DNA & RNA Structure

Beth Walker

What is DNA and why is DNAimportant?

A. DNA is able to determine an organism’s traits by determining the structure of an organism’s proteins

B. DNA makes up segments of information called genes. Many genes make up one chromosome. There are multiple chromosomes found in the nucleus of every cell.

C. Where is DNA found in a eukaryotic cell? Nucleus

D. DNA is the recipe for all living things (code of life).

Structure of DNAA. Made up of many nucleotides linked

together:

1. Nucleotide is composed of:

a. One deoxyribose sugarb. One phosphate groupc. One nitrogenous base

i. Purine: adenine & guanineii. Pyrimidine: thymine, cytosine

Picture of DNA

Shape of DNA• Twisted ladder or double-helix

DNA Continued….

1. Double-stranded (made up of two strands)a. Nitrogen bases are held together

by hydrogen bonds (weak bond) in the middle of the molecule

b. Deoxyribose sugars and phosphates make up the sides of the ladder/molecule

c. Antiparallel run in opposite directions2. Helix twisted or coiled

DNA - Antiparallel

Who discovered the structure of DNA?

1. James Watson American biochemist2. Francis Crick British physicist3. Rosalind Franklin X-Ray

crystallographer4. Occurred in 1953, Watson & Crick were

awarded the Nobel Prize for their work!!!

Structure of RNAA. Made up of many nucleotides linked

together

B. Three main structural differences from DNA:1. Sugar is ribose2. Single-stranded3. Replace thymine with uracil

RNA vs. DNA Structure

RNA Structure Continued…D. May leave the nucleus, unlike DNAE. Three types of RNA:

1. ribosomal RNA (rRNA) makes up the ribosome

2. transfer RNA (tRNA) brings amino acids to the ribosome to make a protein

3. messenger RNA (mRNA) carries DNA message out of the nucleus and to the ribosome

DNA vs. RNA Chart• Take a few minutes to complete the chart

by looking back over your notes for the answers.

• Chart with Answers