life of a cell from the time its first formed from a dividing parent cell until its own division into two cells
One of the three key roles:
-- an amoeba, a single celled eukaryote divides into two cells; each new cell will be an individual organism
a sand dollar embryo shortly after the fertilized egg divided, forming two cells
growth and development
the dividing bone marrow cells will give rise to new blood cells
What is a genome?
a cell's endowment of DNA; its genetic info
Compare prokearyotic and eukaryotic genomes.
--> one circular bacterial chromosome; single; no organelles; no nucleus
--> # of DNA molecules; overall length- ENORMOUS; characteristic # in each cell nucleus
How many chromosomes are in a human somatic cell?
46 (2 sets of 23)
What is a gamete?
reproductive cell; unite during sexual reproduction (fertilization) to produce a diploid zygote; half as many chromosomes as somatic cells; one set of 23 chromosomes in humans
Name two types of gametes.
How many chromosomes in a human gamete?
one set of 23
a complex of DNA and associated protein molecules
- called this when a cell is not dividing
How many DNA molecules are in each somatic cell?
a cellular structure carrying genetic material, found in the nucleus of eukaryotic cells. Each consists of a very long DNA molecule and associated proteins; a bacterial one usually consists of a single circular DNA molecule and associated proteins found in the nucleoid region, which is not membrane bound
each duplicate chromosome has two asister ones that each contain an identical DNA molecule, initially attached all along their lengths by adhesive protein complexes called cohesins
specialized region of the chromosome where two sister chromatids are most closely attached
COMPLEX OF dna AND PROTEINS THAT MAKE UP A EUKARYOTIC CHROMOSOME. wHEn the cell is not dividing, it exists in its dispersed replicated chromosome form, as a mass of very long, thin fibers that are not visible with a light microscope
What is mitosis? cytokinesis?
division of the nucleus
division of the cytoplasm
What occurs in meiosis?
How is the chromosome number of daughter cells different?
produce gametes; modified type of cell division in sexually reproducing organisms consisting of two rounds of cell division, but only one round of DNA replication;
yields nonidentical daughter cells that have only one set of chromosomes thus half as many chromosomes as the parent cell
By what process are the damaged cells in a wound replaced?
By what process are eggs formed?
By what process does a zygote develop into a multicellular organism?
In which process are identical daughter cells produced?
Which process reduces chromosome # of daughter cells?
A cell grows/ first gap
continues to grow as it copies its chromosomes- chromosomes duplicate (synthesis)
completes preparation for cell division (second gap)
What are the components of the mitotic spindle?
What is another name for the centrosome?
What happens to the centrosome during interphase and prophase?
Interphase: centrosomes are duplicated, resulting in two, but they remain together until prophase
Prophase: centrosome begins to separate with microtubules forming between them
a structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindle
What is the difference between kinetochore and nonkinetochore microtubules?
kinetochore: microtubules that attach to kinetochores at the centromere of sister chromatids
non: do not attach to kinetochores and continue elongating and overlapping
At wich end do kinetochore microtubules shorten during anaphase?
the kinetochore ends; metaphase plate end
Describe cytokinesis in an animal cell.
a process called cleavage
forms a cleavage furrow
on cytoplasmic side of the furrow is a contractile ring of actin filaments associated with myosin molecules
actin microfilaments interact with the myosin molecules, causing the ring to contract
cleavage furrow deepens until the parent cell is pinched in two, producing two completely separated cells, each with its own nucleus and share of cytosol, organelles, etc.
Describe cytokinesis in plant cells.
no cleavage furrow
during telophase, vesicles derived from Golgi move along microfilaments to center of cell, where they coalesce forming a cell plate. Cell wall materials carried in the vesicles collect in the cell plate as it grows
cell plate enlarges until it fuses with membrane
two daughter cells result,e ach with own plasma membrane
a new cell wall arising from the chontents of the cell plate has formed between the daughter cells
a method of asexual reproduction by division in 1/2. in prokaryotes, it does not involve mitosis, but in single-celled eukaryotes that undergo it, mitosis is part of the process
Difference between prokaryotic reproduction and eukaryotic.
Prokaryotic: binary fission; one chromosome; circular DNA molecule
Eukaryotic: mitosis: varies in amt. of chromosomes; double helix