Download Cell Life Cycle and Reproduction

Cell Life Cycle and Reproduction Notes
Name__________________________________________ assign.#_ __
Unit Goals:
•
Describe the phases of the
cycle.
•
Describe the process of
.
–
Describe the functions of mitosis.
Unit Goals:
•
Describe the process of
.
–
Describe the functions of meiosis.
–
Explain the consequences of mistakes.
***Why not just one large cell? Difficult to get ___________________ in and waste out.
S phase- DNA synthesis
The Cell Cycle
•
•
•
•
•
Chromosomes _________________.
Chromosomes are inherited genetic information
Chromosomes are made up of _____________.
Can only be seen when cells are _____________.
Chromosomes ____________
-or copy is made
• The two copies are
-_____________ together at a
point called a _____________.
-are called sister
_____________.
G1
phase
Cell
undergoes
________.
G2 phase
M phase
•
Cell division (Mitosis and cytokinesis)
Two parts:
1. Nuclear division
–
_____________________
2. Cytoplasmic Division
–
_____________________
MITOSIS
•
In eukaryotes, it is the main process by which
____________ and tissue ______________ is
accomplished.
•
Mitosis is also the main process by which single-celled and
many multi-celled eukaryotes reproduce ______________.
Preparation for Mitosis. Organelles are
________________.
G1, S, and G2 are known together as
______________________..
 Gametes are ______ cells.
 Somatic cells are “___________” body cells.
4 Steps of Mitosis (PMAT)
Prophase:
 Chromosomes condense and attach
to the ____________ fibers at
their ________________.
 Nuclear Membrane breaks down.
 Centrioles move to opposite sides
of the cell and organize the
spindle fibers.
Metaphase:
 Chromosomes
________ up in
the __________
of the cell.
Anaphase:
Chromosomes
separate-Move to
____________
sides of the cell
Telophase:
 Nuclear Envelope _________
 There are now TWO nuclei in
one cell!
 …And they contain the
___________ genetic
information *SAME
_____________ OF
CHROMOSOMES
Cell Life Cycle and Reproduction Notes
Name__________________________________________ assign.#_ __
Cytokinesis:
•
•
•
•
•
_________________ division
Each cell gets __________ of the organelles.
After mitosis: cell _______________ in half to form two new cells.
Animal cells pinch.
Cytokinesis in plant cells is different from that in animal cells.
•
In plant cells a _______ _________ forms from the inside out.
Results of Mitosis & Cytokinesis
•
new cells.
• The new cells- called daughter cells- have the
________ number of chromosomes as the mother cell.
• This occurs in all
cells in your body.
• You have _______chromosomes in all of your somatic
cells-_____ __________!
Reproduction of Sex Cells



cells- __________and ________
Process is called ____________
Similar to Mitosis


Diploid
MEIOSIS = CHROMOSOME REDUCTION DIVISION




Cell _________ ____________
First division is like mitosis and then the cell
divides again to create 4 ________ cells.
In Humans, starts with ___ and ends up with ____.
Why? Fertilization creates the _________ condition again
Sperm formation- 4 haploid sperm cells are formed.
Egg formation-most of the cytoplasm is used in one cell and
the other three disintegrate. One haploid egg cell is formed.
Crossing Over
• Sometime during
meiosis the
chromosomes
can
___________
information
• Major source of
___________
___________
in species.
Haploid
Prokaryotic Cell Division
• __________
_____________
• DNA is
________ and
then the cell
_________ in
half.
• ____________
__ Reproduction
__________ genetically identical!
Contains _____of the genetic information.
Regulation of the Cell Cycle
• How do cells know when to divide? When to stop dividing?
• _______________-___________ that regulate the cell cycle.
• Unregulated cell growth can form masses of cells called tumors-___________.
•
Cell Life Cycle and Reproduction Notes
Name__________________________________________ assign.#_ __
Mitosis Summary
Read and answer the questions at the end.
Cell division
When a cell divides, its two daughter cells must receive the required number of DNA molecules. In eukaryotes,
DNA is sorted into two nuclei in the process of mitosis. A separate process divides the cytoplasm in two.
Mitosis is the process in which threadlike nuclear material is divided equally between two daughter cells.
Mitosis keeps the number of chromosomes constant from one cell generation to the next. In eukaryotes
mitotic cell division is the main process by which growth and tissue repair is accomplished. Mitosis is also the
main process by which single-celled and many multi-celled eukaryotes reproduce asexually.
Mitosis
Mitosis can be broken into four phases: prophase, metaphase, anaphase, and telophase.
� During prophase, the duplicated chromosomes become distinct and spindle fibers radiate across the cell. The
nuclear envelope starts to break up.
� During metaphase, the duplicated chromosomes line up randomly in the center of the cell between the
spindles at the spindle equator.
� During anaphase, the duplicated chromosomes are pulled to opposite ends of the cell. Every chromosome
that was present in the parent cell is now represented by the daughter chromosome at the poles.
� During telophase, a nuclear membrane forms around the chromosomes at each end of the cell. The spindle
fibers disappear and the chromosomes disperse and become less distinct. Each nucleus has the same
chromosome number as the parent cell. The process of mitosis is now complete.
Cytokinesis
At the end of telophase, the cytoplasm begins to divide. In animal cells, the plasma membrane forms a groove
and “pinches in” at the middle of the cell. This separates the two new nuclei and splits the cell in half. In plant
cells, the rigid cell wall prevents a groove from forming. Instead, a cell plate forms along the center of the cell
and cuts the cell in half. The cell plate forms new cell walls. Two daughter cells are formed as a result of
cytokinesis. They are identical to their parent cell. Cell division allows unicellular organisms to duplicate
themselves in a process called asexual reproduction. In multi-cellular organisms, cell division allows them to
grow (i.e., increase the size of the organism), develop from a single cell into a multi-cellular organism, and make
other cells to repair and replace worn out cells.
****Questions*****
1. In which phase do the chromosomes line up in the middle?
2. When does the cell actually split?
3. What are the two new cells called?
4. Are the two new cells genetically identical or not?
5. Give 2 reasons why a cell might go through mitosis? (I think this would be a great test question. Don’t you?)