IB SL Biology 2015
Study Guide Topic 2.6: Structure of DNA and RNA
Understandings:
1. The nucleic acids DNA and RNA are polymers of nucleotides.
2. DNA differs from RNA in the number of strands present, the base composition and the type of pentose.
3. DNA is a double helix made of two antiparallel strands of nucleotides linked by hydrogen bonding
between complementary base pairs.
Applications and Skills:
1. Skill: Drawing simple diagrams of the structure of single nucleotides of DNA and RNA, using circles,
pentagons and rectangles to represent phosphates, pentoses and bases.
Text references: Campbell’s 7th Edition AP Edition:
Chapter 5 pp. 86 - 89
Study Guide Topic 2.7: DNA replication, transcription and translation
Understandings:
1. The replication of DNA is semi-conservative and depends on complementary
base pairing.
2. Helicase unwinds the double helix and separates the two strands by breaking
hydrogen bonds.
3. DNA polymerase links nucleotides together to form a new strand, using the
pre-existing strand as a template.
4. Transcription is the synthesis of mRNA copied from the DNA base sequences
by RNA polymerase.
5. Translation is the synthesis of polypeptides on ribosomes.
6. The amino acid sequence of polypeptides is determined by mRNA according
to the genetic code.
7. Codons of three bases on mRNA correspond to one amino acid in a
polypeptide.
8. Translation depends on complementary base pairing between codons on
mRNA and anticodons on tRNA.
Applications and Skills:

Skill: Use a table of the genetic code to deduce which codon(s) corresponds
to which amino acid.
Text references: Campbell’s 7th Edition AP Edition:
Chapter 16 pp. 293 – 307; Chapter 17 pp. 309 - 331
Study Guide Topic 3.1: Genes
Understandings:
1. A gene is a heritable factor that consists of a length of DNA and influences a specific characteristic.
2. A gene occupies a specific position on a chromosome.
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Mrs. Leto
HHS
IB Biology | Hillsborough County Public Schools, Fl.
IB SL Biology 2015
3. The various specific forms of a gene are alleles.
4. Alleles differ from each other by one or only a few bases.
Text references: Campbell’s 7th Edition AP Edition:
Chapter 12 pp. 219 – 220; Chapter 14 pp. 251-270
Study Guide Topic 3.2: Chromosomes
Understandings:
4. In a eukaryote species there are different chromosomes that carry different genes.
5. Homologous chromosomes carry the same sequence of genes but not necessarily the same alleles of
those genes.
6. Diploid nuclei have pairs of homologous chromosomes.
7. Haploid nuclei have one chromosome of each pair.
8. The number of chromosomes is a characteristic feature of members of a species.
9. A karyogram shows the chromosomes of an organism in homologous pairs of decreasing length.
10. Sex is determined by sex chromosomes and autosomes are chromosomes that do not determine sex.
Applications and Skills:

Application: Use of karyograms to deduce sex and diagnose Down syndrome in humans.
Text references: Campbell’s 7th Edition AP Edition:
Chapter 12 pp. 218-228; Chapter 13 pp. 238 – 249
Study Guide Topic 3.3: Meiosis
Understandings:
1.
2.
3.
4.
One diploid nucleus divides by meiosis to produce four haploid nuclei.
The halving of the chromosome number allows a sexual life cycle with fusion of gametes.
DNA is replicated before meiosis so that all chromosomes consist of two sister chromatids.
The early stages of meiosis involve pairing of homologous chromosomes and crossing over followed by
condensation.
5. Orientation of pairs of homologous chromosomes prior to separation is random.
6. Separation of pairs of homologous chromosomes in the first division of meiosis halves the chromosome
number.
7. Crossing over and random orientation promotes genetic variation.
8. Fusion of gametes from different parents promotes genetic variation.
Applications and Skills:


Application: Non-disjunction can cause Down syndrome and other chromosome abnormalities.
Skill: Drawing diagrams to show the stages of meiosis resulting in the formation of four haploid cells.
Text references: Campbell’s 7th Edition AP Edition:
Chapter 13 pp. 238 – 249
2
Mrs. Leto
HHS
IB Biology | Hillsborough County Public Schools, Fl.
IB SL Biology 2015
Study Guide Topic 3.4: Inheritance
Understandings:
1. Mendel discovered the principles of inheritance with experiments in which large numbers of pea plants
were crossed.
2. Gametes are haploid so contain only one allele of each gene.
3. The two alleles of each gene separate into different haploid daughter nuclei during meiosis.
4. Fusion of gametes results in diploid zygotes with two alleles of each gene that may be the same allele
or different alleles.
5. Dominant alleles mask the effects of recessive alleles but co-dominant alleles have joint effects.
6. Many genetic diseases in humans are due to recessive alleles of autosomal genes, although some
genetic diseases are due to dominant or co-dominant alleles.
7. Some genetic diseases are sex-linked. The pattern of inheritance is different with sex-linked genes due
to their location on sex chromosomes.
8. Many genetic diseases have been identified in humans but most are very rare.
Text references: Campbell’s 7th Edition AP Edition:
Chapter 13 pp. 238 – 249; Chapter 14 pp. 251-270; Chapter 15 pp. 274 – 290
Chapters to Review:
Campbell: 7th Edition AP Edition:
Allott: Biology for the IB Diploma
(Oxford IB Study Guide):
Chapter 5 pp. 86 - 89
Chapter 12 pp. 218-228
Chapter 13 pp. 238 - 249
Chapter 14 pp. 251-270
Chapter 15 pp. 274 – 290
Chapter 16 pp. 293 – 307
Chapter 17 pp. 309 - 331
Chapter 2 pp. 28 - 31
Chapter 3 pp. 38 - 48
Chapter 7 pp. 88 – 90, 92, 94 - 95
Chapter 10 pp. 122, 125
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Mrs. Leto
HHS
IB Biology | Hillsborough County Public Schools, Fl.
IB SL Biology 2015
Key Terms:
Adenine
Allele
anticodons
Autosomes
Carrier
Chromosome
Codominant
alleles
codons
Color blindness
complementary
base pair
covalent bonds
Crossing over
Cytosine
Diploid cell
Deoxyribose
DNA nucleotide
DNA
polymerase
DNA replication
Dominant allele
F1 generation
F2 generation
Gametes
Gene
Gene locus
Genetic
recombination
Genotype
Guanine
Haploid cell
Helicase
Hemophilia
Homologous
chromosomes
Hydrogen bond
Karyotype
Law of
independent
assortment
Ligase
mRNA
Meiosis
mRNA
ribosomes
Multiple alleles
Nondisjunction
Nucleotide
P generation
Peptide bonds
Phenotype
Phosphate
Polypeptide
Punnett grid
Pure-breeding
Recessive allele
Ribose
RNA primase
rRNA
Sex-linked allele
Sister
chromatids
Thymine
Transcription
Translation
True-breeding
Uracil
X chromosome
Loci
(Locus – singular)
Synapsis
Test cross
Translocation
tRNA
Y chromosome
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Mrs. Leto
HHS
IB Biology | Hillsborough County Public Schools, Fl.
IB SL Biology 2015
Draw:
1. Deoxyribose molecule – number carbon atoms 1 - 6
2. Nucleotide – include labels: pentose sugar, phosphate group, nitrogenous base, 3’end, 5’ end.
3. DNA molecule – include labels: deoxyribose, phosphate, nitrogenous base, adenine, cytosine, guanine,
thymine, sugar-phosphate backbone, hydrogen bonds, 3’ end, 5’ end.
4. Overview of DNA replication – include labels: parent strand, daughter strands, Okasaki fragments, 3’
end, 5’ end.
5. Replication fork – include labels: helicase, primase, DNA polymerase, DNA ligase, leading strand,
lagging strand, origin of replication, 3’ end, 5’ end of each parent strand and daughter strand.
6. A karyotype for a female with trisomy 21. Circle the anomaly and sex chromosomes.
7. Crossing over in chromosomes. Label synapsis.
8. Overview of meiosis – include labels; meiosis I, meiosis II, prophase I – include crossing over,
anaphase I, metaphase I, telophase I, prophase II, metaphase II, anaphase II, telophase II. Identify
where cells are diploid and where they are haploid with “2n” and “n” labels.
9. Punnett grid for a test cross.
10. Punnett grid for hemophilia, a sex-linked trait, between a normal male and a carrier female.
Describe:
1. Transcription – include location in cell where process occurs, DNA, mRNA, promotor, Uracil in place of
Thymine, initiation, elongation, termination, processing, exons, introns,5’ cap, poly – A tail.
2. Translation – include location in cell where process occurs, codons, anti-codons, mRNA, rRNA, tRNA,
translation initiation complex, start codon, codons, anticodons, complementary base pairing, A site, P
site, E site, amino acids, polypeptide, stop codon, release factor, protein.
3. The role of enzymes in DNA replication – include primase, helicase, DNA polymerase, DNA ligase.
4. Semi-conservative DNA replication – include parent molecule, template strand, complementary base
pairing, daughter strands.
5. Complementary base pairing between DNA strands.
6. Complementary base pairing during transcription and translation.
7. Law of independent assortment.
8. Law of segregation.
9. Homozygous genotype, heterozygous genotype, hemi-zygous genotype.
10. Pedigrees and their importance.
11. How sex-linked traits are inherited and why they are more common in males than in females.
5
Mrs. Leto
HHS
IB Biology | Hillsborough County Public Schools, Fl.