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15 Dec Opener: Why do cells
divide? Agenda
Intro Unit 7
Why do cells divide?
Mitosis slide lab
Mitosis stages
Homework
none
Why do cells divide? Growth
Organisms grow by increasing number of cells
Repair/ Renewal
Cell division occurs to repair damaged tissues
Asexual Reproduction
Some single-celled organisms reproduce by dividing
•Cell before division- DNA replication occurs
•DNA condenses into visible chromosomes
•Chromosomes line up at center of the cell
•Spindle fibers pull chromosomes apart
•New nuclei form
Onion Root Tip Cell DivisionFind and draw cells that you think are doing the following steps of cell division.
The chromosomes are not coiled up and are therefore difficult to see
Chromosomes coil up so they can be seen
Chromosomes line up at the center of the cell
Spindle fibers pull chromosomes apart
Two nuclei form and the cell splits
16 Dec Opener:
How does an entire organism arise from 1 cell (zygote)?
Agenda
Mitosis cont.
Mitosis vs. Meiosis
Homework
Stages of Mitosis1. Interphase
2. Prophase
3. Metaphase
4. Anaphase
5. Telophase
6. Cytokinesis
http://www.slideshare.net/anasonea/mitosis-flip-book
http://media.pearsoncmg.com/bc/bc_0media_bio/bioflix/bioflix.htm?8apmitosis
Meiosis Mitosis# of parent cells?
# of daughter cells?
haploid or diploid daughter cells?
Genetically identical or different daughter cells?
Type of cell produced?
# of cellular divisions?
Purpose/Importance?
Contrast Meiosis and Mitosis
Contrast Meiosis and Mitosis
Meiosis Mitosis# of parent cells? 1 1
# of daughter cells? 4 2
haploid or diploid daughter cells? haploid diploid
Genetically identical or different daughter cells? different identical
Type of cell produced? Gametes (sex cells)
Somatic (body cells)
# of cellular divisions? 2 1
Purpose/Importance? Gamete production in
sexual reproduction
Growth, repair/renewal,
asexual reproduction
17 Dec Opener:
Do you think there are really cells that look like this? Agenda
Differentiation
Cell Survey Lab
Homework
Cell Differentiation Specialization in the structure and
function of a cell
Occurs during development of an organism
Results from the activation and deactivation of certain genes in the cell
Human Cell Survey Lab Draw a picture of your cells.
What type of cells are you looking at?
Give a justification of your guess by linking the cell’s structure to its function.
Example:
“I think this is a neuron because it has a lot of fibers that can connect to other cells for communication.”
Cell Types Bone
Skin
Retina (eye)
Blood
Muscle
1. Observe the tissue at your station
2. As a group, come to a conclusion as to what tissue you are observing.
3. Create a sketch of what you see in the correct location in your table (detailed and neat).
4. Describe the structure of the tissue in words.
5. Explain the connection between the tissue structure and tissue function.
Tissues
Small Intestines- Absorb nutrients from food Bone- Provide support for the body
Muscle- Relax and contract to allow for movement Skin- Provide protection from the environment
Blood- Move oxygen and nutrients through the body Lung- Absorb oxygen into the body and release carbon dioxide
Microscope Activity
18 Dec Opener
What’s so special about stem cells?
Agenda
Stem Cells
Homework
Meet in computer lab tomorrow
Stem Cells-undifferentiated cells
Totipotent- can give rise to an entire new organism
Pluripotent- can give rise to any type of tissue, but not a new organism
http://learn.genetics.utah.edu/content/tech/stemcells/scintro/
Epigenetics and Differentiation
In a stem cell, the DNA is arranged loosely, with its genes ready to spring into action.
As signals enter the cell and differentiation begins, genes that will not be needed are shut down, and genes that will be required for a specialized function remain open and active.
http://learn.genetics.utah.edu/content/tech/cloning/clickandclone/
Induced Pluripotent Stem Cells
Until recently, once a cell became specialized, it was referred to as "terminally differentiated.”
In 2007, researchers were able to turn a differentiated cell back into a stem cell with the potential to become any type of cell in the body.
Stem Cells: The Promise vs. The Controversy
http://www.youtube.com/watch?v=2VTA1tXXyTc
http://www.pbs.org/wgbh/nova/body/stem-cells-breakthrough.html
Skin Gun: https://www.youtube.com/watch?v=eXO_ApjKPaI
The promise of research with stem cells
http://www.ted.com/talks/susan_solomon_the_promise_of_research_with_stem_cells/citations
http://www.youtube.com/watch?v=2VTA1tXXyTc
5 Jan Opener
Can you think of an example of how cells communicate in your body?
Agenda
Calendar
Back to business questions
Cell Communication
Cell signaling
Homework
Cell Communication Cells communicate with each other using chemical signals.
In order for a cell to receive a message, it must have the proper receptor. (Think about a radio)
Cells can communicate in a number of ways:
Local-specific ex. Neuron
Local-broadcast ex. Growth factor
Long distance ex. insulin production, fever response
Steps of Cell Signaling1. Reception
A signal binds to a receptor on the receiving cell
2. Transduction The receptor binding causes a change (sometimes
a series of changes) on the inside of the cell.
3. Response This will result some sort of response by the
receiving cell. Passing on a signal, releasing a protein, begin transcription, etc.
Cell signaling reviewApoptosis
http://www.youtube.com/watch?v=9KTDz-ZisZ0
Flu
https://www.youtube.com/watch?v=Rpj0emEGShQ
21 Jan Opener:
What has to happen to a zygote to become a fully formed adult?
Agenda
Embryology
Review cell signaling & Embryology Readings
Homework
Embryology- http
://www.youtube.com/watch?v=lXN_sDnd1ng&feature=related
http://www.youtube.com/watch?v=UgT5rUQ9EmQ&feature=related
Embryo FormationA single cell, formed by the fertilization of an
egg by a sperm, divides to form a morula (Latin – “mulberry”) – a solid ball of cells
Pg 157
Embryo Formation
Solid ball of cells develops into blastula or blastocyst- a fluid filled ball of cells that will develop into the embryo and placenta
Pg 157
The Embryo Takes Shape Gastrulation: (Greek – gastros = “belly”)
primitive gut is formed by infolding of blastula
The Embryo Takes Shape
Inner cell mass forms three distinct layers of cells: ectoderm - “outside skin”, endoderm - “inside skin”, and mesoderm - “middle skin”
What steps do we need to know?1.Fertilized Egg- Zygote2.Cell Division (Mitosis) Solid Ball of Cells
(Morula)3.Morula hollow ball of cells (blastula)4.Gastrulation Indentation that forms
digestive tract
What do the cells have to do in order to develop into a mature organism?
8 Feb Opener:
What’s happening in this photo? Agenda
Intro Dictyostelium
Dictyostelium lab
Homework
none
http://www.nsf.gov/news/special_reports/fibr/dictyo.htm
Sterile technique
http://www.youtube.com/watch?v=Ay2hhujTuvg&feature=relmfu
Students must wash their hands before and after each lab session.
Lab work areas should be wiped down with 70% ethanol prior to lab work.
Equipment (forceps, etc.) should be dipped in 70% ethanol and flamed.
Petri dishes should be kept closed except for the limited time during which materials are being added.
When adding material to the Petri dishes, only open the dish as much as needed; try to keep the agar as covered as possible.
When working with the Petri dish lid tilted open, work as quickly as possible; keep your face back to avoid breathing on the dish and do not position your hand directly above the dish.