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Cell Structure and Function Fetal Movement0

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					Unit 3 Outline & Notes                                    10/22/2008 10:06:00 AM

 Cell Structure and Function


 Lecture Outline


 I. Introduction
 - Cells are the building blocks of all living things
 - Cells are the smallest functioning units of life
 - Cells are produced by the division of preexisting cells
 - Each cell maintains homeostasis


 There are trillions of cells in the human body, they work together to
 maintain homeostasis


 II. Studying Cells


 Cyto/logy: the study of cells


 - first cells were viewed by light microscopes which can magnify up to 1,000
 times
 - 1950’s- Electron microscopes focus a beam of electrons on a preserved
 sample and can reveal fine details of cell structures and intracellular
 structures.
 Scanning electron microscopes reveal 3D structures with a superficial view


 III. An Overview of Cellular Anatomy


 - The “typical” cell is like the “average” person, we will study a model cell
 that is a general representative of a cell
 - know nucleus, cytoplasm, cell membrane


 IV. The Cell Membrane
 V. Membrane Structure
 - 6-10 nm thick
 - lipids, proteins, and carbohydrates

       A. Membrane Lipids
- phospholipids are the major part of the cell membrane
- phosphate (PO4 3-) “head” plus 2 fatty acid “tails”
- 2 layers of phospholipids
the hydrophilic heads are on the outside, hydrophobic tails face the inside
- mixed in are cholesterol molecules and other lipids
- O2 and CO2 are able to move in and out of the membrane, ions and water
cannot just move in and out
       B. Membrane Proteins
- proteins cross from one side to the other side of the membrane and act as
channels for things to move through
- proteins that act as enzymes, receptors (receiving info)
      C. Membrane Carbohydrates
- found on the outer surface of the membrane, act as receptors, adhesive,
lubricant, help with cell recognition


VI. Membrane Transport


Permeable- determines what can enter and leave the cell
- whether a substance can cross over the membrane depends upon the
substance’s size, electrical charge, shape, and lipid solubility


     A. Diffusion- the net movement of molecules form high to low
concentrations, “downhill” does not require energy
- CO2 is high in cells, lower outside so it diffuses out of the cell



            1. Diffusion Across Cell Membranes: alcohol, fatty acids, and
steroids can enter cells easily and go through the lipids of the membrane, so
can O2 and CO2. Ions and water must pass through proteins


          2. Osmosis: A Special Type of Diffusion: the diffusion of water,
water moves towards the more highly concentrated solute


             3. Osmosis and Osmotic Pressure: Solutions of varying
concentration are referred to as hypotonic, hypertonic, and isotonic.
- isotonic: an equilibrium exists, and water movement is equal
- hypotonic- water will flow into the cell causing it to swell up
- hypertonic: water will leave the cell, causing the cell to shrink
Normal saline: a 0.9% solution of NaCl and water that is
approximate to the concentrations in the cell.


Hemolysis- rupturing of the membrane of red blood cells
Crenation: the shrinking of red blood cell


      B. Filtration
      C. Carrier-Mediated Transport
            1. Facilitated Diffusion- moves with no energy through the
membrane
            2. Active Transport: energy is required and pumps substances
form a low to high concentration. An example is the sodium potassium
pump.


      D. Vesicular Transport
           1. Endocytosis: packaging of materials to enter the cell
                  a. Receptor-mediated Endocytosis
                    b. Pinocytosis: “cell drinking”
                    c. Phagocytosis: “cell eating” the entrapment of dead or
living cells, associated most often with an immune system response to the
body
              2. Exocytosis: packaging of materials to leave the cell


VII. The Cytoplasm: includes both cytosol & organelles


      A. The Cytosol
- intra/cellular fluid which contains dissolved nutrients, ions, soluble and
insoluble proteins, and waste products
- is different from the fluid outside of the cell in the following ways:
1. the cytosol contains a higher concentration of potassium ions and a lower
concentration of sodium ions
2. The cytosol contains a high concentration of dissolved proteins, many of
these are enzymes that regulate chemical reactions (metabolism)
3. has relatively small amounts of carbohydrates (making energy) and large
amounts of lipids (back up energy source) and amino acids (making
proteins)


     B. Organelles: little organs, structures that perform specific functions
essential to normal cell structure, maintenance, and metabolism


            1. The Cytoskeleton: internal protein framework of threadlike
filaments and hollow tubes to give strength and flexibility to the cytoplasm


                   a. Microfilaments: the thinnest strands, made up of the
protein actin, these interact with the protein myosin to produce movement
of a part of the cell or change the shape of the cell


