DNA

DNADeoxyribonucleic Acid

WHAT IS DNA

DNA is a molecule that determines the traits a person inherits. DNA is described as containing a code. The codes are the rules that are used to carry

information.

WHAT DOES DNA LOOK LIKE?

DNA is the shape of a twisted ladder called a double helix. The double helix model was

introduced by Watson and Click.

The backbone is made of

sugars and phosphate groups.

WHAT IS DNA MADE UP OF?

Dna is made up of Nucleotides. A base, sugar, and phosphate

group make up a nucleotide. There are 4 bases

(A) adenine (T) thmine (C) cytosine (G) guanine

A’s match with T’s and G’s with C’s

WHITE BOARD PRACTICE

Make the matching sequence on the white boards. Do not waste my materials by playing around with the markers.

A T G G T C T A C C A G

G G A C T G A C T C C T G A C T G A

REPLICATION AND MUTATION

Cells make copies of DNA molecules through a process known as replication.

During replication the two strands of DNA separate two form two new strands of DNA molecules. When the strands are separated, nucleotides

attach to the existing strands to form a new DNA

strand.

MUTATIONS DNA is replicated all the time. It is only expected that

there be errors every now and then. These errors are called mutations. There are three types

of mutations Insertion – when a extra base is added to the strand Deletion – when a base is left out Substitution – when a base replaces another type of base.

Mutations can occur by physical or chemical agents called mutagens. Examples can be UV light and cigarette smoke.

DNA AND RNA BUILDING PROTEINS To build proteins, DNA copies instructions or code to a

molecule called RNA (ribonucleic acid). RNA has the same sugar and phosphate backbone, but

one of the bases change. Instead of having (T) thymine, RNA as (U) Uracil.

The sequencing is the same as DNA but everywhere you would see a T you would now have a U.

A G C C A U G U C G G U A C

TRANSCRIPTION AND TRANSLATION Transcription – when the information in DNA is copied to

messenger RNA Only indivdual genes are transcribed not the whole DNA

molecule. Three step process

DNA opens up where the gene is located RNA bases match up to the complementary bases on the

DNA template Once transcription is complete, mRNA is released and the

DNA closes.

TRANSLATION

Translation is the process of of making proteins from RNA Once mRNA is made is goes through an organelle called a

ribosome. As mRNA passes through ribosomes, which is made up of

rRNA (ribosomal RNA), tRNA (transfer RNA) molecules deliver amino acids to the ribosome. The amino acids join the RNA to form a protein. Amino acids are three bases and its sugar and phosphate

groups. ATC GCC TAG CCA - This strand if connected would have 4

amino acids.

CODING

White boards

Write the matching sequence. ATGAATCG TACTTAGC How many amino acids are in the following strand TGCAACGATCGTAGCTTGACG 7

DNA STRAND MUTATION

GENES TRANCRIPTION RIBOSOME

NUCLEOTIDE

RNA NUCLEUS ORGANELLE

SUGAR THYMINE TRANSLATION

DOUBLE HELIX