Cellular Level Of Organization

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Cellular Level Of Organization

A & P 1 Chapte

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The basic living, structural and functional unit of the body.
Cell Biology
The study of cell structure and function
Parts of a Cell
*Plasma (cell) membrane *Cytoplasm (a)Cytosol (b)Organelles *Nucleus
Plasma Membrane
Surrounds the cell and occurs as a LIPID bilayer (2 back to back lipid layers) with interspersed proteins. *Called a fluid mosaic because the plasma membrane resembles an ever moving sea of lipids that contains a mosaic of many diff. proteins.
orient in a BILAYER to make the basic framework of the membrane. Represent 75% of membrane lipids. Serve to prevent the movement of many chemicals through the membrane. Gives the membrane flexibility.
Help form an outer coat on the cell called the GLYCOCALYX.
STRENGTHENS the membrane and decrease membrane fluidity.
Membrane Proteins
Largley determine what functiona a cell will perform and can vary from cell to cell.
Intergral proteins
If membrane proteins extend into or through cell membranes.
Ion Channels
A water filled pore through which IONS can pass.
(carrie proteins) Move a certain POLAR chemical from one side to the other by CHANGING the transporters shape.
Receptor proteins
BOND to a specific chemical in the extracellular (outside) fluid SIGNAL the cell to carry out a SPECIFIC function.
Molecules (chemicals) that bond to a specific receptor. (Ex. insulin ligan binds to insulin receptor)
Speed up chemical reactions
Cell indentity markers
(glycoproteins) Help cells RECOGNIZE each other.
anchor proteins of neighboring cells to each other or they anchor filaments to the plasma membrane.
Glycoproteins help form the GLYCOCALYX which allows cells to:
PROTECT itself from being digested. Become sticky to HOLD it to other cells. Hold a fluid layer creating a SLIPPERY surface.
Selective Permeability
The membrane allows SOME chemicals to pass through but prevents passage of others.  
Selective Permeability. Of those that PASS through:
*Chemicals that dissolve in lipids are NONPOLAR, UNCHARGED molecules (O2, CO2 and others) and very SMALL POLAR molecules (water and urea) pass through the lipids. *Other molecules will pass through channels or transporters but these are usually very specific as to what they allow through. 
Membranes is flexible enough that it is SELF SEALS after being punctured.
Chemical gradient
(change over a space) The selective permeable membrane maintains different concentrations of various chemicals in the CYTOSOL (fluid inside cell) vs. EXTRACELLULAR fluid.
Electrical gradient
The extracellular side is slightly POSITIVE and the cytosol side is slightly NEGATIVE.
Electrochemical gradient
The combined concentration and electrical gradients.
Passive Process: Diffusion
The movement of a chemical from an area of higher  concentration to lower concentration is a passive process in which the random mixing of particles in a solution occurs because of the particles KINETIC ENERGY (energy of movement.)
The diffusion rate depends on the following:
STEEPNESS of the concentration gradient. TEMPEERATURE. the LARGER THE SURFACE AREA of the membrane the increased rate of diffusion. the GREATER THE DISTANCE over which the substance must travel the LONGER it takes to diffuse.
Simple diffusion
The movement of a chemical through the phospholipids of a membrane from a HIGHER concentration to a LOWER concentration.
Facilitated  diffusion
The movement of a chemical through a TRANSPORTER or ION CHANNEL in the plasma membrane  from a HIGHER concentration to a LOWER concentration. Does NOT require energy. The rate of transfer depends on the number of transporters present in the membrane.
The movement of water molecules through a plasma membrane from a HIGHER concentration  of WATER to a LOWER concentration of WATER.
Water can move through the phospholipids or through channel proteins.
Water moves from an area of:
Lower solute to Higher solute
Osmosis occurs ONLY:
when the membrane is permeable to water but NOT to certain solutes.
Osmotic pressure:
The pressure that must be applied to prevent osmotic movement (water movement) across a membrane. The higher the solute concentration of a solution, the greater its osmotic pressure.
A membrane of a solutions ability  to change the cells shape or tone by altering its water content.
Normal Saline
A solution is a 0.9% NACl solution, which is ISOTONIC to red blood cell (RBC).
IV solutions
Usually isotonic to prevent damage to RBCs.  
Hypertonic solutions
can be used to treat cerebral edema (draws out water)
Hypotonic solutions
can be used to treat dehydration (gets more water to them)
Active transport (requires energy)
The cell uses ENERGY to move a chemical from a LOWER concentration to a HIGHER concentration (AGAINST its concentration gradient) through a transporter protein. The most prevalent primary active transport  mechanism  is the SODIUM ION/K ION PUMP.
NA+/K+ ATPase pump. It is found in all cell membranes and uses 40% of cells ATP (energy).
Primary active transport
The movement of a chemical across a membrane  from lower concentration to higher concentration. This system maintains a HIGH RCF Na+ conc. and a LOW ECF K+ conc.
