Inheritance
Overview
Why do children look like their parents but never exactly the same? The answer lies in the way genes are passed from one generation to the next. Every cell in your body carries a set of instructions written in DNA, and the way those instructions combine at fertilisation determines your inherited characteristics.
In this lesson you will learn how chromosomes carry genes, how dominant and recessive alleles produce different traits, and how to use genetic diagrams and Punnett squares to predict the outcomes of crosses. You will also explore sex determination, the sources of genetic variation, and Darwin's theory of natural selection.
Objectives
- 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
- Describe patterns of monohybrid inheritance using a genetic diagram
- 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 random fertilisation produces genetic variation of offspring
- Understand that variation within a species can be genetic, environmental, or a combination of both
- Explain Darwin's theory of evolution by natural selection
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Inheritance. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- What is an allele? A) A type of chromosome B) An alternative form of a gene C) A section of RNA D) A type of protein Answer: B
- If both parents are heterozygous (Bb), what fraction of offspring would be expected to show the recessive phenotype? A) 0 B) 1/4 C) 1/2 D) 3/4 Answer: B
- Which pair of sex chromosomes is found in a human male? A) XX B) XY C) YY D) XO Answer: B
- An organism with the genotype Bb is described as: A) Homozygous dominant B) Homozygous recessive C) Heterozygous D) Codominant Answer: C
- Which of the following is an example of environmental variation? A) Blood group B) Eye colour C) A scar from an injury D) Earlobe shape Answer: C
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Practice Mock Questions
Want to practice mock questions on Inheritance? Download the Green Bridge CBT app to access mock questions and full practice assessments for this topic.
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