Brief Concepts and Questions EXAM 2 Chapter 8: DNA RNA Protein What is DNA? a ph

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Brief Concepts and Questions EXAM 2 Chapter 8: DNA RNA Protein What is DNA? a phosphate Structure of DNA: Building blocks are called nucleotides Each nucleotide is composed of three br uithofenas bee. What makes DNA so special? Provide 4 reasons, below DNA DNA (Replication): Where does DNA replication take place? When does DNA replication take place? Explain steps involved in DNA replication: DNA RNA Protein (Gene Expression) Involves 2 processes: 1. Transcription 2. Translation Explain the Synthesis of Proteins (Gene Expression): o DNA RNA Protein What is RNA? What is "codon What is "anticodon" What is a protein molecule? DNA mutation; Change in nucleotide bases of DNA Duplex Point mutation Frame shift mutation

Explanation / Answer

Question

Answer

Where does DNA replication take place:

It takes place in the nucleus in case of eukaryotic cells and in the cytoplasm in case of prokaryotic cells

When does DNA replication take place:

DNA replication occurs during the S-phase during cell cycle, so that cell can make an extra copy of genetic material.

Explain steps involved in DNA replication:

Initiation: During initiation, the proteins will bind to the origin of replication; helicase unwinds the DNA helix which results in the formation of two replication forks.

Elongation: A RNA primer sequence will be added to this the DNA pol III will add the nucleotides in 5’ to 3’ direction and chain will elongate.

Termination: In case of bacteria, termination of replication occurs whenever two replication forks meet each other from the opposite end of the parental chromosome.

Transcription

Gene expression first step is transcription, here a particular segment of DNA will be copied into RNA with the help of the enzyme RNA polymerase

Translation

Translation is the final step of the gene expression. Here mRNA will be used to synthesize the polypeptide chain. The information present in the mRNA in the form of codon will code for the amino acids needed for polypeptide chain synthesis.

What is RNA?

RNA is ribonucleic acid and is found in all living cells. It acts as the messenger carrying instructions from DNA for the synthesis of proteins.

Few viruses will have RNA as their genetic material.

What is codon?

Codon is a sequence of three nucleotides and they together form a unit of genetic code in either DNA or RNA.

What is anticodon?

It is found on tRNA and it is a sequence of three nucleotides which forms a genetic code on tRNA, and these anticodon is complementary to the codons found on messenger RNA.

What is a protein molecule?

During translation, when amino acids are added in a sequential manner, the condensation of amino acids will form a peptide bond in between them and finally forms a polypeptide chain. It is the DNA through mRNA directs the protein synthesis.

Point mutation

In point mutation, only one or very few nucleotides will be affected or mutated in a gene sequence.

Frame shift mutation

Either insertions or deletion can result in frame shift mutation, due to this mutation the reading frame will be changed finally resulting in the incorrect polypeptide chain synthesis.