Genetics Flashcards
(16 cards)
How many ATP does one molecule of NADH create? Where does it drop its hydrogen ions off? What about FADH2?
NADH- 2.5 ATP; complex I
FADH2- 1.5 ATP; complex II
What is an abnormality related to “sequence”? What does that mean?
Oligohydramnios. One anomaly leads to other anomalies. In this case, renal agenesis leads to twisted skin, twisted face, pulmonary agenesis because the baby is pushed against the amnion
Describe what it means if an abnormality is related to dysplasia
An intrinsic developmental abnormality related to defective cellular organization. Ex) skeletal dysplasia
Rhizomelic, mesomelic, micromelic
Upper arm segment is short
Lower arm segment is shortened
Both arm segments are shortened
What is the difference between type I and type II osteogenesis Imperfecta?
Type I shows little to no deformity and affects 50% of type I collagen fibers where type II is lethal in prenatal period, affects the long bones, and affects all type I collagen fibers
How do bisphophonates work to reduce the symptoms of osteogenesis Imperfecta?
They increase apoptosis of osteoclasts and decrease apoptosis of osteoblasts
In what way do OI dominant mutations work?
They change the glycine AA in collagen chains to something else (can’t make proper helix)
What is the mechanism by which scurvy causes collagen malformation?
Without vitamin C, hydroxylation of proline doesn’t occur so the collagen becomes more unstable causing it to fall apart
Describe the steps of collagen helix formation
Preprocollagen is translated by an RER ribosome and transported into the ER where the signal sequence is cleaved making it a procollagen molecule. Proline 4 hydroxylase hydroxylates prolines at the Y position. Three pro-a collagen molecules come together by first forming disulfide bonds at the C-terminal position. The triple helix then forms like a zipper. The Golgi secretes the procollagen out of the cell where extracellular procollagen peptidases cleave the C and N terminals. 5 collagens fibers then self-associate via cross-linking
What is Menke’s Syndrome? What are the symptoms?
Defects in Cu2+ metabolism. Kinky, steel colored hair (tyrosinase), connective tissue defects (lysyl oxidase; this one is what crosslinks collagen), neural/behavioral defects (dopamine-B-hydroxylase)
Ehlers Danlos
Genetic mutation causes no ECM procollagen peptidases which means collagen fibrils cannot be formed.
List the collagen fibers you’re supposed to know
Fibril forming- type I (most connective tissue, bone, tendons), type II (cartilage and vitreous humor), type III (extensible tissues; skin, blood vessels, lungs, etc.), type V (wherever type I is)
Fibril associated- type XII (wherever type I is; fibrils with glomerular interruptions)
Network forming- type IV (basal lamina)
Anchoring filaments- type VII (attachment of basal lamina to underlying membrane)
Alport Syndrome
X-linked autosomal recessive disorder that affects Type IV collagen and thus basal lamina (especially of the kidney, cochlea, and eye). Symptoms are proteinuria, hypertension, end stage renal disease (ESRD), and hearing loss.
What is the general structure of elastin? Is it hydrophobic or hydrophilic? What protein makes up the scaffolding that it sits on?
Elastin is made of mostly glycine, alanine, proline, and valine so it is hydrophobic. Fibrillin is a glycoprotein that makes the scaffolding that elastin then fills in.
What is the result of an a1-antitrypsin deficiency?
Antitrypsin’s job is to inhibit excessive breakdown of elastin by elastase. A deficiency causes cirrhosis of the liver and emphysema of the lungs
Marfan syndrome: cause and symptoms? What is the difference between Marfan’s and homocystinuria?
Marfan is caused by a defect in fibrillin gene. Impaired elastin function in the skeleton. Long slender limbs, lens dislocated upward, and aortic root dilation. Homocystinuria is a disease of methionine metabolism and patients have downward dislocated lenses and intellectual disability.
