https://www.khanacademy.org/science/ms-biology/x0c5bb03129646fd6:inheritance-and-variation/x0c5bb03129646fd6:genes-proteins-and-traits/v/genes-proteins-and-traits 2024-05-09T17:42:08.599818576Z Genes, proteins, and traits Genes are specific stretches of nucleotides on a DNA molecule. Genes encode proteins, which are made up of amino acids. The order of nucleotides in a gene determines the order of amino acids in a protein. A protein’s amino acids determine its 3D shape and its functions in the cell, which, in turn, affect an organism’s traits. Khan Academy video https://cdn.kastatic.org/ka_thumbnails_cache/13c2afcc-cd5f-45ff-90f2-08e3c4600c8f_1280_720_base.png Genes, proteins, and traits Genes are specific stretches of nucleotides on a DNA molecule. Genes encode proteins, which are made up of amino acids. The order of nucleotides in a gene determines the order of amino acids in a protein. A protein’s amino acids determine its 3D shape and its functions in the cell, which, in turn, affect an organism’s traits. https://cdn.kastatic.org/ka-youtube-converted/tfZfLDRu39c.mp4/tfZfLDRu39c.mp4 293 Mendelian inheritance and basic genetic principles https://www.khanacademy.org/science/ms-biology/x0c5bb03129646fd6:inheritance-and-variation/x0c5bb03129646fd6:genes-proteins-and-traits/e/understand-genes-proteins-and-traits 2025-07-01T21:05:20.470958635Z Understand: genes, proteins, and traits Check your understanding of genes, proteins, and traits in this set of free, standards-aligned practice questions. Khan Academy exercise https://www.khanacademy.org/science/ms-biology/x0c5bb03129646fd6:inheritance-and-variation/x0c5bb03129646fd6:genes-proteins-and-traits/a/genes-proteins-and-traits-ms 2026-02-27T17:50:36.702607024Z Genes, proteins, and traits Learn about how genes encode proteins, which in turn affect an organism's traits. article https://www.khanacademy.org/science/ap-biology/heredity/mendelian-genetics-ap/v/introduction-to-heredity 2024-05-06T19:22:43.24334365Z Introduction to heredity Genetics is a fascinating world, focusing on the inheritance of traits from parents to offspring. Gregor Mendel, the father of classical genetics, made significant contributions to our understanding of this process. Dominant and recessive traits play a crucial role in determining an individual's characteristics. The difference between genotype and phenotype is also a key concept, illustrated here through the example of eye color. Sal Khan video https://cdn.kastatic.org/googleusercontent/8KIf2nldPHl_YkUGoCt--4xtrssHU4GlREN-E_6zXDvVjyqYNNxv9_z-xHocJlPA3PzezY3GjEdQFMO0rmkNhtdF Introduction to heredity Genetics is a fascinating world, focusing on the inheritance of traits from parents to offspring. Gregor Mendel, the father of classical genetics, made significant contributions to our understanding of this process. Dominant and recessive traits play a crucial role in determining an individual's characteristics. The difference between genotype and phenotype is also a key concept, illustrated here through the example of eye color. https://cdn.kastatic.org/ka-youtube-converted/eEUvRrhmcxM.mp4/eEUvRrhmcxM.mp4 1047 Mendelian inheritance and basic genetic principles https://www.khanacademy.org/science/in-in-class-10-biology/in-in-heredity-and-evolution/in-in-heredity-mendels-experiment/e/hs-introduction-to-heredity 2026-04-02T04:18:15.637466676Z Introduction to heredity Test your knowledge on the basics of heredity! Ashley exercise https://www.khanacademy.org/science/ap-biology/heredity/mendelian-genetics-ap/v/alleles-and-genes 2024-05-06T19:22:43.24334365Z Alleles and genes Genes and alleles are key players in heredity. Genes are sections of DNA that code for specific proteins or functional RNA. Alleles, on the other hand, are different versions of the same gene. They can lead to variations in traits like eye color. Understanding these differences is crucial to studying inheritance patterns. Sal Khan video https://cdn.kastatic.org/googleusercontent/atnlb_82AH8iycsnXpe6IzctbMGY4Z5t7EI_4JQp6wTkWpE565kanLxyJ6GN41UFrIxwvHLdu473BzkK548_KwO4 Alleles and genes Genes and alleles are key players in heredity. Genes are sections of DNA that code for specific proteins or functional RNA. Alleles, on the other hand, are different versions of the same gene. They can lead to variations in traits like eye color. Understanding these differences is crucial