                  b. Microtubules
            2. Microvilli
            3. Centrioles, Cilia, and Flagella
                  a. Centrioles: short, cylindrical, made up of microtubules;
create the spindle fibers during cell division, These cells DO NOT have
centrioles: mature red blood cells, skeletal and cardiac muscle cells,
neurons, they DO NOT divide
                  b. Cilia: tiny, hair like projections that move fluids or
secretions across the cell’s surface; example: cilia that line the respiratory
tract move to remove mucus and dust particles towards the throat and away
from the lungs
                  c. Flagella: moves the entire cell through the fluid that
surrounds it, the only cell in the human body with flagella is the sperm cell
            4. Ribosomes: manufacture proteins following directions from
the DNA
            5. Endoplasmic Reticulum
Rough ER: packages newly synthesized (made) proteins; has ribosomes
attached to it
            6. The Golgi Apparatus
            7. Lyso/somes: vesicles filled with digestive enzymes that clean
up and recycle old organelles, destroy bacteria and other foreign particles
within the cell
            8. Peroxisomes: filled with enzymes, break down fatty acids and
other organic compounds, they produce hydrogen peroxide H2O2 as they
break this stuff down, H2O2 is a free radical which is a potentially dangerous
compound
            9. Mitochondria: have enzymes that regulate the reactions that
provide energy to the cell: cellular respiration;
                   a. Mitochondria
                   b. Mitochondrial Energy Production: aerobic metabolism,
      produces about 95% of the energy the cell needs


VIII. The Nucleus
- is the control center for cellular operations
- a single nucleus stores all the genetic information needed to control the
synthesis (making) of the approximately 100,000 different proteins in the
body
- most cells have a single nucleus, but there are exceptions, skeletal muscle
cells have many nuclei, mature red blood cells have none


- nuclear envelope is a double membrane, the fluid inside has ions,
enzymes, RNA and DNA, and proteins
- chemical communication between the nucleus and the cytosol occurs
through the nuclear pores which cover about 10% of the surface of the
nucleus, too small for DNA and proteins to pass through


- most nuclei contain 1-4 nucleoli, make ribosomes


      A. Chromosome Structure


- DNA is contained in chromosomes, 23 pairs in human cells, one from the
mother and one form the father
- each chromosome is DNA bound to special proteins called histones allowing
the DNA to coil, the amount of coiling determines whether the chromosome
is long and thin or short and fat
- in a dividing cell, chromosomes are tightly coiled and can be clearly seen
as separate structures under the microscope
- in cells that are not dividing, DNA is loosely coiled and called chromatin
      B. The Genetic Code


- this is the method of storing information in the DNA strands
- by understanding this code, we know how cells build proteins and how
traits are inherited
- DNA is a pair of strands held together by hydrogen bonding, info. Is stored
in the sequence of nitrogen bases (A,T,G,C)
adenine
thymine
guanine
cytosine


triplet code: the genetic code is a triplet code because a sequence of 3 bases
is needed to identify a single amino acid. Remember amino acids are the
building blocks of proteins


Gene- the functional unit of heredity, each one consists of all the triplets
needed to produce a single protein, the number of triplets needed to
produce a protein varies form gene to gene


DNA Fingerprinting: Every nucleated cell in the body carries a set of
46 chromosomes. The entire DNA does not all code for proteins,
some sections of the code have no known function. This “useless”
coded section is repeated several times in the DNA, making it
unlikely that any 2 individuals would share the same code. So,
individuals can be identified on the basis of this pattern from skin,
blood, semen, hair, or other tissues.


      C. Protein Synthesis
Each DNA molecule contains information for making thousands of proteins.
In order to make proteins, the following must happen.


            1. Transcription: the process of forming mRNA, copying the DNA
into a useable format that can leave the nucleus and travel to the ribosomes
where proteins are made
            2. Translation: the synthesis of proteins using the information on
the mRNA strand, this is done with the help of transfer RNA. Amino acids are
added to form a protein.


Protein: a chain of amino acids, usually more then 100 amino acids, an
average protein has 1,000 proteins and is made in about 20 seconds.


Mutations: permanent changes in a cell’s DNA that affect the
sequence of one or more genes. The simplest is called a point
mutation, which is a change in a single “letter” in the code.
- there are roughly 3 billion pairs of “letters” in the DNA of a human
cell.
- over 100 inherited disorders have been traced to an abnormality in
enzyme or protein structure such as the mutation mentioned above.
- For example, several cancers, sickle cell anemia, and thalassemia-
a blood disorder, are a result of a point mutation
- most mutations occur when the DNA is copied prior to cell division,
when this occurs is important to how many cells are affected.



IX. The Cell Life Cycle
- During the time between fertilization and physical maturity, the number of
cells that make up an individual increases from one to roughly 75 trillion
cells
- cell division is cellular reproduction
- DNA replicates itself and then mitosis occurs in somatic cells


Somatic Cells- most of the cells in the body (soma= body)
Division and creation of egg and sperm cells is called meiosis and is a
different process


      A. Interphase: - for most of their lives, cells spend in interphase, the
time between cell division when cells operate normally
- some cells are “pre-programmed” to self destruct after a certain period of
time; these are nicknamed “suicide genes”
- apoptosis: the genetically controlled death of cells, very important in
homeostasis
Ex: In fetal development: this destroys the cells that make up the webbing
tissue between fingers and toes.
- Some cells such as nerve cells and skeletal muscle cells never undergo
mitosis or division


