Description
BIOL 3611-001 exam 3 study guide
∙ Six cell signaling pathways
o cAMP
▪ uses G protein
∙ Gs: stimulates
∙ Gi inhibits
∙ G protein diseases
o Cholera: prevents Gs from breaking down GTP to GDP
▪ Adenylyl cyclase is always on, too much cAMP
▪ cAMP stimulates Cystic Fibrosis Chloride
Transporter which leads to diarrhea, death due to
dehydration
o pertussis toxin: inhibits Gi
▪ adenylyl cyclase stays on
▪ too much cAMP in the lungs, whooping cough
▪ ATP
∙ Sugar
∙ Nitrogenous base
▪ Adenylyl cyclase comes in
▪ Cyclic AMP formed
∙ Stimulates protein kinase A
▪ Phosphodiesterase lowers cAMP
∙ High phosphodiesterase causes lower epinephrine
▪ It’s a second messenger and a regulator
o ion channel
▪ acetylcholine nicotinic receptor
∙ an Na channel
∙ no G proteins
∙ Ach binds to alpha subunits in the receptor to open If you want to learn more check out what is the principle task in management?
∙ Na goes into the cell
▪ acetylcholine muscarinic receptor
∙ Gq protein
∙ Opens a K channel
∙ Ligand gated
o Ach binds to receptor
o Gq is activated
o Beta gamma subunits bind to ion channel
o K channel opens, K goes out of the cell
o IP3-Ca release
▪ Epinephrine alpha receptors
▪ Ach releases IP3
▪ Gq protein
▪ PIP2: 2 fatty acids, glycerol backbone, phosphate and charged molecule ▪ Phospholipase C cuts bond between the phosphate and the glucose ∙ Leaves a sugar with two extra phosphates (IP3)
▪ IP3 causes the release of calcium from the endoplasm reticular ▪ DAG is left over
∙ Activates protein kinase C We also discuss several other topics like what is Dyadic Communication?
▪ Calcium release into the cytoplasm binds to and activates calmodulin ∙ Ca-calmodulin complex then binds and activated other proteins ∙ Causes alpha helix bends so the complex can wrap around blood vessels
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If you want to learn more check out What is a stock variable?
o Causes vasoconstriction during fight or flight situations
▪ Calcium pumps
∙ In the plasma membrane
∙ In the ER membrane
∙ Keep Ca low in the cell
o NO (nitric oxide)
▪ Ach muscarinic receptors and g proteins introduce IP3s to the cell ▪ Calcium is released
▪ Calmodulin gets activated
▪ NO synthase gets activated
▪ NO is made
▪ NO activates guanylyl cyclase
▪ cGMP is made which activates protein kinase G
▪ Leads to the relaxation of blood vessels
o Tyrosine kinase receptors
▪ Hormone binds to the tyrosine kinase receptor
▪ A phosphate is added to tyrosine (an amino acid)
▪ Two receptors dimerize to turn each other on
∙ They phosphorylate each other
▪ The activated receptors turn on Map kinase, PLC and PI3 kinase ▪ Examples: insulin and growth factors
∙ Map kinase pathway:
o RAS (a G protein)
o MAPK
o Kinase cascade
o Transcription factors turned on
o Genes for cell division are turned on If you want to learn more check out What did the Native Americans do with Christianity?
∙ Growth factor (and insulin) receptor:
o Stimulates PLC
o Releases calcium
∙ Growth factor receptor:
o Stimulates PI3 kinase (Akt)
o Leads to cell survival (prevents apoptosis) and cell division
▪ Cancer:
∙ Hyperactive PI3 kinase pathway
∙ Overactive GF receptor
∙ Too many GR receptors
o Ex. Breast cancer: too many human epidermal growth If you want to learn more check out When did we became fully human?
