1、【单选题】the symptoms of a certain inherited disorder in humans include respiratory problems and, in males, sterility. which of the following is a reasonable hypothesis for the molecular basis of this disorder? a、defective actin molecules in cellular microfilaments b、defective dynein molecules in cilia and flagella c、abnormal hydrolytic enzymes in the lysosomes d、a defective secretory protein e、a defective enzyme in the mitochondria
1.6.3必交作业
1、【单选题】a 20-month-old boy is diagnosed with hutchinson-gilford progerial syndrome (hgps), a severe form of early-onset premature aging. fetal and early postnatal development are normal, but there is now severe failure to thrive, some lipoatrophy, bony abnormalities, a small, beaked nose and receding mandible, hair loss, and speckled hypopigmentation with some areas of tight hard skin. his neurological and cognitive tests are normal. genetic analysis shows a single spontaneous mutation in codon 608 of the lmna gene, which encodes both lamin a and lamin c. which one of the following would you most likely expect to be a direct effect in cells obtained from this patient? a、increased heterochromatin b、interference with microtubule treadmilling c、increased synthesis of rrna in the nucleolus d、loss of ability to adhere to the basement membrane through integrins e、aberrations in nuclear architecture
1.7.4必交作业
1、【单选题】dolastatin 11 is a promising chemotherapeutic depsipeptide that arrests mitotic cells in the process shown in the accompanying electron micrograph. which one of the following would be a possible mechanism for dolastatin? a、lengthening of kinetochore microtubules b、contraction of a ring composed of cytoskeletal elements c、shortening of polar microtubules d、dysregulation of the m-cdk complex (mpf) e、disruption and rearrangement of cellular actin