Studied by 27 peoplewhat is another term for cell reproduction
cell division
cell division occurs in humans and other organisms at different times in their life when…
new cells are formed
what are 2 types of eukaryotes that perform cell division?
mitosis and meiosis
what type of cells does mitosis produce?
somatic or body cells
examples of mitosis
skin, heart and liver cells
mitosis is a form of ------- reproduction
asexual
what type of cells does meiosis produce?
gametes or sex cells
examples of meiosis
sperm and egg
meiosis is a form of ------- reproduction
sexual
before a cell divides, the ---- is first copied and then distributed
DNA
prokaryotes reproduce by a type of cell division called…….
binary fission
binary fission is a form of ------ reproduction that produces identical offspring
asexual
in asexual reproduction, a single parent passes exact ---------- to its offspring
copies of all of its DNA
how many stages does binary fission occur in?
2
in the first stage of binary fission, the ---- is copied, and then the cell ------
DNA, divides
in the second stage of binary fission, the prokaryote is pinched into….
2 independent cells
a ----- is a segment of DNA that codes for a ---- or RNA molecule
gene, protein
when genes are being used, the ----- is stretched out so that the information it contains can be used to direct the synthesis of proteins
DNA
a loose form of DNA is called….
chromatin
as a eukaryotic cell prepares to divide, the DNA and the proteins associated with the DNA coil up into a structure called a……
replicated chromosome
the two exact copies of DNA that make up each replicated chromosome are called….
chromotids
the two chromotids of a chromosome are attached at a point called a….
centromere
during eukaryotic reproduction, the chromotids become seperated during….
cell division
when chromotids are seperated when a eukaryotic cell reproduces, they are each placed into a new cell to ensure that each new cell will have the same ------------- as the orginal cell
genetic information
how long does it take for a prokaryotic cell to divide
20 minutes
how long does it take for a eukaryotic cell to divide
24 hours
-------- chromosomes are chromosomes that are similar in size, shape, and genetic content
homologous
each --------- in a pair a homologous chromosomes comes from one of the two parents
homologue
the 46 chromosomes in human ------ cells are actually two sets of ---- chromosomes
somatic, 23
when a cell, such as a somatic cell, contains two sets of chromosomes, it is set to be -----. ex: 2n=46 for humans
diploid
when a cell, such as a gamete, contains one set of chromosomes, it is said to be -------. ex: n=23 for humans
haploid
the fusion of 2 haploid gametes, is a process called ------- and forms a dipoid ------
fertilization, zygote
a fertilized egg cell is a….
zygote
------- are chromosomes that are not directly involved in determining the sex (gender) of an individual. they are chromosome numbers ---- in a karyotype
autosomes, 1-22
the -----------, one of the 23 pair of chromosomes in humans, contain genes that will determine the sex of an individual
sex chromosomes
in humans and many other organisms, the two sex chromosomes are referred to as the -- and -- chromosomes
x,y
xx= -----
girl
xy= -----
boy
x= -----
girl with boy like features
y= -----
die
xxy= -----
boy with girl characteristics
humans with more than 2 copies of a ------, a condition called trisomy, will not develop properly
chromosome
another name for trisomy 21
down’s syndrome
abnormalities in chromosome number can be detected by analyzing a --------, a photo of the chromosome in a dividing cell that shows the chromosomes arranged by size
karyotype
changes in an organism’s chromosome structure are called….
mutations
breakage of a chromosome can lead to - types of mutations
4
what are the types of mutations?
deletion, duplication, inversion, translocation
-------- removes a chromosomal segment
deletion mutation
------- repeats a segment
duplication mutation
--------- reverses a segment within
inversion mutation
-------moves a segment from one chromosome to another nonhomologous one
translocation mutation
the ------- is a repeating sequence of cellular growth and division during the life of an organism
cell cycle
a cell spends 90 percent of its time in the first three phases of the cycle which are collectively called -----------. cells such as mature nerves and muscles will never go through -------, but stay in ---
interphase, mitosis, G0
how many phases are in the cell cycle?
5
what stage of the cell cycle does a cell grow rapidly and carries out its routine functions
stage 1, first growth, G1
what stage of the cell cycle does a cell’s DNA and centrioles are copied
stage 2, synthesis, S
what stage of the cell cycle are preparations made for the nucleus to divide, organelles are duplicated and microtubules are formed for the spindle apparatus
stage 3, second growth, G2
what stage of the cell cycle does the nucleus of a cell is divided into two identical nuclei, includes 4 phases of its own
stage 4, mitosis
what stage of the cell cycle does division of the cytoplasm occur, creating 2 identical cells
stage 5, cytokinesis
the cell cycle has key checkpoints at which -------------- from the cell can trigger the next phase of the cell cycle.
feedback signals
other feedback signals can delay the next phase to allow for completion of the ------------
current phase
control of the cell cycle occurs at - principle checkpoints
3
this checkpoint makes the decision of whether the cell will divide
cell growth, G1
DNA replication is checked at this point by DNA repair enzymes
DNA synthesis, G2
this checkpoint triggers the exit from mitosis
mitosis checkpoint
if a cell fails a checkpoint, it may kill itself via…
apoptosis
certain ----- contain the information necessary to make the proteins that regulate cell growth and division.
genes
what is the uncontrolled growth of cells
cancer
during -------, the chromatids on each chromosome are physically moved to opposite sides of the dividing cell with the help of the --------
mitosis, spindle
------- are cell structures made up of both centrioles (animals only) and individual microtubule fibers that are involved in moving chromosomes during cell division. ------- fibers attach directly to the chromosome whereas nonkinetochore fibers overlap at the ------ from opposite poles.
spindles, kinetochore, equator
when a cell enters the ------- phase, the centriole pairs start to seperate, moving toward opposite poles of the cell.
mitotic
as the centrioles move apart, the ------ begins to form
spindle
plant cells lack……
centrioles
the chromatids are moved to each ----- of the cell in a manner similar to bringing in a fish with a fishing rod and reel.
pole
when the microtubule “fishing line” is “reeled in,” the -------- are dragged to opposite poles
chromatids
as soon as the chromatids seperate from eachother they are called ----------
chromosomes
what are the steps of mitosis?
prophase, metaphase, anaphase, telophase
in prophase the nuclear envelope and ------ dissolve, chromotin coils up into visible replicated chromosomes under a scope, causing a ------ to form
nucleolus, spindle
in prophase chromosomes move to the center of the cell and line up along the -------- due to kinetochore fibers. ----- are at the poles. this is the longest stage
equator, asters
in anaphase centromeres divide and ------- part toward opposite poles via kinetochore fibers. the cell shape ------ caused by non-kinetochore fibers. this is the fastest stage
chromatids, elongates
in telephase a nuclear ------ forms around the chromosomes at each pole that uncoil back into chromotin. nucleoli reappear in each new nucleus. spindle breaks down. ---- forms
envelope, cleavage
the purpose of ----- is growth, repair, and routine maintenance
mitosis
as mitosis ends, ------- begins
cytokinesis
during cytokinesis, the ----- of the cell is divided in half, and the cell membrane grows to enclose each cell, forming two seperate cells as a result
cytoplasm
the end result of mitosis and cytokinesis is two genetically ------ cells where only one cell existed before
identical
Note
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