Download Cell Growth and Division

Cell Growth and Division
Chapter 10
Limits to Cell Growth
• What problems does growth cause for cells?
• The larger a cell becomes, the more demands
the cell places on its DNA. In addition, the cell
has trouble moving enough nutrients and
wastes across the cell membrane.
Limits to Cell Growth
• The rate at which food, oxygen, water, and
wastes are moved into and out of the cell is
dependent on the surface area of the cell.
• The rate at which food, oxygen, and water are
used and produced depends on the cell’s
volume.
Surface Area to Volume Ratio
• As the length of cell increases, its volume
increases faster than its surface area.
• The decrease in the cell’s ratio of surface area
to volume makes it difficult for the cell to
move needed material in and waste products
out quickly enough for the cell to survive.
• Why?!
Division of the Cell
• Before it becomes too large, a growing cell
divides, forming two “daughter” cells.
• The process by which a cell divides into two
new daughter cells is called cell division.
Cell Division
• In eukaryotes, cell division occurs in two major
stages:
1. Mitosis = Division of the cells nucleus
2. Cytokinesis = division of the cell cytoplasm
Genetic information is passed from one generation
to the next on chromosomes.
Cell Division
• Before cell division, each
chromosome is duplicated,
or copied.
• Each chromosome consists
of two identical “sister”
chromatids.
• Each pair of chromatids is
attached at an area called
the centromere.
Cell Division
• When the cell divides,
chromatids separate.
Each new cell gets one
chromatid.
The Cell Cycle
• The cell cycle is the series of events that cells
go through as they grow and divide.
• Interphase is the period of growth that occurs
between cell divisions.
During the Cell Cycle…
• A Cell grows
• Prepares for division
• Divides to form two daughter cells, each of
which begins the cycle again.
Cell Cycle
• The cell cycle consists of four phases:
–
–
–
–
G1 (First Gap Phase), or “Growth”
S Phase, or “Synthesis”
G2 (Second Gap Phase), or “Get Ready”
M Phase or “Cell Division”
Events of the Cell Cycle
• During G1, the cell…
– Increases in size
– Synthesize new proteins and organelles
• During the S phase…
– Chromosomes are replicated
– DNA synthesis takes place
– Once a cell enters the S phase, it usually
completes the rest of the cell cycle.
Events of the Cell Cycle…
• The G2 Phase…
– Organelles and molecules required for cell
division are produced
– Once G2 is complete, the cell is ready to start the
M phase (Mitosis first!)
Find your seats from last class!
Warm Up 11/4/16
What are the four stages of
Mitosis? What organelle does
this take place in?
Mitosis – 4 phases
•P = Prophase
•M = Metaphase
•A = Anaphase
•T = Telophase
Steps of Cell Division
• Class Handout!
Cytokinesis
• During cytokinesis, the cytoplasm pinches in
half.
• Each new cell has an identical set of duplicate
chromosomes.
Cytokinesis in Plants
• What is the key difference between plant and
animal cells?
• Plant Cells have a…
Cytokinesis in Plants
Plant Cells have a CELL WALL!
Cytokinesis in Plants
• In plants, a structure known as the cell plate
forms midway between the divided nuclei.
• The cell plate gradually develops into a
separate membrane.
• A cell wall then begins to appear in the cell
plate.
Animal Cell
Plant Cell
Mitosis Lab!
→ Have your computer?!
- No computers - by Welsh’s office
- Computers - by the door! :) PAIR UP!
→ Once you have your partner and desks
arranged, ask Mr. McNish for the handout!
When you’re finished…
→ Turn in your lab up front! (Be sure your
name is on it!)
→ Pick up a Mitosis Crossword!
Exit Ticket
On your Ticket:
What are 3 things you learned today?
What do you want to learn about cell
division?
Happy Monday! → Warm Up
Why is it important for cells to have a
natural limit to the frequency and
amount of growth in their lifecycle?
What are some of the potential issues
arriving from unregulated growth/
division?
Example summary sentence:
First written description of cancer is found in Egyptian writing.
Example summary sentence:
Hippocrates is the first to use the term cancer.
Example summary sentence:
Surgeons perform crude mastectomies using fire, acid and leather binding.
Example summary sentence:
Surgeons began performing radical mastectomies.
Example summary sentence:
High doses of radiation are used to treat tumors.
Example summary sentence:
The National Cancer Institute is created.
Example summary sentence:
Scientists began studying the use of chemicals (chemotherapy) as a
treatment for cancer.
Example summary sentence:
Dr. Sydney Farber creates the Jimmy Fund, a cancer advocacy organization.
Mitosis
Myles Jerique
Tristan Mya
Olivier Josh
Daniel Kylie
Mirage Afra
Nikko
Roz
Skylar
Spencer
McKayla Kayla
Nathan Sage
Adam Janiah
Meiosis
Ben
Phillip
Megan Blake
Leina Brennan
Sarah Jemma
Ruby
Sydney
Zane
Declan
Jonathan Adia
Sasha
Isabella
Lamont Charlie
Bianca
Veronika
Exit Ticket
- What were the most relevant 2 3 portions of today’s class?
- Which concepts do you need
further clarification on?
Exit Ticket
What were the 2 - 3 most important
concepts that you will take away from
today’s class?
Which concepts do you need further
clarification on?