Protein Synthesis Notes: Transcription & Translation
I. Importance of Proteins & DNA
A. DNA carries the instructions for making all ______.
B. A portion of a DNA strand with instructions for making a protein is called a ______.
C. Proteins are made up of many ______or monomers called ______.
D. Proteins perform the following important functions:
1. ______, which speed up chemical reaction sin the body.
2. ______, which makes up our hair and nails.
3. ______, which makes up our skin.
4. ______, which transports O2 in our body
E. There are 20 different amino acids, such as______, ______, and ______, which are put in various arrangements to make proteins
II. How does transcription occur?
1. Location: ______& ______
2. DNA is once again split apart by an ______
3. Free-floating ______nucleotides attach to the exposed DNA
strand.
REMEMBER THERE IS NO THYMINE IN mRNA!!!!!
4. mRNA ______from DNA and we now have a ______-______of messenger RNA.
5. Three nucleotides on an mRNA strand are called a ______. By looking at a codon chart, we can determine the amino acid that mRNA strand will put together. (see the attached codon chart)
PRACTICE USING THE CODON CHART……look up the amino acid for each codon listed below.
UUG à UAC à
ACG à AAA à
***Notice that there are ______and ______codons that will tell where to begin and where to end the protein.
6. The start codon is_____, so the first amino acid in a protein will always be ______
7. The stop codons are ____, ____, and ____. The last amino acid in a protein will always be coded by a “stop” codon.
III. How does translation occur?
1. The amino acids coded for by the codons are ______
together to make a protein.
2. Location: ______
3. _____ travels out of the nucleus to a ______.
4. The ribosome looks for the ______codon.
5. All ______after that will attach to the______.
6. In the cytoplasm, _____, a clover-leaf shaped RNA, will attach to free floating ______and form ______(made up of tRNA).
7. Amino acids come from ______that we eat and they are broken down during digestion.
8. _____ pairs with _____ and brings the correct ______with it to the ribosome.
9. ______bonds are formed between the amino acids, and voila, a protein is formed!
mRNA Codon Chart
U / C / A / GU / UUU / Phe / UCU / Ser / UAU / Tyr / UGU / Cys / U
UUC / Phe / UCC / Ser / UAC / Tyr / UGC / Cys / C
UUA / Leu / UCA / Ser / UAA / Stop / UGA / Stop / A
UUG / Leu / UCG / Ser / UAG / Stop / UGG / Trp / G
C / CUU / Leu / CCU / Pro / CAU / His / CGU / Arg / U
CUC / Leu / CCC / Pro / CAC / His / CGC / Arg / C
CUA / Leu / CCA / Pro / CAA / Gln / CGA / Arg / A
CUG / Leu / CCG / Pro / CAG / Gln / CGG / Arg / G
A / AUU / Ile / ACU / Thr / AAU / Asn / AGU / Ser / U
AUC / Ile / ACC / Thr / AAC / Asn / AGC / Ser / C
AUA / Ile / ACA / Thr / AAA / Lys / AGA / Arg / A
AUG / Met / ACG / Thr / AAG / Lys / ACG / Arg / G
G / GUU / Val / GCU / Ala / GAU / Asp / GGU / Gly / U
GUC / Val / GCC / Ala / GAC / Asp / GGC / Gly / C
GUA / Val / GCA / Ala / GAA / Glu / GGA / Gly / A
GUG / Val / GCG / Ala / GAG / Glu / GGG / Gly / G