IBDP Biology A1.2 Nucleic Acids

3' Terminal

The end of a nucleic acid strand that has a free hydroxyl group (-OH) on the 3' carbon of the sugar molecule.

5' Terminal

The end of a nucleic acid strand that has a free phosphate group on the 5' carbon of the sugar molecule.

Adenine

A nitrogenous base that is one of the four building blocks of DNA and RNA, pairing with thymine in DNA and uracil in RNA.

Amino Acid

The building blocks of proteins, consisting of an amino group, a carboxyl group, and a side chain (R group) that varies among different amino acids.

Antiparallel

Referring to the orientation of two strands of DNA that run in opposite directions, one strand runs 5' to 3' and the other runs 3' to 5'.

Backbone

The structural framework of a nucleic acid molecule, consisting of alternating sugar and phosphate groups.

Bacteriophage

A type of virus that infects bacteria, often used in molecular biology as a tool for genetic engineering.

Codon

A sequence of three nucleotides in mRNA that specifies a particular amino acid or a stop signal during protein synthesis.

Complementary Base Pairing

The specific pairing of nitrogenous bases in DNA and RNA, where adenine pairs with thymine (or uracil in RNA) and cytosine pairs with guanine.

Condensation

A chemical reaction that combines two molecules, resulting in the formation of a larger molecule and the release of water.

Covalent Bond

A strong chemical bond formed when two atoms share one or more pairs of electrons.

Cytosine

A nitrogenous base that is one of the four building blocks of DNA and RNA, pairing with guanine.

Deoxyribonucleic Acid (DNA)

The molecule that carries the genetic instructions for life, consisting of two strands that form a double helix.

Deoxyribose

A five-carbon sugar that is a component of DNA, lacking one oxygen atom compared to ribose.

Double Helix

The structure of DNA, consisting of two intertwined strands that are held together by base pairing.

Gene

A segment of DNA that contains the instructions for synthesizing a specific protein or RNA molecule.

Gene Expression

The process by which the information encoded in a gene is used to produce a functional gene product, typically a protein.

Genetic Code

The set of rules by which information encoded in genetic material is translated into proteins.

Genetic Material

Molecules, such as DNA and RNA, that carry the genetic information necessary for the growth, development, and reproduction of organisms.

Genome

The complete set of genetic material present in an organism, including all of its genes.

Guanine

A nitrogenous base that is one of the four building blocks of DNA and RNA, pairing with cytosine.

Hereditary

Referring to the transmission of genetic traits from parents to offspring.

Histone

A type of protein that helps package and organize DNA into structural units called nucleosomes.

Hydrogen Bond

A weak bond that occurs between a hydrogen atom and an electronegative atom, important in stabilizing the structure of DNA.

Hydroxyl Group

A functional group consisting of an oxygen atom bonded to a hydrogen atom (-OH), commonly found in sugars.

Inheritance

The process by which genetic information is passed from parents to their offspring.

Linker DNA

The stretch of DNA that connects nucleosomes in chromatin, allowing for the compaction of DNA.

Monomer

A small molecule that can join together with other similar molecules to form a polymer.

Mutation

A change in the nucleotide sequence of DNA that can lead to changes in the structure and function of proteins.

Naked DNA

DNA that is not associated with proteins or other molecules, often used in studies of gene expression.

Nitrogenous Base

A molecule that contains nitrogen and acts as a base in nucleic acids, including adenine, thymine, cytosine, guanine, and uracil.

Nucleic Acid

Biomolecules, such as DNA and RNA, that are essential for all known forms of life, composed of nucleotide monomers.

Nucleosome

A structural unit of chromatin, consisting of a segment of DNA wrapped around a core of histone proteins.

Nucleotide

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

Pentose

A five-carbon sugar, such as ribose or deoxyribose, that is a component of nucleotides.

Phosphate Group

A functional group consisting of a phosphorus atom bonded to four oxygen atoms, important in the structure of nucleotides.

Phosphodiester Bond

The covalent bond that links the phosphate group of one nucleotide to the hydroxyl group of the sugar of another nucleotide.

Polymer

A large molecule composed of repeating structural units, typically connected by covalent chemical bonds.

Polynucleotide

A polymer made up of nucleotide monomers, forming the structure of nucleic acids like DNA and RNA.

Polypeptide

A chain of amino acids linked by peptide bonds, which folds into a functional protein.

Purine

A type of nitrogenous base that includes adenine and guanine, characterized by a two-ring structure.

Pyrimidine

A type of nitrogenous base that includes cytosine, thymine, and uracil, characterized by a single-ring structure.

Radioisotope

An isotope of an element that is radioactive, often used in biological research and medical applications.

Replication

The process by which DNA is copied to produce two identical DNA molecules.

Ribonucleic Acid (RNA)

A nucleic acid that plays a central role in the synthesis of proteins, consisting of a single strand of nucleotides.

Ribose

A five-carbon sugar that is a component of RNA, differing from deoxyribose by having an additional oxygen atom.

Semi-Conservative

Referring to the method of DNA replication in which each new DNA molecule consists of one original strand and one new strand.

Sequence

The order of nucleotides in a DNA or RNA molecule, which determines the genetic information carried.

Template

A strand of nucleic acid that serves as a guide for the synthesis of a complementary strand during replication or transcription.

Thymine

A nitrogenous base that is one of the four building blocks of DNA, pairing with adenine.

Transcription

The process of synthesizing RNA from a DNA template, resulting in the formation of messenger RNA (mRNA).

Translation

The process by which ribosomes synthesize proteins using the information encoded in mRNA.

Universal

Referring to the genetic code, which is nearly the same in all organisms, indicating a common evolutionary origin.

Uracil

A nitrogenous base found in RNA that replaces thymine and pairs with adenine.