Biochemistry Chapters 4 and 5
 Henderson-Hasselbalch equation  pH = pKa + log ([conjugate base]/[conjugate acid])
 Cytosol – cytoplasm without the stuff in it
 Hutchinson-Gilford progeria syndrome (HGPS) – patients experience rapid rate of aging
beginning at birth – very rare (1/4-8 million births)
o Detected early in life with limited growth, loss of hair, distinctive facial characteristics,
small fragile bodies, wrinkled skin, atherosclerosis, and cardiovascular problems –
everything you see in the elderly
o Do not have neurodegenerative diseases
o Rarely live past their early teens
o 6-8x normal rate of aging
o Nuclear envelope of these patients is distorted – have a deficit in conversion of lamina A
to its usual attached-to-the-nuclear-membrane form, and thus accumulate abnormal
lamina A, causing blebbing of nucleus, alteration in gene expression, and interference
with mitosis
 Lufts disease – defect in mechanism that controls mitochondrial oxygen utilization – first
specifically mitochondrial defect disease discovered
 Leber Hereditary Optic Neuropathy – leads to sudden blindness in early adulthood – caused by
mutation of mitochondrial DNA
 Gout – uric acid produced in excess, leading to increase of uric acid in blood and deposition of
urate crystals in joints – inflammation, pain, and swelling in joints, especially big toe
 Lysosomal acid lipase – hydrolyzes triacylglycerol to free fatty acids and glycerol, and cholesteryl
esters to cholesterol and fatty acids
o Wolman disease – usually fatal by age 1 – no detectable activity of hLAL and both
triacylglycerol and cholesteryl esters accumulate in tissues – homozygous mutation
causes
o Cholesteryl ester storage disease (CESD) – usually diagnosed in adulthood and is
evidenced by hypercholesterolemia, hepatomegaly, and early onset of severe
atherosclerosis – have hLAL activity, but at a very low level, sufficient to hydrolyze
triacylglycerol but not cholesteryl esters – homozygous for mutation at splice junction
 Zellweger syndrome – absence of functional peroxisomes, leading to death around 6 months of
age
 Monocistronic mRNA – only contains info for one polypeptide
 Polycistronic mRNA – can make more than one protein
 Peptide – has less than 50 AA’s on its chain; protein – more than 50 AA’s
 RNA Hybridase – enzyme that removes 5’ ends of Okazaki fragments and catalyzes hydrolysis of
RNA chain hydrogen bonded to DNA chain
 Antibiotics that target DNA gyrase rapidly stop E. coli DNA replication because preventing the
reduction in linking number of parental strands prevents strands from untwisting
o Nalidixic acid is used against urinary tract infections – targets swivelase subunits
encoded by gyrA
o Ciprofloxacin – one of the most effective oral antibiotics in clinic use today – used to
prevent and treat anthrax
o Novobiocin and coumermycin A1 target ATPase subunits encoded by gyrB
 Triplet expansion – great increase in the number of repeating triplets
o
o
o
Huntington disease – when length of a triplet repeat gets much longer than normal, and
thus causes a much longer than normal stretch of the same amino acid residue in the
encoded polypeptide
Fragile X syndrome – greatly lengthened triplet sequence in promoter alters gene
expression
In diseases such as these, the disease gets worse in succeeding generations as a result of
even further increases in triplet length