AP®︎ Biology: Unit 5 Practice Test
Prepare for your quiz, test, or the AP exam with focused practice questions on Unit 5 of AP Biology – Heredity.
Questions List
Unit 5 (All Topics)
Question 1 Topic 5.1Easy
This question tests the following: IST-1.F
What type of cells does meiosis create?
What You’re Being Tested On:
Explore the learning objectives taken directly from the College Board’s AP® Biology Curriculum. Ensure you’re prepared for the exact topics covered on the AP® exam, in-class tests, and quizzes, and gain confidence in your mastery of the material.
Unit 5: Heredity
Covers how traits are passed down through meiosis and genetic inheritance, including Mendelian and non-Mendelian genetics.
Topic 5.1: Meiosis
Learning Objective: 5.1.A
Explain how meiosis results in the transmission of chromosomes from one generation to the next.
Essential Knowledge: 5.1.A.1
Meiosis is a process that ensures the formation of haploid gamete cells, sometimes referred to as daughter cells, in sexually reproducing diploid organisms.
Essential Knowledge: 5.1.A.2
Meiosis I involves the following steps: i. Prophase I: Homologous chromosomes pair up and condense, synapsis occurs and then chiasmata may form, meiotic spindle begins to form, centrosomes move to opposite poles of the cell, and the nuclear envelope breaks down. ii. Metaphase I: Meiotic spindle fibers align homologous pairs of chromosomes along the equator of the cell at the metaphase plate. iii . Anaphase I: Homologous chromosomes separate, while sister chromatids remain attached, as meiotic spindle fibers pull chromosomes toward poles. iv . Telophase I: Meiotic spindle breaks down, a new nuclear envelope develops, a cleavage furrow (animal cell) or cell plate (plant cell) forms, and cytokinesis occurs. Two haploid daughter cells are formed (at the end of meiosis I).
Essential Knowledge: 5.1.A.3
Meiosis II involves the following steps: i. Prophase II: Meiotic spindle forms; sister chromatids connected at the centromere attach to meiotic spindle. ii. Metaphase II: Chromosomes align along the metaphase plate; the kinetochore of each chromatid is attached to a microtubule extending from the poles. iii. Anaphase II: Proteins at the centromeres break down, and sister chromatids are pulled apart and toward opposite poles in the cell. iv. Telophase II: Meiotic spindle breaks down, a new nuclear envelope develops, a cleavage furrow (animal cell) or a cell plate (plant cell) forms, chromatids begin to decondense, and cytokinesis occurs. Four haploid daughter cells are formed, each with an unduplicated chromatid.
Learning Objective: 5.1.B
Describe similarities and differences between the phases and outcomes of mitosis and meiosis.
Essential Knowledge: 5.1.B.1
Mitosis and meiosis are similar in the use of a spindle apparatus to move chromosomes but differ in the number of cells produced and the genetic content of the daughter cells.
Topic 5.2: Meiosis and Genetic Diversity
Learning Objective: 5.2.A
Explain how the process of meiosis generates genetic diversity.
Essential Knowledge: 5.2.A.1
Correct separation of the homologous chromosomes in meiosis I and sister chromatids in meiosis II ensures that each gamete receives a haploid (1n) set of chromosomes that comprises an assortment of both maternal and paternal chromosomes. When incorrect separation occurs (nondisjunction), gametes are no longer haploid.
Essential Knowledge: 5.2.A.2
During prophase I of meiosis, non-sister chromatids exchange genetic material via a process called crossing over (recombination), which increases genetic diversity among the resultant gametes.
Essential Knowledge: 5.2.A.3
Sexual reproduction in eukaryotes increases genetic variation, including crossing over, random assortment of chromosomes during meiosis, and subsequent fertilization of gametes. Exclusion: Knowledge of the details of sexual reproduction cycles in various plants and animals is beyond the scope of the AP Exam.
Topic 5.3: Mendelian Genetics
Learning Objective: 5.3.A
Explain the inheritance of genes and traits as described by Mendel’s laws. Patterns of inheritance (autosomal, genetically linked, sex-linked) and whether an allele is dominant or recessive can often be predicted from data, including pedigrees. Punnett squares can be used to predict the genotypes and phenotypes of parents and offspring.
Essential Knowledge: 5.3.A.1
Mendel’s laws of segregation and independent assortment can be applied to genes that are on different chromosomes.
