Biology 12: Unit 3 - DNA, Protein Synthesis, and Enzymes

This set of vocabulary flashcards covers key biochemical concepts including DNA structure and replication, protein synthesis (transcription and translation), enzyme kinetics and inhibition, and core biotechnology terms as outlined in the Biology 12 learning guide.

DNA

The acronym for Deoxyribonucleic acid; the molecule that makes up Chromosomes and serves as hereditary information.

Nucleotides

Polymers that form genetic material; they are composed of three key parts: phosphoric acid (phosphate group), a $5$ carbon sugar (deoxyribose), and one of four nitrogenous bases.

Purines

Two-carbon nitrogen ring bases in DNA, specifically adenine and guanine.

Pyrimidines

One-carbon nitrogen ring bases in DNA, specifically thymine and cytosine.

Complementary Base Pairing

The set pattern where Adenine bonds to Thymine with $2$ hydrogen bonds, and Guanine bonds to Cytosine with $3$ hydrogen bonds.

Helicase

The enzyme responsible for breaking the weak hydrogen bonds between nitrogenous base pairs to unzip the DNA molecule during replication.

DNA Polymerase

The enzyme that assists with complementary base pairing by adding new nucleotides to the exposed DNA template strands.

Ligase

The enzyme that glues the alternating sugar-phosphate backbone together during DNA replication and recombinant DNA processes.

Semiconservative Replication

The process of DNA replication where each new double helix is composed of one old (parental) strand and one new (daughter) strand.

Recombinant DNA

DNA created by introducing foreign genes into a bacterial plasmid or viral vector, resulting in a new combination of genes from two different organisms.

Vector

A vehicle used to introduce recombinant DNA into a cell, such as a bacterial plasmid or viral DNA.

Restriction Enzyme

An enzyme used to break plasmid DNA so that a new foreign DNA segment can be inserted.

Genomic Library

A collection of engineered viruses that carry all the genes of a particular species, such as a mouse.

Transcription

The process of making a messenger RNA (mRNA) molecule from a DNA template in the nucleus.

Translation

The process occurring in the cytoplasm where the code on an mRNA strand is used to synthesize a protein at the ribosome.

Codon

A set of $3$ bases on an mRNA strand that codes for one specific amino acid.

Degeneracy

The duplication of codons in the genetic code, where multiple different codons can stand for the same amino acid.

Polyribosome

A group of ribosomes found together, all reading the same mRNA strand simultaneously to mass-produce proteins.

Germline Mutation

Hereditary mutations present in egg or sperm cells that are passed to offspring and exist in every cell of their body.

Somatic Mutation

An acquired mutation occurring in body cells during a person's life that is present only in certain cells and cannot be passed to the next generation.

Metabolism

A term referring to all the chemical reactions occurring within a cell.

Apoenzyme

The protein portion of an incomplete enzyme structure.

Coenzyme

The non-protein portion of an enzyme, such as a vitamin, that can donate or accept atoms to or from a reaction.

Activation Energy

The input of energy required to start a chemical reaction; enzymes function by lowering this energy requirement.

Thyroxin

A protein hormone produced by the thyroid gland that governs the rate at which cells consume oxygen and stimulates body metabolism.

Noncompetitive Inhibition

When an inhibitor fits into a site on the enzyme other than the active site, changing the enzyme's shape and distorting the active site so the substrate cannot bond.

Competitive Inhibition

When a molecule shaped similarly to a substrate competes for and fits into the enzyme's active site, blocking the correct substrate from reacting.

Induced Pluripotent Stem (iPS) cells

Adult skin cells that have been reprogrammed to act like embryonic stem cells, capable of differentiating into nearly all other cell types.

Genotype

The term coined by Wilhelm Johannsen to describe the genetic constitution of an organism.

Phenotype

The term coined by Wilhelm Johannsen to describe the physical structure or observable traits of an organism.