Download Notes Chapter 4 Cell Reproduction 4.1 Cell Division and Mitosis

Notes Chapter 4
Cell Reproduction
4.1 Cell Division and Mitosis
Many organisms start as __________ _____________.
That cell divided and becomes two, two become ___________, four become eight, and so
on.
Many-celled organisms, including you, ____________ because cell division
___________________ the total number of cells in an organism.
Even after growth stops, cell division is still important.
Every day ___________ of red blood cells in your body wear out and are replaced.
During a few seconds, your __________ ____________ produces about _______ million
red blood cells.
Cell division is important to one-celled organisms too, it’s how they ______________
themselves.
A living organism has a __________ ____________.
A life cycle begins with the organisms __________________, is followed by
_____________ and ________________, and finally ends in ________________.
Individual cells also have life cycles.
The life cycle is a series of events that takes place from one _________ division to the
next.
The time it takes to complete a cell cycle is ________ the same in all cells.
Most of the life of any eukaryotic cell- _______ ___________ ____________ _____
__________________- is spent in a period of ___________ and _________________
called ___________________.
Cells in your body that no longer divide, such as _______ and ____________ cells, are
always in _______________.
An actively dividing cell, such as a skin cell, copies its hereditary material and prepares
for cell division during interphase.
Before a cell divides, a _______ of the hereditary material must be made so that each of
the two new cells will get a complete copy.
Each cell needs a _____________ set of hereditary material to carry out life functions.
After interpahse, _____________ ______________ begins.
The ______________ divides, and then the _______________ separates to form two
___________ _____________.
________________ is the process in which the nucleus divides to form two identical
nuclei.
Each new nucleus also is _______________ to the original nucleus.
_________ is described as a series of phases, or steps.
The steps of mitosis in order are named _____________, _____________,
____________, and _________________. (PMAT)
A _______________ is a structure that contains ______________ material.
During ___________________ each chromosome ___________________.
When the _____________ is ready to divide, each duplicated chromosome
_____________ tightly into two thickened identical strands called ______________.
During prophase, the pairs of chromatids are fully ________________ when viewed
under a microscope.
The nucleolus and the __________ ____________ ____________________.
Two small structures called _______________ move to opposite ends of the cell.
Between the centrioles, threadlike _____________ _____________ begin to stretch
across the cell.
Plant cells also form spindle fibers during mitosis but do not have centrioles.
In ____________ the pairs of chromatids line up across the ___________ of the cell.
The __________________of each pair usually becomes attached to two spindle fibersone from each side of the cell.
In ________________, each centromere ____________________ and the
_____________ fibers _________________.
Each pair of chromatids _________________, and chromatids begin to move to
____________________ ends of the cell.
The separated chromatids are now called chromosomes.
In the final step, _____________, spindle fibers start to __________, the chromosomes
start to ___________, and a new ______________ forms.
For most cells, after the nucleus has divided, the __________ separates and two new cells
are formed.
In animal cells, the cell membrane pinches in the middle like a balloon with a string
tightened around it, and the cytoplasm divides. (cytokinesis)
In plant cells, the appearance of a _________ ___________ tells you that the cytoplasm
is being _________________.
New cell walls form along the cell plate, and new membranes develop inside the
_________ __________________.
Following division of the cytoplasm, most new cells begin the period of growth, or
_________________ again.
Every cell in your body except __________ ______________, has a nucleus with
____________ chromosomes- ______________ pairs.
Each of the trillions of cells in your body, except sex cells, has a copy of the same
_______________________ _____________________.
All of your cells use different parts of the same hereditary material to become
__________ _________________ of cells.
Cell division allows ________________ and _______________ ______________
_______________ or ________________ cells.
If you cut yourself the wound heals because cell division replaces damaged cells.
Another way some organisms use cell division is to produce new organisms.
___________________ is the process by which an organism produces others of its same
kind.
Among living organisms, there are _________ types of reproduction-_____________ and
__________________.
Sexual reproduction usually requires two organisms.
In ______________ ______________ a new organism (sometimes more than one) is
produced from ____________ organism.
The new organisms will have hereditary material ______________ to the hereditary
material of the ____________ organism.
Organisms with __________________ cells ______________ reproduce by
______________ __________________.
However, _______________ do not have a nucleus so they can’t use ___________.
Instead, bacteria reproduce asexually by ________________.
