71 terms

Honors Biology 3rd Nine Weeks Exam Review PART 1 (Cell Division)

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Diffusion
the net movement of particles from an area of higher concentration to an area of lower concentration
3 cell size limitations
Diffusion
DNA
Surface area-to-volume ratio
Diffusion in cells can cause limitation to cell size because:
it's slow and inefficient and cells won't always be able to get rid of waste products and get needed nutrients
DNA in in cells can cause limitation to cell size because:
DNA controls the production of proteins and all cells have a certain amount of DNA so a larger cell won't have enough DNA to make all the needed proteins
Surface area-to-volume ratio in cells can cause limitation to cell size because:
If the volume increases faster than the surface area, it will become harder to get things in and out of the cell.
What makes up the plasma membrane?
A phospholipid bilayer
Cell reproduction is another name for
cell division
Cell division
The process by which new cells are produced from existing cells. One cell divides into two, with both being identical to the original cell.
DNA
holds the information to make more DNA, to make proteins
is double helix-- made up of nucleotides
Nucleotides
the monomers (subunits) of DNA they are composed of a sugar (deoxyribose, ribose, etc)
A phosphate group
A nitrogen base (adenine, thymine, ect)
When a word ends in -ose
its a sugar
Chromatin
Long strands of DNA wrapped around proteins (tangled up spaghetti).-- most a cell's lifetime
Chromosomes
during division, the DNA coils and becomes highly organized
Centriole
small dark, cylindrical structures that are made of microtubules and are located outside the nucleus
Centromere
holds the daughter chromosome together-- its in the middle
Sister Chromatid
the 2 halves of the chromosome
Homologous Chromosome
the 2 chromosomes of each pair in a diploid cell that help determine what the individual organism looks like
another name for Homologous pair is
tetrad
Cell Cycle
the sequence of growth and division in a cell
Order of cell cycle
Interphase -> Mitosis -> Cytokinesis
interphase
the phase or part of meiosis where the cell replicates its chromosomes. the chromosomes coil up and and a spindle forms. a pair of homologous chromosomes then come together to form a tetrad. crossing over then occurs
Crossing Over
the process where non-sister chromatids (from the homologous chromosomes) pair together so tightly that genetic material is sometimes exchanged
Order of the steps of interphase:
G1 -> S -> G2
G1
the cell increases in size; there is rapid protein synthesis; new organelles are formed
S
chromosomes are replicated (synthesis)
Replication
the process where DNA makes a copy of itself before cell division
G2
structures needed for mitosis are formed (centrioles, spindle fibers); there is lots of protein synthesis
Mitosis
the process by which 2 daughter cells are formed, each having a complete set of chromosomes.
Mitosis is what?
nuclear division
Order of Mitosis:
PMAT: Prophase -> Metaphase -> Anaphase -> Telophase
Prophase
the first and longest stage. the chromosomes are replicated. The nuclear membrane, nucleus, and nucleolus disappear. the centrioles move to different sides and spindle fiber form between them
Spindle Fiber
football-shaped cagelike structure consisting of thin fibers made of microtubules. they play a vital role in the separation of sister chromosomes
Metaphase
the centromere of each chromosome becomes attached to a spindle fiber. they pull the tetrads into he middle(equator) of the spindle.
Anaphase
homologous cells separate and move to different sides.. (ensures that only only 1 chromosome from that parent goes into the new cell) centromeres split and spindle fibers contract pulling the sister chromatids to opposite sides of the cell
Telophase
opposite of Prophase.... The spindle is broken down, the chromosomes uncoil, and the cytoplasm divides to yield 2 new cells. Each cell has only half the genetic information of the original cell because it has only one chromosome from each homologous pair
Cytokinesis
the division of the cytoplasm.
Meiosis
a kind of cell division. it produces gambits containing half the number of chromosomes as a parent's body cell
Which goes through PMAT once?
Mitosis
Which goes through PMAT twice?
Meiosis
Which starts with 2 diploids and ends with 4 haploids?
Meiosis
Which starts with 1 cell and makes 2 cells?
Mitosis
can meiosis occur in all organisms?
YES
The purpose of Mitosis is to
make new cells
The purpose of Meiosis is to
make gametes
Steps of Meiosis
(Phase I)
Prophase I
Metaphase I
Anaphase I
Telophase I

(Phase II)
Prophase II
Metaphase II
Anaphase II
Telophase II
Prophase I
The same events as prophase of mitosis occur
Metaphase I
tetrads line up in the equator
Anaphase I
Homologous chromosomes of a tetrad separate and move to opposite poles. Centromeres do not split, ensuring that each new cell receives one chromosome of a homologous pair.
Telophase I
The events are the same as those of telophase in mitosis, except that each cell has one chromosome of each homologous pair (rather than one chromatid of a chromosome).
One original cell divides into two cells.
Meiosis II
The events of meiosis II are just like those of mitosis.
Each of the two cells from meiosis I proceed through meiosis II. The two cells will divide into four cells.
Four cells have been formed from the original diploid cell, each containing one chromatid of each chromosome.
it then enters interphase
Nondisjunction
The failure of chromosomes to separate correctly in meiosis I
In nondisjunction...
The resulting gametes could have either an extra chromosome or a missing chromosome.
trisomy
When there is an extra chromosome
monosomy
When there is a missing chromosome and it is fatal
polyploid
Organisms with more than the usual number of chromosomes sets. it's rare in animals, but common in plants.
triploid
If a zygote gets one extra set
Genetic recombination
the re-assortment of chromosomes
a gamete is a
sex cell
Egg
female gametes
Sperm
male gametes
Sexual Reproduction
a type of reproduction. it involves the production and subsequent fusion of haploid sex cells
a zygote is a
fertilized gamete
Diploid
Cell with two kinds of chromosome; is said to contain a diploid, or 2n, number of chromosomes
Haploid
Cell with one of each kind of chromosome; is said to contain a haploid or n, number of chromosomes
The diploid number is___the number of the haploid
twice
The haploid number is __ the number of the diploid.
half
If i have 12 diploids, I have __ haploids.
6
Difference between plant and animal mitosis
in plants: there is no centrioles and no cytokinesis
How many chromosomes do humans have?
46 chromosomes
How many pair of chromosomes do humans have?
23 pairs
Diploid cells
body cells (somatic cells)