Genetics ( Dna-Chromosomes

GENETICS (DNA - CHROMOSOMES)
7/16/2013

DNA – Chromosomes - Genes

DNA
•DNA: the chemical inside the nucleus of a cell that carries the genetic instructions for making living organisms. •The material inside the nucleus of cells that carries genetic information. • The scientific name for DNA is deoxyribonucleic acid.

D.J.A

1

7/16/2013

http://www.ncbi.nlm.nih.gov/

Chromosomes
• A chromosome is one of the threadlike "packages" of genes and other DNA in the nucleus of a cell. • Different kinds of organisms have different numbers of chromosomes. • Humans have 23 pairs of chromosomes, 46 in all: 44 autosomes and two sex chromosomes. • Each parent contributes one chromosome to each pair, so children get half of their chromosomes from their mothers and half from their fathers.

D.J.A

2

7/16/2013

http://www.ncbi.nlm.nih.gov

Gene
• A gene is the functional and physical unit of heredity passed from parent to offspring. • Genes are pieces of DNA, and most genes contain the information for making a specific protein.

D.J.A

3

7/16/2013

http://www.ncbi.nlm.nih.gov

Genome
• A genome is all the DNA contained in an organism or a cell, which includes the chromosomes plus the DNA in mitochondria (and DNA in the chloroplasts of plant cells).

D.J.A

4

7/16/2013

http://www.ncbi.nlm.nih.gov

Genetic material of cells…
• GENES – units of genetic material that CODES FOR A SPECIFIC TRAIT • Called NUCLEIC ACIDS • DNA is made up of repeating molecules called NUCLEOTIDES

D.J.A

5

7/16/2013

DNA Nucleotide
Phosphate Group

O O=P-O O

5

CH2 O N C4 C1
Nitrogenous base (A, G, C, or T)

Sugar (deoxyribose)

C3

C2

A HISTORY OF DNA
SEE p. 292-293 • Discovery of the DNA double helix A. Frederick Griffith – Discovers that a factor in diseased bacteria can transform harmless bacteria into deadly bacteria (1928) B. Rosalind Franklin - X-ray photo of DNA. (1952) C. Watson and Crick - described the DNA