to studying inheritance patterns. https://cdn.kastatic.org/ka-youtube-converted/P0nMnPPdW_k.mp4/P0nMnPPdW_k.mp4 498 Mendelian inheritance and basic genetic principles https://www.khanacademy.org/science/ap-biology/heredity/meiosis-and-genetic-diversity/v/fertilization-haploid-diploid-gamete-zygote-homologous 2023-06-22T09:32:02.370557018Z Fertilization terminology: gametes, zygotes, haploid, diploid Sperm and egg cells, known as gametes, fuse during fertilization to create a zygote. Gametes have half the chromosomes (haploid) of a typical body cell, while zygotes have the full set (diploid). Homologous chromosomes from each parent determine traits, including sex. Understanding haploid and diploid numbers is essential in studying cell division and genetics. Sal Khan video https://cdn.kastatic.org/googleusercontent/_B-0JAgVd28pAi9-Az9SL_hzmtoTyLkIoWL7JB58chL1G4YDCF0I3Ph_BY067hId_WUI_FwDLT0QbWSfM2-E8dgI Fertilization terminology: gametes, zygotes, haploid, diploid Sperm and egg cells, known as gametes, fuse during fertilization to create a zygote. Gametes have half the chromosomes (haploid) of a typical body cell, while zygotes have the full set (diploid). Homologous chromosomes from each parent determine traits, including sex. Understanding haploid and diploid numbers is essential in studying cell division and genetics. https://cdn.kastatic.org/ka-youtube-converted/dNp7vErqlaA.mp4/dNp7vErqlaA.mp4 627 Mendelian inheritance and basic genetic principles https://www.khanacademy.org/science/ap-biology/heredity/mendelian-genetics-ap/a/the-law-of-segregation 2024-06-28T21:00:15.59562973Z The law of segregation Learn about the law of segregation, the terms genotype, phenotype, alleles, heterozygous, and homozygous, and how to solve 2 x 2 Punnett squares. article https://www.khanacademy.org/science/ap-biology/heredity/mendelian-genetics-ap/v/punnett-square-fun 2023-05-19T13:48:00.997234898Z Worked example: Punnett squares Punnett squares help predict offspring traits by showing possible gene combinations from parents. In addition, Punnett squares can illustrate trends among dominant and recessive traits, incomplete dominance, codominance, and dihybrid crosses. Punnett squares are useful for understanding genetics and inheritance patterns. Sal Khan video https://cdn.kastatic.org/googleusercontent/R8VkM8uRLyXHFhrMl2vBUmr9L7OLlYouzHTDCZgQA7kXviEbs4eEGif-g00nX6V3uMq7K0-EVhLIK6WYE2MvqrJbwA Worked example: Punnett squares Punnett squares help predict offspring traits by showing possible gene combinations from parents. In addition, Punnett squares can illustrate trends among dominant and recessive traits, incomplete dominance, codominance, and dihybrid crosses. Punnett squares are useful for understanding genetics and inheritance patterns. https://cdn.kastatic.org/ka-youtube-converted/D5ymMYcLtv0.mp4/D5ymMYcLtv0.mp4 1516 Mendelian inheritance and basic genetic principles https://www.khanacademy.org/science/ap-biology/heredity/mendelian-genetics-ap/a/mendel-and-his-peas 2024-06-28T21:00:15.59562973Z Mendel and his peas Learn about how Austrian monk Gregor Mendel laid the foundations of genetics. article https://www.khanacademy.org/science/shs-biology-2/x2ea931c66bba6acd:3rd-quarter/x2ea931c66bba6acd:lesson-1-genetics/e/punnett-squares 2023-05-19T13:48:00.997234898Z Monohybrid punnett squares Test your knowledge of punnett squares! Ashley exercise https://www.khanacademy.org/science/ap-biology/heredity/mendelian-genetics-ap/v/pedigrees 2023-06-28T10:25:59.601084121Z Pedigrees Pedigrees are a useful method to model the inheritance patterns of traits within families. By using symbols and analyzing phenotypes, we can infer genotypes and understand the role of autosomal dominant traits. The trait of freckles serves as a practical example here and shows the complex world of genetic inheritance patterns. Sal Khan video https://cdn.kastatic.org/googleusercontent/Afo7Cb0lkI0fz6vVEK7wnX7SeI_wP8CfxydkzCAud4aSCxNys39TjC_JTecAWBbEQomCQ_YaC0o9CKAZq0SVnffj Pedigrees Pedigrees are a useful method to model the inheritance patterns of traits within families. By using symbols and analyzing phenotypes, we can infer genotypes and understand the role of autosomal dominant traits. The trait of freckles serves as a practical example here and shows the complex world of genetic inheritance patterns. https://cdn.kastatic.org/ka-youtube-converted/11s5Biyi9q4.mp4/11s5Biyi9q4.mp4 