Lecture And Reading 1 Flashcards
What concept is defined by dynamic equilibrium?
Homeostasis
Homeostatic feedback mechanisms
- Stimulus
- Receptor
- Control (integration) center
- Effector
Negative Feedback Loop
Reduces or switches the effect of the original stimulus to return the system back to a stable state.
Positive feedback loop
Reinforces a stimulus in the same direction moving the system farther from homeostasis, until a climactic event.
Glycolysis
Anaerobic process of ten sequential reactions that break glucose down into pyruvic acid molecules—- and eventually 2ATP
Aerobic ATP production processes
Citric acid cycle, electron transport chain (produce 34 ATP).
Cytosol functional activities
- Enzymatic regulation of intermediary metabolism
- Ribosomal protein synthesis
- Storage of fat, carbohydrate, and secretory vesicles.
Microfilament function
- Contractile systems - actin/myosin
Pinches cells in 2 - Amoeboid- WBCs, fibroblasts, skin cells
- Mechanical stiffeners, microvilli
Mechanisms in maintaining homeostatic blood sugar
Rising blood glucose levels
- Sensor - pancreatic beta cells - secretes insulin
- Effectors-
a)increased rate of glucose transport into target cell
b) increased rate of glucose utilization and atp generation
c)increased conversion of glucose to glycogen at the liver and skeletal muscle level
d)Increased amino acid absorption and protein synthesis
e) increased fat synthesis
3) Effect- glucose levels decline to homeostasis
Anatomy of a phospholipid
-Polar (hydrophilic) head made up of :
Choline
Phosphate
Glycerol
-Non Polar Tails
(Hydrophobic)
Hydrocarbons
How steroid cholesterol effects the plasma membrane
Higher temperatures cholesterol packs together making the membrane less fluid.
Lower temperatures more fluid
*acts as the main temperature buffer
Major functions of membrane proteins
- Transport
- Enzymatic activity
- Signal transduction
- Cell-cell recognition
- Intercellular joining (via gap junctions)
- Attachment to cytoskeleton and extracellular matrix.
Protein influence in membrane function
- Structural support
- Recognition
- Communication
- Transport
Passive transport types
(No energy investment- down concentration gradient)
- Simple diffusion
- Facilitated diffusion
- Osmosis
Facilitated diffusion functional components
Uses a transport protein via high to low concentration.
a) channel
b) carrier
Osmosis attributes
Diffusion of water across semi permeable membrane from hypotonic to hypertonic solution.
Uses aquaporins - (water protein channels, non-gated)
Shifts solvent to equalize the system.
Osmotic pressure
Pressure needed to keep system in equilibrium with pure water
** the higher the concentration of solutes, the higher the osmotic pressure.
Active transport components
Requires ATP, uses membrane pumps and coupled transport
Membrane Pump
Carrier protein that uses ATP to move a substance across a membrane against its concentration gradient.
ex. Sodium/Potassium pump
Physiology of sodium-potassium pump
- 3 Na+ bind to cytoplasmic side of protein.
- Phosphate is transferred from atp to protein.
- Phosphorylation changes shape of protein and moves Na across membrane.
- K+ binds to the protein causing phosphate release.
- Phosphate release changes protein shape moving K+ into cytoplasm.
Types of bulk transport
Exocytosis - via transport vesicles
Endocytosis- plasma membrane envelops small particles or fluid to form vesicle and enters cell.
Endocytosis types
- Phagocytosis - creates vacuole engulfing particles.
- Pinocytosis - gulps droplets of extracellular fluid.
Peroxisome function
Organelle that aids in lipid metabolism, and counteract oxidative stress and redox balance.
