Download Name: Chapter 8 DNA Study Guide There are two main nucleic

Name: ___________________________________________
Chapter 8 DNA Study Guide
1. There are two main nucleic acids
1.
2.
2. ___________________ (DNA) is the genetic enzymes that is critical for an organism’s function
because they control the chemical reactions needed for life
3. DNA is a polymer made of repeating subunits called _____________
4. Nucleotides have three parts:
1.
2.
3.
5. The simple sugar in DNA, called __________________, gives DNA its name—deoxyribonucleic
acid.
6. The ____________ is composed of one atom of phosphorus surrounded by four oxygen atoms
7. A _______________ is a carbon ring structure that contains one or more atoms of nitrogen.
8. In DNA, there are four possible nitrogenous bases:
1. A
2. T
3. G
4. C
9. Nucleotides join together to form long chains, with the phosphate group of one nucleotide
bonding to the deoxyribose sugar of an adjacent nucleotide. The phosphate groups and
deoxyribose molecules form the backbone of the chain, and the nitrogenous bases stick out like
the teeth of a zipper. Each nitrogen base is held together by a _______________________
10. Because DNA is composed of two strands twisted together, its shape is called __________
11. In 1953, __________ and _________ proposed that DNA is made of two chains of nucleotides
held together by nitrogenous bases. They also proposed that DNA is shaped like a long zipper
that is twisted into a coil like a spring
12. Before a cell can divide by mitosis or meiosis, it must first make a copy of its chromosomes. The
DNA in the chromosomes is copied in a process called _______________. Without DNA
replication, new cells would have only half the DNA of their parents
13. DNA is copied during _________ prior to mitosis and meiosis. It is important that the new copies
are exactly like the original molecules
14. Scientists use nucleotide sequences to determine
1. Evolutionary relationships among _________
2. to determine whether two people are _________
3. to identify bodies of _________
RNA
15. Three parts of the RNA nucleotide
1.
2.
3.
16. The 4 nitrogen bases
1.
2.
3.
4.
17. RNA and DNA differ in 3 ways:
RNA
1.
DNA
2.
3.
18. RNA takes instructions from DNA on the assembly of proteins, then—amino acid by amino
acid—they assemble the protein.
There are three types of RNA that help build proteins.
1.
2.
3.
19. _______________________________ (mRNA) brings instructions from DNA in the nucleus to
then transfers the information to the ribosome
20. ___________________________ (rRNA) binds to the mRNA and uses the instructions to
assemble amino acids in the correct order
21. ___________________________ (tRNA) is the supplier. Transfer RNA delivers amino acids to
the ribosome to be assembled into a protein
22. In the nucleus, enzymes make an RNA copy of a portion of a DNA strand in a process called
________________________
23. The main difference between transcription and DNA replication is that transcription results in
the formation of one single-stranded __________ molecule rather than a double-stranded
___________ molecule
24. A group of three nitrogenous bases in mRNA code for one amino acid. Each group is known as a
______________.
64 Different combinations are possible when a sequence of 3 bases are used; thus, 64 different
mRNA codons are in the genetic code
Checking for understanding:
25. For the following DNA sequences, match its replicated pair.
AATCGCCTTACGTTT
26. What would be the RNA strand (transcription) for the DNA sequence?
27. What are the codons for the strands?
28. For proteins to be built, the __________ different amino acids dissolved in the cytoplasm must
be brought to the ribosomes
29. A chain of amino acids is formed until the _____________ codon is reached on the mRNA
strand.
30. Mutations take place by changing the sequence of ____________within a gene in a sperm or an
egg cell
31. A ____________________ is a change in a single base pair in DNA
A change in a single nitrogenous base can change the entire structure of a protein because a
change in a single amino acid can affect the shape of the protein.
32. An example is:
33. ____________________ is an addition or deletion of a base in a DNA strand
34. An example is:
35. Any agent that can cause a change in DNA is called a _________________
36. Mutagens are caused by:
1.
2.
3.