Possible Written Questions for Biology 12 Unit Exam #2
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List the four principal types of biological molecules and give an example of each.
What roles do nucleotides play in living organisms?
Describe and compare dehydration synthesis and hydrolysis. Give an example of a substance formed using
each chemical reaction, and describe the specific reaction in each instance.
Distinguish among the following: monosaccharide, disaccharide and polysaccharide. Give two examples of
each and their functions.
Describe the primary, secondary, tertiary and quaternary structure of a protein.
Most structurally supportive materials in living organisms are polymers of special sorts. State one structural
polymer, its’ specific source, and its’ unique arrangement of monomers.
Which elements are commonly found in biological molecules?
List two features of water molecules that give rise to all of the beneficial attributes of water?
What are acids and bases, and how do living things regulate pH?
How do saturated fatty acids differ from unsaturated fatty acids?
How do the structures of triglycerides differ from that of phospholipids?
What are some of the many functions of proteins in cells? Give an example of a protein for each function.
Are the building blocks of nucleic acids the same for RNA and DNA?
Describe the properties of carbon that make carbon compounds so numerous in living organisms.
One of the digestive juices in the human stomach is hydrochloric acid. Sometimes an excess of the acid
causes stomach discomfort. In such a case, a person might take an antacid such as magnesium hydroxide.
Explain why this substance works to relieve the discomfort.
Relate the structure of a phospholipid to the property that makes it so important in forming cell membranes.
What role do lipids play in living organisms?
Define metabolism and explain how reactions can be coupled to one another.
What is activation energy? How do catalysts affect activation energy? How does this change the rate of
reactions?
Describe the structure and function of enzymes, and compare them to inorganic catalysts. How is enzyme
activity regulated?
Which organelles are common to both plant and animal cells, and which are unique to each?
Describe the important differences between prokaryotic and eukaryotic cells.
Describe the nucleus, including the nuclear membrane, chromatin, chromosomes, DNA and the nucleolus.
What are the functions of the mitochondrion and the chloroplast? Explain how the internal structures of these
organelles support its function.
What is the function of the ribosome? Where in the cell are they typically found?
Describe the structure and function of the endoplasmic reticulum and the Golgi apparatus.
How are lysosomes formed? What is their function?
Why is the term “fluid-mosaic” used to describe the cell membrane?
What is meant by the term “selectively permeable” in the context of cross membrane transport?
Describe the structure of a cell membrane. What are the two principal types of molecules in the cell
membrane? What are the two principal functions of the cell membrane?
What are three types of proteins found in the cell membrane and what is the function of each?
What does it mean when membrane cross-membrane transport proteins are said to be “specific”?
Define diffusion and compare it to osmosis.
An artificial cell consisting of an aqueous solution of 0.03 M sucrose and 0.02 M glucose is enclosed in a
selectively permeable membrane has just been immersed in a beaker containing a different solution of 0.01 M
sucrose, 0.01 M glucose and 0.01 M fructose. The membrane is permeable to water and to simple sugars such
as glucose and fructose, but not complex sugars such as disaccharides and polysaccharides. Which solutes
will exhibit a net diffusion into the cell? Which solute(s) will exhibit a net diffusion out of the cell? Which
solution – the cell or the beaker – is hypertonic to the other?
A beaker is filled with a concentrated glucose solution. A dialysis bag (selectively permeable membrane) is
filled with a dilute glucose and concentrated starch solution. Predict what you think will happen in this bagbeaker system. Please use the words hypertonic, hypotonic, isotonic, diffusion and osmosis in your
description.
Five dialysis bags (selectively permeable membrane) are filled with a 0.5 M sucrose solution. One bag is
placed into one beaker. The beakers contain the following series of sucrose concentrations: 0 M, 0.25 M. 0.5
M, 0.75 M and 1.0 M. Use the words hypertonic, hypotonic, isotonic, diffusion and osmosis in your answer
to describe what will happen to the beaker-bag systems after thirty minutes.
Define hypertonic, hypotonic and isotonic. What would happen to an animal cell immersed in each of these
three solutions?
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Describe the following types of transport processes: diffusion, facilitated diffusion, osmosis, active transport.
Describe endocytosis and exocytosis, including pinocytosis and phagocytosis.
List three main ideas of the cell theory.
What are the three cytoskeleton components of a eukaryotic cell?
How did prokaryotic cells give rise to eukaryotic cells according to the endosymbiotic hypothesis?
Explain the importance of enzymes to living things. Be sure to include in your answer: catalyst, substrate,
active site, activation energy, lock and key.
Define metabolism, using the terms catabolism and anabolism in your answer.
What is activation energy? How do catalysts affect activation energy? How does this change the rate of the
reaction?
Describe some exergonic and endergonic reactions that occur in plants and animals very regularly.
Explain how chemical reaction in the cell can be coupled together. Name the molecule that is intimately
involved in this process.
Explain how pH, temperature, substrate concentration and enzyme concentration affect the rate of the
reaction
Describe how competitive inhibition regulates the activity of a metabolic pathway.
Describe how allosteric inhibition regulates the activity of a metabolic pathway.
What type of biological molecule are nucleotides? What are the subunits of nucleotides? What type of bond
holds together the subunits of the nucleotide? What type of bond holds together the adjacent nucleotides in a
single strand?
What is the significance of DNA replication for your body? Why is DNA replication called “semiconservative replication”? Illustrate your answer with a diagram.
Name the nitrogen bases in the DNA molecule, and state which normally pairs with which. What type of
bond holds together complementary nitrogen bases?
Briefly describe the events of DNA replication, being sure to include the enzymes involved in the process.
When you eat fish, you take in fish protein and DNA; however, you do not assume the characteristics of a
fish. Explain why the nucleic acids of the fish do not change your appearance.
In what ways is the structure of mRNA similar to DNA? How does mRNA differ from DNA?
What is the function of mRNA? What is the function of tRNA? What is a codon? What is an anticodon?
Explain the interrelationship of these four concepts.
Differentiate between transcription and translation.
Compare and contrast DNA and RNA with respect to a) structure, b) synthesis, c) location in the cell, d)
nitrogen bases, and e) sugars.
Draw the structure of a nucleotide. Which parts are identical in all nucleotides, and which can vary?
What are the three types of RNA? What are their functions? Where and how are they synthesized?
Given the template strand of DNA: TAC CCT CAA GAT GCG TTC. Determine the complementary strands
of mRNA and tRNA and the corresponding strand of amino acids.
Given the template strand of DNA: ACC GTC TCG CAT CGA AAA. Determine the complementary strands
of mRNA and tRNA and the corresponding strand of amino acids.
Diagram and describe the processes of transcription and translation.
UAG is a stop codon. What might happen if the uracil in this codon was changed to cytosine?
A certain protein is made up of 100 amino acids. What is the smallest number of bases in the messenger RNA
molecule that is needed to carry the code for the synthesis of this protein?
Describe the contribution of James Watson and Francis Crick to the study of molecular biology.
What is the function of the ribosome? What is the function of the polyribosome?
How many guanines are in a DNA molecule 1000 base pairs long if 20% of the molecule consists of
thymines?
Given the template strand of DNA: ACA ATA TAG CTT TTG ACG GGG AAC CCC ATT. Determine the
complementary strands of mRNA and tRNA and the corresponding strand of amino acids.