Discontinuous and Continuous Data and DNA (copy)

Discontinuous Variation

Discontinuous- The data can only be a limited set of values. (Few options none in between) e.g. Blood groups, eye colour, hair colour, detached and attached ear lobe, shoe sizes, abilty to roll your toungue. You use a bar graph for discontinuous variation.

Continuous Variation

The data can be any value in a range e.g. foot length, arm spam, wing span, temperature, age and length of leaf. You would use a Histogram (bar graph without gaps) for continuous data.

Normal Distrubution

When you plot continuous data about the population or any group on a graph, it forms a bell shaped curve which is normal distribution.

DNA

DNA stands for Deoxyribonucleic Acid.

It’s found in the nucleus(controls cell activities) of cells.

DNA is found in structures called chromosomes inside the nuclei of cells, each chromosome contains one long DNA molecule. DNA stores genetic information which is responsible for inherited characteristics.

Chromosomes

They are made up of TIGHTLY coiled DNA and contains genetic information and  is found in the nucleus of the cell

23 pairs= 46 chromosomes. Each pair will contain the same genes and are the same size.

The 23rd pair of chromosomes

The 23rd pair of chromosomes determine your sex which is why it is call the sex chromosomes. All pairs have the same gene and same size but for the 23rd chromosome if it is a male then it will not be the same size and will not have the same genes, since the Y chromosome will be much smaller than the X chromosome because it underwent gene loss

XX is Female XY is Male

Which cells do not have 23 pairs of chromosomes?

Red Blood Cells do not have a nucleus so that they can carry more oxygen, and hemoglobin which bonds with the oxygen, they do not have any chromosomes.

Male and Female gamete has 23 chromosomes NOT 23 pairs because they form a zygote which must have 46 chromosomes and 23 pairs.

Genes

A section of DNA is called gene, it stores genetic information. (This is the instructions for inherited characteristics stored inside the nuclei of cells).

People to do with DNA

James Watson and Francis Crick: Used data from themeselves and other scientists to build the first model of DNA in 1953

Rosalind Franklin and Maurice Wilkins: Took x-ray images of DNA and showed it was a spiral structure.