AP Biology 6.1 Vocab

DNA

Double stranded nuclear acid polymer that stores and transmits genetic information for the development, function, and reproduction of all living organisms

RNA

A single stranded nucleic acids essential for protein synthesis and gene regulation, synthesized from DNA via transcription

Chromosome

A thread-like structure composed of a single, long DNA molecule coiled around histone proteins, found in the nucleus of eukatyotic cells

Nucleoid

Irregular, non-membrane-bound region within a prokaryotic cell that contains the majority of the genetic material, specifically a single, circular chromosome

Pyrimidine

Nitrogenous bases in DNA and DNA characterized by a single six-memebered ring structure containing four carbon atoms and two nitrogen atoms

Complementary Base Pair

The specific, hydrogen-bonded pairing of nitrogenous bases

Chargaff’s Rule

DNA, the amount of adenine (A) equals thymine (T), and guanine (G) equals cytosine (C)

Adenine

purine nitrogenous base that serves as a fundamental building block of DNA and RNA, pairing with thymine (in DNA) or uracil (in RNA) via two hydrogen bonds

Thymine

pyrimidine nitrogenous base (nucleobase) found in DNA, denoted by the letter 'T', that pairs specifically with Adenine (A) via two hydrogen bonds

Cytosine

pyrimidine nitrogenous base, one of the four main building blocks of DNA and RNA that encodes genetic information. In both DNA and RNA, it pairs specifically with guanine (G) via three hydrogen bonds

Guanine

nitrogenous purine base found in DNA and RNA, pairing specifically with cytosine via three hydrogen bonds

Uracil

a nitrogenous pyrimidine base found exclusively in RNA, replacing thymine (T) to pair with adenine (A)

Nucleotide

monomer (building block) of nucleic acids (DNA and RNA), consisting of a five-carbon sugar (deoxyribose or ribose), a phosphate group, and a nitrogenous base. They store genetic information via sequence, and include ATP for energy transport

DNA Replication

the semiconservative process occurring in the S-phase of the cell cycle, where a double-stranded DNA molecule is copied to produce two identical DNA molecules

Semi-conservative Replication

the mechanism of DNA duplication where each new double helix consists of one original (parental) strand and one newly synthesized daughter strand

Conservative Replication

a disproved theoretical model of DNA synthesis where the original parent double helix remains entirely intact, while a completely new daughter molecule is synthesized from scratch

Dispersive Replication

a disproved model of DNA synthesis where both strands of daughter DNA molecules consist of a random, patched-together mixture of parental (old) and newly synthesized DNA segments

Replication Fork

a Y-shaped structure formed during DNA replication where the double helix is unwound and separated into two single strands

Template strand/Parental strand

an original, single-stranded DNA molecule used as a guide by DNA polymerase during replication to synthesize a new, complementary daughter strand

Complementary strand/daughter strand

the newly synthesized DNA strand produced during replication, which is complementary to the template "parent" strand

Helicase

an essential enzyme that unwinds double-stranded nucleic acids (DNA or RNA) by breaking hydrogen bonds between base pairs, utilizing ATP energy

Topoisomerase

essential enzymes that regulate DNA supercoiling, tension, and topological state during replication, transcription, and repair

DNA Polymerase

a type of enzyme essential for life that synthesizes new DNA strands by adding nucleotides to a pre-existing template during DNA replication and repair

DNA ligase

a specialized enzyme that functions as a molecular "glue" in biology, repairing and joining DNA strands together by creating phosphodiester bonds between a 3'-hydroxyl group and a 5'-phosphate group

Single-strand binding proteins

essential proteins that bind to single-stranded DNA (ssDNA) during replication, repair, and recombination

Primase

an essential enzyme (a type of RNA polymerase) that initiates DNA replication by synthesizing short RNA primers on single-stranded DNA templates

Leading Strand

the DNA daughter strand synthesized continuously in the same direction as the advancing replication fork during DNA replication.

Plasmid

a small, circular, double-stranded, extrachromosomal DNA molecule, primarily found in bacterial cells, that replicates independently of the chromosomal DNA

Double helix

the physical structure of DNA, characterized by two complementary polynucleotide strands running anti-parallel and twisting around each other to form a spiral ladder

Antiparallel

opposite orientation of the two strands in a DNA double helix, where one strand runs in a direction

Nitrogenous Base

a nitrogen-containing, heterocyclic aromatic organic molecule that acts as a fundamental building block of nucleic acids (DNA and RNA)

Purine

a heterocyclic aromatic compound composed of a pyrimidine ring and an imidazole ring fused together

Lagging Strand

the DNA daughter strand synthesized discontinuously in short, 5' to 3' segments called Okazaki fragments during DNA replication.

Okazaki Fragment

short, discontinuously synthesized DNA segments formed on the lagging strand during DNA replication

Biotechnology

The use of biology-based technology, living organisms, cells, or their molecular components to develop products and processes that improve human life and environmental health

Polymerase Chain Reaction

a fundamental molecular biology laboratory technique used to amplify or make millions to billions of copies of a specific, tiny segment of DNA

Amplification

Primers

a short, single-stranded nucleic acid sequence (RNA or DNA) that serves as the mandatory starting point for DNA synthesis

dNTP

a monomeric unit of DNA and formed by reducing ribonucleotides with the enzyme ribonucleotide reductase (RNR).

Denaturation

the process where proteins or nucleic acids lose their native shape (secondary, tertiary, or quaternary structure) and biological activity due to external stress, such as intense heat, extreme pH, or chemicals.

Annealing

the process where separated single strands of nucleic acids (DNA or RNA) pair up and rejoin to form a stable double-stranded molecule

Extension

the movement at a joint that increases the angle between two bones, resulting in straightening or lengthening of a limb

Recombinant DNA

a form of synthetic DNA constructed in a laboratory by joining DNA molecules from two or more different species or sources.

Plasmid/vector

a small, circular, double-stranded DNA molecule that exists independently of chromosomal DNA, primarily in bacteria. A vector is a DNA molecule used as a vehicle to artificially carry foreign genetic material into another cell.

Restriction enzyme

a protein produced by bacteria that cuts DNA at specific, short palindromic nucleotide sequences.

Digestion reaction

the catabolic process of breaking down large, insoluble food molecules into small, water-soluble molecules (monomers) that can be absorbed into the bloodstream

Ligase/ligation

an enzyme that catalyzes the joining of two large molecules by forming a new chemical bond

Gel Electrophoresis

a laboratory technique used in biology to separate mixtures of DNA, RNA, or protein molecules based on their size and electric charge

Agarose gel

a porous, three-dimensional matrix created from a polysaccharide extracted from seaweed (red algae)

Transformation

a type of horizontal gene transfer where a bacterial cell directly takes up exogenous (free) DNA from its surrounding environment and incorporates it into its own genome

Cloning

the process of producing genetically identical copies of biological entities, including genes, cells, tissues, or entire organisms.

DNA sequencing

the precise, ordered arrangement of nucleotide bases—adenine (A), thymine (T), cytosine (C), and guanine (G)—within a DNA molecule.

Gene-editing

a group of technologies enabling precise, targeted changes to an organism’s DNA sequence

CRISPR-Cas9 system

a precise, fast, and versatile gene-editing technology adapted from a natural prokaryotic immune mechanism