Chapter 8 (Blakely)

These flashcards cover key concepts related to DNA structure and function, including historical figures, replication processes, and chromosomal concepts.

Johannes Miescher

First described DNA in 1869; determined that DNA is not a protein and is rich in nitrogen and phosphorus.

Frederick Griffith

Discovered clues about DNA's function; noted hereditary material could be transferred between dead S cells and live R cells.

Oswald Avery

Identified the 'transforming principle' as a nucleic acid in 1940, concluding DNA is responsible for transformation.

Alfred Hershey and Martha Chase

Established that DNA transmits hereditary information by showing bacteriophages inject DNA, not protein, into bacteria.

Karyotype

An image of an individual's diploid set of chromosomes.

Chargaff's Rules

1st rule: Amounts of thymine (T) and adenine (A) are identical, as are amounts of cytosine (C) and guanine (G); 2nd rule: DNA of different species varies in proportions of A and G.

Nucleosome

A length of DNA wound around a core of histone proteins.

Chromosome

Structure consisting of DNA and associated proteins that carries genetic information.

Diploid

Having two sets of chromosomes; human body cells contain two sets of 23 chromosomes.

Mutation

A permanent change in the DNA sequence of a cell's chromosome, which can occur during replication or due to DNA damage.

DNA replication

The process by which a cell copies its DNA before division, ensuring each new cell received an identical set of genetic information.

Proofreading

Mechanism by which DNA polymerases correct mismatches during DNA replication to reduce errors.

Somatic cell nuclear transfer (SCNT)

Cloning technique that involves replacing the nucleus of an unfertilized egg with the nucleus of a somatic cell.

Reproductive cloning

Technology that produces genetically identical individuals, like artificial embryo splitting.

Hydrogen bonding

The type of bond that holds the two strands of DNA together, occurring between complementary base pairs.

Base pairing

The specific pairing of nitrogenous bases in DNA: adenine to thymine (A-T) and cytosine to guanine (C-G).

Discontinuous synthesis

The process of synthesizing one strand of DNA in fragments, requiring ligation to join them together.