DNA Replication and Protein Synthesis – Online Activity
An embryonic cell divides again and again. Where there was one cell there are two, then four, then eight,...
Each holds all the genetic information needed to create a human being. How, exactly, do these cells make
copies of themselves? Hair grows from your head, nonstop, day in and day out. The cells of your hair
follicles somehow generate all of the protein that make up this hair. How is this protein created?
The answers to these questions are DNA replication and protein synthesis.
Knowledge of the structure of DNA began with the discovery of nucleic acids in 1869. That genes control
the synthesis of enzymes was understood in the 1940s. In 1953, an accurate model of the DNA molecule
was presented, thanks to the work of Rosalind Franklin, James Watson, and Francis Crick.
The activity in this section places you within the cell, involving you with the processes of DNA replication
and protein synthesis.
1. DNA, the molecule that holds ________________ ___________________, makes
an exact copy of itself whenever a cell _______________.
2. Click on DNA Replication then answer the following. Where in the cell does DNA
replication occur? ___________________________________________
3. Click on unzip. In a real cell the molecule _________________ from spools made of
protein, then ______________.
4. The DNA now resembles a ______________________. Enzymes, special types of
proteins, move up the ladder, breaking the ___________.
5. Match bases to make two new DNA strands. When you are done, draw your DNA
6. Each human chromosome contains _____________ of base pairs. All _______
human chromosomes contain _____ _____________ __________.
7. Click Protein Synthesis. ___________ controls the manufacture of proteins within a
cell through a process called ________________ ___________________.
8. Click unzip. Click ok. Transcription: Match ________ and _________ bases to
make __________ strand.
9. How are the RNA bases different from the DNA bases? _______________________
10. Draw the mRNA strand you’ve just transcribed below.
11. In a real cell, the RNA molecule would be anywhere from _______ to ___________
12. An RNA molecule transcribed from a DNA molecule is called _________________,
or ___________ for short.
13. The mRNA now moves away from the DNA and leaves the cell’s nucleus. Outside
the nucleus _____________ attach themselves to the ______________.
14. Click ok Where in the cell does Translation occur? ______________________.
15. Match the tRNA anticodon to mRNA codon. A _______________ attached itself
to the mRNA. Ribosomes are the cell’s structures for constructing ________________.
16. The mRNA bases are grouped into sets of __________, or ___________. Each
codon has a complimentary set of bases called an ________________. These are part of
tRNA (transfer RNA) molecules.
17. Attached to each tRNA molecule is an __________ __________. Click ok.
18. The protein under construction is now 3 amino acids long. The chain will continue
to grow until it is ________ to _____________ amino acids long.
19. Protein synthesis will end when a special _________ ___________ is reached.
20. The_______________ will then _____________ the polypeptide chain.