes to the respective centrosomes
-nonkinetochore elongate the cell
Characteristics/events of telophase and cytokinesis
-cytoplasm simultaneously divides (cytokinesis)
-reformation of nucleolus
-nuclear envelop reforms
-chromosome become less condensed
-microtubules depolymerize (or shrink)
-tightening in the middle (cleavage furrow)
instead of a cleavage furrow, plants have cell plate
Do plant cells have centrosome?
no, they instead have spindle microtubules organizing center
*vesicles form cell plate derived from the Golgi apparatus
What is the asexual reproduction of new organisms
Binary fission
