Name: _________________________________________ Date: _________________ Period: _________________
C 5.1: DNA and RNA
What is DNA?
1. _______ is a molecule that stores information – that’s all it does.
Proteins vs. Amino Acids
2. DNA stores information, but most of the work of the cell is done by ___________
3. ________________ different amino acids come together in different combinations to
make the _________________________ of proteins found in the human body.
4. DNA is a “____________” that tells a cell how to make different
______________________
DNA and the Genetic Code
5. The DNA molecule takes the _________________ of a double-stranded spiral, which, as
you can see in the diagram, looks something like a ______________ ladder. There are
_________ strands stuck together to make the “ladder.”
6. Nucleotide subunits make up each of the two strands of the DNA __________________.
7. There are ________ different nucleotides in DNA, identified by their bases: adenine (A),
thymine (T), cytosine (C), and guanine (G).
8. Because of differences in size and shape, _________________ always pairs with
_____________ (A-T), and ______________ always pairs with __________________ (C-G)
DNA Codes for Proteins
9. The sequence of ________________ in a strand of DNA is the code for making
______________________.
10. The genetic code is a ______________ code. Each sequence of 3 ____________ codes for
___________________ specific amino acid.
a. Ex: T-C-T codes for the amino acid ___________________________.
What is a gene?
11. A gene is the entire _________________________ of bases that codes for all of the
____________________________________ in a protein.
Replication
12. When a cell divides into two cells, each __________________________ cell receives an
____________________________ copy of the DNA.
13. Before a cell divides, all of its DNA is copied, a process called _____________________
14. First, the two strands of DNA ________________, almost like two threads in a string being
unwound.
15. New _________________________ pair up with nucleotides on the DNA strand through
complementary base pairing. A pairs with _______ and G pairs with ____.
16. When replication is _________________, there are ________ identical DNA molecules.
17. Each one has one strand of the ________ DNA and one strand of the ________ DNA.
What is RNA?
18. _____________________________ stands for ribonucleic acid.
19. RNA is a “middle step” between __________________ and ____________________
20. Similar to DNA: formed by _______ of the same ______________ as DNA – G, C, and A.
21. Different from DNA:
a. The 4th nucleotide base is uracil (U) instead of T. Uracil pairs with ____________.
b. RNA is a ________________ strand, whereas DNA is double-stranded.
22. There are _______ types of RNA:
a. mRNA: ________________________________ RNA
b. rRNA: ribosomal RNA
c. tRNA: _________________________________ RNA
Transcription
23. Transcription is the process of transferring _________________ from DNA into ________.
24. DNA opens up the _______________ to be copied, and RNA ________________ match up
to the DNA template through _______________________________ base pairing.
25. A ___________________ strand of RNA is produced and __________ from the DNA.
26. When transcription is complete, the original DNA ______________________ back up.
Translation
27. To make a protein, the DNA/RNA ___________________ has to be translated from
_____________________ to amino acids.
28. Takes place in the ______________________ of a cell using ______________________.
29. mRNA forms the _______________________ – tells the ribosome what order the
_______________________________ go in. (This is why it’s _______________________
RNA – it brings the “message” of the code from the DNA to the cytoplasm!)
DNA sequences can change
Errors in DNA
Mutations
30. tRNA brings the amino acids to the __________________________. (It “____________”
the amino acids from place to place.)
31. rRNA is part of the ________________ and helps put the amino acids in the correct order.
32. A _____________ of amino acids is formed and eventually becomes a _______________.
33. Differences, or ____________________________, in DNA are what make one organism
different from another.
34. Each human cell has __________ chromosomes and contains 6 billion base ___________
in its DNA.
35. The ____________________ of differences between any two individuals of the same
species is _______________________.
36. For example, about _______% of the DNA in the cells of two different humans is the
_______________________________.
37. Given the huge ________________ of base pairs in DNA of any organism, it is not
surprising that ____________________ occur when DNA is copied.
38. DNA is also affected by the _______________________________.
39. For example, exposure to ultraviolet radiation or x-rays can ___________________ DNA.
40. Both natural and human-made toxins, which are ___________________________
chemicals, can also _______________________ DNA.
41. Any change in DNA is called a ____________________________.
42. When a mutation occurs in a gene, the coding region of DNA, the __________ amino acid
might be placed in the amino-acid chain.
43. If that happens, there are three possible outcomes:
a. The mutation causes ____________ effect.
b. The effect of the mutation is _________________.
c. The effect of a mutation is _________________. The effect can be ___________,
or the effect can be _______________________.
Questions:
1. What does DNA do? _____________________________________________________
2. Describe the shape of DNA.
3.
Define complementary base pairing.
4.
5.
6.
7.
8.
What bases always pair together? ___________________________________________
How many bases code for one amino acid? _________
What is a gene? ________________________________________________________
RNA is the “middle step” between _____________ and ______________.
How is RNA different from DNA?
9. What are the 3 types of RNA?
10. What is replication?
11. What is transcription?
12. What is translation?
13. How many chromosomes do humans have? ___________
14. What is a mutation? ___________________________________________________
15. What can happen if there’s a mutation in a gene?