CHAPTER 9 & 10 CHAPTER 9 & 10 NOTES PART 2NOTES PART 2

DNA DNA PROCESSESPROCESSES

I. REPLICATIONI. REPLICATION

The DNA molecule can build an The DNA molecule can build an exact exact copycopy of itself. of itself.

DNA separates into DNA separates into twotwo strandsstrands exposing the bases. The exposed exposing the bases. The exposed bases combine with free nucleotides. bases combine with free nucleotides. This process is repeated until This process is repeated until twotwo wholewhole DNA molecules are formed. DNA molecules are formed.

WebsiteWebsite

This is a website showing the This is a website showing the process of replication.process of replication.

http://http://www.dnai.org/a/index.html

II. TRANSCRIPTIONII. TRANSCRIPTION

The information contained in the DNA The information contained in the DNA must be delivered to the must be delivered to the ribosomesribosomes where where proteins are synthesized (made).proteins are synthesized (made).

The information on one strand of DNA is The information on one strand of DNA is copied almost exactly in a process called copied almost exactly in a process called transcriptiontranscription..

This near copy of DNA is called This near copy of DNA is called ribonucleic acidribonucleic acid – RNA. – RNA.

When When nitrogen bases nitrogen bases do not copy do not copy correctly, a correctly, a mutationmutation happens. happens.

What is RNA?What is RNA?

RNA differs from DNA in 3 ways:RNA differs from DNA in 3 ways: 1. The sugar in RNA is called 1. The sugar in RNA is called riboseribose.. 2. In RNA, the base 2. In RNA, the base uraciluracil replaces replaces

thymine.thymine. 3. RNA is a 3. RNA is a singlesingle strand. strand.

What are the types of What are the types of RNA?RNA?

There are 3 types of RNA:There are 3 types of RNA: 1. mRNA (messenger RNA) – acts as a 1. mRNA (messenger RNA) – acts as a

pattern for the order of amino acids in pattern for the order of amino acids in the protein.the protein.

2. tRNA (transfer RNA) – carries amino 2. tRNA (transfer RNA) – carries amino acids in the cytoplasm to the ribosomes.acids in the cytoplasm to the ribosomes.

3. rRNA (ribosomal RNA) – found in the 3. rRNA (ribosomal RNA) – found in the ribosomes. ribosomes.

WebsiteWebsite

This is a website showing the is a website showing the process of transcription.process of transcription.

III. TRANSLATIONIII. TRANSLATION

The bases on the mRNA act as a code for The bases on the mRNA act as a code for each each aminoamino acidacid. Groups of 3 bases, . Groups of 3 bases, called called codonscodons, act as a specific code for , act as a specific code for each amino acid.each amino acid.

The The ribosomesribosomes move along the mRNA move along the mRNA reading the codons. The reading the codons. The tRNAtRNA picks up picks up the correct amino acid and brings it to the correct amino acid and brings it to the the mRNAmRNA..

A chain of amino acids builds up a A chain of amino acids builds up a proteinprotein..

WebsiteWebsite

This is a website showing the is a website showing the process of translation.process of translation.