Molecular Genetics (Chapter 14) - DNA Structure, Gene Expression, and Genetic Engineering

Vocabulary flashcards covering DNA structure, gene expression, and genetic engineering concepts from the lecture notes.

DNA

Deoxyribonucleic acid; a molecule that contains the genetic information of the organism.

Nucleus

Organelle in which DNA is stored in eukaryotic cells; the DNA carries genetic information for cellular functions.

Gene

A segment of DNA that carries the genetic information of a trait and codes for one polypeptide; a unit of inheritance.

Chromosome

A condensed structure formed when DNA wraps around histones into chromatin and coils; carries genes.

Chromatin

DNA wrapped around histone proteins that condenses to form a chromosome.

Histone

Proteins around which DNA coils to form chromatin.

Nucleotide

The building block of DNA, comprising a sugar (deoxyribose), a phosphate group, and a nitrogen base.

Deoxyribose

The sugar component of DNA nucleotides.

Phosphate

A phosphate group that links nucleotides together to form the backbone.

Nitrogen bases

The four bases in DNA: Adenine (A), Thymine (T), Cytosine (C), Guanine (G).

Adenine (A)

One of the four DNA bases; pairs with Thymine.

Thymine (T)

One of the four DNA bases; pairs with Adenine.

Cytosine (C)

One of the four DNA bases; pairs with Guanine.

Guanine (G)

One of the four DNA bases; pairs with Cytosine.

Base pairs

Pairs of nucleotides on opposite DNA strands: A–T (2 hydrogen bonds) and C–G (3 hydrogen bonds).

Complementary base pairing

Rule that A pairs with T and C pairs with G.

Backbone (sugar-phosphate backbone)

The repeating sugar-phosphate chain of each DNA strand.

Double helix

The two anti-parallel strands of DNA twisted into a spiral shape.

Anti-parallel

The two DNA strands run in opposite directions.

Hydrogen bonds

Weak bonds that hold paired bases together in the DNA double helix.

Base pairs (A–T and C–G)

The specific pairing of bases: Adenine with Thymine, Cytosine with Guanine.

Complementary base pairing rule

A binds to T and C binds to G, forming stable DNA structure.

DNA helix

Another term for the double-helix structure of DNA.

Transcription

The process by which the DNA template is used to make messenger RNA (mRNA).

mRNA

Messenger RNA; single-stranded RNA that carries genetic code from DNA to ribosome.

Translation

The process by which ribosomes read mRNA codons and assemble amino acids into a polypeptide.

Codon

A sequence of three nucleotides on mRNA that codes for one amino acid.

Template strand

The DNA strand that is used as a template to synthesize mRNA during transcription.

Polypeptide

A chain of amino acids that folds to form a protein.

Protein

A molecule formed from one or more polypeptides; performs a wide range of cellular functions.

Insulin gene

The gene that codes for human insulin; can be transferred into bacteria in genetic engineering.

Restriction enzyme

Enzyme used to cut DNA at specific sequences to produce sticky ends.

Sticky ends

Single-stranded ends of DNA fragments that can be joined to complementary ends.

Plasmid

A circular DNA molecule in bacteria used as a vector to carry foreign genes.

Recombinant plasmid

Plasmid that has had a foreign gene (e.g., insulin gene) inserted into it.

Vector

An organism or molecule used to transfer genetic material from one organism to another; bacteria can act as vectors.

Bacterial transformation

Genetic engineering technique in which bacteria take up recombinant DNA.

Transgenic organism

An organism that contains a foreign gene inserted into its genome.

Heat/electrical shock transformation

Method used to insert recombinant plasmids into bacteria by increasing membrane permeability.

Insulin production (bacterial transformation)

Producing human insulin in bacteria; advantages include identical insulin to humans, lower cost, and reduced contamination risk.

Benefits of genetic engineering (medicine and agriculture)

In medicine and agriculture, genetic engineering can lower drug costs, increase crop durability, pest resistance, and enable improved nutrition.

GURT (terminator technology)

Genetic Use Restriction Technology; patented crops that may be unable to produce seeds, raising cost and dependency for farmers.

Ethical considerations in genetic engineering

Concerns include allergies from new proteins, patenting and seed costs, use of animals in research, dual-use risks, and antibiotic resistance.