Nucleic Acids: DNA and RNA

Nucleic Acids: DNA and RNA

Nucleic Acids

DNA (polymer) RNA (polymer)

Monomers: Nucleotides Monomers: Nucleotides

Sugar(Deoxyribose), Phosphate, Base Sugar(Ribose), Phosphate, Base

Adenine (A), Cytosine (C), Guanine (G), Thymine (T) Adenine (A), Cytosine (C), Guanine (G), Uracil (U)

DNA (Deoxyribonucleic Acid)

Structure

-composed of monomers called nucleotides

-each nucleotide consists of:

a) Phosphate Group

b) Sugar

c) Nitrogen-containing Base

This picture shows an UNTWISTED DNA molecule made up of chains of nucleotides.

The circle shows ONE NUCLEOTIDE.

-DNA Molecules are double stranded. The bases in the middle join the two strands to each other.

-DNA molecules are twisted up to form a structure called a DOUBLE HELIX.

If you are given one DNA strand, you can find out what the other strand (the rest of molecule) will look like. This is because the bases follow Base-Pairing Rules:

-the four bases in DNA are letters A (Adenine), T (Thymine), C (Cytosine) and G (Guanine)

A always bonds to T and vice versa.

G always bonds to C and vice versa.

IF THE LEFT HAND STRAND OF DNA HAD THE FOLLOWING ORDER OF BASES, WHAT WOULD THE RIGHT HAND SIDE ORDER OF BASES LOOK LIKE?

Left-Hand Backbone↓ / Left Hand Base↓ / Right Hand Base↓ / Right Hand Backbone↓
Sugar / Adenine / Sugar
Phosphate / Phosphate
Sugar / Thymine / Sugar
Phosphate / Phosphate
Sugar / Guanine / Sugar
Phosphate / Phosphate
Sugar / Cytosine / Sugar

Functions of DNA

1-DNA contains genetic (hereditary) information that is passed from one generation to the next (our genes are made out of DNA!)

2-DNA stores the information for making proteins. The order of nucleotides in DNA forms a code that ultimately specifies the order of amino acids in a particular protein.

3-The set of instructions in DNA that codes for an entire complete protein is called a gene

Results from the Human Genome Project, a research study that has determined the number and sequence of nucleotides in all 46 chromosomes of a human, have shown that there are more than 3 billion base pairs, and between 30 000 and 35 000 genes in the human genome.

RNA (Ribonucleic Acid)

Structure:

-also composed of nucleotides: Sugar (ribose), Phosphate and Bases

-4 bases are Adenine (A), Guanine (G), Cytosine (C) and Uracil (U) (* no Thymine!)

-only consist of a SINGLE strand, not a double strand

Functions:

-RNA molecules perform many important functions in a cell.

-RNA molecules called messenger RNA (mRNA) takes the genetic information in DNA out of the nucleus to ribosomes in the cytoplasm where proteins are produced.

-RNA molecules also form part of the structure of ribosomes.

Think of the RNA as being the messenger that delivers the information from DNA about how to make proteins!

DNA (order of bases= order of amino acids)

-contains instructions

RNA (delivers DNA message)

Ribosomes (reads messages)

-makes polypeptide chains (proteins)

Building DNA class activity

Pg 35 #9, 10, 11, 12

Summary of Important Biological Molecules: