Genetics Vocab U1

DNA

Deoxyribonucleic acid; the molecule that stores genetic instructions.

RNA

Ribonucleic acid; a molecule that helps use genetic information to make proteins.

mRNA

Messenger RNA; carries instructions from DNA to the ribosome.

tRNA

Transfer RNA; brings amino acids to the ribosome during protein synthesis.

rRNA

Ribosomal RNA; helps form ribosomes, where proteins are made.

Watson & Crick

Scientists credited with proposing the double-helix model of DNA.

Double helix

twisted ladder shape formed by two linear strands of DNA that run in opposite directions.

5-carbon sugar

A sugar molecule with five carbon atoms; part of a nucleotide.

Sugar-phosphate backbone

The alternating sugars and phosphates forming the sides of a DNA strand.

Nitrogenous base

A nitrogen-containing molecule that makes up the "rungs" of DNA/RNA.

Adenine (A)

A nitrogenous base that pairs with thymine in DNA.

Thymine (T)

A DNA base that pairs with adenine.

Cytosine (C)

A nitrogenous base that pairs with guanine.

Guanine (G)

A nitrogenous base that pairs with cytosine.

Purine

A type of nitrogenous base with two rings; adenine and guanine are purines.

Pyrimidine

A type of nitrogenous base with one ring; cytosine and thymine are pyrimidines.

Base pair

Two complementary nitrogenous bases connected across DNA.

Antiparallel

The two DNA strands run in opposite directions.

5′ & 3′ ends

Labels showing the direction of a DNA or RNA strand.

Phosphodiester bonds

Strong chemical bonds that connect sugar and phosphate molecules in the backbone.

Hydrogen bonds

Weak bonds that hold complementary DNA bases together.

Ribose

The 5-carbon sugar found in RNA.

Deoxyribose

The 5-carbon sugar found in DNA.

Chromosome

A tightly condensed structure made of DNA and proteins that contains genes.

Chromatin

Loose, uncoiled DNA wrapped around proteins in the nucleus.

Nucleosome

DNA wrapped around a group of histone proteins; a basic unit of chromatin.

Nucleotide

The building block of DNA and RNA; made of a phosphate, sugar, and nitrogenous base.

Histone

A type of protein that DNA wraps around to help package and organize DNA inside the nucleus.

Nucleus

The control center of a cell that contains and protects the cell's DNA.

Nuclease

An enzyme that cuts or breaks down nucleic acids, such as DNA or RNA.