A&P Chapter 3

The study of cells

cytology

Human cells have three basic parts

plasma membrane, nucleus, and cytoplasm

Plasma membrane is a ___ ___ in which membrane ____ are embedded

It has a ___ fluid structure, is ___ ___ and ___ intracellular fluid from extracellular fluid

phospholipid bilayer; proteins

dynamic; selectively permeable; separates

Membrane lipids (3)

phospholipids (75%), glycolipids (5%), and cholesterol (20%)

__ proteins are firmly inserted in membrane, mostly transmembrane proteins

integral

__ proteins are loosely attached to integral proteins on either side

Petipheral

___ is a fuzzy, sticky, “sugar covering” at cell’s surface; and acts as cell identification marker

Glycocalyx

Extracellular fluid contains more …

Sodium (Na+)

Intracellular fluid contains more …

Potassium (K+)

Three different types of cell junctions

Tight junction, desmosome, and gap junction

Passive Process

Does not use energy/ATP to move substances down a concentration gradient (ex: diffusion)

Simple diffusion

solutes through the plasma membrane without using a channel o carrier, restricted to small molecules and lipids

Factors that increase speed in diffusion

smaller molecules, warmer temperatures, steeper concentration gradient (thicker)

Facilitated diffusion: Carrier mediated

sugars and amino acids are moved though the membrane with protein carriers

Facilitated diffusion: Channel mediated

Ions and water are moved though the membrane via protein channels

Osmosis

diffusion of a solvent through a selectively permeable membrane

Moves from high solvent concentration to lower solvent concentration

Osmolarity

Total concentration of solute particles in a solution

Tonicity

ability of a solution to change the cells internal water volume

Isotonic solution

same solute concentration as intracellular fluid

Hypertonic solution

higher solute concentration than intracellular fluid

cells crenate (dehydrate)

Hypotonic solution

lower solute concentration than intracellular fluid

cells swell and lyse (explode)

Active Processes

Use energy contained in ATP to move substances across a membrane

Active Transport

Use of solute pumps to move substances against a concentration gradient

Primary Active Transport

energy used to transport molecules is directly from ATP

Secondary Active Transport

energy used to transport molecules is from energy stored in ionic gradients (created by primary active transport)

Vesicular Transport

uses membranous sacs called vesicles to transport particles, macromolecules, and fluids across the plasma membrane or within the cell

Endocytosis

Transport into the cell

Phagocytosis

endocytosis in which large, solid materials are brought into the cell

Exocytosis

transport out of the cell

Vesicular trafficking

transport from one area in the cell to another area

Transcytosis

transport into, across, and out of cell (whole process of vesicular transport)

Resting Potential Membrane

inside of a cell membrane is negatively charged compared to the positively charged outside (creates voltage or potential)

RMP ranges from __-__ mv in different cells

-50; -100

RMP is determined by the concentration gradient of …

Potassium K+

RMP is maintained by what kind of pumps?

Active transport pumps

Cytoplasm

cellular material between the cell membrane and the nucleus

Three parts of cytoplasm

Cytosol, Organelles, and Inclusions

Cytosol

Water with solutes (proteins, salts, sugars, ect.)

Organelles

metabolic machinery of cell; specialized function; (membranous or non-membranous)

Inclusions

help identify cell; vary with cell type (glycogen granules, pigments, lipid droplets, ect.)

Mitochondria

powerhouse of the cell; membranous organelles that produce ATP for cell (through aerobic cellular respiration) and contain their own DNA, RNA, and ribosomes

Ribosomes

small granules consisting of ribosomal RNA and protein; site of protein synthesis (free or membrane bound)

Endoplasmic Reticulum

extensive system of tubes and membranes throughout cytosol enclosing fluid-filled cavities (cisterns)

Rough ER

has ribosomes that synthesize all proteins for secretion and all plasma membrane proteins

Smooth ER

Enzymes function in lipid synthesis and drug detoxification

continuation of rough ER; looping network of tubes;

Golgi Apparatus

series of flattened membranous sacs associated with membranous vesicles; modifies, concentrates, and packages

Peroxisomes

membranous sacs containing enzymes such oxidases and catalases; detoxes harmful substances (alcohol)

Lysosomes

membranous sacs containing digestive enzymes; digest worn-out organelles, ingested bacteria, viruses, and toxins

Cytoskeleton

series of rods and fibers that un throughout the cytosol; supporting cellular structures and aiding in cell movement

Microfilaments

AKA: actin filaments: made from protein actin; extend into microvilli

Intermediate Fillaments

though protein fibers constructed like ropes

Microtubules

hollow tubes made from protein subunits called tubulins; form centrioles, cilia, flagella

Centrosome

region near nucleus that functions to organize microtubules and miotic spindle

Centrioles

Small, barrel-shaped organelles associated with the centrosome

Cillia

whiplike extensions that move substances across cell surfaces

Flagella

long projections that move whole cells (sperm)

Microvilli

fingerlike extensions of membrane that increase surface area

Nucleus

largest organelle; contains DNA, which determines the kinds of proteins the cell with synthesize

Nucleolus

ribosome factory of the cell (nucleus)

Meiosis

cell division producing gametes

Mitosis

cell division producing identical daughter cells (essential for growth and repair)

Interphase

G1 (initial growth phase), S phase (makes copy of DNA, called semiconservative replication, each DNA molecule has one old strand and one new strand), G2

Cell division (mitosis)

prophase, metaphase, anaphase, telophase

Cytokinesis

division of cytoplasm

Master blueprint for the structure of all proteins that the body synthesizes are found on the …

DNA

Segment of DNA with blueprint for one polypeptide chain

amino acid

Protein Synthesis: Transcription

DNA information is coded into mRNA (happens in nucleus)

Protein Synthesis: Translation

mRNA is decoded to assemble a polypeptide (happens in cytoplasm)

Messenger RNA (mRNA)

long nucleotide strands that reflect exact nucleotide sequences of DNA, provide genetic information needed for protein synthesis

Transfer RNA

shorth RNA molecules that transfer amino acids to the ribosomes; each contain a three-based sequence complementary to the mRNA

Ribosomal RNA

large and small RNA subunits that combine to form ribosomes (build new DNA)