Following statements are regarding to the role of the Disheveled and β-catenin proteins in specifying the cells of the sea urchin embryo.

A. During normal development, β-catenin accumulates predominantly in the micromeres and somewhat less in the veg2 tier cells.

B. In embryos treated with lithium chloride, β-catenin accumulates in the nuclei of all blastula cells and the cells of the animal pole become specified as ectoderm.

C. When β-catenin is prevented from entering the nuclei (i.e., it remains in the cytoplasm), the vegetal cell fates are not specified, and the entire embryo develops as a ciliated ectodermal ball.

D. When β-catenin is prevented from entering the nuclei (i.e., it remains in the cytoplasm), the vegetal cell fates are specified, and the entire embryo specified as endoderm and mesoderm .

Which of the following statements are true?

#Question id: 527

#Unit 1. Molecules and their Interaction Relevant to Biology

What chemical species activates the GLUT4 protein to transport glucose into cells?

#Question id: 528

#Unit 1. Molecules and their Interaction Relevant to Biology

Once inside a cell, glucose is rapidly phosphorylated to glucose-6-phosphate. What is the main purpose of this phosphorylation?

#Question id: 529

#Unit 1. Molecules and their Interaction Relevant to Biology

When a muscle is stimulated to contract aerobically, less lactic acid is formed than when it contracts anaerobically because:

#Question id: 531

#Unit 1. Molecules and their Interaction Relevant to Biology

Glucose labeled with ¹⁴C in C-1 and C-6 gives rise in glycolysis to pyruvate labeled in:

#Question id: 532

#Unit 1. Molecules and their Interaction Relevant to Biology

In glycolysis, fructose 1,6-bisphosphate is converted to two products with a standard free-energy change (DG'°) of 23.8 kJ/mol.  Under what conditions (encountered in a normal cell) will the free-energy change (DG) be negative, enabling the reaction to proceed to the right?

#Question id: 533

#Unit 1. Molecules and their Interaction Relevant to Biology

Glucose, labeled with 14C in different carbon atoms, is added to a crude extract of a tissue rich in the enzymes of the pentose phosphate pathway.  The most rapid production of 14CO2 will occur when the glucose is labeled in: