Download Unit 2 Study Objectivies

Unit 2 Study Objectivies
State that the most frequently occurring chemical elements in living things are carbon,
hydrogen, oxygen and nitrogen.
State that a variety of other elements are needed by living organisms, including sulfur,
calcium, phosphorus, iron and sodium.
State one role for each of the elements mentioned above.
Note: Refer to the roles in plants, animals and prokaryotes.
Draw and label a diagram showing the structure of water molecules to show their
polarity and hydrogen bond formation.
Outline the thermal, cohesive and solvent properties of water.
Explain the relationship between the properties of water and its uses in living organisms
as a coolant, medium for metabolic reactions and transport medium.
Describe the properties of the carbon atom that make the diversity of carbon
compounds possible.
Discuss the special properties of water that contribute to Earth's suitability as an
environment for life.
Explain what isotopes are and why are radioisotopes important to biologists?
Explain the octet rule and predict how many bonds an atom might form.
Explain how electrons influence the chemical behavior of an atom.
Identify molecules which contain covalent and ionic bonds.
Describe a hydrogen bond.
Explain how carbon’s electrons determine the kinds and number of bonds carbon will
form.
Describe how carbon skeletons may vary, and explain how this variation contributes to
the diversity and complexity of organic molecules.
Distinguish among the three types of isomers.
Name and draw the major functional groups, and describe the chemical properties of
the organic molecules in which they appear.
Explain the basis for the pH scale.
State the relative concentration of H+ and OH- ions at any pH.
Using the bicarbonate buffer system as an example, explain how buffers work.
Describe the causes of acid precipitation, and explain how it adversely affects the
fitness of the environment.
Carbohydrates & lipids
Distinguish between organic and inorganic compounds.
Note: Compounds containing carbon that are found in living organisms (except
hydrogencarbonates, carbonates and oxides of carbon) are regarded as organic.
Identify amino acids, glucose, ribose and fatty acids from diagrams showing their
structure.
Note: Specific names of amino acids and fatty acids are not expected.
List three examples each of monosaccharides, disaccharides and polysaccharides.
Note: The examples used should be:
 glucose, galactose and fructose
 maltose, lactose and sucrose
 starch, glycogen and cellulose.
State one function of glucose, lactose and glycogen in animals, and of fructose, sucrose
and cellulose in plants.
Outline the role of condensation and hydrolysis in the relationships between
monosaccharides, disaccharides and polysaccharides; between fatty
acids, glycerol and triglycerides; and between amino acids and
polypeptides.
Describe how covalent linkages are formed and broken in organic polymers.
Describe the distinguishing characteristics of carbohydrates, and explain how they are
classified.
List four characteristics of a sugar.
Identify a glycosidic linkage and describe how it is formed.
Describe the important biological functions of polysaccharides.
Distinguish between the glycosidic bonds found in starch and cellulose, and explain why
the difference is biologically important.
Identify both the straight and ring form of a carbohydrate
State three functions of lipids.
Note: Include energy storage and thermal insulation.
Explain what distinguished lipids from other major classes of macromolecules.
Describe the unique properties, building block molecules and biological importance of
the three important groups of lipids.
Identify an ester bond and describe how it is formed.
Distinguish between a saturated and unsaturated fat and list some unique properties
that come from these structural differences.
Compare the use of carbohydrates and lipids in energy storage.
DNA structure
Outline DNA nucleotide structure in terms of sugar (deoxyribose), base and phosphate.
State the names of the four bases in DNA.
Outline how DNA nucleotides are linked together by covalent bonds into a single strand.
Explain how a DNA double helix is formed using complementary base pairing and
hydrogen bonds.
Draw and label a simple diagram of the molecular structure of DNA.
Protein Structure
Explain the four levels of protein structure, indicating the significance of each level.
Note: Quaternary structure may involve the binding of a prosthetic group to form
a conjugated protein.
Outline the difference between fibrous and globular proteins, with reference to two
examples of each protein type.
Explain the significance of polar and non-polar amino acids.
Note: Include the position of proteins in membranes, creating hydrophilic
channels through membranes, and the specificity of active sites in enzymes.
State four functions of proteins, giving a named example of each.
Note: Membrane proteins should not be included as part of the four.
Describe the characteristics that distinguish proteins from the other major classes of
macromolecules, and explain the biologically important functions of this group
List and recognize the four major groups that make up the amino acid.
Explain how amino acids may be grouped according to the physical and chemical
properties of the R-groups/side chains.
Identify a peptide bond and explain how it is formed.
Explain what determines protein conformation and why it is important.
Explain how proteins may be denatured.
Free Energy & Enzymes
State whether the reaction is exergonic or endergonic.
Determine if a reaction is spontaneous or not spontaneous
Define enzyme and active site.
Explain enzyme–substrate specificity.
