Transcript Reproduction PPT

The Power of Reproduction
Review
CHAPTER 1
Cell Theory
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Over time scientists came have been able to
use technological developments to assist in the
creation of what we call today Cell Theory.
Cell Theory States That:
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All living organisms are composed of one or
more cells.
Cells are the basic units of structure and
function in all organisms.
All cells come from previously existing cells.
The activity of an entire organism depends
on the total activity of its independent cells.
A typical cell has numerous membrane-bound ORGANELLES,
specialized structures that perform specific functions in the cell.
Animal Cell
Plant Cell
YOU NEED TO KNOW THE
FOLLOWING DEFINITIONS:
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Nucleus
Nuclear Membrane
DNA –
Deoxyribonucleic Acid
Chromatin
Nucleolus
Ribosome
Cell Membrane
Cytoplasm
Endoplasmic
Reticulum
Mitochondria
Golgi Bodies
Vacuoles
Lysosomes
Animal and Plant Cells
Animal and plant cells have many similarities. They do however
have a few differences.
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Plant cells have a fibrous cell wall that
provides structure and support for the cell.
Plants need this cell wall to provide with
support. Example and sunflower.
Plant cells contain chloroplasts. They are
organelles that enable the plant to make their
own food through the process of
photosynthesis.
The Importance of Cell Division
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Repair tissue & healing
Growth
Reproduction of Organism
MITOSIS
The Process that ensures each new cell has a nucleus with a
complete set on instructions (DNA) is called MITOSIS.
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Before mitosis can begin, the nucleus must
make a copy, or replica of its chromatin, so
that there are two complete sets of DNA. This
is known as replication. The replicated
chromatin coils up to form double-stranded
chromosomes. The end result of mitosis is the
separation of replicated DNA into two
complete sets of DNA, one for each new cell’s
nucleus.
Prophase
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The nucleolus and the nuclear membrane
disappear. Spindle fibers form and stretch
across the cell from centrioles that have moved
to opposite ends of the cell. The spindle fibers
attach to one side of each centromere.
Metaphase
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The tugging action of the spindle fibers pulls
the double-stranded chromosomes into a line
across the middle of the cell
Anaphase
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The spindle fibers begin to contract and
shorten which pulls the centromere apart. One
of each of the replicated strands to moves to
opposite ends (pole) of the cell.
Telophase
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The spindle fibers begin to disappear. And a
nuclear membrane forms around each set of
chromosomes. A nucleolus appears within
each new nucleus. The single stranded
chromosomes start to uncoil into thin strands
of chromatin.
NOW THERE ARE TWO NUCLEI
IN ONE CELL
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In animal cells, the cell membrane pinches in
near the middle of the cell, dividing the
cytoplasm into two new cells.
In plant cells, a cell plate develops across the
center of the cell, forming a new cell wall
between the two new cells
Interphase
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During Interphase the cell grows, replicates its
DNA, and becomes prepared for the first phase
of mitosis
AS A RESULT OF MITOSIS, THE
NUMBER OF CHROMOSOMES IN THE
NUCLEUS OF EACH CELL IS
IDENTICAL TO EACH OTHER AND TO
THE NUMBER IN THE ORIGINAL CELL
CANCER
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-is the direct result of cells dividing
uncontrollably
-the continue dividing and pile up on top of
one another, forming a tumor or lump
-these excess cells can stay contained in one
area or, move to other parts of the organism
-the gobble up oxygen and nutrients for
themselves, crowding out other cells and
robbing them of their food
Asexual Reproduction
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Mitosis and cell division are not only
important to human growth and tissue repair,
but are also important in asexual reproduction.
Asexual Reproduction is the formation of a
new individual that has identical genetic
information to its parent
BACTERIA
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Are unicellular organisms that do not contain a
true nucleus
Reproduce asexually through a process known
as binary fission
In binary fission a parent cell divides so that
each new cell contains a single chromosome
carrying a complete set of DNA identical to
that of the parent
PROTISTS
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Are unicellular organisms that do contain a
true nucleus
Mitotic cell division results in the formation of
two identical offspring
Protists are important because they form the
basis of many food chains and are responsible
for many diseases that affect humans.
FUNGI
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Fungi are composed of many filaments called hyphae which
grow over the surface of and into the bodies of other
organisms to obtain food
Can reproduce asexually three ways, fragmentation, budding
and spores.
In fragmentation, a small piece or fragment, breaks away
from the main mass and grows into a new individual.
In budding a copy of the nucleus is made, then a tiny bud
begins to form on the cell wall. This bud, containing the new
nucleus continues to grow and eventually breaks away.
A spore is a reproductive cell that can grow into a new
individual through mitotic cell division. When mature, spores
can float about on air currents.
ANIMALS
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Animals can be divided into two main groups,
vertebrates (those with backbones) and
invertebrates (those without backbones)
Many invertebrates can reproduce asexually to
form one or more identical offspring from a
single parent
PLANTS
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Unlike many animals, plants continue to grow
throughout their lives.
The tips of their roots and stems contain
growing areas called meristem.
Meristem is made up of unspecialized cells
that undergo mitosis and cell division
repeatedly, producing new cells.
The Power of Reproduction
Review
CHAPTER 2
Sexual Reproduction
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Your body has specialized organs (GONADS
– testes and ovaries), that make specialized
cells (GAMETES – sperm and eggs), for
sexual reproduction. The gametes from two
parents combine during a process called
fertilization to form a new cell or ZYGOTE.
This zygote is the first body cell of a new
organism.
Sexual Reproduction Cont…
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The total number of chromosomes in a human
body cell is 46 – this is referred to as diploid.
These 46 chromosomes can be arranged into
23 pairs of chromosomes that resemble each
other in size and shape. These matching pairs
of chromosomes are known as homologous
pairs. You receive one pair from your mother
and on from your father.
Sexual Reproduction Cont…
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Human gametes (sperm and eggs) have 23
chromosomes and are called haploid. Only haploid
gametes can combine during fertilization to form a
diploid zygote. Mitosis ensures that the chromosome
number does not change, while the process that
ensures each gamete contains only one-half set of
chromosomes is called MEIOSIS. Meiosis ensures
that each gamete has a different combination of the
chromosomes that were present before meiosis.
Despite the differences among animals, the
fundamental sequence that allows them to reproduce
sexually is the same:
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Meiosis produces gametes
A male gamete combine with a female gamete
A zygote is produced and develops into an
embryo
The embryo develops through mitosis and cell
division into mature offspring
For sexual reproduction to be successful, the
following two requirements must be met:
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Both male and female gametes must arrive at
the same place and time for fertilization
The zygote must receive adequate food,
moisture, warmth, and protection to develop
EXTERNAL FERTILIZATION
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The sperm and the egg meet outside the bodies
of both parents
Most water-dwelling animals reproduce
through external fertilization
INTERNAL FERTILIZATION
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The sperm and the egg meet inside the body of
the female. The sperm travel from the male’s
body into the female’s body to meet the egg.
Most animals on land reproduce through
internal fertilization
HEMAPHRODITES
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Individuals that have both female and male
reproductive organs
Additional Information
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You need to know all of the information from
your cancer brochure
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For Homework tomorrow, or Tuesday, write a
test (with answers). Test should include 20-30
questions
Questions should be a combination of MC,
matching, fill-in-the-blank, diagrams, and
short answer
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