- DNA is the moecule of heredity. It is what is inherited from cell to cell, parent organism to offspring. DNA moleculesare very long; thay are polymers of nucleotide monomers. Nucleotides are made up of three parts: a nitrogenous base,a five carbon sugar called a pentose, and a phosphate group.
-There are two types of nitrogenous bases, purines, and pyrimidines. The purines are adenine(A), and guanine(G) and the pyrimidines are cytosine(C), Thymine(T), Uracil(U).
-Thymine is found ONLY in DNA, and uracil is found ONLY in RNA. In DNA, adenine always pairs with thymine, and cytosine always pairs with guanine.
*All Girls are Pure (A & G are Purines)*
*Hook-ups: A & T, C & G*
-4 groups of Amino Acids:
- Polar- they can dissolve in water (-OH, O, SH)
- Nonpolar- they do not dissociate (HC)
- Basic- Amine group with + charge
-In DNA,, the pentose sugar is deoxyribose, and in RNA, the pentose sugar is ribose. Deoxyribose has one less oxygen than ribose.
-In DNA and RNA, the nucleotides are joined by phosphodiester bonds. In DNA, two polynucleotide chains wrap around each other. In a helical shape, whereas RNA is a single polynucleotide.
-Size of the carbon skeleton varies from 3 to 7 carbons.
- Trimose= 3
1. Each chromosome contains one long DNA molecule that usually carries how many genes?
A) One hundred
B) One Thousand
2. When a cell reproduces itself by dividing, its DNA molecules are:
A)attached on to others
B) Copied & passed along
C)newly rebuilt into something different
3. What carries protein-coding instructions from DNA to protein-synthesizing machinery?
B) RNAC) Both
*Answers: 1. c, 2. b, 3. b