AP Biology – Intro to Heredity Review (Campbell Biology Chapters 12-15)
Key terms
Allele
Asexual
Autosomes
Back cross
Chiasma
Codominance
Continuous variation
Cross
Crossing over
Dihybrid cross
Diploid
Discontinuous variation
Dominant allele
Epistasis
Experimental test cross
F1/F2 Generation
Gene linkage
Genetic counseling
Genomic imprinting
Genome
Genotype
Haploid
Homologous chromosome
Homozygous/Heterozygous
Incomplete dominance
Independent assortment
Lethal allele
Locus
Meiosis
Mitosis
Monohybrid cross
Multiple alleles
Mutant phenotype
Nondisjunction
Non-nuclear inheritance
Parental type
Pedigree analysis
Phenotype
Phenotypic plasticity
Polygenic inheritance
Punnett square
Pure-breeding (aka true-breeding)
Recessive allele
Recombinant phenotype
Recombination frequency
Rule of Addition
Rule of Multiplication
Segregation
Selfing
Sex chromosome
Sex-Influenced traits
Sex-limited traits
Sex-linkage
Synapsis
Synaptonemal Complex
Test Cross
Tetrads
Trait
Trisomy
Wild type
AP Learning Objectives:
Can you……………..
…represent the connection between meiosis and increased genetic diversity necessary for evolution?
…evaluate evidence provided by data sets to support the claim that heritable information is passed from one generation to another generation through mitosis, or
meiosis followed by fertilization?
…construct a representation that connects the process of meiosis to the passage of traits from parent to offspring?
…pose questions about ethical, social or medical issues surrounding human genetic disorders?
…apply mathematical routines to determine Mendelian patterns of inheritance provided by data sets?
…explain deviations from Mendel’s model of the inheritance of traits?
…explain how the inheritance patterns of many traits cannot be accounted for by Mendelian genetics?
…describe representations of an appropriate example of inheritance patterns that cannot be explained by Mendel’s model of the inheritance of traits?
…predict how a change in genotype, when expressed as a phenotype, provides a variation that can be subject to natural selection?
…explain the connection between genetic variations in organisms and phenotypic variations in populations?
…compare and contrast processes by which genetic variation is produced and maintained in organisms from multiple domains?
…construct an explanation of the multiple processes that increase variation within a population?
…define, apply and identify all of the genetics literacy terms?
AP Biology Curriculum Framework
Enduring Understanding 3.A: Heritable information provides continuity of life.
Essential Knowledge 3.A.3: The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring.
1. Look at yourself in the mirror. Do you look more like your mother, father or no one?
2. How does the process of meiosis apply to Mendel’s Law of Dominance? Law of Segregation? Law of Independent Assortment?
3. What do you know about Mendel’s data?
4. Describe the cause and consequences of the following genetic disorders: Albinism, sickle cell, Tay-Sachs, Huntington’s, Trisomy 21, Monosomy X,
Kleinfelter’s Syndrome, Fragile X, Edward’s Syndrome
Essential Knowledge 3.A.4: The inheritance pattern of many traits cannot be explained by simple Mendelian genetics.
1. Blood types used to be presented as evidence for or against paternity law suits. Why might this be inconclusive evidence?
2. Why are there more boys than girls born with color-blindness?
3. Are all alleles completely dominant or recessive? Give an example.
4. If flower color shows incomplete dominance, what would be phenotype ratio of the F1 generation be if you crossed a red flower with a white flower? The F2
generation?
5. Can an O- female and an AB+ male have an A- child?
6. Investigate the Romanov’s history with hemophilia. How is hemophilia inherited? Why was Alexis the only child to exhibit hemophilia?
7. How can mitochondrial DNA be used to establish identity? It is as accurate as nuclear DNA?
Enduring Understanding 3.C: The processing of genetic information is imperfect and is a source of genetic variation
Essential Knowledge 3.C.1: Changes in genotype can result in changes in phenotype
1. What are mutations?
2. How can a change in chromosome number occur? If the mistake occurs in Meiosis I or II, how does it affect the cells which are produced?