Secondary active transportation
SIMULTANEOUS movement of Na+ (or H+) and ANOTHER chemical.  This depends on a Na+ (or H+) concentration  gradient which is MAINTAINED by primary active transport.
Transporter protein that moves the other chemical in the SAME directions as Na+
Transporter protein  that moves the other chemical in the OPPOSITE direction  to the Na+
Vesicular transport
The movement of a material by small membrane bound spheres (vesicles)
Materials move INTO the cell in a vesicle formed from the plasma membrane.
Receptor mediated  endocytosis
A specific LIGAND bonds to its receptor on the cell which stimulates that cell to engulf that ligand and form a vesicle.
movement of SOLID particles  into the cell by a vesicle.
Bulk phase endocytosis (pinocytosis)
Movements of FLUID with dissolved SOLUTES into the cell by a vesicle. NO recceptor proteins are involved.
A vesicle fuses with the plasma membrane and releases its contents to the outside. (ex. Glands)
A substance is moved THROUGH a cell, into one side and out the oppisite side.
The fluid inside the cell. It surrounds the other structures. Composed mostly of water. The medium in which many metabolic REACTIONS occur.
The are between the plasma membrane and the nucleus. It includes the cytosol and the organelles.
An internal network of protein filaments that serves to maintain cell's shape, move structures within cells and also move the entire cell.
Serves as a center for organizing microtubules in dividing cells (mitotic spindle) and nondividing cells. *Centrioles- are paird cylinders arranged at RIGHT angles to one another.
Long whip like appendages that serve in cell LOCOMOTION.
Short bristle like appendages, which serve to MOVE materials over the surface of a stationary cell.
Serve to directly produce the PROTEINS (sites for protein synthesis) *Tiny spheres that occur FREE or BOUND to endoplasmic reticulum. *Assemble AMINO ACIDS  in proteins. *Made in the cell's nucleolus.
Rough endoplasmic reticulum
Studded with ribosomes and acts as a site for synthesis of PROTEINS and phospholipids. Extends from the nuclear membrane.
Smoothe endoplasmic reticulum
Acts as the major site for synthesis of LIPIDS in general. It also detoxifies toxins.
Golgi complex
4-6 stacked flattened membraneous sacs. Serves to process, package, and deliver proteins and lipids to the plasma membrane for incorporation into the membrane or for secretion.
Lysosomes (ly-breakdown)
Vesicles  that contain DIGESTIVE enzymes to break down materials for the cell.
Perioxisomes (periox-detoxify)
Vesicles that contain enzymes (oxidases) that DETOXIFY materials.
Proteosomes (prote-protein)
Breakdown UNNEEDED, DAMAGED, or FAULTY proteins in the cytosol. Failure of proteosomes function has been found in Alzheimers disease.
(Power House) Serves to produce ATP using energy from the breakdown of food (cell respiration). *Self replicate using their OWN circular DNA. *Genes are usually inherited only from the mother.
Cell Nucleus: Function
Nucleus contains the GENES which CONTROL the structure and many activities of the cell.
Cell Nucleus: Structure   Nuclear Envelope
The double membrane  that surrounds the nucleus, it has PORES that allow water and dissolved materials in and out.
Smaller spheres in the nucleus that produces the RIBOSOMES.
A single long DNA molecule or two DNA's that are duplicated and attatched to each other .
Half of a duplicated chromosomes.
The material that is composed of DNA and histone proteins. (Chromosomes are composed of chromatin.)
A segment of DNA, which controls one or more TRAITS by coding for a certain polypeptide.
TOTAL genetic information carried in a cell or an organism (all of their genes)
Sequence of events invovled in PROTEIN SYNTHESIS.
DNA has a genetic message that is in the form of a SEQUENCE of nucleotide bases along the molecule. This genetic code is in the form of TRIPLETS of neucleotide bases. Each TRIPLET will cause a certain AMINO ACID to be deposited at a certain spot in a protein that is being synthesized. Protein synthesis occurs in TWO major steps, TRANSCRIPTION and TRANSLATION.
The genetic information on the DNA is passed  to a messenger  RNA (mRNA) molecule.  (mRNA is produced from a DNA template)
The___of the gene unwinds and ____between the bases break.
DNA / bonds
A_____molecule forms off of one side of the DNA  by matching their bases. In this process the ____ picks up the genetic information from the _____. The sequence of base triplets of ____ serves as templates for copying the info to _____.
mRNA /  mRNA / DNA / DNA / mRNA
Transcription is catalyzed by
Segmants of mRNA called ____ are cut out and remaining segmants called ____ are spliced together before the mRNA leaves the _____. Different exons can be spliced together to make a greater ______ of proteins.
Introns / exons / nucleus / variety
Base sequence along the mRNA is used  to MAKE a protein that has a CERTAIN SEQUENCE of amino acids.
