Nucleic acids

Nucleic acid

A macromolecule composed of nucleotides that stores and transmits genetic information (e.g., DNA and RNA).

Deoxyribonucleic acid (DNA)

A double-stranded nucleic acid that carries genetic instructions for the development, functioning, growth, and reproduction of living organisms.

Ribonucleic acid (RNA)

A single-stranded nucleic acid involved in protein synthesis and gene expression.

Nucleotide

The basic building block of nucleic acids, consisting of a phosphate group, a pentose sugar, and a nitrogenous base.

Phosphate group

A functional group consisting of a phosphorus atom bonded to four oxygen atoms, forming part of the nucleotide structure.

Pentose sugar

A five-carbon sugar found in nucleotides; deoxyribose in DNA and ribose in RNA.

Nitrogenous base

A nitrogen-containing molecule that is a component of nucleotides, classified as purines or pyrimidines.

Purine

A double-ring nitrogenous base found in nucleotides; includes adenine (A) and guanine (G).

Pyrimidine

A single-ring nitrogenous base found in nucleotides; includes cytosine (C), thymine (T), and uracil (U).

Adenine (A)

A purine nitrogenous base that pairs with thymine (T) in DNA and uracil (U) in RNA.

Thymine (T)

A pyrimidine nitrogenous base that pairs with adenine (A) in DNA; not found in RNA.

Cytosine (C)

A pyrimidine nitrogenous base that pairs with guanine (G) in both DNA and RNA.

Guanine (G)

A purine nitrogenous base that pairs with cytosine (C) in both DNA and RNA.

Uracil (U)

A pyrimidine nitrogenous base found only in RNA, replacing thymine (T) and pairing with adenine (A).

Double helix

The spiral, ladder-like structure of DNA, formed by two complementary strands held together by hydrogen bonds.

Complementary base pairing

The principle that specific nitrogenous bases pair together in nucleic acids: A pairs with T (or U in RNA), and G pairs with C.

Hydrogen bond (in DNA)

A weak bond that forms between complementary nitrogenous bases, stabilizing the double helix structure.

Phosphodiester bond

A covalent bond that links nucleotides together by connecting the phosphate group of one nucleotide to the sugar of another.

DNA replication

The process by which DNA makes an identical copy of itself before cell division.

Transcription

The process of synthesizing RNA from a DNA template, occurring in the nucleus.

Translation

The process of synthesizing proteins using mRNA as a template, occurring in the ribosome.

Messenger RNA (mRNA)

A type of RNA that carries genetic instructions from DNA to the ribosome for protein synthesis.

Transfer RNA (tRNA)

A type of RNA that carries amino acids to the ribosome during translation.

Ribosomal RNA (rRNA)

A type of RNA that forms part of the ribosome and aids in protein synthesis.

Central dogma of molecular biology

The flow of genetic information from DNA to RNA to protein.

Adenosine triphosphate (ATP)

A nucleotide that serves as the main energy carrier in cells, consisting of adenine, ribose, and three phosphate groups.

High-Energy Bonds

The bonds between phosphate groups in ATP that store a lot of energy due to the repulsion of negatively charged phosphate groups.

Energy Release

When ATP undergoes hydrolysis, it loses a phosphate group, forming ADP and releasing energy used for various cellular processes.

Regeneration

The continuous process of regenerating ATP from ADP and inorganic phosphate through cellular respiration.

What is the role of DNA in living organisms?

DNA carries genetic instructions essential for the development, functioning, growth, and reproduction of all living organisms.

How does RNA differ from DNA?

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

What is a nucleotide composed of?

A nucleotide is composed of a phosphate group, a pentose sugar, and a nitrogenous base.

What is the function of messenger RNA (mRNA)?

mRNA carries genetic information from DNA to the ribosome, where it serves as a template for protein synthesis.

What is transcription in the context of genetics?

Transcription is the process by which RNA is synthesized from a DNA template in the nucleus.

What is translation in protein synthesis?

Translation is the process of synthesizing proteins from mRNA at the ribosome.

What are the two types of nitrogenous bases in nucleotides?

The two types are purines (adenine and guanine) and pyrimidines (cytosine, thymine, uracil).

What is the significance of the double helix structure of DNA?

The double helix structure allows DNA to be stable and compact while facilitating replication and encoding genetic information.

What is the central dogma of molecular biology?

The central dogma describes the flow of genetic information from DNA to RNA to protein.

What process converts ATP to ADP?

Hydrolysis of ATP converts it to ADP, releasing energy for cellular processes.