      B. Mitosis
- the process that separates and encloses the duplicated chromosomes of
the original cell into 2 identical nuclei
              Stage 1: Prophase
             Stage 2: Metaphase
              Stage 3: Anaphase
              Stage 4: Telophase
       C. Cytokinesis: the separation of the cytoplasm, marks the end of cell
division
       D. Cell Division and Cancer
- in normal cell division the rate of division is balanced with the rate of cell
loss. If this balance breaks down, abnormal cell growth occurs and tumors
form


- benign tumors, the abnormal cells remain together in connective tissue
and seldom threaten a person’s life. These can be removed with surgery if
necessary


- malignant tumors- tumors that no longer respond to normal control
mechanisms, these cells then spread to the nearby tissue from the primary
tumor to form secondary tumors sometimes in distant tissues and organs
- spreading is called metastasis


Cancer- an illness characterized by malignant cells, lose their resemblance to
normal cells and cause organ functions to deteriorate as their numbers
increase. They also use energy less efficiently and can steal nutrients from
normal cells, this accounts for the “starved appearance”

X. Cell Diversity and Differentiation
Important Vocabulary                    10/22/2008 10:06:00 AM

 III. An Overview of Cellular Anatomy


 extracellular fluid:
 cell membrane:
 cytoplasm:
 nucleus:


 IV. The Cell Membrane



 phospholipid bilayer:
 permeability:
 diffusion:
 concentration gradient:
 solutes:
 osmotic pressure:
 isotonic:
 hypotonic:
 hemolysis:
 hypertonic:
 crenation:
 normal saline:
 filtration:
 carrier-mediated transport:
 facilitated diffusion:
 active transport:
 vesicular transport:
 endocytosis:
 pinocytosis:
 phagocytosis:
 exocytosis:




 VII. The Cytoplasm
cytosol:
organelles:
cytoskeleton:
microfilaments:
actin:
myosin:
microtubules:
tubulin:
microvilli:
centrioles:
cilia:
flagella:
ribosomes:
endoplasmic reticulum:
        smooth:
        rough:
Golgi apparatus:
Lysosomes:
Peroxisomes:
Free radicals:
Mitochondria:
Aerobic metabolism:


End for test 1


VIII. The Nucleus


nucleus:
nuclear pores:
nucleoli:
chromosomes:
genetic code:
DNA fingerprinting:
Protein synthesis:
mRNA:
tRNA:
translation:
anticodon:
codon:
mutations:


End test 2


IX. The Cell Life Cycle


cell division:
mitosis:
somatic cells:
meiosis:
interphase:
apoptosis:
DNA replication:
Prophase:
Centromere:
Spindle fibers:
Metaphase:
Anaphase:
Daughter chromosomes:
Telophase:
Cytokinesis:
Benign tumor:
Tumor:
Malignant tumor:
Metastasis:
Differentiation:


End test 3
Mini Projects                                             10/22/2008 10:06:00 AM

  Project 1: Creation of a cell model


  Project 2: Clinical Terminology related to the cell


  1.   DNA fingerprinting
  2.   genetic engineering
  3.   benign and malignant tumors
  4.   metastasis and primary or secondary tumors


  Choose one of the above topics to write a one page paper about. Include 1-2
  references cited at the end of your paper.
     - include your name, the date, and a title of your creation
     - may double space, 12 font



       1.   The Nature of pathogens, bacteria- Caine
       2.   The Nature of Pathogens, viruses- Marge
       3.   The Nature of Pathogens, prions- Jake
       4.   Lysosomal storage diseases- Tim
       5. Mitochondrial DNA, Disease, and Evolution- Chris



  Choose one of the above topics to create a brief presentation of to your
  classmates. You should include a one page fact sheet and a visual and will
  present it to the class. Only one topic will be used twice in the class and I
  will give you the resource page you need to complete this.
The Human Genome Project                                10/22/2008 10:06:00 AM

 You will study and complete research on the human genome project based
 on the following guidelines:


 You should be able to obtain most of your research information on
 www.genome.gov


 1. What is the project? Include some history, facts, and background.


 2. What is the human genome? Include some background on DNA’s structure
 and how instructions for making proteins are used in the cell.


 3. What are the implications of the HGP? Meaning, What will or could this
 information do for you, your family, your community now or in the future?


 4. Discuss how this will help medical science.


 5. Include some extra research you find to be interesting on the topic.


 You may create a power point presentation, a written paper, a poster, or
 combination of any. You may come up with your own way of presenting your
 information such as an informational booklet.


 All writing must be in your own words and all visuals must be cited unless
 created by you. You will have 1-2 class periods to work on this and then will
 need to work on the project at home.


 DUE DATE: Tuesday, December 2nd


 Grading Guidelines: 100% project grade


 Content: 80 points
 - includes information on all of the above # 1-5
 - content is in your own words and relevant to the project
 - important information is cited as needed
 - there is detail included on the topics beyond simple statements of facts
 - there is demonstrated understanding of the topic
Presentation: 20 points
- format
- creativity
- appealing to the audience
- spelling and grammar checked

				
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