Review_ch._14_-_17-2

DNA

Deoxyribonucleic acid, a nucleotide polymer that carries genetic information.

RNA

Ribonucleic acid, a nucleotide polymer involved in protein synthesis and carries genetic information.

Nucleotide

The basic building block of DNA and RNA, consisting of a sugar, phosphate group, and nitrogenous base.

Thymine

One of the four nucleotide bases in DNA, replaced by uracil in RNA.

Uracil

A nitrogenous base found in RNA, replacing thymine in DNA.

Phosphodiester bond

The linkage between the phosphate group of one nucleotide and the sugar of another, forming the backbone of DNA and RNA.

Chargaff's rules

The principle that states that in DNA, the amount of adenine equals thymine and guanine equals cytosine.

Rosalind Franklin

A scientist who contributed to the understanding of DNA's structure through X-ray crystallography.

Watson & Crick

Scientists who deduced the double helical structure of DNA based on Franklin's data.

Double helix

The three-dimensional structure of DNA, consisting of two intertwined strands.

H-bond pairing

Hydrogen bond interactions between complementary nitrogenous bases in DNA (A:T and G:C).

Antiparallel configuration

The arrangement of DNA strands in opposite directions; one strand runs 5' to 3' and the other 3' to 5'.

DNA replication

The process by which DNA makes a copy of itself prior to cell division.

Initiation

The first stage of DNA replication where the DNA strands are unwound.

Elongation

The second stage of DNA replication where new DNA strands are synthesized.

Termination

The final stage of DNA replication where the process concludes at specific sites.

DNA polymerase III

The main enzyme responsible for DNA replication in E. coli.

Lagging strand

The strand of DNA that is synthesized discontinuously in short fragments during replication.

Okazaki fragments

Short segments of DNA synthesized on the lagging strand during DNA replication.

DNA primase

An enzyme that synthesizes a short RNA primer to initiate DNA replication.

Replisome

The complex of proteins and enzymes involved in DNA replication.

Primosome

Part of the replisome, composed of primase, helicase, and accessory proteins.

DNA gyrase

A topoisomerase enzyme that prevents DNA coiling during replication.

Helicase

An enzyme that unwinds the DNA double helix during replication.

Single-strand binding proteins (SSBs)

Proteins that stabilize unwound single-stranded DNA during replication.

Polymerase activity

The ability of DNA polymerases to synthesize new DNA strands.

Telomeres

Repeated sequences at the ends of chromosomes that protect them from degradation.

Telomerase

An enzyme that extends telomeres by adding nucleotides.

Mismatch repair (MMR)

A DNA repair mechanism that corrects erroneous insertion of bases.

Excision repair

A DNA repair process that removes damaged regions and replaces them using the undamaged strand as a template.

Central Dogma

The principle that genetic information flows from DNA to RNA to protein.

Transcription

The process of synthesizing RNA from a DNA template.

Translation

The process of synthesizing proteins based on the sequence of mRNA.

Codon

A sequence of three nucleotides in mRNA that specifies an amino acid.

Ribosomes

Cellular structures that facilitate the translation of mRNA into proteins.

Anticodon

A sequence of three bases on tRNA that is complementary to a codon on mRNA.

Peptidyl transferase

An enzymatic activity of ribosomes that catalyzes peptide bond formation.

Point mutation

A genetic mutation where a single nucleotide is changed or substituted.

Frameshift mutation

A genetic mutation caused by insertions or deletions that shift the reading frame of the mRNA.

Transcription factors

Proteins that regulate the transcription of genes by binding to nearby DNA.

Chromatin remodeling

The reorganization of chromatin structure that impacts gene expression.

Epigenetics

The study of heritable changes in gene function not involving changes to the DNA sequence.

miRNA

MicroRNA, small non-coding RNA molecules that regulate gene expression.

CRISPR-Cas9

A genome-editing technology that enables precise modifications to DNA.

Recombinant DNA

DNA molecules formed from two different sources, used in genetic engineering.

Gel electrophoresis

A laboratory technique used to separate DNA fragments by size.

PCR (Polymerase Chain Reaction)

A technique used to amplify a specific segment of DNA.

Transgenic organisms

Organisms that have been genetically modified to contain DNA from other species.

Golden rice

Genetically modified rice that produces beta-carotene, a precursor of vitamin A.

Bioremediation

The use of microorganisms to degrade pollutants or treat wastewater.

Insulin

A hormone produced by the pancreas often synthesized using recombinant DNA technology.

Genetic code

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

SNP (Single Nucleotide Polymorphism)

A variation in a DNA sequence that occurs when a single nucleotide is altered.

Repressor

A regulatory protein that inhibits the expression of one or more genes.

Operator site

A segment of DNA where a repressor binds to regulate gene transcription.

Operons

Clusters of genes under the control of a single promoter, commonly found in prokaryotes.

Lac operon

A gene system that controls the metabolism of lactose in E. coli.

Trp operon

A cluster of genes involved in the synthesis of tryptophan in bacteria.

Bacterial plasmid

A small, circular DNA molecule found in bacteria that is distinct from chromosomal DNA.