368 Mendelian inheritance and basic genetic principles https://www.khanacademy.org/science/ap-biology/heredity/mendelian-genetics-ap/e/mendelian-genetics-exercise 2023-09-18T04:47:02.457024108Z Mendelian genetics Test your knowledge of Mendelian genetics! Haider Ali Bhatti exercise https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:inheritance-and-variation-of-traits/x230b3ff252126bb6:mendelian-genetics/v/dihybrid-cross-and-the-law-of-independent-assortment 2024-06-28T21:00:15.59562973Z Dihybrid cross and the law of independent assortment The probabilities of different offspring genotypes and phenotypes can be determined using a Punnett square. A dihybrid cross results in a roughly 9:3:3:1 ratio of offspring phenotypes. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/9a837eb7-e3ee-4758-94a1-3ae480cf24ec_1280_720_base.png Dihybrid cross and the law of independent assortment The probabilities of different offspring genotypes and phenotypes can be determined using a Punnett square. A dihybrid cross results in a roughly 9:3:3:1 ratio of offspring phenotypes. https://cdn.kastatic.org/ka-youtube-converted/ZkyX3TmmMag.mp4/ZkyX3TmmMag.mp4 548 Mendelian inheritance and basic genetic principles https://www.khanacademy.org/science/up-class-10th-science/x5d08d26681869997:heredity/x5d08d26681869997:heredity-and-mendel-s-experiments/e/dihybrid-cross-in 2025-03-30T13:01:39.012708499Z Dihybrid cross Let's solve some questions! vibhor exercise https://www.khanacademy.org/science/grade-11-biology-snc-aligned/x58c107ba92d3f0b2:domain-h-reproduction-and-inheritance/x58c107ba92d3f0b2:mendelian-genetics-and-inheritance-laws/v/genetic-recombination-1 2022-11-16T04:22:43.7414897Z Genetic recombination Genetic recombination is a process that occurs during meiosis, which is the type of cell division that produces gametes. During this process, homologous chromosomes pair up and form a unit called a tetrad. The chromosomes can then cross over and exchange genetic material, which results in new combinations of alleles. This process is important because it increases genetic variability, which can be beneficial for a species. Efrat Bruck video https://cdn.kastatic.org/googleusercontent/WZRJvlM7tQVrcLaEMmKX7njgSnbCqK6GmpQhHC48KRmiQicEpOgAqA-SHz1_t_cMsdY0_AxAGPcgsgZ_712mATA Genetic recombination Genetic recombination is a process that occurs during meiosis, which is the type of cell division that produces gametes. During this process, homologous chromosomes pair up and form a unit called a tetrad. The chromosomes can then cross over and exchange genetic material, which results in new combinations of alleles. This process is important because it increases genetic variability, which can be beneficial for a species. https://cdn.kastatic.org/ka-youtube-converted/BlnUNmfGn7I.mp4/BlnUNmfGn7I.mp4 372 Mendelian inheritance and basic genetic principles https://www.khanacademy.org/science/ap-biology/heredity/mendelian-genetics-ap/a/the-law-of-independent-assortment 2024-06-28T21:00:15.59562973Z The law of independent assortment Learn about the law of independent assortment, dihybrid crosses, and how to solve 4 x 4 Punnett squares. article https://www.khanacademy.org/science/ap-biology/heredity/meiosis-and-genetic-diversity/v/chromosomal-crossover-in-meiosis-i 2023-09-14T11:22:40.102153098Z Chromosomal crossover in meiosis I Meiosis is a process where germ cells divide to produce gametes, such as sperm and egg cells. In prophase I of meiosis, chromosomes condense and homologous recombination takes place, leading to genetic variation through chromosomal crossover. This forms a tetrad, which is made up of four chromatids (two sister chromatids per chromosome). Sal Khan video https://cdn.kastatic.org/googleusercontent/psK-SXXmGmEgFbcsXqGFcFzxeISQE5UOch7140SY4rw72J2577ffgYYSg_za8sG3AT9Sm10Tgk-6selPwL2w9YIh Chromosomal crossover in meiosis I Meiosis is a process where germ cells divide to produce gametes, such as sperm and egg cells. In prophase I of meiosis, chromosomes condense and homologous recombination takes place, leading to genetic variation through chromosomal crossover. This forms a tetrad, which is made up of four chromatids (two sister chromatids per chromosome). https://cdn.kastatic.org/ka-youtube-converted/04gQ0bQu6xk.mp4/04gQ0bQu6xk.mp4 736 Mendelian inheritance and basic genetic principles