Anatomy and Physiology 12 - DNA, RNA, and Genetic Material

Comprehensive vocabulary flashcards covering DNA structure, history of genetic research, replication enzymes, and the differences between DNA and RNA.

Frederick Griffith

A scientist who, in the late $1920\text{s}$, identified a transforming substance that could change nonlethal bacteria to lethal bacteria.

Hershey and Chase

Scientists who in the early $1950\text{s}$ established DNA as the genetic material using viruses ($T \text{ phage}$) labeled with radioactive DNA and protein.

Deoxyribonucleic acid (DNA)

The genetic material and control molecule of life that carries encoded genetic instructions in its sequence of bases.

Three Major Functions of DNA

$1$. Controls cellular activities and reproduction; $2$. Makes exact copies of itself (replication); $3$. Undergoes mutations to provide life's diversity.

Nucleotide

The building block of DNA, consisting of a phosphate group, a deoxyribose sugar, and a nitrogen-containing base.

Purines

A category of nitrogenous bases that includes adenine ($A$) and guanine ($G$).

Pyrimidines

A category of nitrogenous bases that includes cytosine ($C$) and thymine ($T$).

Double Helix

The structure formed by two DNA strands twisting about each other, featuring a backbone of alternating phosphate and sugar molecules.

Complementary Base Pairing

The specific bonding between purines and pyrimidines on opposite DNA strands where $A$ bonds with $T$ and $G$ bonds with $C$ via hydrogen bonds.

Genes

Units of inheritance located on chromosomes consisting of segments of DNA; they usually consist of a sequence of about $1000$ base-pairs.

Human Chromosome Count

Humans have $46$ chromosomes, while other species vary (e.g., fruit fly has $8$, fern has $1200$).

DNA Replication

The process of copying one double helix into two identical double helices.

Semi-conservative

A term describing DNA replication where each new double helix consists of one original strand and one newly synthesized strand.

DNA Helicase

The enzyme that separates DNA strands by breaking the hydrogen bonds between bases during replication.

DNA Polymerase

An enzyme that catalyzes the incorporation of new nucleotides by complementary base pairing and can only add nucleotides to one end of the growing chain.

Leading Strand

The DNA strand synthesized continuously following the path of the helicase enzyme.

Lagging Strand

The DNA strand synthesized in fragments away from the replication fork.

Okazaki Fragments

Short segments of DNA synthesized on the lagging strand during DNA replication.

DNA Ligase

The enzyme that connects Okazaki fragments and seals any breaks in the sugar-phosphate backbone.

Ribonucleic Acid (RNA)

A single-stranded nucleic acid necessary for protein synthesis that may have been the original nucleic acid when life arose $3.8 \text{ billion}$ years ago.

Ribose

The five-carbon sugar molecule found in the nucleotides of RNA.

Uracil

The nitrogenous base found in RNA that replaces thymine ($T$) found in DNA.

Transcription

The process through which RNA is synthesized from a DNA template.