During ________________, an organism whose cells do not contain a nucleus copies its
genetic material and then divides into ______________ identical organisms.
________________ is a type of asexual reproduction made possible because of cell
division.
When the _______ on the adult becomes large enough, it breaks away to live on its
__________.
Some organisms can _____________ damaged or lost body parts.
____________________ is the process that uses cell division to regrow body parts.
_____________, __________, ________ _______________, and some other organisms
can use regeneration for asexual reproduction.
4.2 Sexual Reproduction and Meiosis
During _______________ reproduction, ____________ sex cells, sometimes called an
____________ and a ________________, come together.
_____________ cells are formed from cells in _________________ organs.
________________ are formed in the male reproductive organs.
_________________ are formed in the female reproductive organs.
The joining of an egg and a sperm is celled ____________________ and the cell that
forms is called a ________________________.
Following fertilization, cell division begins. A new organism with a unique
____________________ develops.
A typical __________________ body cell has 46 ___________________.
Each chromosome has a mate that is similar to it in size and shape ad has similar DNA.
Human body cells have __________ pairs of chromosomes.
When cells have __________ of similar chromosomes they are said to be
_____________________.
Because sex cells ________ _________________ have pairs of chromosomes they are
said to be _________________.
They have only half the number of chromosomes as body cells. Haploid means ________
_______________.
Human sex cells have only __________ chromosomes one from each of the 23 pairs of
similar chromosomes.
A process called ________________ produces _____________ sex cells.
Meiosis ensures that the _______________ will have the same diploid number as its
parent.
After two haploid sex cells combine, a ____________ ________________ is produced
that develops into a new diploid organism.
During meiosis, __________ divisions of the nucleus occur. These divisions are called
meiosis ______ and meiosis ______.
The steps of each division have names like those in _________________ and are
numbered for the division in which they occur.
Before meiosis begins, each chromosome is ________________ just as in mitosis.
When the cell is ready for meiosis, each duplicated chromosome is _____________
under the microscope as two chromatids.
The events of prophase I are similar to those of prophase in mitosis.
In meiosis each duplicated chromosome comes near its similar ____________mate.
In mitosis they do not come near each other.
In metaphase I the pairs of duplicated chromosomes _______ _____________ in the
_________________ of the cell.
The ___________________ of each chromatid pair becomes _______________ to the
________________ ______________, so chromatids do not separate in anaphase I.
In anaphase I the two pairs of chromatids of each similar pair move away from each other
to opposite ends of the cell.
Each duplicated chromosome still has __________ chromatids.
In telophase I the cytoplasm divides and two new cells form.
Each new cell has _______ duplicated chromosome from each similar pair.
The two cells formed during _____________ ___ now begin _____________ ______.
The chomatids of each duplicated chromosome will be separated during this division.
In prophase II the duplicated chromosomes and spindle fibers reappear in each new cell.
In metaphase II the duplicated chromosomes move to the __________ of the cell.
Unlike what occurs in metaphase I, each centromere now attaches to _____________
spindle fibers instead of one.
The centromere _______________ during anaphase II, and the chromatids separate and
move to __________ ends of the cell.
Each chromatid is now an individual _______________________.
AS telophase II begins, the spindle fibers disappear and a ______________ membrane
forms around the chromosomes at each end of the cell.
When meiosis II is finished the cytoplasm ______________________.
Meiosis occurs many times in reproductive organs.
Mistakes can produce sex cells with _________ _____________ or ___________
_____________ chromosomes.
Sometimes, ___________________ produced from these sex cells __________.
If the zygote lives, every cell in the organism that grows from that zygote usually will
have the ______________________ number or chromosomes.
Organisms with the wrong number of __________________ may not grow normally.
4.3 DNA
A cell uses a ____________ in its hereditary material. The code is a chemical called
deoxyribonucleic acid or ___________.
It contains information for an organisms _____________ and ______________.
DNA is __________ in cells that have a nucleus.
When a cell divides the DNA code is _______________ and passed to the new cells.
In this way, new cells receive the same coded information that was in the
_____________ cell.
Since the mid 1800’s scientists have known that the nuclei of cells contain large
molecules called _______________ _________________.
By 1950, chemists has learned what nucleic acid DNA was made of, but they didn’t
_______________________ how the parts of DNA were arranged.
In 1952, scientist Rosalind Franklin discovered that DNA is _________ chains of
molecules in a ______________ form.
