Which statement correctly describes the structure of a centriole? a) 3 groups of 9 microtubules b) 4 groups of 6 microtubules c) 6 groups of 4 microtubules d) 9 groups of 3 microtubules

The right answer is D) 9 groups of 3 microtubules

Centrioles are the constituents of a so-called centrosome structure: every animal cell has a centrosome, which is made of two centrioles and which together form a functional unit. A centriole consists of nine triplets inclined microtubules, surrounded by a number of proteins.

you are certainly talking about this picture:

a: is the label of the white square, it is showing the  replication fork, formed by helicase (d) ==> so it is the site of dna separation and replication 

b: is a new dna brand that is following directly the replication fork, so it is continuous ==> built continuously from 5' to 3

c: dna polymerase cannot replicate dna on its own, it needs the of their proteins, and one of them plays the role of a clamp which fixes  the dna with the dna template and increases  the processivity of the enzyme. ==>   stops polymerase from falling off the  template.

d: is the enzyme responsible for forming the replication fork (helicase) ==> unwinds and separates dna into two strands

e: is the delayed strand, it is built  in the opposite sense of the helicase, so dna will be built in fragments ==> built  fragments from 5' to 3 joins

and finally f: is the enzyme that builds  the new dna strand (dna polymerase) ==>   adds nucleotides to make a new dna helix.

credit: gradman555p98x9p

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