Chromosomes And Genes
Overview
Inside almost every one of your cells is a full instruction manual for building you, written in DNA and packaged into chromosomes. The manual is divided into genes, and small differences between versions of a gene, called alleles, are why no two people (except identical twins) are exactly alike.
In this lesson you will see what chromosomes are made of, define a gene and an allele, and work out how the X and Y chromosomes decide whether a baby is a boy or a girl, predicting the familiar 1:1 ratio of sexes with a genetic diagram.
Objectives
- State that chromosomes are made of DNA, which contains genetic information in the form of genes
- Define a gene as a length of DNA that codes for a protein
- Define an allele as an alternative form of a gene
- Describe the inheritance of sex in humans with reference to X and Y chromosomes
- [Supplement] State that the sequence of bases in a gene determines the sequence of amino acids used to make a specific protein (knowledge of the details of nucleotide structure is not required)
- [Supplement] Explain that different sequences of amino acids give different shapes to protein molecules
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Chromosomes And Genes. 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.
- A gene is best defined as: A. a whole chromosome B. a length of DNA that codes for a protein C. an alternative form of an allele D. a type of cell Answer: B
- An allele is: A. a length of protein B. an alternative form of a gene C. a sex chromosome D. a type of nucleus Answer: B
- The sex chromosomes of a human male are: A. XX B. XY C. YY D. XXY Answer: B
- What is the approximate ratio of male to female babies born, and why? A. 3:1, because of dominance B. 1:1, because equal numbers of X and Y sperm are made C. 2:1, because Y sperm swim faster D. 1:0, because the mother decides sex Answer: B
- Chromosomes are made of: A. protein only B. DNA C. carbohydrate D. lipid Answer: B
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.
Recommended Books
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