topic 4.1 - evolutionary change

nucleus

the control centre of the cell, directing all activities, including cell division

DNA

a long, double-stranded molecule inside nucleus that provides instructions for making/replacing, running & repairing a cell

storing info (function of DNA)

genes control patterns of development

copying info (function of DNA)

before cell divides, it replicates another copy itself

transmitting info (function of DNA)

genes are transmitted from one generation to the next; DNA info must be sorted to achieve this

gene expression

info is transferred from DNA to RNA to protein

selective breeding/cultivation

- allowing only those animals with "desirable" characteristics to reproduce
- takes advantage of naturally occurring genetic variation passing wanted traits to future progeny/offspring

hybridization

crossing dissimilar individuals to bring out the BEST traits of both
- hybrids are harder/stronger than either parent
- eg peach hybrid from a disease-resistant & high-fruit density strain will increase food production

inbreeding

to maintain desirable characteristics in a genetic line people will breed individuals with similar characteristics
- creates dog breeds; eg poodles
- ensures that the characteristics of each breed are preserved

risks

breeding genetically similar individuals (relatives) can pass on 2 copies of recessive alleles for a genetic defect

combining DNA fragments = recombinant DNA (rDNA)

- can create a custom-built DNA in the lab with desired genes of diff organisms, & insert into living cells
- DNA synthesizer machines produce short DNA segments several 100 bases long; they're joined using ligase enzyme & merged with natural sequences
- this will happen after the organisms genetic composition

plasmid

small, circular DNA molecule that serves as a vector/carrier for rDNA segments found in bacteria & yeast
- we use a restriction enzyme to cut the plasmid open
- always cuts DNA with the sequence GAATTIC
- plasmid DNA contains a replication signal to ensure that it gets replicated once inside the host cell

genetic marker

a gene that allows us to distinguish among transgenic (have foreign DNA) & normal bacteria