dna structure and replication

What are the main differences between DNA and RNA?

DNA is double-stranded and contains deoxyribose sugar, whereas RNA is single-stranded and contains ribose sugar.

What are the roles of DNA and RNA in the cell?

DNA stores genetic information, while RNA plays a key role in protein synthesis, serving as a messenger between DNA and ribosomes.

What bases are present in DNA and RNA?

DNA contains adenine, thymine, cytosine, and guanine. RNA contains adenine, uracil, cytosine, and guanine.

How stable are DNA and RNA molecules?

DNA is more stable due to its double-stranded structure and deoxyribose sugar, while RNA is more prone to degradation.

What are the base pairing rules of DNA?

Adenine (A) pairs with Thymine (T) and Cytosine (C) pairs with Guanine (G).

How many hydrogen bonds form between A and T?

Two hydrogen bonds form between Adenine (A) and Thymine (T).

How many hydrogen bonds form between C and G?

Three hydrogen bonds form between Cytosine (C) and Guanine (G).

Why are base pairing rules important?

Base pairing rules are crucial for the structure of the DNA double helix and ensure accurate DNA replication.

What is the structure of a nucleotide?

A nucleotide consists of three main parts: a nitrogenous base, a five-carbon sugar (deoxyribose in DNA and ribose in RNA), and one or more phosphate groups.

What is DNA replication?

DNA replication is the process by which a cell makes an exact copy of its DNA prior to cell division.

Why is DNA replication important?

It is essential for growth, reproduction, and tissue repair, ensuring that each daughter cell receives an identical set of chromosomes.

What are the stages of DNA replication?

The stages include initiation, elongation, and termination, involving the separation of DNA strands and synthesis of new complementary strands.

What enzymes are involved in DNA replication?

Key enzymes include DNA helicase (unwinds the DNA), DNA polymerase (adds nucleotides), and DNA ligase (joins fragments).

What is the role of DNA helicase in replication?

DNA helicase unwinds and separates the double-stranded DNA to create two single strands for replication.

What ensures the accuracy of DNA replication?

DNA polymerase has proofreading abilities to correct errors during nucleotide addition.

What can happen if DNA replication is faulty?

Faulty replication may lead to mutations, which can result in diseases, including cancer.

What is semi-conservative replication?

In semi-conservative replication, each new DNA molecule consists of one original strand and one newly synthesized strand.

Why is DNA replication semi-conservative?

each new double helix contains one original strand and one new strand, conserving genetic information.

nucleic acid

that serves as the building blocks of DNA and RNA, composed of nucleotide monomers.

nucleotide

the basic structural unit of nucleic acids, consisting of a sugar, phosphate group, and a nitrogenous base.

DNA polymerase

an enzyme that synthesizes new DNA strands by adding nucleotides to a pre-existing chain during DNA replication.

Ligase

an enzyme that joins together DNA fragments by forming phosphodiester bonds, essential for DNA replication and repair.