25/11/2020
Protein Synthesis (Higher only)
1. What part of a DNA strand contains the instructions for a
protein?
2. What are the letters of the bases that form the DNA code?
3. How do these bases pair up in DNA?
4. Apart from bases, what other parts are needed in a DNA
molecule?
5. What is one phosphate group, one sugar and one base
called?
6. Why is DNA a polymer?
7. Why are proteins polymers?
8. Give an example of a protein.
9. How is the active site of an enzyme formed?
25/11/2020
Answers
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What part of a DNA strand contains the instructions for a protein? (gene)
What are the letters of the bases that form the DNA code? (A, C, T and G)
How do these bases pair up in DNA? (A with T, C with G)
Apart from bases, what other parts are needed in a DNA molecule?
(phosphate group, sugar)
What is one phosphate group, one sugar and one base called?
(nucleotide)
Why is DNA a polymer? (It is made of many nucleotides joined in a
chain.)
Why are proteins polymers? (They are made of many amino acids joined
in a chain.)
Give an example of a protein. (any example, e.g. an enzyme)
How is the active site of an enzyme formed? (by folding of
protein/polypeptide/amino acid chains)
L/O
Recall where proteins are made.
Describe how the shape of a protein is
determined.
Explain how the order of amino acids in a protein
is determined.
Describe what happens during the transcription
stage of protein synthesis.
Describe what happens during the translation
stage of protein synthesis.
Compare and Contrast
• What similarities and differences do you
notice? Why do you think those similarities
and differences are there?
DNA
mRNA
tRNA
Suggested Answers
• DNA is double stranded and mRNA and tRNA
are both single stranded
• The bases in DNA are ATCG but in RNA are
AUCG
• RNAs are shorter than DNA
• tRNA has an anticodon binding site
Protein Synthesis
There are two stages to building a protein.
1. Transcription, which is copying the code for the
protein from DNA
2. Translation, which is making the protein, using the
copy from DNA (mRNA)
Transcription
1. RNA polymerase attaches to a
non-coding region on the DNA
molecule.
2. The enzyme separates the two
DNA strands.
3. The enzyme then moves along
the template strand adding
complementary RNA
nucleotides.
4. They contain the same bases as
DNA except Uracil (U) which
replaces Thymine (T)
5. The nucleotides link to form a
strand of mRNA
Quick Check
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Where does transcription take place?
What is meant by non coding region?
Which enzyme is used to build a mRNA?
What base is found in RNA, but is not found in
DNA?
Translation
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The mRNA travels out of the nucleus
through the nuclear pores (small
holes in the nuclear membrane).
It then enters the cytoplasm and
attaches to a ribosome.
A ribosome moves along the mRNA,
three bases at a time. (Each triplet
base is called a codon).
At each codon, a molecule of transfer
RNA (tRNA), lines up with
complementary bases.
Each tRNA carries a specific amino
acid.
As the ribosome moves along it joins
the amino acids from the tRNA
molecules together, form a
polypeptide chain.
Summary
• In table groups complete the sort card
Answers
Task
Need help?
Complete the protein synthesis
cut and stick activity. Add in the
extra keywords used during this
lesson. E.g DNA polymerase
Confident?
Complete sb3d.3 Start with the
harder section if you are very
confident or with strengthen if you
want more consolidation. Answer
E1 in the textbook (pages 58-59)
Answers
Words in order: Double, helix, mRNA, Transcription, mRNA,
nucleus, mRNA ribosome, mRNA, tRNA, Translation, Amino
acids, tRNA, amino acids, polypeptide, polypeptide, protein
Answers
Bingo
• Pick six words from the list below:
Codon, nuclear pore, RNA polymerase, DNA,
tRNA, mRNA, Transcription, Translation, genetic
code, polypeptide, protein, ribosome, template
uracil, hydrogen bonds, amino acids