dna structure and function. what is dna and why is this molecule important? a. dna –...
TRANSCRIPT
DNA Structure and Function
What is DNA and why is this molecule important?
A. DNA – Deoxyribonucleic Acid
B. Codes for our traits
Why is the structure of DNA important?
Structure must be able to be:
1.A “blueprint” for our traits
2.Easily copied
What does DNA look like?
What does DNA look like?
1953 – James Watson and Francis Crick discovered structure of DNA; later won Nobel Prize
What does DNA look like?
-“Twisted ladder” or “Spiral Staircase”
- Double helix
- 2 connected strands wrapped around each other
What is DNA made of?
A. Sugar “Deoxyribose”B. Phosphate
C. Base
Sugar + phosphate + base = 1 nucleotide
Four different nucleotides1. Deoxyribose2. Phosphate3. Base - Adenine
1. Deoxyribose2. Phosphate3. Base - Thymine
1. Deoxyribose2. Phosphate3. Base - Cytosine
1. Deoxyribose2. Phosphate3. Base - Guanine
DNA is shaped like a ladderRAILSRAILS
RUNGS
DNA is shaped like a ladder
Nucleotides are connected so:-Rails are alternating sugar - phosphate
-Bases are pointed to center
DNA is shaped like a ladder
DNA is made of:
-Two strands
-Strands connect at bases
Basepair rules
- Adenine always connects with Thymine
-Cytosine always connects with Guanine
Code of Life
- Order of bases spells out a code for your traits.
-Sequences of DNA which code for a trait are called “genes”.
-Change the order of the bases (mutation) and you may have a new trait.
DNA Structure Summary Video – click here
Fun DNA Facts
-DNA is 1/10th width of human hair, but DNA in each cell is 6 feet long (over 3 billion nucleotides)!
-If all DNA from one person were connected end to end, it would stretch from the Earth to the Sun – 4 times!
Fun DNA Facts-Every person’s DNA sequence is unique (forensics, paternity tests).
-BUT . . . sequence is 99.8% IDENTICAL to any other person!
-Humans and Bananas – 50% identical
-Humans and Mice – 85% identical
Fun DNA Facts-Why is the DNA sequence of every living thing have almost the same DNA sequence?
-All are made of cells
-Cell division
-Making nutrients
Fun DNA Facts-Only 2% of our DNA codes for genes. Rest is . . .
“junk DNA” that may come from viruses!
Review Animations
• DNA structure review
• Base pair review
• DNA structure review #2