1. Genetics 3.2

2. Genome size Genome size varies by organisms.
Smallest genomes are in viruses even though they are not regarded as living organisms.
Unlike the number of genes the genome size is directly proportional to the complexity of the organism
Organism
Description
Genome Size (million bp)
T2 phage
Virus that attacks E. coli
0.18
Escherichia coli
Gut bacteria 5
Drosphilia melanegaster
Fruit fly
140
Homo sapiens
Humans
3,000
Paris japonica
Woodland plant
150,000

3. Autoradiography
Collecting quantitative data on the number of bases in a genome.
John Cairns first produced images of DNA
E.coli was used in the first experiment
1. cells were grown for 2 generations in a solution containing thymidine.
Radioactive isotope
2. Cell membranes were digested using lysozyme
3. During the next 2 months the radioactive DNA decayed and emitted high energy electrons
4. These electrons were captured on a photographic film and measured using microscopes

4. Ploidy Haploid - One set of chromosomes (n)
Diploid - Two sets of homologous chromosomes (2n)
Polyploid - More than two sets of chromosomes

5. Haploid and Diploid
The advantage of having diploid cells is that the effects of harmful recessive mutations can be avoided if a dominant allele is also present.
One of the most fundamental characteristics of a species is the number of chromosomes they have in each of their cells
This number can change due to evolution!

6. Who has more chromosomes?