DNA Structure and Function Notes PDF

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DNA STRUCTURE AND FUNCTION NOTES Go to www.EDpuzzle.com or link through Google Classroom

deoxyribonucleic acid DNA stands for ______________________________ __________ Why is DNA important? It is pivotal to our 1.growth, reproduction, Molecule that and health. It contains the determines instructions necessary your for your cells to produce proteins that affect physical traits. in many different processes and functions your body. 2. Molecule of heredity. Unique for each person.

To understand how DNA stores information and why some DNA leads to genetic disorders, two strands that scientists needed to learn what it looks like. They had trouble believing that form a double hel structure, double the goop that you extracted earlier somehow determines your traits and is helix looks like a twisted ladder, inheritable. Although, DNA’s structure is too small to see with any "stairs" are pairs o microscope, what does DNA look like on a molecular level? nitrogenous bases and the sides of th Watson Crick In 1953, _____________________ and ________________________ ladder are made u of phosphate discovered the 3-D structure of DNA. What did people know prior to that groups and what did Watson and Crick figure out? DNA was made up of two chains of nucleotide pairs that encode the genetic information for all living things nucleotides DNA is made of __________________________. Nucleotides have 3 parts: A. Nitrogen base B. Phosphate group C. sugar group

DEOXYRIBOSE Part ofsugar, DNA phosphate backbone A. "bose"nitrogen basessugar A,T,C,G (pentose) B. 5-sided (one prime), identifying the carbon immediately to the 1’ – right of the oxygen (five prime)(three prime). The 5' and 3' 3’ and 5’ – refer to the number of carbon atom in a deoxyribose sugar molecule to which a phosphate group bonds. 2’ – Two prime

PHOSPHATE chargecharge to DNA A. Negative Give negative backbonetothe portion the DNA sugar to of make backbone B. Connect double helix that provides structural of DNA strand. support to the molecule. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups. C. Sugar-phosphate bonds are called “phosphodiester” bonds DNA consists of twoinstrands that wind around each other like a twisted ladder. Each strand has a D. Connect to sugar 5’ to 3’ direction backbone made of alternating sugar (deoxyribose) and phosphate groups.

NITROGENOUS BASE A. Four different bases Thymine 1. Adenine Adenine 2. Thymine Guanine 3. Cytosine 4. Cytosine Guanine

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B. Pyrimidines Pyrimidine is an aromatic heterocyclic organic compound similar to pyridine. One of the six-membered heterocyclics with two nitrogen atoms in the ring has the nitrogen atoms at positions 1 and 3 in the ring.

C. Purines Purines are organic compounds that are not necessarily harmful. natural for the body to contain some purines at all times. purines break down into a waste substance called uric acid.

of bases “spells out” traits. D. Order Codon Ex.

ATTACGACAT = blue eye gene ATTCCGACAT = brown eye gene

E. Only 1% of human base sequences code for anything. NUCLEOTIDE PLUS NUCLEOTIDE . . . A. DNA has 2 strands connected together B. A-T pair together

C-G pair together

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Together called a basepair (bp) C. Bases are connected using hydrogen bonds A-T = 2 H bonds C-G = 3 H bonds

D. Strands are connected in an antiparallel orientation

E. When strands are connected, they form a clockwise twist (also called B form).

F. Twisted so every 10 bp is one full turn NOTE: 1 Angstrom = 1.0 x 10-10 meters or 1 hundred-millionth of a centimeter Width of DNA is 20 angstroms or One tenth width of human hair G. Human DNA in each cell is 3 billion bp long (approximately 6 feet) H. In order to fit DNA in nucleus, DNA is folded around proteins called histones and arranged in packages called chromosomes

Histones

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