Unit 5 - Heredity

Sep 29, 2026

AP Biology Unit 5: Heredity materials focus on meiosis and key genetic processes. The content outlines Meiosis I and II stages, including chromatin condensation, homologous chromosome alignment, crossing over, independent assortment, sister chromatid separation, and the formation of haploid daughter cells. It also compares mitosis versus meiosis in terms of chromosome behavior and genetic outcomes, then summarizes core inheritance patterns such as complete dominance, codominance, incomplete dominance, monohybrid and dihybrid ratios, and genetic linkage, autosomal, sex-linked, maternal, and X-linked recessive concepts. Included practice and review elements reinforce comprehension.

LanguageEnglish

CategoryExam

FormatPDF

Pages30

Reading Time1 h 16 min

AccessFree to download

Today’s Plan

Meiosis

Meiosis I: Homologous Chromosomes

Meiosis II: Sister Chromatids

Mitosis

Mitosis vs. Meiosis

Inheritance Patterns

Monohybrid and Dihybrid Ratios

Types of Inheritance (Autosomal, Sex-Linked, Maternal, Linked Genes, X-linked)

Unit 5: Heredity @apbiopenguins AP Biology students are penguins because they are Dressed for Success! You are now an AP Bio Penguin! Resource Reminders: Daily Review on IG stories 374 page Review Guide on Weebly Recorded FRQ Fridays on YouTube 120+ Quizizz Games on Weebly Review PowerPoints on Weebly Weebly: [www.apbiopenguins.weebly.com](www.apbiopenguins.weebly.com) Today’s Plan Meiosis Genetics NoMnndelianMendelian Chromosomal Practice Questions Unit 5 Q&A Prophase I Chromatin condenses Sister chromatids/homologous chromosomes align CROSSING OVER Meiosis Prophase I Chromatin condenses Sister chromatids/homologous chromosomes align CROSSING OVER Anaphase I HOMOLOGOUS CHROMOSOMES Metaphase I HOMOLOGOUS CHROMOSOMES align on the metaphase plate INDEPENDENT ASSORTMENT separate to opposite poles Telophase I Nuclear envelope forms around the HAPLOID daughter cells Meiosis I: Homologous Chromosomes Meiosis Meiosis II: Sister Chromatids Chromatin condenses Sister chromatids align Prophase II SISTER CHROMATIDS separate to opposite poles Anaphase II SISTER CHROMATIDS align on the metaphase plate Metaphase II Nuclear envelope forms around the HAPLOID daughter cells Telophase II Mitosis Meiosis Parent Cell Ploidy Diploid Diploid Rounds of DNA Replication 1 1 Rounds of Nuclear Division 1 2 Daughter Cell Ploidy Diploid Haploid Number of Daughter Cells 2 4 Mitosis vs. Meiosis Mitosis Meiosis Compare to Parent Cell Identical Genetically Distinct Crossing Over Does not occur Occurs in Prophase I Independent Assortment Does not occur Occurs in Metaphase I Inheritance Patterns Complete Dominance Homozygous dominant and heterozygous look the same Codominance Heterozygous is both dominant traits in organism Incomplete Dominance Heterozygous is a blend between he two dominant traits | | Y | y | | --- | --- | --- | | Y | YY | Yy | | y | Yy | yy | | | R | r | | --- | --- | --- | | R | RR | Rr | | r | Rr | rr | Yellow: ¾ Green: ¼ Round: ¾ Wrinkled: ¼ Yellow & Round: ¾ x ¾ = 9/16 Yellow & Wrinkled: ¾ x ¼ = 3/16 Green & Round: ¼ x ¾ = 3/16 Green & Wrinkled: ¼ x ¼ = 1/16 Monohybrid Heterozygous for ONE trait Complete Dominance: 3:1 ratio Incomplete or Codominance: 1:2 :1 Dihybrid Heterozygous for TWO traits Complete Dominance: 9:3:3:1 ratio Incomplete or Codominance: 6 :3:3:2 :1:1 Inheritance Patterns Autosomal Inheritance Allele is located on an autosome (non-sex chromosome) Sex-Linked Allele is located on a sex chromosome Maternal Inheritance Allele is located on the DNA found in a mitochondrial or chloroplast Linked Genes Genes located on the same chromosome closely together Autosomal Recessive Inheritance Patterns Autosomal Inheritance Allele is located on an autosome (non-sex chromosome) Sex-Linked Allele is located on a sex chromosome Maternal Inheritance Allele is located on the DNA found in a mitochondrial or chloroplast Linked Genes Genes located on the same chromosome closely together X-linked recessive

FAQs

What happens during Prophase I of meiosis?

Chromatin condenses, sister chromatids remain associated, and homologous chromosomes align. Crossing over occurs during Prophase I.

How do independent assortment and crossing over relate to meiosis?

Independent assortment occurs when homologous chromosomes align on the metaphase plate during Meiosis I. Crossing over occurs earlier, during Prophase I.

What are the expected genotype ratios for monohybrid crosses under different dominance types?

Complete dominance produces a 3:1 ratio, while incomplete or codominance produces a 1:2:1 ratio.

Sep 29, 2026

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