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CellsAnatomy & Physiology
Mackenzie, at 4 years old, was diagnosed with pneumonia. Her parents were worried, it seemed that Mackenzie was always sick. She always had a runny nose and had frequent ear infections. The diagnosis of pneumonia also revealed something else - Mackenzie had a condition known as situs inversus.
1. What do you think situs inversus is?
2. How might Mackenzie’s condition be related to cell disfunction? This mini case is based on a real person (
Source), images are stock images from morguefile.com
Cells vary in SIZE and STRUCTURE
Depends on what they do
Cytology = the study of cells
All Animal Cells have 3 main parts
●Nucleus●Cytoplasm (cytosol)●Cell Membrane
Cell Membrane is
selectively
permeable
Lipid bilayer (phospholipids) make up the membrane with proteins embedded to help regulate what comes across the membrane
Given Mackenzie’s history of illness, sniffles, and ear infections, doctors wanted to rule out cystic fibrosis. A simple “sweat test” is used to diagnose CF.
Examine the image. Why is CF considered a disorder related to the cell membrane.
Could CF have caused Mackenzie’s symptoms?
The sweat test showed that Mackenzie did not have extra chloride in her sweat. Does this mean that she does not have CF? Could there be another cause for Mackenzie’s frequent infections?
The cytoplasm (cytosol) is the area between the nucleus and the membrane.
Many of the cell’s metabolic reactions occur in this area.
Do you remember what metabolism is?
ORGANELLES- "little organs" within the cell that perform specific functionsThe nucleus is to the cell what the __________is to a person.
The cell membrane is to a cell what the ________ is to a person.
ENDOPLASMIC RETICULUM
Transport system; canals and channels that connect
membrane to nucleus and to organelles within the cell
Function = transport system
Smooth ER (lipid synthesis)
Rough ER (contains ribosomes for protein manufacture)
Golgi Apparatus
Flattened membranes;
Function = package and delivery of proteins produced
by the ribosomes
Proteins are exported in vesicles
Mitochondria ( The “powerhouse” of the cell )
Chemical energy from food is converted to a useable
form (ATP) -- process is called Cellular Respiration
What does respiration have to do with metabolism?
Lysosomes - contain digestive enzymes to break down
substances (“suicide sac”)
Remember the video on how beans become farts?
What is the enzyme in this image and how do you know?
Enzymes break down
substances in the cell,
such as food or worn out
cell parts, even bacteria.
What organ is your body is most like the lysosome?
Centrosome – two cylinders, centrioles, that sit
perpendicular
During cell division, the centrioles separate and
form a spindle.
The spindle moves chromosomes during cell division so that each new cell gets the proper number.
CYTOSKELETON
made of microfilaments and microtubules which
maintain shape and functions in movement
Cilia & Flagella
Doctors wanted to test Mackenzie for a disorder called “PRIMARY CILIARY DYSKINESIA”This disorder causes cells to not create normal cilia.
Cells scraped from the sinuses showed an irregularity in Mackenzie’s cilia.
What is different about this cilia?
Why would problems with cilia cause pneumonia, ear infections, and a constant runny nose?
NUCLEUS - (the “brain” of the cell)
Directs cell activities (the “brain” of the cell)
Contains genetic information (DNA) in the form of chromatin
Also contains a nucleolus – makes ribosomes
Has tiny pores in the nuclear membrane is where RNA can
exit the nucleus
Mackenzie can live with PCD, but she will always have a cough and deal with lung and ear infections.
What about the situs inversus?
Doctors have warned her parents that when she gets older, she may have trouble conceiving a child and is at risk for an ECTOPIC pregnancy.
What role does cilia play in reproduction?
It is believed that the motion of cilia may play a part in determining the placement of organs within the thoracic and abdominal cavities. In the absence of ciliary motion, organ placement becomes a random event, giving each affected embryo a 50/50 chance of having typical or atypical placement.
More analogies
1. What part of the cell is most like the stomach?
2. What part of the cell is most like your circulatory system?
3. What part of the cell is most like your brain?
4. What part of the cell is most like your bones?
5. What part of the cell is most like your skin?
Super Difficult Bonus Question
Which part of the cell do you think is the most responsible for maintaining homeostasis?
Cells - Part 2Movement of Substances Across the Membrane
Cells must bring in materials, like food and oxygen and remove wastes.
These processes occur at the cell membrane.
PHOSPHOLIPID BILAYER
Cells are limited in size by the surface area (membrane) and volume (insides) ratio.
Increasing surface area can increase the cell’s efficiency moving substances.
Cells of the digestive system have projects called villi that aid in absorbing nutrients.
Diffusion - molecules tend to spread out; moving from
areas of high concentration to low concentration
Diffusion Animation
This process requires no energy, it is called
PASSIVE TRANSPORT
Movement of Substances Through the Membrane
Diffusion - molecules tend to spread out
Facilitated Diffusion - uses proteins as passageways
Diffusion Animation
OSMOSIS - the diffusion of water
Hypertonic HypotonicIsotonic
SALT
SUCKS
Osmosis Animation
Active Transport - requires energy (ATP)
Exocytosis - secretion; things exit cell
Endocytosis (phagocytosis & pinocytosis)
A. Interphase = growth phase, *differentiation occurs
B. Mitosis = nuclear division
C. Mitosis is followed by cytokinesis (cell division)
Cells - Part 3 The Life Cycle of the Cell
The steps of mitosis ensure that
each new cell has the exact same
number of chromosomes as the
original
●Interphase • Prophase • Metaphase • Anaphase • Telophase
●IPMAT
The structure of a chromosome
1. chromosomes visible (chromatids)
2. centrioles migrate to the poles
3. nuclear membrane disappears
4. nucleolus disappears
5. spindle forms
chromosomes line up on the equator, spindle
attaches
chromatids separate at the centromere and move
to opposite poles
1. chromosomes disappear • chromatin
2. nuclear membrane reforms
3. nucleoli reappears
4. spindle disappears
5. centrioles duplicate
- division of the cytoplasm to form 2 new daughter
cells
- organelles are divided
- daughter cells are genetically identical
Cells return to interphase
DIFFERENTIATION
occurs as cells multiply and organism develops and grows
Cancer: caused by uncontrolled cell division
1.Name the phases
starting at the top.
1.Name the phase2.Identify X3.Identify Y
5. Name the phase
6. Name the structure
1.Name the structure
2.What is its function?
9. Which beaker(S) contains a solution that is hypertonic relative to the bag
A B C D E
10. What will happen to the baggie in the hypertonic solutions?