3. How can a change in chromosome structure occur?
4. Give an example of a positive, negative or neutral mutation.
5. Explain heterozygote advantage and give an example.
Essential Knowledge 3.C.2: Biological systems have multiple processes that increase genetic variation.
1. How does sexual reproduction generate variation? How do bacteria reproduce?
2. How do bacteria which asexually reproduce increase genetic variation?
3. Pictorially represent random assortment and crossing over. Why does DNA replication cause increased genetic variation?
4. What is the difference between conjugation, transformation and transduction?
Enduring Understanding 4.C: Naturally occurring diversity among and between components within biological systems affects interactions with the environment.
Essential Knowledge 4.C.2: Environmental factors influence the expression of the genotype in an organism
1. Given what you know about inheritance, account for the phenotypic differences within the human species for traits such as height and weight.
2. If skin color is heritable, explain tanning in the sun. How do UV rays accelerate melanin production?
Questions and Practice
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How is genetic information organized in the eukaryotic chromosome?
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How does this organization contribute to both continuity of and variability in the genetic information?
3.
How did Mendel’s work lay the foundation of modern genetics?
4.
What are the principal patterns of inheritance?
5.
What are the similarities and differences between prokaryotic and eukaryotic genomes?
6.
What is one way genetic information can be altered?
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What problems can it cause?
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Draw a picture to show the relationship between chromosome, gene, allele, homologous chromosome, sister chromatid, non-sister chromatid.
State the composition of eukaryotic chromosomes.
Explain the consequence of a base substitution mutation in relation to the process of transcription and translation, using the example of sickle cell anemia.
Define meiosis in terms of a reduction division in terms of diploid and haploid numbers of chromosomes.
Define homologous chromosomes.
Outline, using a chart, the process of meiosis including pairing of chromosomes followed by two divisions which result in four haploid cells.
Explain that non-disjunction can lead to changes in chromosome number, illustrated by reference to Down's Syndrome.
Describe karyotyping in terms of its definition, its use and how it is constructed.
Describe the behavior of the chromosomes in the phases of meiosis (create a comparison chart).
Outline the process of crossing-over and the formation of chiasmata.
Explain how crossing over in Prophase I (between non-sister chromatids of a homologous pair) can result in an exchange of alleles).
Explain how meiosis results in an effectively infinite genetic variety in gametes through crossing over in Prophase I and random orientation in Metaphase I.
State Mendel's Second Law (Law of Independent Assortment).
Explain the relationship between Mendel's Law of independent assortment and meiosis.
Outline the processes involved in spermatogenesis within the testis including mitosis, cell growth, the two divisions of meiosis and cell differentiation.
Outline the processes involved in oogenesis within the ovary including mitosis, cell growth, the two divisions of meiosis and the unequal division of cytoplasm
and the degeneration of polar bodies.
Compare the processes of spermatogenesis and oogenesis including number of gametes and the timing of the formation and release of gametes.
Describe ABO blood groups as an example of codominance and multiple alleles.
State the difference between autosomes and sex chromosomes.
Outline how the sex chromosomes determine gender, by referring to the inheritance of X and Y chromosomes of humans.
Compare the number of genes present on the X chromosome and the shorter Y chromosome in humans.
Define sex linkage.
State two examples of sex linkage.
Show that a human female can be homozygous or heterozygous, with respect to sex-linked traits and a male cannot.
Explain that female carriers are heterozygous for sex-linked genes.
Calculate and predict the genotypic and phenotypic ratios of offspring of monohybrid crosses involving any of the above patterns of inheritance.
Deduce the genotypes or phenotypes of individuals in pedigree charts.
Calculate and predict the genotypic and phenotypic ratios of offspring of dihybrid crosses involving unlinked autosomal genes.
Define linkage group.
Explain an example of a cross between two linked genes.
Identify which of the offspring are recombinants in a dihybrid cross involving linked genes.
Give examples of polygenic inheritance.
Explain that polygenic inheritance can contribute to continuous variation, using two examples including human skin color.