factor receptor 2 genes, too many receptors
o Herceptine is an antibody
∙ Mutated RA, RAF, or MEK
o Steroid
▪ Four connected rings of carbon
∙ Very hydrophobic
▪ Go from bloodstream carrier proteins to plasma membranes
▪ Plasma membranes to cytoplasmic soluble receptor protein (GR) ▪ GR is the transcription factor
▪ New mRNA is made
▪ New proteins are made
∙ Cell parts
o Nucleus
▪ Nuclear pores: used by proteins (such as transcription factors) to enter the nucleus and for mRNA to leave the nucleus
▪ Nuclear lamina: within the nuclear envelope
▪ Nuclear envelope: has two membranes, where proteins are made on bound ribosomes, connects to the rough ER
o Smooth ER
▪ Functions
∙ SER enzymes remove negative phosphate groups from glucose-6-
phosphate
o So glucose can pass through the membrane by facilitated
diffusion
▪ Glucose -6-phosphate deficiency
∙ Growth retardation
∙ Enlarged kidney and liver
∙ Low blood sugar
∙ Tendency to bleed
∙ Lowered white blood cells
∙ Infections
∙ Synthesis of many lipids, fatty acids, phospholipids, steroids
∙ Stores calcium
o IP3 receptor located here
∙ Drug breakdown
o Hydroxylation reaction
▪ Hydrophobic drug sticks in the membrane
∙ NADPH, H, and O are all present
▪ Mixed function oxidases react
▪ Left with hydrophilic compound that is easy to
urinate out
∙ And NADP, water
▪ Problems:
∙ SER and mixed function oxidases are
inducible
o Drug addicts have many more than
clean people
∙ Creates carcinogens
∙ Grapefruit juice inhibits mixed function
oxidases
o Some medicines become 15 times
stronger
▪ Overdose
o Rough ER
▪ Receptors for ribosomes
▪ Closer to the nucleus
▪ Continuous, nuclear envelope to RER to SER
▪ Functions
∙ Lipid synthesis
∙ Synthesis of proteins that will be secreted, put into the membrane or sent to the lysosome
o Ribosomes
▪ Free ribosomes
∙ Not bound to RER
∙ Make proteins that stay in the cytoplasm
▪ Bound ribosomes
∙ Bind to RER
∙ Make plasma membrane proteins, lysosomal proteins, ad secreted proteins
o Golgi
▪ Cis
∙ Same side as RER
▪ Trans
∙ Opposite side of RER
▪ Functions
∙ Store sugars
∙ Add and remove sugars from proteins
∙ Moves enzymes to the lysosome
o Enzymes within the lysosome are called acid hydrolases
▪ Acidic to breakdown
▪ Made in the RER
▪ Mannose (sugar) gets phosphorylated
▪ Mannose-6-phosphate binds to receptor
▪ Enzymes are packaged into transport vesicles
▪ Transport enzymes to late endosome
▪ Turns into lysosome
o Lysosomes
▪ Acid hydrolases break down biomolecules to monomers
▪ pH is 4
▪ functions
∙ phagocytosis
∙ receptor mediated endocytosis
∙ autophagy
o destroys old organelles
∙ exocytosis of lysosome
∙ autolysis
o death of the entire cell
▪ formation
∙ endosome forms at the plasma membrane
∙ moves to early endosome
∙ acid hydrolases carried to the late endosome
∙ hydrogen is pumped into the lumen of the late endosome
∙ more acidic and mature
∙ lysosome
o peroxisomes
▪ mixed function oxidases
▪ catalase
∙ reacts with hydrogen peroxide to make oxygen and water
▪ function
∙ control oxygen levels in the cell
∙ breakdown of very long chain fatty acids (VLCFA)
o VLCFA anything longer than 16 carbons
o Broken down in the mitochondria to make ATP
∙ Remove 2 H atoms to break down ethanol, formaldehyde, nitrogen compounds
o Acetaldehyde produced
o Hydrogen peroxide produced
▪ ALD sink model
▪ Lorenzo’s Oil
∙ Lowers levels of dangerous saturated VLCFA
∙ Competitive inhibition
∙ Exocytosis
o Starts at RER
▪ Sugars added to nitrogen on the protein
o Golgi
▪ Sugars added to hydroxyl on the protein
o Secretory vesicle
∙ Endocytosis
o Phagocytosis
▪ Ingestion of large particles
▪ Vacuoles fuse with early and late endosomes
▪ Become lysosomes
o Receptor mediated
▪ Receptor resent
▪ Ligand binds
▪ Receptor ligand complexes diffuse laterally through the membrane ▪ Clathrin coat forms
▪ Invagination
∙ Clathrate binding
▪ Coated endocytic vesicle formation
▪ Uncoating
∙ Adaptor protein recycled
∙ Clathrin recycled
∙ Dynamin recycled
▪ Fusion with early endosome
∙ Release of the ligand
▪ Transport to late endosome
▪ To lysosome
∙ Breakdown
∙ Snare hypothesis
o Transport vesicle binds 2 tethering proteins
o t and V snares bind loosely (weak bonding)
o more weak bonds form to wrap snares around each other o strength of the bonds force the membranes together
∙ Secretion pathway
o Nuclear envelope
▪ Proteins made
o Rough ER
▪ Proteins made
▪ Proteins stuck in the lumen of the RER
o Transport vesicles
o Golgi
▪ Adds sugars to the protein
o Secretory vesicles
o Plasma membrane
o Exocytosis