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BIOL1414 Introduction to Biotechnology
Chapter 2 Guided Notes
An Introduction to Genes & Genomes
1. Using your textbook and its glossary, define the following terms:
a. Genes
b. Genomes
c. cell membrane
d. organelles
2. Approximately how many cells and cell types are there in the human body?
3. What distinguishes a prokaryotic cell from a eukaryotic cell? What cellular structures do
plants have that animal cells don’t have?
4. It took quite some time and many lines of research to determine that DNA is the
hereditary substance of cells, and to determine how DNA could store all the genetic
information of an organism. Briefly describe the contributions made by the following
scientists:
o 1869 Miescher
o 1928 Griffith
o 1944 Avery, McCarty, & MacLeod
o 1947 Chargaff
o 1954 Wilkins, Franklin, Watson, & Crick
5. The nucleotide:
a. Make a table with a column for “pentose sugar”, “nitrogenous base”, and “phosphate
group”. Make a row for DNA and a row for RNA. Fill in your table with the types
of each type of group found in DNA and RNA.
b. What are the complementary base pairs in DNA? In RNA?
c. To which carbon of pentose sugars are the nitrogenous bases attached in RNA and
DNA?
d. To which carbon of pentose sugars are the phosphate groups attached in RNA and
DNA?
e. What type of bond holds the nucleotides together in DNA and RNA?
f. What does the “antiparallel” structure of DNA refer to?
6. What is the difference between a trait and a gene?
7. What is the difference between chromatin and a chromosome?
8. Describe the role of the following enzymes during the process of DNA replication:
o DNA helicase
o Single-strand binding proteins
o Primase
o DNA polymerase
o DNA ligase
9. Explain why Okazaki fragments must be synthesized along the lagging strand of DNA
during replication.
10. There are 4 fundamental types of biomolecules found in cells: nucleic acids, lipids,
carbohydrates, and proteins. Briefly describe some functions of proteins in the living cell.
11. Genes are “expressed” in cells by transcription, followed by translation. Where in the
eukaryotic cell does each of these two processes occur, and what are the main enzymes
involved in each?
a. Describe how mRNA synthesized in eukaryotic cells must be processed before it can
become functional.
b. Explain how alternative splicing of RNA has made it difficult for scientists to count the
number of genes present in a given organism.
12. Translation occurs in three major stages: initiation, elongation, and termination.
a. What are the 3 types of RNA synthesized during transcription, what how do they
function during translation of proteins?
b. Describe the sequence of events during initiation and the role that the following
play: 5’ cap, initiation factors, small subunit, AUG, tRNA-Met, large subunit.
c. What are the sites of the ribosome along the mRNA being translated? In what
direction does the tRNA travel along these sites during elongation?
d. What is the bond called that links the amino acids together?
e. What becomes of the tRNA that has released its amino acid during translation by the
ribosome?
13. In what ways can mutations be beneficial and detrimental for organisms?
a. What are some examples of physical and chemical agents that can act as mutagens?
b. What are the types of point mutations, and under what conditions can a point
mutation be “silent”?
c. Explain why a nonsense mutation or a frameshift mutation would be more likely to
cause a more severe effect than a missense mutation.
14. Describe the mutation that gives rise to sickle cell anemia, and the effect this mutation has
on the functioning of the hemoglobin.
15. To what extent do DNA sequences vary among different people? Can you think of
reasons that this variation is useful to the human race?