Genetics Unit Review

Double helix

The structure of DNA, consisting of two strands twisted around each other.

Backbone of DNA

Composed of sugar and phosphate groups, located on the outside of the DNA structure.

Nitrogenous bases

The building blocks of DNA located inside the double helix; include adenine (A), cytosine (C), thymine (T), and guanine (G).

Complementary base pairing

The pairing of nitrogenous bases in DNA; adenine pairs with thymine (A-T) and cytosine pairs with guanine (C-G).

Hydrogen bonds in DNA

The connections between nitrogenous bases; A-T have 2 hydrogen bonds, C-G have 3 hydrogen bonds.

Purines

Nitrogenous bases with a double-ring structure; include adenine (A) and guanine (G).

Pyrimidines

Nitrogenous bases with a single-ring structure; include thymine (T) and cytosine (C).

Anti-parallel strands

The orientation of the two strands of DNA running in opposite directions (3’ to 5’ and 5’ to 3’).

DNA methylation

The addition of a methyl group to DNA, which can inhibit gene expression.

Acetylation

The addition of an acetyl group to DNA, which can promote gene expression.

Semi-conservative model of DNA replication

The model that describes how each new DNA molecule consists of one original strand and one new strand.

RNA polymerase

The enzyme that synthesizes RNA from a DNA template during transcription.

Translation

The process of converting mRNA into a polypeptide chain (protein).

Operon

A cluster of genes under the control of a single promoter that produce a protein.

Mutagens

Physical or chemical agents that cause mutations in the DNA.

Point mutation

A mutation where a single base pair in DNA is altered.

Frameshift mutation

A mutation caused by insertion or deletion of nucleotides that alters the reading frame of the gene.

Transposon

Segments of DNA that can move within and between chromosomes, not causing mutations.

Biotechnology

The use of biological systems to develop products or processes.

Polymerase chain reaction (PCR)

A technique used to make multiple copies of a specific DNA segment.

Gel electrophoresis

A technique used to separate DNA fragments based on their size.

Bioethics

The area of ethics that deals with the implications of biological research and applications, particularly in biotechnology.