CH. 3 Cells I Flashcards
Cells
- Smallest living units of biology.
- They carry out all chemical activities needed to sustain life.
- Basic structural and functional unit of living organisms.
- Vary in shape, size, and function.
- Trillions of cells organized in groups of tissues in organs.
- Human body is based on proper cell function, by examining them at cellular level we can study normal and disease states.
- can study cellular activity of the bod by measuring vital signs (body temp, respiration rate, blood pressure)
- cells link monomers (CHON) into molecules polymers. Like carbohydrates (C6H12O6), proteins and lipids.
- Cells produce enzymes that perform many chemical reactions (assembly and breakdown)
- cells share common structures that we study as generalized cell model.
Uses ATP as energy source
O2 + C6H12O6 -> CO2 + H2O + (ATP)
Energy for life activities
3 main parts of the cell:
- Plasma membrane
- Cytoplasm with organelles
- Nucleus/ DNA
Plasma Membrane
Membrane is (attached sugar groups) Composed of phospholipids, cholesterol, and proteins, that encloses cell contents outer limiting cell membrane.
Fluid Mosaic Model: membrane is neither rigid nor static in structure but instead highly flexible and can change its shape and composition through time.
Cell barrier transports substances in and out of the cell, keeps resting environment. Separates Intra/extracellular fluids of the body.
extracellular (out) OOOOO -receptors for hormones
{}{}{}{}{} cell to cell recognition
Intracellular (in) OOOOO- transport proteins
Produces a charge difference called membrane potential across the membrane by regulation of intracellular and extracellular ion concentrations.
Inside is negatively charged with respect to outside positively charged.
Plasma Membrane: construction
Phospholipids
Cell-to-cell recognition Receptor signals for (do you belong or do I need to attack).
Hydrophilic head groups face water in the interior and exterior of the cell.
Hydrophobic tails face each other on interior of membrane
Can keep some substances from flowing directly though membrane.
Plasma Membrane: construction
Proteins
Peripheral (transmembrane): one sided, Carries bind substances to move it through membrane.
Integral proteins: both sided, not embedded in bilateral can be removed / support membrane from cytoplasmic side.
Function as transport channels, receptors for signal transduction, attachment to cytoskeleton and extracellular matrix, enzymatic activity, intercellular joining, cell-to-cell recognition, etc.
Plasma Membrane: construction
Cholesterol
Stabilizes membrane while decreasing the mobility of the phospholipids and the fluidity of the membrane.
Amount determines how fluid membrane will be.
Plasma Membrane: Selective Permeability
Transport= permeability can go through Diffusion Some substances (small, hydrophobic, not charged) can cross more easily than others
But if large charged hydrophilic go through gate protein
Membrane transport-movement of substances into and out of the cell.
Plasma Membrane: Selective Permeability
Simple Diffusion
Nonvolatile and lipid silk able substances diffuse through movement of molecules done their concentration gradient
(High -> Low ) No energy required.
Solutes are lipid-soluble materials and small enough to pass through membrane pores
(Ex: fat solvable vitamins)
Plasma Membrane: Selective Permeability
Facilitated Diffusion
kinetic energy
Movement of solute from done its concentration gradient (High -> Low).
Diffusion with transport/ carrier proteins.
Mechanism for glucose, amino acids, and ion transport
Specificity for a single type of molecule.
Competition among molecule of similar shape.
Saturation-rate of transport limited to number of available transport proteins.
Plasma Membrane: Selective Permeability
Active Transport
Movement of ions uphill against concentration gradient, from (Low -> High)
Uses transport protein and energy ATP is required.
Example: Na+/K+ exchange pump that creates electrical potentials across membranes.
Cardiac skeletal, muscle, neuron function.
Plasma Membrane: Selective Permeability
Vesicular Transport
Transport of Large particles and macromolecules across plasma membrane inside bubble sacs called vesicles.
Plasma Membrane: Selective Permeability
Vesicular Transport: Endocytosis:
Phagocytosis
Endocytosis (Bring vesicle in)
Bulk or large molecule transport into cell
Phagocytosis: (function) protect body from bacteria, dead tissue, etc.
Lysosomes are in charge of their destruction merge with phagocytosis. White blood cells engulf invaders or cell debris and take into cell
Plasma Membrane: Selective Permeability
Vesicular Transport: Endocytosis
Pinocytosis
“Cell shrinking” small stuff
Surrounds a small volume of extra cellular fluid containing dissolved molecules.
Routine activity for cells by sampling fluid to absorb nutrients.
Plasma Membrane: Selective Permeability
Vesicular Transport: Endocytosis
Receptors mediated Endocytosis
When protein receptors are activated on the surface the membrane takes in substances from the outside.
Clinical: Hypercholesterolemia:
Cholesterol receptors bring cholesterol out of blood into the cell
HH normal cholesterol receptors
Hh 1/2 # cholesterol receptors (high ch,even with low ch. diet)
hh no cholesterol diet (have heart attacks at young age)
Plasma Membrane: Selective Permeability
Vesicular Transport: Exocytosis
Exocytosis: bring vesicle out
Bulk or large molecule transport out of cell.
Hormone-secretion and mucus secretion neurotransmitter release.
Target T-snare, V-snare
Plasma Membrane: Selective Permeability
Osmosis
H2O always more hypotonic to hypertonic.
Important because large volume changes caused by water movement disrupt normal cell function.
Plasma Membrane: Selective Permeability
Osmosis
Based on its total solute concentration
Tonicity based on how the solution affects the cell volume.
Diffusion of water across a selectively permeable membrane from an area of High H2O to Low H2O
Affected by total concentration of all solute particles in a solution (called osmolarity)
Plasma Membrane: Selective Permeability
Osmosis
Hypotonic
Low solute concentration- More dilute compared to human body plasma compartment
Cells plump up as H2O enters them
Plasma Membrane: Selective Permeability
Osmosis
Hypertonic
high solute concentration compared to human body plasma compartment.
Cell immersed in hypertonic solutions lose H2O and shrink.
Plasma Membrane: Selective Permeability
Osmosis
Isotonic
Same solute concentration compared to human body plasma compartment.
Cytoplasm
Synthesize proteins and generate ATP.
Fluid matrix like jello (cytosol of protein usage and water embedded organelle structures inclusions. The cellular material surrounding the nucleus and enclosed by the plasma membrane.
Consists of fluid cytosol contains dissolved salutes, organelles (metabolic machinery of the cytoplasm) and inclusions (stored nutrients, secretory products, pigment granules).