AP Biology Review In a Nut Shell – Introduction to Heredity
A.
Mendel’s Laws (remember he laid groundwork for genetics but these rules can all be broken looking at chromosome theory and molecular genetics)
1.
Law of Dominance- one allele will be expressed over another (ex. Aa – if big A is purple it will be seen over little a which is white)
2.
Law of Segregation- alleles pairs separate from each other during meiosis
3.
Law of Independent Assortment- alleles assort independently during meiosis IF they are on separate chromosomes (i.e. AaBb can make gametes AB, Ab,
aB or ab)
4.
Genetics Literacy (see terms above)
B. Probability,Patterns and Exceptions to Mendel’s Rules
1.
product rule- multiply chance of one event happening by the chance of another event happening to get the chance of both events occurring together
2.
Inheritance patterns
3.
autosomal vs. sex-linked (on the X or Y chromosome)
4.
monohybrid cross; one trait; 3:1 (Aa x Aa); 1:1 (Aa x aa) or 4:1 (AA x_), (aa x aa)
5.
dihybrid cross; 9:3:3:1 genotype (AaBb x AaBb) or test cross 1:1:1:1(AaBb x aabb)
6.
Thomas Hunt Morgan- fruit flies, X- linked traits
a. male- heterozygous XY; Y chromosome is very small in mammals and fruit flies with few genes
b. female- homozygous XX
c. not for all living things sometime sex is determined by haploid/diploid or temperature or it is reversed in birds, moths, butterflies (XX is boy)
d. single gene mutations on X chromosome cause disease such as hemophilia or colorblindness
e. sex limited traits are dependent on sex of individual like milk production or male patterned baldness
7.
incomplete dominance- red X white  pink; both protein product are expressed and blended
8. codominance- red x white  red and white; both protein products are equally expressed ex.AB blood types
9. multiple alleles- blood types- ABO
10. epistasis- one gene affects expression of another
11. linked genes- genes on same chromosome that are inherited together (can be unlinked by crossing over); recombination frequency calculated by
recombinants/total; used for chromosome mapping; genes further apart cross over more often
12. gene/environment- phenotypes affect by environment, Siamese cat, flower color with soil pH, seasonal color in arctic animals, human height and weight
13. polygenic- continuous variation, many genes affect one trait- height, color
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Chloroplasts and mitochondria (come from egg in mammals)are randomly assorted in cell division so they do not follow Mendelian rules.
C.
Human Genetics
1.
karyotype- 22 pair autosomes & 1 pair sex chromosomes + 46 total chromosomes
2.
Chromosomal Mutations (occur during gamete formation)
1. deletion, inversion, addition of genes as a result of crossing over mistakes, ex. Prader Willi
2. chromosomal number abnormalities
a. nondisjunction- failure of chromosomes to separate at anaphase of meiosis
b. monosomy- 45 chromosomes- Turner’s- XO
c. trisomy- Down’s- trisomy 21; Kleinfelters- XXY
3. amniocentesis/chorionic villus sampling - for prenatal diagnosis
-------------------------------------------------------------------------------------------------------------------------------------------------Equations: See Chi-Square Analysis
Laws of Probability
If A and B are mutually exclusive, then P (A or B) = P(A) + P(B)
If A and B are independent, then P (A and B) = P(A) x P(B)
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Enduring Understanding 3.A: Heritable information provides continuity of life.
EK 3.A.3: The chromosomal basis of inheritance provides an understanding of the pattern of
transmission of genes from parent to offspring.
EK 3.A.4: The inheritance pattern of many traits cannot be explained by simple Mendelian genetics.
Enduring Understanding 3.C: The processing of genetic information is imperfect and is a source of genetic
variation
EK 3.C.1: Changes in genotype can result in changes in phenotype
EK 3.C.2: Biological systems have multiple processes that increase genetic variation.
Enduring Understanding 4.C: Naturally occurring diversity among and between components within biological
systems affects interactions with the environment.
EK 4.C.2: Environmental factors influence the expression of the genotype in an organism