Biology Study Guide: Unit 8

Biology Study Guide: Unit 8 Genetics II Benchmark: Molecular DNA-RNA (ch: 12 - 13)
1. Diagram and explain Griffith’s experiment indicated by Figure 12-2. What is the main point proven in this
experiment? (288)
The main point is that biologist found out that genetic information could be transferred from one bacterium to
another.
2. Compare and Contrast DNA and RNA. (300)
Both are composed of a long chain of nucleotides. Nucleotides are made up of a 5-carbon sugar, a phosphate
group, and a nitrogenous base. The main differences are the sugar in RNA is ribose instead of deoxyribose. RNA
is single stranded instead of double stranded like DNA. RNA contains uracil in place of thymine.
3. What is the significance of the order of DNA Bases? (302)
Each three-letter sequence is known as a codon. A codon consists of three consecutive nucleotides that specify a
single amino acid that is to be added to the polypeptide. The polypeptide chain determine what protein it becomes.
4. What is the function of each of the following: mRNA, rRNA, tRNA (301)
mRNA is to carry copies of instructions for assembling proteins. rRNA make up ribosomes where proteins are
assembled. tRNA transfers each amino acid to the ribosome as it is specifically coded by mRNA.
5. Define each of the following:
♣ Replication (299)
DNA is duplicated before the cell divides. This ensures that each resulting cell will have a complete set of
DNA molecules.
♣ Transcription (301)
RNA molecules are produced by copying part of the nucleotide sequence of DNA into a complementary
sequence in RNA.
♣ Translation (304)
Translation is the decoding of an mRNA message into a polypeptide chain.
♣ protein synthesis (304)
Also known as translation.
6. What is a codon and how many nucleotides are needed to make one piece of code? (302)
A codon consists of three consecutive nucleotides that specify a single amino acid that is to be added to the
polypeptide.
7. Are you able to use a chart to determine what Amino Acid is coded for by a codon? (303)
Figure 12-17 – know how to use that figure.
8. What are stop codons? How many are there? What is their function? (303)
Stop codons act like the period at the end of each sentence; they signify the end of a polypeptide, which consist of
many amino acids. There are three stop codons.
9. What is a point mutation? What are the effects? (307-308)
Gene mutations involving changes in one or few nucleotides. Most mutations are neutral, meaning they have little
or no effect on the expression of genes. Mutations that causes dramatic changes in the protein structure are often
harmful, producing defective proteins that disrupt normal biological activities.

Biology Study Guide: Unit 8 Genetics II Benchmark: Molecular DNA-RNA (ch: 12 - 13)
10. What is a gene? How does a gene mutation effect the protein coded for? (265, 307-308)
The chemical factor that determines traits is called genes. Sometimes there is no effect at all, other times the effect
will be harmful to the individual, creating defective proteins that disrupt normal activity.
11. What is a frame shift mutation? (307)
When a nucleotide is added or deleted, the bases are still read in groups of three but now those groupings are
shifted for every codon that follows.
12. What is meant by gene expression? (309)
An expressed gene is a gene that is transcribed into RNA.
13. What is meant by differentiation? (312)
Differentiation is the specialization of cells during embryonic development to become more specialized in
structure and function.
14. What impact does the regulation of gene expression have on the cells in your body? (310-311)
Cells turn their genes on and off as needed, by the use of enhancer sequences and repressor proteins. There are
also start and stop codons.
15. What makes proteins different? (302)
Proteins are made by joining amino acids into long chains called polypeptides. Each polypeptide contains a
combination of the 20 different amino acids. The properties of proteins are determined by the order which
different amino acids are joined together.
16. What determines the proteins shape and what does the shape determine? (302)
The sequence of amino acids determines the proteins shape. The shape determines the function for the proteins.
17. Read about Cystic Fibrosis, page 346 and Fig 14-8 page 347. What effect does the mutation have on the CFTR
protein? (347)
The deletion of one amino acid causes the protein to be destroyed before reaching the cell membrane and failing to
regulate the chloride ion channels.
18. What is the function of each of the following?
♣ DNA Polymerase (299) It joins individual nucleotides together to produce a DNA molecule and also
“Proofreads” each new DNA strand.
♣ RNA Polymerase (301) It binds to DNA and separates the DNA strands. It then uses one strand of DNA as a
template from which nucleotides are assembled into a strand of RNA.
19. What are the base pairing rules for DNA and RNA? (294, 302)
In DNA, adenine pairs with Thymine and Cytosine pairs with Guanine. In RNA Thymine is replaced by Uracil
20. What is genetic engineering? What are the benefits to humans? (322,331-333)
Genetic engineering is making changes in the DNA code. The benefits
21. What are transgenic organisms? How are they developed? (331)
Transgenic organisms contains genes from other organisms. By the process of genetic engineering a gene from
another organism is isolated and inserted into the organism.

Biology Study Guide: Unit 8 Genetics II Benchmark: Molecular DNA-RNA (ch: 12 - 13)
22. What is the significance of transgenic rice that contains vitamin A? (333)
Rice is the major food for billions of humans. Vitamin A is a nutrient essential to human health. Therefore the rice
may improve the diets and health of many people.
23. Diagram and explain how to clone a mammal, page 332 Figure 13-13. (332)
Take a donor cell from a mammal and a donor egg from another mammal. Fuse the two eggs by using electric
shock. Take the fused eggs and let it develop into an embryo. The embryo is then placed into the uterus of another
mammal to develop into a fully grown mammal.
24. What happens to proteins when they are heated? (notes)
(Changes the Shape of the protein)
25. What are plasmids? (327-328)
The foreign DNA is joined to a small circular DNA known as a plasmid.
26. How is Bacterial Transformation used to create human growth hormone? (327)
Gene for human growth is isolated and cut by using Recombinant DNA. That gene is inserted into a bacterial
DNA, which is then inserted into the bacteria and allowed to reproduce in the bacteria.
27. Define the following chromosomal mutations: (308, Figure 12-21)
♣ Inversion – reverse the direction of parts of a chromosome.
♣ Translocation – part of one chromosome breaks off and attaches to another.
♣ Deletion – involve the loss of all or part of a chromosome.
♣ Duplication – produces extra copies of parts of a chromosome.