Explain the effects of temperature, pH and substrate concentration on enzyme activity.
Define denaturation.
Note: Denaturation is a structural change in a protein that results in the loss
(usually permanent) of its biological properties. Refer only to heat and pH as
agents.
Explain the use of lactase in the production of lactose-free milk.
State that metabolic pathways consist of chains and cycles of enzyme-catalysed
reactions.
Describe the induced-fit model.
Note: This is an extension of the lock-and-key model. The German scientist Emil
Fischer introduced the lock-and-key model for enzymes and their substrates in
1890. It was not until 1958 that Daniel Koshland in the United States suggested
that the binding of the substrate to the active site caused a conformational
change, hence the induced-fit model. This is an example of one model or theory,
accepted for many years, being superseded by another that offers a fuller
explanation of a process.The mechanism helps explain how some enzymes can
catalyze more than one substrate.
Explain that enzymes lower the activation energy of the chemical reactions that they
catalyse.
Note: Only exothermic reactions need be considered. Specific energy values do
not need to be recalled.
Explain the difference between competitive and non-competitive inhibition, with
reference to one example of each.
Note: Competitive inhibition is the situation when an inhibiting molecule that is
structurally similar to the substrate molecule binds to the active site, preventing
substrate binding.
Limit non-competitive inhibition to an inhibitor binding to an enzyme (not to its
active site) that causes a conformational change in its active site, resulting in a
decrease in activity.
Explain the control of metabolic pathways by end-product inhibition, including the role of
allosteric sites.
Explain the role of catabolic and anabolic pathways in the energy exchanges of cellular
metabolism.
List two major factors capable of driving spontaneous processes.
State the first and second Laws of Thermodynamics.
Draw a molecule of ATP and identify its chemical class.
Explain the regeneration of ATP from ADP.
Describe the function of ATP in the cell.
Explain why chemical disequilibrium is essential for life.
Describe the energy profile of a chemical reaction.
Describe the function of enzymes in biological system.
Explain the relationship between enzyme structure and enzyme specificity.
Describe several mechanisms by which enzymes lower activation energy.
Explain how substrate concentration affects the rate of an enzyme-controlled reaction.
Explain how enzyme activity can be regulated or controlled by environmental conditions,
cofactors, enzyme inhibitors and allosteric regulators.
Ecology
Define species, habitat, population, community, ecosystem and ecology, trophic levels
Distinguish between autotroph and heterotroph.
Distinguish between consumers, detritivores and saprotrophs.
Describe what is meant by a food chain, giving three examples, each with at least three
linkages (four organisms).
Note: Only real examples should be used from natural ecosystems. An arrow
indicates the direction of energy flow. Each food chain should include a producer
and consumers, but not decomposers. Named organisms at either species or
genus level should be used. Common species names can be used instead of
binomial names. General names such as “tree” or “fish” should not be used.
Describe what is meant by a food web.
Deduce the trophic level of organisms in a food chain and a food web.
Note: Students should be able to place an organism at the level of producer,
primary consumer, secondary consumer, and so on, as the terms herbivore and
carnivore are not always applicable.
Construct a food web containing up to 10 organisms, using appropriate information.
State that light is the initial energy source for almost all communities.
Note: No reference to communities where food chains start with chemical energy
is required (such as in very deep ocean environments)
.
Explain the energy flow in a food chain.
Note: Energy losses between trophic levels include material not consumed or
material not assimilated, and heat loss through cell respiration.
State that energy transformations are never 100% efficient.
Explain reasons for the shape of pyramids of energy.
Note: A pyramid of energy shows the flow of energy from one trophic level to the
next in a community. The units of pyramids of energy are, therefore, energy per
unit area per unit time, for example, kJ m–2 yr–1.
Explain that energy enters and leaves ecosystems, but nutrients must be recycled.
State that saprotrophic bacteria and fungi (decomposers) recycle nutrients.
Draw and label a diagram of the carbon cycle to show the processes involved.
Note: The details of the carbon cycle should include the interaction of living
organisms and the biosphere through the processes of photosynthesis, cell
respiration, fossilization and combustion. Recall of specific quantitative data is
not required.
Analyse the changes in concentration of atmospheric carbon dioxide using historical
records.
Note: Data from the Mauna Loa, Hawaii, or Cape Grim, Tasmania, monitoring
stations may be used.
Explain the relationship between rises in concentrations of atmospheric carbon dioxide,
methane and oxides of nitrogen and the enhanced greenhouse effect.
Note: You should be aware that the greenhouse effect is a natural phenomenon
and that it is the increased greenhouse effect that is currently being monitored
and debated. Reference should be made to transmission of incoming shorterwave radiation and re-radiated longer-wave radiation. Knowledge that other
gases, including methane and oxides of nitrogen, are greenhouse gases is
expected.