By using an x-ray technique, Dr. Franklin showed that the large spiral was probably made
up of two spirals.
In 1953, scientists James Watson and Francis Crick made a _____________ of a DNA
molecule.
According to the______________ and ______________ DNA model, each side of the
____________________ is made up of ________________-________________
molecules.
Each molecule consists of the sugar called ________________ and a
________________________ group.
The ___________ of the ladder are made up of other molecules called
______________________ __________________.
Four kinds of nitrogen bases are found in DNA- _______________,
__________________, _________________, and ____________________.
The bases are represented by the letters ________, ________, ________, and _______.
The amount of ______________ always equals the amount of _________________, and
the amount of ____________________ always equals the amount of
_________________.
Adenine always pairs with thymine and guanine always pairs with cytosine.
When chromosomes are ___________________ before mitosis or meiosis, the amount of
___________________ in a nucleus is _____________________.
The two sides of DNA __________________ and separate.
Each side becomes a _________________ on which a new side forms.
The new DNA has bases that are identical to those of the original DNA and are in the
same __________________.
Most of your characteristics such as the color of your hair and your height and even how
things taste to you depend on the kinds of ______________ your cells make.
DNA in your cells stores the _____________________ for making these proteins.
Proteins _____________ cells and ___________________ or work as
________________________.
The instructions for making a specific protein are found in a _____________ which is a
section of DNA on a _____________________.
Each chromosome contains _______________ of genes.
Proteins are made of chains of hundreds or thousands of ____________
______________.
The gene determines the _______________ of amino acids in a protein.
Changing the order of the amino acids makes a different _______________.
Genes are found in the nucleus, but proteins are made on __________________ in the
_________________.
The codes for making proteins are carried from the ______________ to the
____________ by another type of nucleic acid called ribonucleic acid or ____________.
RNA is made in the nucleus on a DNA ___________. However, RNA is different from
DNA.
RNA is like a ladder that has all its rungs sawed in __________.
RNA has the bases A, G, and C like DNA but has the ___________ ____________(U)
instead of ________________ (T).
The sugar phosphate molecules in RNA contain the sugar _________ not deoxyribose.
The three main kinds of RNA made form DNA in a cells nucleus are
________________________ RNA, _________________ RNA, and
_____________________ RNA.
Protein production begins when _____________ moves into the cytoplasm. There,
____________ attach to it.
_________________ are made of RNA.
_____________________ RNA molecules in the cytoplasm bring amino acids to these
ribosomes.
Inside the ribosomes, three nitrogen bases on the mRNA temporarily match with three
nitrogen bases on the tRNA.
The same thing happens for the mRNA and another tRNA molecule.
The amino acids that are attached to the two tRNA molecules ___________. This is the
beginning of a ________________.
The code carried on the mRNA ______________ the order in which the amino acids
bond.
After a tRNA molecule has lost its amino acid, it can move about the cytoplasm and pick
up another amino acid just like the ____________ one.
The ribosome moves along the _______________.
The new tRNA molecules with amino acids match up and add amino acids to the
_________________ molecule.
In many celled organisms like you, each cell uses only some of the thousands of
________________ that is has to make proteins.
Each cell uses only the genes that direct the making of proteins that it ____________.
Cells must be able to _______________ genes by turning on some genes off and turning
other genes on.
Sometime the DNA is twisted so tightly that __________ cannot be made.
Other times chemicals bind to the DNA so that it cannot be ___________.
If the incorrect proteins are produced, the organism cannot function properly.
If DNA is not copied _________, the proteins made form the instructions might not be
made correctly.
The mistakes called ______________ are permanent changes in the DNA sequence of a
gene or chromosome of a cell.
Outside factors such as _______ ____________, ___________________, and some
____________________ have been known to cause mutations.
Genes control the _________________ you ___________________.
Without correctly coded proteins, an organism can’t grow, repair, or maintain itself.
A change in a gene or chromosome can change the _____________ of an organism.
If the mutation occurs in a body cell, it might or ____________ ________________ be
life threatening to the organism.
If a mutation occurs in a sex cell, then ____________ the cells that are formed from that
sex cell will have that __________________.
Mutations add ______________ to a _________________ when the organism
reproduces.
Many ___________________ are ________________ to organisms often causing their
________________.
Some mutations do not appear to have _____________ effect on the organism, and some
can even be ______________________.