Bonds with mRNA and move along it
Each Transfer RNA...
has a certain sequence of 3 BASES exposed at one end (anticodon), and at the other end contains a certain amino acid.
As the ribosomes move along the ____ it helps the corresponding ____ BOND to each triplet of bases on the _____ (codon)
mRNA / tRNA / mRNA
The amino acid on the new tRNA forms a _______ with the amino acid next to it and the peptide chain grows as again a new _____ arrives.
Peptide Bond / tRNA
The cell carries on every life process EXCEPT devision.
Interphase consist of 3 phases:
G1, S, and G2
G1 Phase
(Gap Phase 1) The cell produces new organelles to replace those that were lost tothe other cell in cell devision
S Phase
(S=synthesis) The chromosomes are duplicated  (new DNA is synthesized)
G2 Phase
 (Gap Phase 2) Proteins needed for cell division are produced.
M Phase
(M=mitosis) Nucleus divides  (mitosis) and the cytoplasm  divides  (cytokenesis)
Somatic Cell Division
(Mitosis) Occurs in all body cells except for those cells that directly produce  gametes (sperm or egg) * It serves to produce new cells for growth or replacement of dead and injured cells.
Each somatic cell devision produces:
2 daughter cells, each with the same number and kinds of chromosomes as the original mother cell.
Diploid Number
2 of each kind of chromosome
What is the order of Somatic cell devision?
Prophase, Metaphase, Anaphase, Telephase
Chromosomes condense or thicken, Nuclear envelope dissapears, Nucleoli dissapear, Mitotic spindle forms, Centrosomes move to oppisite poles.
Chromosomes line up in a single row along the middle of the cell.
Chromosomes seperate at their centromeres and one  copy of each travels to a separate pole.
Chromosomes unwind into more diffuse structures, Nuclear envelope reappears, Nucleoli reappear, Mitotic spindle disappears.
The division of a parents cell's cytoplasm and organelles. Begins in late Anaphase or early Telophase with the formation of a cleavage furrow.
When cytokinesis is complete:
Interphase begins
Proteins that increase in concentration in between cell divisions to activate other chemicals (Cdks) which stimulate division. (responsible for switching on and off Cdks)
Cdks (Cyclin dependent protein kinases)
Proteins that stimulate replication of DNA, or prophase to begin.
A normal, genetically programmed cell death that occurs in cells scattered throughout a tissue.
A pathological cell death that results from tissue injury of many adjacent cells, and usually it stimulates and immune response.
Function of Reproductive Cell Devision:
produces gametes that will unite to form a new individual in sexual reproduction.
What happens when the chromosomes number is cut in half in the gametes?
It serves to keep the chromosome number constant from generation to generation. * it also serves to increase genetic variation in a population of individuals.
Meiosis involves 2 cell devisions:
Meiosis I and Meiosis II
During meiosis I:
The chromosomes number is cut in half and a major mechanism that produces genetic variation in a population of individuals.
Some cells ( muscle, skeletal and nerve) are not replaced because:
 they wont divide or divide a limited  number of times.
Telomeres are
at  the ends of chromosomes which erode with each mitosis event. This contributes to cell death.
Loss of ______, ______ , due to glucose forming cross links between proteins.
Elasticity, Stiffening
______ damage cells by oxidizing (stealing e- s from) lipids, proteins, or nucleic acids.
Free radicals
Autoimmune reponses
as cells age, their cell identity markers sometimes change, which stimulates the immune repsonse to attack those cells.
An abnormal, out of control, division of cells. Growth is at expense of normal tissue. 
Tumor (neoplasm)
excess tissue that develops from uncontrolled cell proliferation.
Benign Tumor
An abnormal growth of cells that has not spread.
Malignant Tumor
An abnormal growth of cells that often has spread to other parts of the body.
The spread of cancer cells to other parts of the body.
What is the root cause of cancer?
 Mutation in genes that normally control cell division, to form oncogenes. CARCINOGENS are  chemicals or radiation that causes these mutations.
Produces an abnormal protein that stimulates cell devision or can produce a growth factor in excessive ammounts or at the wrong time.
Chromosomal rearrangement
Occurs to bring a regulator gene near a dormant oncogene to activate it.
Tumor suppressor genes
inhibit cell division, but if a mutation occurs to make them nonfunctional, then cancer can develope.
A virus may splice an oncogene into a cells _____ when it invades that cell.
The loss of tissue differention and function that is characteristics of most malignancies.
Decreased size of cells, with a subsequent decreased size of the affected tissue or organ; waste away.
Alteration in size, shape and organization of cells due to chronic irritation or inflammation; may progress to malignancy or revert to normal if irritation removed.
Increased number of cells in a tissue due to increased frequency of cell division.
Increased size of cells without cell division.
The transformation of one type of cell into another