BIOLOGY 251 Lecture Notes - Lecture 2: Tay–Sachs Disease, Brossard, Oxidative Phosphorylation

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27 Aug 2016
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Homeostasis
-homeostasis: keeping the internal environment constant
-necessary to maintain function
-negative feedback: enough of a variable is present to cause a reduction of the production of the
variable, not enough of one variable is present to cause the production of the variable
thermostat
blood glucose level and insulin
-positive feedback: a variable causes the release of more of the variable
not related to homeostasis
oxytocin, contractions, and prostaglandins
The Cell
Mr. and Mrs. Brossard from Breaux Bridge, LA bring their 6 month old baby to you.
Symptoms:
Red spot on retina
Suddenly seems to have trouble hearing
Is not moving like he used to
This baby has Tay Sachs Disease.
Tay Sachs Disease
fatal genetic disorder
no cure
infants develop normally for a few months
single gene malfunction
single enzyme deficiency inside the lysosome
accumulation of fatty ganglioside in the nerve cells in the brain
never cells fill with fat causing a decline mental and physical abilities
blind, deaf, and unable to swallow
muscle atrophy and paralysis
death by age 5
Oxidative Damage
free oxygen radicals (O2-) produced during oxidative phosphorylation
dangerous and damages cell membranes, proteins, and DNA
anti-oxidants eliminate most of them
most likely proximal cause of aging and many diseases
Structure
-cell membrane (plasma membrane): mechanical boundary of the cell
selectively permeable
ICF on the inside
ECF on the outside
-cytoplasm: everything inside the cell that isn’t the nucleus
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organelles: membrane bound structures that have a specific function
-endoplasmic reticulum (ER)
rough endoplasmic reticulum (RER): synthesize and release proteins, contains
ribosomes
smooth endoplasmic reticulum (SER): package and transport system for proteins
created in the RER
-Golgi complex (Golgi apparatus): destination for the proteins released from the SER,
sorts and directs proteins to their final destination
-Lysosomes: hydrolytic enzymes, destroy everything that they come into contact with that
contains water, digests cell waste and destroys broken organelles and cells
-mitochondria: outer membrane and inner membrane, produces high energy molecules
(ATP), POWERHOUSE OF THE CELL
RNA is translated into proteins on the ribosomes
-nucleus: contains DNA packaged in chromosomes
has its own membrane
DNA transcribed into RNA
DNA is regulatory and it does not code for proteins
Cell Energetics
-ATP: energetic currency of the cell
ATP —-> ADP + Pi + energy
synthesis of new compounds
membrane transport
mechanical work
-ATP Production
Glucose + O2 —-> ATP + CO2 + H2O + heat
Glycolysis: glucose—-> ATP + high energy coenzyme + pyruvate
Linking Step: pyruvate —-> high energy coenzyme + CO2 + acetyl CoA
Krebs Cycle: acetyl CoA—-> high energy coenzymes + ATP + CO2
-most of the high energy coenzymes are produced
Oxidative Phosphorylation: high energy coenzymes—-> ATP + H2O
-most of the ATP is produced
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find more resources at oneclass.com