Molecular Biology Unit Review Guide
IB Biology
DNA Structure
1. Draw and label a model of the structure of DNA (helix unwound). Include the following terms
in your labeling and write a brief description of the function/definition of each: nucleotide,
deoxyribose sugar, phosphate, nitrogenous base, hydrogen bonds, covalent bonds
(phosphodiester in this case), 3’ end, 5’ end, antiparallel strands, adenine, guanine, cytosine,
thymine, complimentary base pairs, purines, and pyrimidines.
2. What is the structure and function of a nucleosome? (use the article online)
3. What is in a human’s genome, besides unique DNA codes called genes? Why?
4. What are introns and exons?
DNA Replication
5. DNA is said to be replicated semi-conservatively. What does that mean? And how is
complimentary base pairing involved?
6. Label the following 2 diagrams with these terms (briefly mention the function/definition of
each): DNA polymerase III, RNA primase, Ligase, DNA polymerase I, replication bubble,
replication fork, leading strand, lagging strand, Okazaki fragments, 5’ end, 3’ end, template
strand, and new strand
7. What are deoxynucleoside triphosphates, and why are they important to replication?
8. How is the process of DNA replication made more efficient or faster?
Protein Synthesis
9. Describe 3 differences between DNA and RNA.
10. How does the information in a gene produce a protein (a brief synopsis)?
Transcription:
11. Name the 3 stages of transcription and briefly describe the details that occur during each of
them:
1)
2)
3)
12. Label the diagrams below with the following terms (briefly explain the function/definition of
each): RNA primase, transcription factor proteins, promoter, coding region, sense strand, antisense strand, mRNA, 5’ end (of each), 3’ end (of each), nucleoside triphosphate,
complimentary base pairing, and uracil.
(later)
13. Describe what is happening at each of the 2 points with arrows in the diagram below:
14. What modifications must the mRNA undergo after transcription, but prior to translation? Why?
Translation:
14. What is a protein made of? Where are proteins made (free vs. bound)?
15. What is the role of tRNA in translation? And how does it come to be attached to an amino
acid?
16. Draw a ribosome in the space below and label the following: small ribosomal subunit, large
ribosomal subunit, mRNA binding site, and tRNA binding sites (E, P, and A). What is your
ribosome made of (2 parts)?
17. Name the 3 stages of translation and briefly describe what takes place during each:
1)
2)
3)
18. Label the diagrams below with the following terms (briefly giving the function/definition of
each): small ribosomal subunit, large ribosomal subunit, amino acids, peptide bond, tRNA,
mRNA, 5’ end (mRNA), 3’ end (mRNA), codons, start codon, stop codon, anti-codons,
polypeptide, and release factor.
(Later)
19. Draw a diagram in the space below of two amino acids being connected by a peptide bond,
include the important elemental symbols and structures where the bond is made and any
elements or molecules that are added or subtracted from the final product. What is this reaction
called?
20. What is meant by the term polysome? How do these contribute to the efficiency of translation?
21. What is the difference between proteins made on free ribosomes and those made on bound
ribosomes?
22. What must happen to a polypeptide before a complete protein is synthesized?
23. How do mutations happen, name a few types, and why do they cause ineffective proteins?
24. What things can affect gene expression (should have a few)? How (briefly) does each work?