MMG 301 1.2 Vocab

genotype

Actual set of genes in an organism’s genome.

phenotype

The physical features and functional traits of an organism expressed by genes in the genotype.

RNA primer

RNA molecule used by DNA polymerase or reverse transcriptase as a starting point for DNA synthesis.

messenger RNA (mRNA)

Form of ribonucleic acid that carries genetic information from DNA to a ribosome.

transfer RNA (tRNA)

Form of ribonucleic acid that carries amino acids to the ribosome.

ribosomal RNA (rRNA)

Form of ribonucleic acid that, together with polypeptides, makes up the structure of ribosomes.

regulatory RNA

Form of ribonucleic acid used to control gene expression.

ribozyme

RNA molecule functioning as an enzyme.

central dogma

In genetics, fundamental description of protein synthesis that states that genetic information is transferred from DNA to RNA to polypeptides, which function alone or in conjunction as proteins.

transcription

Process in which the genetic code from DNA is copied as RNA nucleotide sequences.

RNA polymerase

Enzyme that synthesizes RNA by linking RNA nucleotides that are complementary to genetic sequences in DNA.

promoter

Region of DNA where transcription begins.

terminator

Region of DNA where transcription ends.

intron

Noncoding sequence of mRNA that is removed to make functional mRNA.

exon

Coding sequence of mRNA. Exons are connected to produce a functional mRNA molecule.

translation

Process in which the sequence of genetic information carried by mRNA is used by ribosomes to construct polypeptides with specific amino acid sequences.

codon

Triplet of mRNA nucleotides that codes for specific amino acids. For example, AAA is a codon for lysine.

anticodon

Portion of tRNA molecule that is complementary to a codon on mRNA.

A site

In a ribosome, a binding site that accommodates tRNA delivering an amino acid.

P site

In a ribosome, a binding site that holds a tRNA and the growing polypeptide.

E site

In translation, site at which tRNA exits from the ribosome.

quorum sensing

Process by which bacteria measure their density in an environment by utilizing signal and receptor molecules.

operon

A series of genes, a promoter, and often an operator sequence controlled by one regulatory gene. The operon model explains gene regulation in prokaryotes.

operator

Regulatory element in an operon where repressor protein binds to stop transcription.

inducible operon

Type of operon that is not normally transcribed and must be activated by inducers.

repressible operon

Type of operon that is continually transcribed until deactivated by repressors.

micro RNA (miRNA)

Short (about 21-nucleotide) RNA molecule that binds to complementary segment of messenger RNA (mRNA), preventing translation.

riboswitch

RNA molecule that changes shape in response to shifts in environmental conditions, which results in genetic regulation.

small interfering RNA (siRNA)

RNA molecule complementary to a portion of a molecule of mRNA, tRNA, or a gene, rendering the target ineffective.

functional group

An arrangement of atoms common to all members of a class of organic molecules, such as the amine group found in all amino acids.

monomer

A subunit of a macromolecule, such as a protein.

polymer

Repeating chains of covalently linked monomers found in macromolecules.

lipid

Any of a diverse group of organic macromolecules not composed of monomers and insoluble in water.

hydrophobic

Insoluble in water.

fats

Compounds composed of three fatty acid molecules linked to a molecule of glycerol.

saturated fatty acid

Saturated fatty acid

A long-chain, organic acid in which all but the terminal carbon atoms are covalently linked to two hydrogen atoms.

unsaturated fatty acids

A long-chain, organic acid with at least one double bond between adjacent carbon atoms, and thus at least one carbon atom bound to only a single hydrogen atom.

phospholipid

Phosphate-containing lipid made up of molecules with two fatty acid chains.

hydrophilic

Attracted to water.

wax

Alcohol-containing lipid made up of molecules with one fatty acid chain.

steroid

Lipids consisting of four fused carbon rings attached to various side chains and functional groups.

carbohydrate

Organic macromolecule consisting of atoms of carbon, hydrogen, and oxygen.

monosaccharide

(*simple sugar*) A monomer of carbohydrate, such as a molecule of glucose.

disaccharide

Carbohydrate consisting of two monosaccharide molecules joined together.

polysaccharide

Carbohydrate polymer composed of several to thousands of covalently linked monosaccharides.

protein

A complex macromolecule consisting of carbon, hydrogen, oxygen, nitrogen, and sulfur that is important to many cell functions.

amino acid

A monomer of polypeptides.

peptide bond

A covalent bond between amino acids in proteins.

denaturation

Process by which a protein’s three-dimensional structure is altered, eliminating function.

deoxyribonucleic acid (DNA)

Nucleic acid consisting of nucleotides made up of phosphate, a deoxyribose pentose sugar, and an arrangement of the bases adenine, guanine, cytosine, and thymine.

ribonucleic acid (RNA)

Nucleic acid consisting of nucleotides made up of phosphate, a ribose pentose sugar, and an arrangement of the bases adenine, guanine, cytosine, and uracil.

nucleotide

Monomer of a nucleic acid, which is composed of a nucleoside and a phosphate.

adenine/guanine/cytosine/thymine

Ring-shaped nitrogenous base found in nucleotides of DNA and RNA.

uracil

Ring-shaped nitrogenous base found in nucleotides of RNA.

nucleoside

Component of a nucleotide consisting of a nitrogenous base and a five-carbon sugar.

adenosine triphosphate (ATP)

The primary short-term, recyclable energy molecule fueling cellular reactions.