Year 10 Biology Notes

Steps in selective breeding:

Decide which characteristic is most important

Select parents that show high levels of that characteristic

Breed these individuals together

Select the best offspring and repeat the process

Repeat for many generations

Steps in natural selection

Variation in a species exists

Some organisms are better adapted to the environment

The organisms that are better adapted survive to become adults

They reproduce and pass on the genes

Over time, the species changes or evolves

Steps in Genetic modification using insulin

Genes that code for insulin are inserted into the bacteria- into the plasmids   

The bacteria produce insulin

The bacteria multiply in large quantities to produce insulin

The bacteria are removed, leaving the useful insulin

Variation is due to 2 factors: genetic and environmental

Invertebrates -Animals without a backbone

Vertebrates- Animals with a backbone

Chordata- Spinal chord

All chordates have 5 classes: fish, amphibians, mammals, birds, reptiles

Variation is the differences between members of the same species

For binomial naming, you include the Genus and the Species

Heredity is the process by which genetic information is passed from parent to child

Genes are codes for characteristics

DNA is the chemical that is found in the nucleus of our cells

DNA is a double helix. This means it is like a twisted ladder. Each “rung” is made up of 2 chemicals called bases. This is known as a base pair. A and T pair, C and G pair. The rungs are covered in a sugar phosphate backbone.

The bases are bonded together with individually weak, but collectively strong hydrogen bonds.

A nucleotide is the backbone and 1 base.

We have on average between 20k and 21k genes.

Chromosomes 1-22: autosomes/ somatic chromosomes, Chromosome 23: sex chromosome

An adaptation is a characteristic that helps an organism survive in its environment

DNA is the molecule that contains the complete genetic instructions for building, maintaining and reproducing an organism.

Chromosomes are long strings of DNA compactly packaged into small structures

Natural selection is the process where organisms are better adapted to their environment and are more likely to survive, reproduce and pass on their advantageous genes to the next generation so that the next generation is more adapted and even more evolved.

Selective breeding is the process of intentionally picking the best individuals of species to reproduce, generation after generation.

Bases: DNA is a sequence of bases, not base pairs.

We have 46 chromosomes in each of our cells, 23 pairs

The classification hierarchy:

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species