CH 8: DNA Structure and Function (Pt1/2)

Johannes Miescher

1869. first to actually see DNA, didn't learn its function

Frederick Griffith

accidentally discovered DNA function while studying pneumonia causing bacteria

hereditary

passing down of genetic information

Hershey and Chase

proved bacteria is responsible for passing down genetic info, found bacteria was injecting its DNA into host bacteria, not protein

bacteriophage

virus that infects bacteria

properties of hereditary molecules

Transmits full genetic information
Cells from specific species have the same amount of DNA
RNA and protein content varies (but not DNA)
Encodes a huge amount of information

nucleotides

Monomers of nucleic acids AKA bases

bases

Adenine (A), Cytosine (C), Guanine (G), Thymine (T), Uracil (U)

nucleic acids

DNA and RNA

DNA

deoxyribonucleic acid. double helix held together by hydrogen bonds, information to build an organism.

Watson and Crick

proteins are often in helix shape, suspect DNA is too. won a Nobel Prize for their work.

Rosalind Franklin

finds the exact shape of DNA. A colleague stole her work and gave it to Watson and Crick who received credit, the discovery that it was her work didn't take place til after her death

hydrogen bonds

(this) gives helix shape to DNA and proteins

DNA sequence

Order of nucleotides in DNA, gives us diversity of traits

chromosomes

tightly packed DNA

histones

a protein that DNA wraps itself around

nucleosomes

DNA + histones

chromatin fibers

tight fibers formed by the interaction of histones

sister chromatids

pair of duplicate centromeres

chromosome

x-shape formed by joint sister chromatids

chromosome number

Number of chromosomes in a cell of a given species; characteristic of different species

diploid

two sets of chromosomes

haploid

one set of chromosomes

karyotype

image of an individual cell's chromosomes

Autosomes

chromosomes that are the same in both males and females

sex chromosomes

chromosomes that determine the sex of an individual

haploidy

sex-determination system in which males develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are diploid.