Two curves showing the rate versus substrate concentration are shown below for an enzyme-catalyzed reaction. One curve is for the reaction in the presence of substance X. The other curve is for data in the absence of substance X. Examine the curves and tell which statement below is false.

#Question id: 2889

#Unit 2. Cellular Organization

The edges of each base pair are exposed in the major and minor grooves, creating a pattern of hydrogen-bond donors and acceptors and of hydrophobic groups (allowing for Vander Waals interactions) that identifies the base pair. The edge of an C : G base pair displays the following chemical groups in the following order in the major groove:

#Question id: 2890

#Unit 2. Cellular Organization

Match individual variant histones i) to iv) to one or more of the possible functions listed in a) to g).

Variant histones              Functions 

i) CENP-A                         a) DNA replication

ii) H2A.X                           b) As a barrier to stop heterochromatin spreading

iii) H2A.Z                          c) DNA repair

iv) H3.3                             d) Transcriptional activation

                                          e) Kinetochore assembly 

                                           f) Recombination

                                          g) Genome maintenance

#Question id: 2891

#Unit 2. Cellular Organization

Which of the following statements regarding the Structural Maintenance Chromosomal proteins is correct?

A. The cohesins, along with a third protein, kleisin, are thought to form a ring around the replicated chromosomes.

B. Condensin binding causes the DNA to become underwound, in contrast to the overwinding induced by the binding of nucleosomes.

C. Cohesins are made up of pairs of Smc1 and Smc3 proteins, and condensins consist of Smc2-Smc4 pairs.

D. The primary structure of SMC proteins consists of three distinct domains.

#Question id: 2892

#Unit 2. Cellular Organization

The edges of each base pair are exposed in the major and minor grooves, creating a pattern of hydrogen-bond donors and acceptors and of hydrophobic groups (allowing for Vander Waals interactions) that identifies the base pair. The edge of an T : A base pair displays the following chemical groups in the following order in the major groove:

#Question id: 2893

#Unit 2. Cellular Organization

Which of the following statement regarding the Nucleosome-remodeling complexes is CORRECT?

#Question id: 2894

#Unit 2. Cellular Organization

Which of the following statements is INCORRECT regarding the assembly of DNA into higher-order chromatin structure?

I. Histone H1 is not part of the histone octamer, but binds to linker DNA and is responsible for higher-order chromatin structure.

II. The 30 nm fibers of a chromosome are attached to a/an RNA-protein scaffold that holds the fibers in large loops.

III. It is not possible for linear DNA to be supercoiled. Only circular DNA, which has no ends, can have regions of supercoiling.

IV. Core histones lacking their amino-terminal tails are capable of forming 30-nm fibers as they help to stabilize the 30-nm fiber in internucleosomal interactions.