Diseases
A genetic disorder caused by mutations in the LDL receptor (LDL-R), leading to elevated plasma cholesterol levels
Familial Hypercholesterolemia
The maintenance of nearly constant conditions in the internal environment of the body, crucial for optimal functioning.
Homeostasis
An enzyme that synthesizes DNA from an RNA template
Reverse transcriptase
Results in no functional protein product, either by producing no protein or a completely nonfunctional one.
Null mutation
Lacks ribosomes and is involved in lipid synthesis, detoxification, and calcium storage.
Smooth ER
Characterized by muscle weakness, contractures, and arrhythmias due to mutations in emerin or lamin A/C.
Emery-Dreifuss Muscular Dystrophy?
The ideal value for a physiological variable, such as body temperature (98.6°F).
Setpoint
A cluster of genes encoding products involved in the same biochemical pathway.
Operons
Insertions or deletions that are not a multiple of 3. Likely abolishes function of that allele.
Frameshift mutations
Is crucial for sorting proteins to their final destinations, including lysosomes and the plasma membrane.
Characterized by bilateral ptosis, muscle weakness, and exercise intolerance, typically presenting in late adolescence to early adulthood.
Progressive External Ophthalmoplegia (PEO)
States that for a substance to remain constant in the body, any gain must be offset by an equal loss, crucial for maintaining homeostasis
Law of mass balance
Protect single-stranded DNA from nuclease attack and prevent reannealing.
What is the role of single-stranded DNA binding proteins (SSBs)
Mediated by Mut factors MutS, MutL, and MutH.
Prokaryotic mismatch repair
Are microdomains within the membrane that are rich in cholesterol and glycosphingolipids, providing a thicker and less fluid environment.
Lipid rafts
Characterized by subacute, painless bilateral visual failure, often with a median age of onset around 24 years.
Leber's Hereditary Optic Neuropathy (LHON)
Detect changes in plasma osmolarity and stimulate thirst and ADH release.
Hypothalamic osmoreceptors
Prevent enhancers or silencers from regulating the inappropriate genes
Insulator elements
In a protein-coding gene, this mutation is most likely to result in decreased but residual activity of
the encoded protein:
3 base-pair deletion
These products would most likely be released from a cell by the constitutive secretory pathway instead of the regulated secretory pathway:
glycosylaminoglycans
A deficiency in the enzyme alpha-L-iduronidase, causing accumulation of glycosaminoglycans and resulting in various systemic symptoms.
Hurler Syndrome
An uncharged solute (S) that enters a cell by channel-mediated facilitated
diffusion:
will have an increased net flux of S into the cell with any increase in extracellular [S]
Type I topoisomerase inhibitors
Irinotecan and topotecan
During the annual checkup of a 6-year-old girl, her physician noted corneal arcus and xanthomas on her elbows. A blood test showed greatly elevated LDL and total plasma cholesterol. Her mother reported no family history of hypercholesterolemia. Her LDLR gene was sequenced, and a single-base insertion was identified in the seventh codon of the first exon. The most likely effect that this mutation would have on the function of the LDLR gene is:
Complete loss-of-function
The following most closely approximates the typical constituent concentrations of pulmonary surfactants:
80% phospholipids, 10% protein, and 10% cholesterol.