Course
Objectives for IB Biology
Gresham
HS
Topic Two: Chemistry of Life
Reading:
Chapter 2- Basic Chemistry
Chapter 3- Organic Chemistry
Chapter 8- Enzymes
Chapter 14- DNA: The Genetic Material
Chapter 15- Genes and How They Work
Chapter 16- Control of Gene Expression
Chapter 18- Gene Technology
2.1 Elements of life (2 hours) (pp.
19-34)
2.1.1 State that the 3 commonest elements of life are carbon,
hydrogen and oxygen. (pg. 25)
2.1.2 State that a variety of other elements are needed by living
organisms including nitrogen, sulfur, phosphorus, iron and potassium. (pg.
25)
2.1.3 State one role for each of the elements (in plant or animals)
mentioned in 2.1.2. (pg. 25)
2.1.4 Outline the difference between an atom and an ion. (Ions
only in terms of being charged particles.) (pg. 26)
2.1.5 Define organic. (pg. 38)
2.1.6 Outline the significance of water in biology including
transparency, cohesion, surface tension, solvent properties and thermal properties,
referring to the polarity of water molecules and hydrogen bonding where relevant.
(One example of each is sufficient.) (pp. 28-33)
2.1.7 Discuss the significance of water to organisms (in plant
or animals) as a coolant, transport medium and habitat, in terms of its properties.
(pp. 28-33)
2.2 Carbohydrates, lipids and proteins
(4 hours) (pp. 38-55)
2.2.1 Draw the basic structure of a generalized amino acid. (pp.
50-51)
2.2.2 Draw the ring structure of alpha-D-glucose. (pg.
44)
2.2.3 Draw the basic structure of glycerol and a generalized
fatty acid. (pp. 46-47)
2.2.4 Outline the role of condensation and hydrolysis in the
relationships between monosaccharides and disaccharides; fatty acids, glycerol
and triglycerides; amino acids, dipeptides and polypeptides. (pg.
50)
2.2.5 Draw the structure of a generalized dipeptide, showing
the peptide linkage. (pg. 50)
2.2.6 Explain the relative solubility of carbohydrates, lipids
and protein in water. (This is easy to try on your own
at home!)
2.2.7 Compare the energy content of carbohydrates, lipids and
proteins. (pg. 46)
2.2.8 List 2 examples each of monosaccharides, disaccharides
and one for a polysaccharide. (pg. 40)
2.2.9 State 1 function for a monosaccharide and 1 for a polysaccharide.
(pg. 40)
2.2.10 State 3 functions of lipids. (pp.
45-47)
8.5 Proteins (1 hour) (pp.
48-55)
8.5.1 Explain the four levels of structure of proteins, indicating
their significance (primary, secondary, tertiary, quaternary). (pp.
52-55)
8.5.2 Outline the difference between fibrous and globular proteins,
with reference to two examples of each type. (fibrous ?, globular pp.
52-55)
8.5.3 State six functions of proteins, giving a named example
of each. (pp. 48-49)
2.3 Enzymes (4 hours) (pp.
148-154)
2.3.1 Define enzyme. (pp. 150-151)
2.3.2 Define active site. (pg. 151)
2.3.3 Describe the "lock-and-key" model. (pg.
151)
2.3.4 List 3 factors that affect enzyme activity (include at
least temp. and substrate concentration). (pg. 152)
2.3.5 Outline the effects of temperature and substrate concentration
on enzyme activity. (pg. 152)
2.3.6 Define denaturation. (pg. 55)
2.3.7 Explain 2 applications of enzymes in biotechnology.
8.6.1 State that metabolic pathways consist of chains and cycles
of enzyme catalyzed reactions.
8.6.2 Describe the "induced fit" model. (Include its
importance in the reduction of the activation energy and how it can account
for the broad specificity of some enzymes (ability to bind several substrates).)
(pg. 151)
8.6.3 Explain that enzymes lower the activation energy of the
chemical reactions that they catalyze. (Graphically cover both exergonic and
endergonic reactions. An understanding of how to calculate the activation energy
of a reaction when reversed is also needed.) (pp. 148-149)
8.6.4 Explain the difference between competitive and non-competitive
inhibition, with reference to one example of each type. (pg.
152)
8.6.5 Explain the role of allostery with respect to feedback
inhibition and the control of metabolic pathways. (pg.
152)
2.4 DNA structure (1 hour)
2.4.1 Outline DNA nucleotide structure in terms of sugar (deoxyribose),
base and phosphate. (pp. 56-57)
2.4.2 State the names of the four bases in DNA. (pg.
57)
2.4.3 Outline how the DNA nucleotides are linked together by
covalent bonds into a single strand. (pg. 57)
2.4.4 Explain how a DNA double helix is formed using complementary
base pairing and hydrogen bonds. (pg. 58)
2.4.5 Draw a simple diagram of the molecular structure of DNA.
(pg. 56-58)
8.1 DNA Structure (1 hour)
8.1.1 Outline the structure of nucleosomes including histone
proteins and DNA (Limit the discussion to the fact that a nucleosome consists
of 8 small histone protein molecules wrapped around with DNA and held together
by another histone protein.). (pp. 89, 208-209, 327)
8.1.2 State that only a small proportion of the DNA in the nucleus
constitutes genes and that the majority consists of repetitive sequences (See
8.3.4.). (The function of these repetitive sequences is not required but students
should know that their presence is used in profiling.) (pg.
310)
8.1.3 Explain the structure of DNA including the antiparallel
strands, 3'-5' linkages and hydrogen bonding between purines and pyrimidines.
