HBS Lesson 1.3

Question 1

What is the structure and function of DNA?

Answer 1

•DNA - Deoxyribose Nucleic Acid
• Shape of a Double Helix - Two strands that are twisted
• Made of nucleotides - Repeating units of DNA
• Sugar Phosphate Backbone
• Nitrogenous bases
-Purines
*2 rings
* Adenine & Guanine
-Pyrimidines
*1 ring
*Cytosine & Thymine
- Base Pairing
*A pairs with T & has 2 hydrogen bonds
*G pairs with C & has 3 hydrogen bonds

Question 2

How does DNA differ from person to person ?

Answer 2

There is only a 0.1% difference and it is due to the sequence of bases

Question 3

How can tools of molecular biology be used to compare the DNA of two individuals?

What are restriction endoucleases?

What are restriction fragment length polymorphisms?

Answer 3

• Restriction endonucleases (enzymes) are used to cut the DNA into different sized fragments (RFLP’s) that are determined by the sequence
• The DNA is run on a gel to separate the fragments & determines the length
• The fragments lengths can be compared by viewing the bands on the gel

Question 4

RFLP’s

Restriction Fragment Length Polymorphism

Answer 4

• The bits of DNA after the long strand has been cut by the restriction enzymes
• They are what we see in the electrophoresis gel

Question 5

What is gel electrophoresis & how can the results of this technique be interpreted?

Answer 5

• DNA runs through the a gel, propelled by an electric current
• The DNA moves towards the positive charge since the molecule is negatively charged
• The smaller fragments move farther through the gel than the larger fragments
• The DNA shows up as bands on the gel

Question 6

How can the field of biometrics be used to verify & protect identity?

Answer 6

• Iris scan
• Voice analysis
• Fingerprinting
• Gait measurement
• Facial recognition