Essential Knowledge: 5.3.A.2
In most cases, fertilization involves the fusion of two haploid gametes, restoring the diploid number of chromosomes and increasing genetic variation in populations by creating new combinations of alleles in the zygote. i. Rules of probability can be applied to analyze the passing of single-gene traits from parent to offspring. ii. Monohybrid, dihybrid, and test crosses can be used to determine whether alleles are dominant or recessive. iii. An organism’s genotype is the set of alleles inherited for one or more genes by an individual organism. An organism’s genotype can be homozygous or heterozygous for each gene. iv. An organism’s phenotype is the observable expression of the inherited traits. RELEVANT EQUATIONS 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 ) × P ( B )
Learning Objective: 5.3.A
Explain the inheritance of genes and traits as described by Mendel’s laws. Patterns of inheritance (autosomal, genetically linked, sex-linked) and whether an allele is dominant or recessive can often be predicted from data, including pedigrees. Punnett squares can be used to predict the genotypes and phenotypes of parents and offspring.
Essential Knowledge: 5.3.A.1
Mendel’s laws of segregation and independent assortment can be applied to genes that are on different chromosomes.
Essential Knowledge: 5.3.A.2
In most cases, fertilization involves the fusion of two haploid gametes, restoring the diploid number of chromosomes and increasing genetic variation in populations by creating new combinations of alleles in the zygote. i. Rules of probability can be applied to analyze the passing of single-gene traits from parent to offspring. ii. Monohybrid, dihybrid, and test crosses can be used to determine whether alleles are dominant or recessive. iii. An organism’s genotype is the set of alleles inherited for one or more genes by an individual organism. An organism’s genotype can be homozygous or heterozygous for each gene. iv. An organism’s phenotype is the observable expression of the inherited traits. RELEVANT EQUATIONS 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 ) × P ( B )
Topic 5.4: Non-Mendelian Genetics
Learning Objective: 5.4.A
Explain deviations from Mendel’s model of the inheritance of traits.
Essential Knowledge: 5.4.A.1
Patterns of inheritance of many traits do not follow the ratios predicted by Mendel’s laws and can be identified by quantitative analysis, when the observed phenotypic ratios statistically differ from the predicted ratios. i. Genes located on the same chromosome are referred to as being genetically linked. The probability that these linked genes segregate together during meiosis can be used to calculate the map distance (or map units) between them on a chromosome. This calculation is called gene or genetic mapping. ii. Codominance occurs when the phenotype from both alleles is expressed such that the heterozygote would have a different phenotype than either homozygote. iii. Incomplete dominance occurs when neither allele of a gene can mask the other, so the phenotype of the heterozygote is a blended version of the dominant and recessive phenotypes.
Essential Knowledge: 5.4.A.2
Some traits, known as sex-linked traits (X- or Y-linked), are determined by genes on sex chromosomes. The pattern of inheritance of sex-linked traits can often be predicted from data, including pedigrees, indicating the genotypes and phenotypes of both parents and offspring. Illustrative examples: Sex-linked traits (X- or Y-linked) reside on sex chromosomes.; Sex-linked traits (X- or Y-linked) are inherited at higher rates in XY individuals than they are in XX individuals.; In certain species, the chromosomal basis of sex determination is not based on X and Y chromosomes (e.g., ZW in birds, haplodiploidy in bees).
Essential Knowledge: 5.4.A.3
Pleiotropy is a phenomenon in which the expression of a single gene results in multiple traits or effects; these traits therefore do not segregate independently.
Essential Knowledge: 5.4.A.4
Some traits result from non-nuclear inheritance. i. Chloroplasts and mitochondria are randomly assorted to gametes and daughter cells; thus, traits determined by chloroplast and mitochondrial DNA do not follow simple Mendelian rules. ii. In animals, mitochondria are usually transmitted by the egg and not by sperm; thus, traits determined by the mitochondrial DNA are typically maternally inherited. iii. In plants, mitochondria and chloroplasts are transmitted in the ovule and not in the pollen; as such, mitochondria-determined and chloroplast-determined traits are typically maternally inherited.
Topic 5.5: Environmental Effects on Phenotype
Learning Objective: 5.5.A
Explain how the same genotype can result in multiple phenotypes under different environmental conditions.
Essential Knowledge: 5.5.A.1
Environmental conditions influence gene expression and can lead to phenotypic plasticity (e.g., the ability of individual genotypes to produce different phenotypes). Illustrative examples: Height and weight in humans; Flower color based on soil pH; Seasonal fur color in arctic animals; Sex determination in reptiles; Effect of increased UV on melanin production in animals; Presence of the opposite mating type on pheromone production in yeast and other fungi.
