Introduction to DNA

Question:

• From your on-line computer activity, what do you know about the structure of DNA?

Structure of DNA

• DNA is a polymer of what????

Nuclotides!

There are two types of bases:

Adenine & Guanine ( A & G ) =

Thymine & Cytosine( T & C) =

There are two types of bases:

Intro to DNA• Chromosomes exist

in “matching pairs” in the nucleus of a cell

• Scientists call the matching pairs “homologous pairs”.

• In every human body cell, there are 23 homologous pairs of chromosomes.

Example of a human Karyotype

IN HUMANS

Pair # 1- 22 = “autosomes”

Pair #23 = “Sex chromosomes”* XX =

* XY =

Karyotype

• What does the prefix “homo” mean?

• How are homologs similar?#1#2#3#4

Karyotype

Q: How are homologs different????

• GENE –

A:

IMPORTANT !!• All 46 chromosomes

are present in every human body cell!!! Therefore

• All 30,000 genes pairs which make up a human are in every human body cell!

IMPORTANT !!• Genome –

• *** Every body cell of an organism contains its entire genome !!!! *****