3.2 Describe the basic process of DNA replication and how it relates to the transmission and conservation of the genetic code. Explain the basic processes of transcription and translation, and how they result in the expression of genes. Distinguish among the end products of replication, transcription, and translation.
Vocabulary
Tier 3
Replication - copying the DNA
RNA - the other nucleic acid
mRNA - copies the DNA gene and brings the code to the ribosome
tRNA - carries an amino acid to the ribosome
Transcription - process in the nucleus of getting the code from the DNA to the RNA
Translation - process in the cytoplasm where ribosomes make protein using tRNA amino acids
Codon - Three base pairs
Amino Acid - link together during translation to make a protein
Protein - large molecule made from the DNA code by the ribosome
Essential Questions
1. What are the similarities and differences between the nucleic acids DNA and RNA?
2. How does transcription work?
3. How does translation make a protein?
Replication
During S phase in the cell cycle, the DNA copies itself. Enzymes unzip then open the DNA molecule while other enzymes make copies of the left and right strands until the whole chromosome is copied.
What does DNA actually do?
DNA tells the ribosomes what proteins to make!!
The only problem is, DNA cannot leave the nucleus and get the message to the ribosome...soooo....
The DNA sends a messenger, messenger RNA or mRNA.
Summary of what DNA does...
DNA puts the gene on a mRNA molecule. The mRNA goes to the ribosome where a protein is made one amino acid at a time.
Transcription
The mRNA is copied from the DNA template in a process called TRANSCRIPTION.
The mRNA leaves the nucleus and goes to the ribosome where the message is translated and converted into a protein one amino acid at a time. This is called TRANSLATION DNA strand opens up with the help of an enzyme. The enzyme RNA polymerase makes a new mRNA strand from the DNA gene that it wants to copy. The RNA is the red strand above
RNA has has two major differences: 1. It is only a single strand and 2. It does not contain the base pair T, instead it uses the base pair U.
The mRNA leaves the nucleus and goes to the ribosome where the message is translated and converted into a protein one amino acid at a time. This is called TRANSLATION DNA strand opens up with the help of an enzyme. The enzyme RNA polymerase makes a new mRNA strand from the DNA gene that it wants to copy. The RNA is the red strand above
RNA has has two major differences: 1. It is only a single strand and 2. It does not contain the base pair T, instead it uses the base pair U.
RNA also has a different base pair called Uracil or U. It does not use T thymine.
So for RNA, A goes with U!!
Translation
The mRNA leaves the nucleus with the message and goes to a ribosome. At the ribosome it is met by another RNA called tRNA. The tRNA has three base pairs and fits together into the mRNA strand. Every three base pairs is called a Codon. The tRNA three base pairs is called the Anticodon. The codon and anticodon fit together like a puzzle.
Every tRNA brings 1 amino acid for the new protein. Thousands of tRNA's can be used to build a protein. The protein grows one amino acid at a time.
Every tRNA brings 1 amino acid for the new protein. Thousands of tRNA's can be used to build a protein. The protein grows one amino acid at a time.