DNA, genes and chromosomes：练习题

A nucleotide was isolated and found to contain a phosphate group, a ribose sugar, and the base Uracil. In which molecule would this nucleotide be found?

Which of the following describes the precise action of DNA helicase during the process of DNA replication?

Which of the following correctly describes the DNA found within the mitochondria of a eukaryotic cell?

In eukaryotes, much of the nuclear DNA does not code for polypeptides. Where are non-coding multiple repeats of base sequences primarily located on a chromosome?

In the provided diagram of a chromosome, the arrow points to a specific fixed position labelled X where a particular gene is located. What is the correct biological term for position X?

Define the term genome and explain how it differs from a single gene located at a specific locus.

Explain why the genetic code is described as degenerate and describe how this feature provides a degree of protection against the effects of base substitution mutations.

Identify the specific role of DNA polymerase during semi-conservative replication and state the type of bond it catalyzes between nucleotides.

DNA replication is a semi-conservative process that occurs during the S-phase of the cell cycle.

(a) Describe the role of DNA helicase and DNA polymerase during the process of replication. (3 points)

(b) Explain why the term 'semi-conservative' is used to describe this process. (2 points)

Compare the structures and functions of mRNA and tRNA.

(a) Identify two structural differences between an mRNA molecule and a tRNA molecule. (2 points)

(b) Explain the importance of the anticodon on the tRNA molecule in ensuring the correct primary structure of a protein is formed. (2 points)

(c) Describe the process by which amino acids are joined together at the ribosome during translation. (2 points)