bio 121 test 3

Mitotic (M) phase of the cell cycle alternates with the much longer ________

M phase includes

interphase accounts for ___% of the cell cycle

during interphase, the cell grows by:
producing ________ and cytoplasmic organelles
copies its ________
and prepares for ________ ________

G1 phase of interphase

S phase of interphase

G2 phase of interphase

M phase of interphase

mitosis is broken down into 5 subphases:

by late interphase, the chromosomes have been duplicated but are ________ packed. the centrosomes have been duplicated and begin to organize microtubules into an ________ ("star")

loosely/tightly

-chromosomes are tightly coiled with sister chromatids joined together
-nucleoli disappear
-mitotic spindle begins to form and appears to push the centrosomes away from each other toward opposite ends of the cell

-nuclear envelope fragments and microtubules from the spindle interact with the chromosomes
-microtubules from one pole attach to one of two ________, special regions of the centromere, while microtubules from the other pole attach to the other ________

the spindle fibers push the sister chromatids until they are all arranged at the ________ ________, an imaginary plane equidistant between the poles, defining metaphase

-centromeres divide, separating sister chromatids
-each is now pulled toward the pole to which it is attached by spindle fibers
-by the end, the two poles have equivalent collections of chromosomes

-cell continues to elongate as free spindle fibers from each centrosome push off each other
-two nuclei begin to form, surrounded by the fragments of the parent's nuclear envelope
-chromatin becomes less tightly coiled
-cytokinesis begins

cytokinesis

in animals, first sign of cytokinesis (cleavage) is the appearance of a cleavage ________ in the cell surface near the old metaphase plate

-on the cytoplasmic side of the cleavage furrow, a contractile ring of actin microfilaments and the motor protein myosin form
-________ of the ring pinches the cell in two

cytokinesis in plants, which have cell walls, involves a completely different mechanism.
-during telophase, vesicles from the Golgi coalesce at the metaphase plate, forming a ________ ________

mitosis in eukaryotes may have evolved from binary fission in bacteria
>prokaryotes reproduce by ________ ________, not mitosis

in binary fission, chromosome replication begins at one point in the circular chromosome, the ________ of ________ ________
-these copied regions begin to move to opposite ends of the cell

cell division involved inward growth of the ________ ________, dividing the parent cell into two daughter cells, each with a complete genome

generation-to-generation sequence of stages in the reproductive history of an organism
-starts at conception of an organism until it produces its own offspring

in humans, each somatic cell (all cells other than sperm or ovum) has ________ chromosomes

a ________ display of the 46 chromosomes shows 23 pairs of chromosomes, each pair with the same length, centromere position, and staining pattern

these ________ chromosome pairs carry genes that control the same inherited characters

an exception to the rule of homologous chromosomes is found in the ________ chromosomes, the X and the Y

homologous pair of X chromosomes (XX)

have an X and a Y chromosome (XY)

a cell with a single chromosome set is ________
-for humans, the ________ number of chromosomes is 23 (n=23)

gametes, which develop in the gonads, are/are not produced by mitosis

all cells with two sets of chromosomes are ________ cells
-for humans, the ________ number of chromosomes is 46 (2n=46)

________ restores the diploid condition by combining two haploid sets of chromosomes
________ and meiosis alternate in sexual life cycles

after fusion of two gametes to form a zygote, the zygote undergoes ________ to produce haploid cells
-these haploid cells undergo mitosis to develop into a haploid multicellular adult organism

in ________ I, the chromosomes condense and homologous chromosomes pair up to form tetrads

at ________ I, the tetrads are all arranged at the metaphase plate

in ________ I, the homologous chromosomes separate and are pulled toward opposite poles

in ________ I, movement of homologous chromosomes continues until there is a haploid set at each pole, each chromosome consists of linked sister chromatids

pleiotropy

epistasis

polygenes

polyploidy

aneuploidy

haploid sperm reaches and fuses with haploid ovum, resulting in

asexual division
does not involve having a partner
increase #'s
identical to parent cells

sexual division
results in increasing variability

study of heredity and variation

the transmission of traits from one generation to the next is ________

offspring somewhat differ from parents/siblings because of _______

when cells turn cancerous, alter cell regulation

uncontrolled growth (of cells)

mass of abnormal cells

cancers occur in ________ ________ cells

if abnormal cells remain at originating site, lump is a ________ tumor
-usually can be removed by surgery and do not cause serious problems

cells leave origin to impair functions of one or more other organs

cancer cells often lose attachment to nearby cells, are carried by blood and lymph system to other tissues, and start creating more tumors

treatments for metastasizing cancers include:
-target actively dividing cells

nuclear envelope fragments and microtubules from spindle interact with chromosomes

centromeres divide, separating sister chromatids

chromosomes line up

cell continues to elongate as free spindle fibers from each centrosome pushing off each other

divides the cytoplasm, typically follows mitosis
-in animals, first sign of ________ is appearance of cleavage furrow

prokaryotes reproduce by ________ ________, not mitosis

"first gap"
centered on growth

"synthesis"
chromosomes copied

"second gap"
cell completes preparation for cell division

cell divides