There is evidence that the accumulation of abnormal or damaged proteins due to impairment of the pathway contributes to a number of neurodegenerative diseases, including Alzheimer’s. In contrast, deliberately blocking the pathway in cancer cells could lead to a disruption of protein regulation that in turn could cause the apoptosis of the malignant cells. Accordingly, proteasome inhibitors have been developed for evaluation as anti-tumour agents against selected cancers. Bortezomib is one such inhibitor that targets the 26S proteasome, and in combination with other chemotherapeutic agents has been shown to have therapeutic potential. In contrast to the long-term control, there are several mechanisms by which the activity of an enzyme can be altered almost instantaneously:

A. Reversible inhibition by small molecules (drugs)

B. Product inhibition

C. Allosteric regulation

D. Reversible covalent modification

Which of the above mechanism follow the process of negative-feedback control and ADP-ribosylation respectively?

#Question id: 7282

#Unit 5. Developmental Biology

In humans, neural tube closure defects occur in about 1 in every 1000 live births. Failure to close the neural tube can result from both genetic and environmental causes. A recent report has demonstrated that zinc deficiency disrupts neural tube closure by:

#Question id: 7283

#Unit 5. Developmental Biology

The Drosophila orthodenticle gene and the vertebrate Otx genes are homologous and provide a good example of the conservation of gene function during evolution. Which of the following statement is correct regarding to the expression of gene expression.

#Question id: 7284

#Unit 5. Developmental Biology

Choose the correct match.

#Question id: 7285

#Unit 5. Developmental Biology

During xenopus gastrulation, C3a functions as a short-range chemoattractant to guide the radial intercalation movements of cells. If Knockdown of C3a with antisense morpholinos results:

#Question id: 7286

#Unit 5. Developmental Biology

Which of the floral whorls is affected in apetala 3/pistillata (ap3/pi) mutants?

#Question id: 7287

#Unit 5. Developmental Biology

Following statements are regarding to the the floral quartet model and the underlying ABCDE model of organ identity determination in Arabidopsis thaliana.

A. Five floral organ identities (sepals, petals, stamens, carpels, and ovules) are specified by the formation of floral organ-specific tetrameric complexes of MADS-domain transcription factors that bind to two nearby enhancer elements, forming a DNA loop in between.

B. A complex of two class A proteins (APETALA 1) and two class E proteins  (SEPALLATA) determines petal identity.

C. A complex of one class A protein, one class E protein, and one of each of the class B proteins (APETALA 3 and PISTILLATA) determines sepal identity.

D. A complex of one class E protein, two class B proteins, and one class C protein (AGAMOUS) determines stamen identity, while a complex of two class E proteins and two class C proteins determines carpel identity.D. A complex of one class E protein, two class B proteins, and one class C protein (AGAMOUS) determines stamen identity, while a complex of two class E proteins and two class C proteins determines carpel identity.

E. A complex of one class E protein, one class C protein, and one of each of the class D proteins (SHATTERPROOF and SEEDSTICK) controls ovule identity.

Which of the following combination are correct?