(pp. 286-287)
2.5 DNA replication (1 hour)
2.5.1 State that DNA replication is semi-conservative. (pg.
288)
2.5.2 Outline DNA replication in terms of unwinding the double
helix and separation of the strands by helicase followed by formation of the
new complementary strands by DNA polymerase. (pp. 290-293)
2.5.3 Explain the significance of complementary base pairing
in the conservation of the base sequence of DNA. (pp.
286-287)
8.2 DNA replication (1 hour)
8.2.1 State that DNA replication is carried out in a 5'----->3'
direction. (pp. 290-291)
8.2.2 Explain the process of DNA replication in eukaryotes including
the role of enzymes (helicase, DNA polymerase III, RNA primase, DNA polymerase
I and DNA ligase), Okazaki fragments and deoxynucleoside triphosphates. (The
function of the enzymes should be stated in general terms only. The explanation
of the Okazaki fragments in relation to the direction of action of DNA Polymerase
III is required.) (pp. 290-293)
8.2.3 State that in an eukaryotic chromosome, replication is
initiated at many points. (pg. 291)
2.6 Transcription and translation (2
hours)
2.6.1 Compare the structure of RNA and DNA. (Limit it to names
of sugars, bases and number of strands.) (pg. 58)
2.6.2 State one function of messenger RNA and one function of
transfer RNA. (pg. 300)
2.6.3 Outline DNA transcription in terms of the formation of
a RNA strand complementary to the DNA strands by RNA polymerase. (pg.
301)
2.6.4 Describe the genetic code in terms of codons composed of
triplets of bases. (pg. 302-303)
2.6.5 Describe translation including the roles of mRNA codons,
t RNA anticodons and ribosomes leading to peptide linkage formation. (pp.
306-309)
2.6.6 Define the terms degeneracy and universal as they relate
to the genetic code.
2.6.7 Explain the relationship between one gene and one polypeptide
and its significance.
8.3 Transcription (2 hours)
8.3.1 State that transcription is carried out in a 5'---->3'
direction. (pg. 304)
8.3.2 Outline the Lac Operon model as an example of the control
of gene expression in prokaryotes. (Operons are only found in prokaryotes. Mention
only the idea of a regulator gene producing a protein that prevents RNA polymerase
binding to the promoter region.) (pp. 322-323)
8.3.3 Explain the process of transcription in eukaryotes including
the role of the promoter region, RNA polymerase, ATP, and terminator. (See IB
syllabus for further details.) (pg. 304-305)
8.3.4 State that eukaryotic chromosomes contain far more DNA
than is needed to code for their protein products (See 8.1.2.). (pg.
310)
8.3.5 Outline the difference between introns and exons. (pg.
310)
8.3.6 State that eukaryotic RNA needs the removal of introns
to form mature mRNA and that this process is called splicing.
8.3.7 State that a small group of viruses, known as retroviruses,
cause host cells to synthesize viral reverse transcriptase (See 5.3.6 and 12.1.5.).
(pg. 343)
8.3.8 State that reverse transcriptase catalyzes the production
of single-stranded 'novel' DNA from RNA. (These latter 2 bullets afford an opportunity
to relate some aspects of DNA viral life cycle with that of the AIDS virus.)
8.3.9 Explain why reverse transcriptase is a useful tool for
molecular biologists. This enzyme can make DNA from mature mRNA (such as human
insulin), which can then be spliced into host DNA (Ex.- E. coli), without the
introns. (pg. 374)
8.4 Translation (2 hours)
8.4.1 Outline that the structure of a tRNA allows recognition
by a tRNA activating enzyme that binds a specific amino acid to it using ATP
for energy. (Each amino acid has a specific tRNA activating enzyme. Degeneracy,
that is, some amino acids have more than one tRNA, should also be included.)
(pp. 306-307)
8.4.2 Outline the structure of ribosomes including protein and
RNA composition, large and small subunits, two tRNA binding sites and mRNA binding
sites. (The cloverleaf shape of tRNA and CCA at the 3' end should be included.
Mention that prokaryote, chloroplast and mitochondrial ribosomes are 70s, whereas
eukaryote ribosomes are 80s.)
8.4.3 State that translation consists of initiation, elongation
and termination. (pp. 308-309)
8.4.4 State that translation occurs in a 5'---> 3' direction.
(pg. 309)
8.4.5 Explain in detail the process of translation including
GTP, ribosomes (including peptidyl transferase), polysomes, start codon and
stop codons.
8.4.6 State that free ribosomes synthesize proteins for use primarily
with in the cell itself and that bound ribosomes synthesize proteins primarily
for secretion and lysosomes.
2.7 Genetic engineering (3 hours)
2.7.1 State that genetic material can be transferred between
species because the genetic code is universal (See 2.6.6).
2.7.2 Outline a basic technique used for gene transfer involving
plasmids, a host cell (bacterium, yeast or other cell), restriction enzymes
(endonuclease) and DNA ligase. (pp. 364-371)
2.7.3 State 2 examples of the current uses of genetic engineering
in agriculture and/or pharmacy. (pp. 378-79, 380-83)
2.7.4 Explain 1 potential harmful result of genetic engineering.
(pg. 386 ?)
2.7.5 State that PCR (polymerase chain reaction) copies and amplifies
minute quantities of nucleic acid. (pg. 372)
2.7.6 State that gel electrophoresis involves the separation
of fragmented pieces of DNA according to their charge and size. (pg.
368)
2.7.7 State that gel electrophoresis is used in DNA profiling.
(pg. 377)
2.7.8 Describe 2 applications of DNA profiling.
2.7.9 Outline the process of gene therapy using a named example.
Long & Slichter