TLS Online TPP Program

#Question id: 7154


Cancer is believed to often arise from stem cells, rather than fully differentiated cells. Which of the following are consistent with this view?

#Unit 4. Cell Communication and Cell Signaling
  1. Stem cells are actively dividing and express few differentiated functions, so they may have fewer changes to undergo than do fully differentiated cells in becoming cancer cells.
  2. DNA replication is necessary for mutations to occur, and stem cells are replicating their DNA whereas differentiated cells are for the most part not replicating their DNA.
  3. Teratocarcinomas are tumors that arise from germ cells or embryonic stem (ES) cells, under certain circumstances, demonstrating that tumors can arise from stem cells without further mutation.
  4. All of the above are reasons that cancer cells may more readily arise from stem cells than from fully differentiated cells.
More Questions
TLS Online TPP Program

#Question id: 3528

#Unit 8. Inheritance Biology

Consider the following cross:

A/a ; B/b ; C/c ; D/d ; E/e  X a/a ; B/b ; c/c ; D/d ; e/e

What proportion of progeny will phenotypically resemble the first parent?

TLS Online TPP Program

#Question id: 3982

#Unit 3. Fundamental Processes

The diagram below represents a hypothetical operon in the bacterium E. coli.  The operon consists of two structural genes (A and B) that code for the enzymes A-ase and B-ase, respectively, and also includes P (promoter) and O (operator) regions as shown.

 When a certain compound (X) is added to the growth medium of E. coli, the separate enzymes A-ase and B-ase are both synthesized at a 50-fold higher rate than in the absence of X (which has a molecular weight of about 200).  Which one of the following statements is true of such an operon?

TLS Online TPP Program

#Question id: 4117

#Unit 3. Fundamental Processes

The RNA recognition motif (RRM), also called the RNP motif and the RNA-binding domain (RBD), is the most common RNA-binding domain in hnRNP proteins. Choose important characteristics of RBD

a. RRM domain consists of a four-stranded b sheet flanked on one side by two a helices.

b. To interact with the negatively charged RNA phosphates, the b sheet forms a positively charged surface

c. The 45-residue KH motif is also found in the hnRNP and several other RNA-binding proteins

Which of the following statements are correct?

TLS Online TPP Program

#Question id: 4127

#Unit 3. Fundamental Processes

Which one of the following statements about ribosomes is true?

TLS Online TPP Program

#Question id: 2742

#Unit 2. Cellular Organization

In the beads on a string model, the bead is made up of __________