CSI Lesson Six (15/8/2011)

Evidence---possible location of DNA on the Evidence:
baseball bat or similar weapon--- handle, end ---sweat, skin, blood(NOTE: ONLY IN WBC-presence of nucleus), tissue

eyeglasses ---nose or ear pieces, lens ---sweat, skin

facial tissue, cotton swabs ---surface area ---skin cells

used cigarette ---cigarette butt ---saliva

stamp or envelope ---licked area ---saliva

blanket, pillow, sheet---surface area ---sweat, hair, urine(CELLS, DNA, SUGAR CONTENT-probably diabetic, chemicals can be found e.g. steroid), saliva

fingernail, partial fingernail---scrapings--- blood, sweat, tissue

WHERE ARE DNA SOURCES?
NUCLEUS IN CELLS.
***red blood cells do not have nuclei.

From Cells to Chromosomes to DNA & Traits
Each cell in our body contains a lot of DNA. In fact, if you pulled the DNA from a single human cell and stretched it out, it would be 3m long!
That’s about as long as a car!
How does all of DNA fit into a cell? The DNA is packaged into compact units called “chromosomes.”

How many chromosomes are there in each of our cell?
23 pairs.

What is DNA?
A nucleic acid that carries the genetic information in the cell and is capable of self-replication and synthesis of RNA. DNA consists of two long chains of nucleotides twisted into a double helix and joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine. The sequence of nucleotides determines individual hereditary characteristics.

What is a gene?
A hereditary unit consisting of a sequence of DNA that occupies a specific location on a chromosome and determines a particular characteristic in an organism. Genes undergo mutation when their DNA sequence changes.

What is a chromosome?
A threadlike linear strand of DNA and associated proteins in the nucleus of eukaryotic cells that carries the genes and functions in the transmission of hereditary information.

What is hereditary?
Transmitted or capable of being transmitted genetically from parent to offspring

What is a gene?
A genetically determined characteristic or condition:

What is a trait?
A genetically determined characteristic or condition

DNA:
Where is DNA found in the human body?
Overview:
-From cells to chromosomes to DNa and traits
-Karotyping
-DNA extraction
-DNA fingerprinting

Understand Hereditary:
Our traits are the way we look, what we can do and sometimes what we are that we cannot see like blood type. Some of our traits can be changed whereas some cannot. Most traits that can’t be changed are inherited from our parents. These are called genetic traits. It is our genes, contained in our DNA, that determine the traits. Some traits can be changed, like hair colour, as they are determined by what we do and how we live, i.e. by our environment. However there are also traits that are affected by both our genetics and the environment, such as weight and height.