Introduction to DNA and RNABiology Standards

B-4.1: Compare DNA and RNA in terms of structure, nucleotides, and base pairs.

B-4.2: Summarize the relationship among DNA, genes, and chromosomes.

Nucleic AcidsRemember, there are 4 major Organic Compounds1. Carbohydrates

2. Lipids

3. Proteins

4. Nucleic Acids

Nucleic Acids Nucleic acids are organic molecules that serve as the blueprint for proteinsThese proteins give organisms their unique traitsExample: hair color, eye color, blood type,

height, digestive enzymes, skin color, etc.

2 types of Nucleic AcidsThere are two types of nucleic acidsDNA = Deoxyribonucleic acidRNA = Ribonucleic acid

Both DNA and RNA are composed of small units called nucleotides

Nucleotides have 3 parts:1. Nitrogenous Base

2. Pentose Sugar

3. Phosphate Group

All about DNADNA is a double Helix

Double = 2 strandsHelix = twisted/winded

DNA has 3 parts1. Nitrogenous bases Adenine Thymine Guanine Cytosine

2. Sugar Deoxyribose

3. Phosphate Group

All about RNARNA is a single helix

Single = 1 strandHelix = twisted/winded

RNA has 3 parts1. Nitrogenous bases Adenine Uracil Guanine Cytosine

2. Sugar Ribose

3. Phosphate group

Let’s Compare DNA and RNADNA RNA

Type of base Cytosine (C)Adenine (A)Guanine (G)Thymine (T)

Cytosine (C)Adenine (A)Guanine (G)

Uracil (U)

Type of sugar Deoxyribose Ribose

Molecule structure/shape

Double Helix Single Helix

Complimentary Base Pairing in DNAWhen the nitrogenous bases of two strands of

DNA chemically bond through the center of the helix, each base can bond to only one type of base

Bases that bond are called complementary bases Adenine (A) will only pair with Thymine (T) Guanine (G) will only pair with Cytosine (C)

When the nitrogenous bases of RNA chemically bond to a strand of DNA, each RNA base can bond with only one type of DNA base. These bases are also called complementary bases Adenine (A) will only pair with Uracil (U) Guanine (G) will only pair with Cytosine (C) **essentially, uracil replaces thymine in RNA**

Try This…Write the complementary strand of DNA for the following 2 sequences of DNA:1. A T G C A T G C T T A G T C C A

2. G C A T G G A A T C A C A G T T

Write the complementary strand of RNA for the following 2 sequences of DNA:1. A T G C A T G C T T A G T C C A

2. G C A T G G A A T C A C A G T T

Chromosomes to Genes

What do these terms mean?Chromosome – structure in the nucleus consisting of one long, tightly coiled thread of DNA

DNA – composed of nucleotides, provides the blueprint for protein synthesis by the specific arrangement of nitrogenous bases

Gene – a specific location on a chromosome, consisting of a segment of DNA, that codes for a particular protein. These determine the characteristics of an organism.Each chromosome consists of hundreds of genes

determining the many proteins for an individual organism