2. 3 types:  mRNA – used in transcription  tRNA – used in translation  rRNA – makes up ribosomes Composed of nucleotides  5 carbon sugar = ribose  phosphate group  nitrogen bases (no Thymine…uses Uracil) A,U,C,G RNA has a Single strand

4. The information that tells a cell which proteins to make is encoded in the DNA by the arrangement of nucleotides. DNA is in the nucleus. Proteins are made in the cytoplasm on ribosomes. Problem: The message on DNA has to be carried to the ribosomes.

5. Solution: The message from DNA is carried to the ribosomes using RNA. The process of copying the DNA message in the nucleus onto RNA to be carried to the ribosomes is called TRANSCRIPTION.

6. Copying the information on DNA to a strand of messenger RNA (mRNA)

7. Starts in the nucleus DNA opens One side of DNA is a template Makes a section of mRNA

8. 1) RNA polymerase unzips DNA double strand. 1) New RNA nucleotides are attached to one side of DNA. 2) mRNA is removed, DNA reforms, mRNA leaves the nucleus.

9. Base pair rule is still used but there is never any thymine in RNA so: (A-U & C-G). DNA can never leave the nucleus, so mRNA serves as the messenger to the ribosome RNA has one strand while DNA has 2. mRNA leaves the nucleus and travels to the ribosome to start Translation.

12. 1) Made of amino acids 2) There are only 20 amino acids to make up 100s of proteins 3) Proteins are a major component of cells 4) Proteins are made on ribosomes

13.  Amino acids are added to a protein based on 3- nucleotide sequences called codons.  Codons are “read” on the ribosome and the appropriate amino acid is added to the protein chain by tRNA.  Each tRNA molecule has an “anticodon” that matches with the nucleotide sequence on the mRNA strand.

14. …process of making protein from information carried by mRNA. …occurs on the ribosome

16. 1) mRNA travels to the ribosome. 3 bases on mRNA make a codon. 2) tRNA has anticodons. Each anticodon attaches to a complementary codon.

17. 3) A tRNA gets its amino acid in position then releases it. 4)The next codon is “read” in order and another tRNA brings the next amino acids. 5) A chain of amino acids forms.

18. A start codon begins the process. Once the amino acids are delivered the tRNA leaves and gathers more. A stop codon ends the process and the amino acid chain makes a protein.

20. …is based on the sequence of bases in DNA (sequence of triplets) …is universal. …some amino acids have more than one codon …there are stop & start codons