Cell Physiology The Cellular Environment Body Fluids Composed primarily of water Intracellular fluid- fluid found inside cell. Extracellular fluid- fluid outside cell. Interstitial fluid- fluid contained within the tissue, except for blood found within lymph and blood vessels.

Passive Transport Processes Remember: No Energy Required! 4 Passive Processes: Diffusion Facilitated Diffusion Osmosis Filtration

Diffusion Kinetic movement of molecules from higher to lower concentration via concentration gradient- the difference between the concentration of one area and the concentration of another. Will continue until the molecule is evenly dispersed throughout the solution Determining factors for Diffusion thru a membrane: 1. Molecular size – small can move through 2. Lipid solubility – lipids can pass lipid bilayer 3. Molecular charge – ions move through special channel proteins 4. Temperature – faster in hot solution

The spectrum between the most concentrated and least concentrated area is called the concentration gradient. As molecules move from high concentration to low, they are said to be moving down the concentration gradient, defusion can be defined as moving down the concentration gradient.

Facilitated Diffusion Selective carrier proteins assist in movement of molecules from higher to lower concentration; speed of diffusion is limited by saturation of carrier molecules.

Osmosis Passive movement of water through a semipermeable membrane from dilute solution to more concentrated one. Opposite of diffusion as water, not solute is moving. Also requires semipermeable membrane.

If the concentration is the same inside and outside of the cell, it’s called isotonic. If the extracellular fluid is hypotonic, the inside of the cell is more concentrated than the outside. If the extracellular fluid is hypertonic, then the outside is more concentrated than the outside.

Filtration Hydrostatic pressure (caused by the beating heart) forces liquid and small molecules through a membrane. Liquids pushed through a membrane when the pressure on one side is greater than that on the other side. An example is the blood pressure, or coffee through the filter of a coffee maker.

Active membrane process: When the cell is required to use energy. Some molecules can’t enter the cell with passive routes because… They are not lipid soluble They are too large They are on the wrong side of the concentration gradient. They can move in or out of the cell by either active transport or cytosis

Endocytosis Phagocytosis Pinocytosis Receptor mediated Cells engulf solid substances Pinocytosis Cells engulf liquid substances Receptor mediated Specialized protein receptors bind to ligands specific receptors. Ligand-small molecules that bond to larger chemical groups or molecules.

Exocytosis Excretion of waste products and secretion of manufactured substances. Packaged in secretory vesicles which fuse with cell membrane and are ejected to extracellular space.

Interphase Period between cell divisions. Originally thought to be a resting phase, but the cell is carrying out it’s normal life, so this is called the metabolic phase. Nucleus and nucleoli are visible and chromatin is arranged loosely throughout the nucleus.

Mitotic Phase- Cell Division Cytokinesis- division of the cytoplasm. Prophase Chromatin coils and are composed of two identical chromatids Spindle apparatus appears Normal synthetic processes cease. Nuclear envelope disintegrates

Metaphase Chromosomes are lined up in center of spindle. Centromere of each chromosome is attached to a spindle fiber.

Anaphase Centromeres split apart and each chromatid becomes its own chromosome. Spindle fiber separates, and chromosomes are pulled away from each other. Cytoplasm constricts along metaphase plate.

Telophase Final stage of mitosis When chromosomal movement stops Chromosomes reach poles and begin to unravel. New nuclear envelope appears as well nucleoli. Cytokinesis ends telophase. New daughter cells enter interphase.

Protein Synthesis Protein synthesis is essential for life. Begins in nucleus tRNA transcribes DNA information Transcription-Genetic information in DNA is copied onto messenger RNA (mRNA) Codon- series of 3 RNA nucleotides. mRNA sends information to cytoplasm Translation- Ribosomes bind to mRNA strand (rRNA). New protein building as codes are translated from nucleotides to amino acids

Genetic Mutations A genetic error. Mutations may be so severe that cell dies, but may also cause no issues whatsoever. Some can be repaired by repair enzymes. May occur spontaneously or due to mutagens. Viruses Ionizing radiation Certain chemicals What is cancer? What is chemotherapy?

Cell Differentiation and Development Differentiation- The progressive acquisition of individual characteristics by cells to enable them to perform different functions. Differentiation is important as it keeps cells focused on a particular function.