Inheritance
Aperçu
Why do children look like their parents but never look exactly the same? The answer lies in the way genes are inherited, shuffled during cell division, and expressed as visible characteristics. Inheritance is also the mechanism behind evolution and the growing problem of antibiotic resistance.
In this lesson you will learn how chromosomes carry genes, how alleles determine phenotype, and how to use Punnett squares to predict the outcomes of monohybrid crosses. You will also compare mitosis and meiosis, explore mutation and variation, and explain Darwin's theory of natural selection.
Objectifs
- Understand that the genome is the entire DNA of an organism and that a gene is a section of a molecule of DNA that codes for a specific protein
- Understand that the nucleus of a cell contains chromosomes on which genes are located
- Understand how genes exist in alternative forms called alleles which give rise to differences in inherited characteristics
- Understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype and genotype
- Understand that most phenotypic features are the result of polygenic inheritance rather than single genes
- Describe patterns of monohybrid inheritance using a genetic diagram
- Understand how to interpret family pedigrees
- Predict probabilities of outcomes from monohybrid crosses
- Understand how the sex of a person is controlled by one pair of chromosomes, XX in a female and XY in a male
- Describe the determination of the sex of offspring at fertilisation using a genetic diagram
- Understand how division of a diploid cell by mitosis produces two cells that contain identical sets of chromosomes
- Understand that mitosis occurs during growth, repair, cloning and asexual reproduction
- Understand how division of a cell by meiosis produces four cells, each with half the number of chromosomes
- Understand how random fertilisation produces genetic variation of offspring
- Know that in human cells the diploid number of chromosomes is 46 and the haploid number is 23
- Understand that variation within a species can be genetic, environmental, or a combination of both
- Understand that mutation is a rare, random change in genetic material that can be inherited
- Explain Darwin's theory of evolution by natural selection
- Understand how resistance to antibiotics can increase in bacterial populations
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Évaluation de la leçon
Félicitations, vous avez terminé la leçon sur Inheritance. Maintenant que vous avez exploré le concepts et idées clés, il est temps de mettre vos connaissances à l'épreuve. Cette section propose une variété de pratiques des questions conçues pour renforcer votre compréhension et vous aider à évaluer votre compréhension de la matière.
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- What is the diploid number of chromosomes in human body cells? A) 23 B) 46 C) 44 D) 92 Answer: B
- If a heterozygous tall plant (Tt) is crossed with a short plant (tt), what ratio of tall to short offspring is expected? A) 3:1 B) 1:1 C) 4:0 D) 1:3 Answer: B
- Which type of cell division produces gametes? A) Mitosis B) Meiosis C) Binary fission D) Fertilisation Answer: B
- A mutation in a gene is best described as: A) A change in chromosome number B) A change in the DNA base sequence C) The loss of an entire chromosome D) The addition of a new protein Answer: B
- Antibiotic resistance in bacteria is an example of: A) Artificial selection B) Genetic engineering C) Natural selection D) Selective breeding Answer: C
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Livres recommandés
Pour aller plus loin, ressources libres
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Section de manuel
Characteristics and Traits
Explain the relationship between genotypes and phenotypes in dominant and recessive gene systems
"Biology: Characteristics and Traits" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/biology/pages/12-2-characteristics-and-traits. Access for free at https://openstax.org/books/biology/pages/1-introduction
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Section de manuel
Cell Division
Describe the structure of prokaryotic and eukaryotic genomes
"Biology: Cell Division" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/biology/pages/10-1-cell-division. Access for free at https://openstax.org/books/biology/pages/1-introduction
Publiées par d'autres organisations sous licence libre, créditées comme elles le demandent. Les liens ouvrent leurs sites.
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