Name: ______________________ Date: ________
Chapter 8 Part 2 Notes: The Cell Cycle
Cell Growth
As organisms grow, do they grow because cells get larger and
larger or because more cells are produced?
___________________ instead of growing larger for _______________
______________ :
As a cell grows larger, there are more demands placed on
its _______.
As a cell grows larger, the cell has more trouble moving
enough nutrients and wastes ____________________________
______________.
Deoxyribonucleic Acid (DNA) is the genetic information of a cell.
In eukaryotes it is found in the ______________.
A cell typically only has _____________________of its’ DNA.
Imagine going to the library to use the computers. As more
and more students arrive, there are not enough computers
for everyone.
All materials enter and/or leave the cell through the _______
_____________________.
The rate at which things can pass through the cell (through
active or passive transport) is dependent on the ______________
______________ of that cell.
The rate at which resources are used up and waste leaves the
cell is a dependent on the ______________ of that cell.
You have to look at the ratio of _______________________________.
The higher it is, the more efficient the cell is. Surface area is
calculated as length x width x # of sides.
Let’s look at three cells.
If a cube has height of 1 cm what is the surface area?
______. What is the volume? ______ Therefore the ratio is
______.
If a cube has height of 2 cm what is the surface area?
______. What is the volume? ______ Therefore the ratio is
______.
If a cube has height of 3 cm what is the surface area?
______. What is the volume? ______ Therefore the ratio is
______.
If you think of a town it’s like cars on a main street. If the number
of cars is increased, but the road isn’t widened, it becomes more
and more crowded.
Cell Division
Before a cell grows too large, it will divide into two “_____________
_______”.
The process of division is called _____________________.
Before a cell can divide, it must replicate all of its’ DNA. It will
begin with _______ copy and end with _______ copies.
This _____________________ gives one copy of DNA to each
daughter cell.
This also _______ the surface area to volume ratio of each cell.
The Cell Cycle
Prokaryotes can just divide into two cells, but eukaryotes must go
through a lot of preparation. Cell division is in three sections:
_____________________-The cell grows and replicates DNA.
______________-The nucleus divides.
______________-The cytoplasm and the rest of the cell divide.
In eukaryotes, DNA is carried in the form of ____________________.
How many chromosomes are present depends on the _______
____________________________.
Fruit flies have 8 chromosomes.
Humans have ____ chromosomes.
Chromosomes can only be seen in most cells during __________.
Before cell division each chromosome is replicated and has two
different “__________________________”. When the cell divides, the
chromosome splits and each daughter cell gets a chromatid.
The chromatids are connected in an area called a
_____________________.
Cells are always in the cell cycle. It consists of 4 main phases:
______________ and _________________ are in __________.
Two “_______” phases where the cell grows. They are called
_____________________ and _____________________.
DNA replication occurs in ______________.
Events of the Cell Cycle
First, in ______________, cells grow and make new organelles and
proteins.
Second, in ______________, the chromosomes are replicated.
Usually a cell proceeds to division if it enters S phase.
Third, in ______________, many of the organelles and molecules
needed for cell division are produced.
It is the ______________ of the 4 phases.
All three of these phases take place in ______________.
Mitosis
The fourth stage is mitosis. It consists of 5 stages:
_____________________
_____________________
_____________________
_____________________
_____________________
After these _____________________ occurs.
In ______________, the DNA condenses into chromosomes. The
______________ separate and a spindle begins to form.
In _____________________ the nuclear envelope
_____________________ and the centrioles begin to __________ out
their spindles to find the chromosomes.
In ______________ the chromosomes line up in the ______________ of
the cell and a spindle fiber connects to each ______________.
In ______________ the sister chromatids are _____________
___________ towards opposite ends of the cells.
In ______________ the chromosomes gather at
____________________________ of the cell and revert to their usual form
(______________). Two new ___________________________begin to form.
Cytokinesis
The cytoplasm ____________________________and two daughter
cells are formed. Each daughter cell has a duplicate set of
chromosomes.
In _____________________the cell membrane pinches inward
until two equal parts are formed.
In _____________________a structure known as a
______________forms between the nuclei and develops into
a separating membrane. The cell wall then forms and
spreads outwards.
Controlling the Cell Cycle
Proteins called ___________ regulate the timing of the cell cycle in
eukaryotic cells.
They can be divided into two groups:
____________________________ are proteins that respond to
events inside of the cell. For example: making sure that the
cell does not proceed to G2 phase or mitosis unless all of the
chromosomes have been replicated.
____________________________ are proteins that respond to
events outside of the cell. For example: if there is not
enough space outside of a cell for others to exist, the cell
may not enter or proceed past G1 phase.
This is also why when a scab forms over a cut it does not rise
much above the surface of the skin. It limits new cells to
within a certain distance of the others.
G0 phase
______________ is when a cell is in a _____________________. This
occurs for some cells such as heart or nerve cells which are not
replicated and typically survive for a long time.
It can also occur for cells that do not have enough resources to
enter cell division.
It typically occurs before cytokinesis or after G1 depending on
the type of cell.
Uncontrolled Cell Growth
In uncontrolled cell growth, the ______________ are bypassed or
do not work correctly and the cells grow and divide whether or
not they are ready.
____________ is when some of a body’s cells ____________________
______________ to control growth.
The masses of cells formed by the uncontrolled growth are
called __________. These can damage surrounding tissues.
When cancer _____________________, cancer cells break
loose from the tumor and spread throughout the body
affecting other areas of cells.
The loss of control can be caused by many different factors
depending on the type of cancer such as:
______________
____________________________
____________________________
Damage to the _________________ which halts the cell cycle
until all the chromosomes have replicated.
Tumors can be:
______________: not usually caused by cancer. It does not
spread to surrounding healthy cells or tissue.
_____________________: cancerous cells that can invade and
destroy surrounding healthy cells or tissue.