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78 terms

bio exam 4: 3 (ch8)

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telophase
opposite of prophase in terms of nuclear changes
gametes
production of ______ in diploid cells is a function of mitosis in humans
cleavage
cytochalasin B is a chemical that disrupts microfilament formation. this chemical would interfere with _______
interphase
it's hard to observe the individual chromosomes during ______ because
inversion
if a fragment of a chromosome breaks off and then reattaches to the original chromosome but in the reverse direction, the resulting chromosomal abnormality is called an _________
fatal
extra copies of chromosomes aside from 21 are probably _______
cell division
a cell undergoes reproduction, and 2 genetically identical daughter cells result during _____ _______
chromosomes
structures that contain most of the cell's DNA
asexual reproduction
the creation of genetically identical offspring by a SINGLE parent, without the participation of sperm&egg
sexual reproduction
fertilization of an egg by a sperm
binary fission
cell division where they divide in half
single parent
binary fission is classified as asexual reproduction because the genetically identical offspring inherit their DNA from a ....
reproduction
in an amoeba, cell division plays the role of ______
development, growth, and repair
in the human body, cell division plays the role of....
chromatin
fibers composed of roughly equal amounts of DNA & protein molecules. too thin to see with a light microscope
centromere
the ______ is visible near the center of each chromosome
chromatids
a chromosome consists of 2 identical ________ when the cell is preparing to divide and has duplicated its chromosomes, but before the duplicates actually separate
interphase
during _______ a cell's metabolic activity is very high and the cell performs its various functions within the organism
mitotic phase
during the ______ phase, a cell actually divides

only accounts for about 10% of the total time required for the cell cycle
mitosis
during _______ the nucleus and its contents (most importantly duplicated chromosomes) divide and are evenly distribute, forming 2 daughter nuclei
cytokinesis
during _________ the cytoplasm is divided in 2
mitosis
prophase
prometaphase
anaphase
metaphase &
telophase

are the 5 main stages of _________
mitotic spindle
football-shaped structure of microtubules that guides the separation of the 2 sets of daughter chromosomes
centrosomes
clouds of cytoplasmic material that contains pairs of centrioles in animal cells

(spindle microtubules emerge from these)
interphase
during ______ the cell synthesizes new molecules and organelles
prophase
during ______ changes occur in both the nucleus and the cytoplasm.

within the nucleus, the chromatin fibers become more tightly coiled and folded
prometaphase
nuclear envelope breaks into fragments and disappears
metaphase
during ______ the mitotic spindle is fully formed, with its poles at opposite ends of the cell
anaphase
________ begins when the 2 centromeres of each chromosome come apart, separating the sister chromatids.

once separated, each sister chromatid is considered a full-fledged daughter chromosome
telophase
during _______, the cell elongation that started in anaphase continues, and mitosis is eventually finished
cytokinesis
the division of the cytoplasm -- usually occurs along with telophase--

with 2 daughter cellscompletely separating soon after the end of mitosis
cytokinesis
during _________ in animal cells, a cleavage furrow forms and the cell pinches into 2
cleavage furrow
a shallow indentation in the cell surface
microfilaments
at the site of a cleavage furrow, the cytoplasm has a ring of _________ made of actin
cell plate
membranous disk formed when vesicles fuse
growth factor
a protein secreted by certain body cells that stimulates other cells to divide
density-dependent inhibition
crowded cells stop dividing during this
cell division
scientists have discovered at least 50 different growth factors that can trigger....
anchorage dependence
animal cells must be in contact with a solid surface (like a culture dish/extracellular tissue matrix) to divide
cell cycle control system
a cyclically operating set of molecules in the cell that both triggers and coordinates key events in the cell cycle
tumor
abnormally growing mass of body cells
benign tumor
if abnormal cells remain at the original site
malignant tumors
these can spread into neighboring tissues and other body parts, displacing normal tissue and interrupting organ function
metastasis
spread of cancer cells beyond their original site
carcinomas
cancers that originate in the external/internal coverings of the body (like skin/intestine lining)
sarcomas
arise in tissues that support the body, such as bone & muscle
leukemias/lymphomas
cancers of blood-forming tissues (like bone marrow/spleen/lymph nodes)
somatic cell
typical body cell in humans with 46 chromosomes
autosomes
22 remaining pairs of chromosomes found in males & females
life cycle
sequence of stages leading from the adults of one generation to the adults of the next
diploid
cells with two sets of homologous chromosomes.


humans & most other animals, and many plants are _____ organisms
gametes
egg&sperm cells are collectively known as ____
haploid
cell with a single chromosome set is a ____ cell-- only 1 member of each homologous pair
zygote
fertilized egg
homologous
if you are female, all your chromosomes are fully _______.not so with guys (X & Y)
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chiasma
where 2 homologous (nonsister) chromatids are attached to each other
genetic recombination
production of gene combinations different from those carried by the original parental chromosomes
karyotype
magnified images of someone's chromosomes arranged in pairs
nondisjunction
when members of a chromosome pair fail to separate
survival
abnormal numbers of sex chromosomes don't usually affect _________
polypoid organism
organism with more than 2 sets of homologous chromosomes in its body cells (ex: tree frog)
deletion
when a fragment of a chromosome is lost
duplication
when a fragment from 1 chromosome joins to a sister chromatid or homologous chromosome
inversion
when a fragment of a chromosome reattaches to the original one, but in reverse
translocation
attachment of a chromosomal fragment to a non-homologous chromosome
gametes
______ have a single set of chromosomes
23
humans have ____pairs of homologous chromosomes
mitosis
this provides for..

growth
cell replacement &
asexual reproduction
growth factors
signal the cell cycle control system
cell division
this is affected by anchorage, cell density, and chemical growth factors
cytokinesis
this differs for plant and animal cells
multiplies
the cell cycle _____ cells
prokaryotes
_______ reproduce by binary fission
asexually
prokaryotic cells reproduce ______ by cell division
number
accidents during meiosis can alter chromosome _______
reduces
meiosis _____ chromosome number from diploid to haploid
genes
homologous chromosomes may carry different versions of the genes