Sex-Linked Genes: Knowledge Catalog Grade 9 Biology #10

Summary

In this Grade 9 biology session, students explore non-Mendelian inheritance patterns, focusing on sex determination and sex-linked genes. The lesson begins with a discussion on how human sex is determined, using a Punnett square to illustrate sex chromosome inheritance. It then delves into sex-linked traits, such as color blindness and hypertrichosis spinae oris, explaining their genetic transmission. The session concludes with an activity where students calculate the probabilities of inheriting color blindness. The instructor encourages engagement through interactive questions and provides answers to reinforce learning.

Takeaways

• 📚 The session is designed for grade 9 biology students focusing on non-Mendelian inheritance patterns.
• 🔍 Students are instructed to refer to their learner's module, specifically module number 2, unit 1, pages 12 to 15.
• 📈 The presentation is divided into three parts: an activity on determining sex in humans, a discussion on sex-linked genes, and another activity where gender matters.
• 🧬 The activity titled 'Boy or Girl' explores how sex is determined in humans, including the recognition of intersex individuals.
• 🎓 A Punnett square is used to illustrate the inheritance of sex chromosomes, with XX representing females and XY representing males.
• 🤔 Questions are posed to engage students in thinking about the sex of offspring resulting from different types of fertilization.
• 🧵 The discussion on sex-linked genes covers three types of inheritance: sex-linked, sex-limited, and sex-influenced.
• 👁️‍🗨️ Color blindness is presented as an example of an X-linked recessive trait, affecting males more frequently than females.
• 🧔 Hypertrichosis spinae oris, a condition causing hairiness on the ears, is described as a Y-linked trait, passed from father to sons.
• 🔄 The final activity involves solving problems related to sex-linked traits, such as calculating the chances of offspring being colorblind given the parents' genotypes.
• 🌟 The session concludes with a recap of the key points covered and an invitation for students to engage with the content creator's channel.

Q & A

What is the main topic of session 10 in the grade 9 biology course?

The main topic of session 10 in the grade 9 biology course is explaining the different patterns of non-Mendelian inheritance.

What materials are students expected to have for this biology session?

Students are expected to have their learner's module opened to module number 2, unit 1, pages 12 to 15.

How can students get a copy of the presentation or video lessons discussed in the script?

Students can contact the teacher through the Facebook page 'facebook.com/knowledgecatalog/yen' to get a copy of the presentation or video lessons.

What is the objective of activity number four titled 'Boy or Girl'?

The objective of activity number four is for students to discuss how sex in humans is determined.

What is represented by the XX and XY chromosomes in the context of the script?

In the context of the script, XX represents the female sex chromosomes, and XY represents the male sex chromosomes.

What is the expected sex of a child if an egg is fertilized by a sperm with a Y chromosome?

The expected sex of a child if an egg is fertilized by a sperm with a Y chromosome is male.

What type of sperm must fertilize an egg to result in a female child?

An egg must be fertilized by a sperm carrying an X chromosome to result in a female child.

According to the Punnett square discussed in the script, what is the percentage of children expected to be male?

According to the Punnett square, the percentage of children expected to be male is 50%.

Which sex chromosome is present in both males and females?

The X chromosome is present in both males and females.

What is the role of the Y chromosome in determining a person's sex according to the script?

The Y chromosome is the sex chromosome that better means a person's sex, as it is responsible for determining male sex when present in an individual's genetic makeup.

What are some factors that can influence the expression of human sexuality as discussed in the script?

Some factors that can influence the expression of human sexuality include environmental factors such as the age of the mother, which may lead to non-disjunction and trisomy 21, and social interactions during birth.

What are the three kinds of sex-related inheritance mentioned in the script?

The three kinds of sex-related inheritance mentioned in the script are sex-linked, sex-limited, and sex-influenced.

What is the relationship between color blindness and sex chromosomes as discussed in the script?

Color blindness is an X-linked recessive disorder, meaning the gene for color blindness is located on the X chromosome. Males are more likely to be affected because they have only one X chromosome.

How does the script explain the inheritance of hypertrichosis spinae oris?

Hypertrichosis spinae oris is explained as a trait found in the Y chromosome, meaning only males can have the trait, and a father will pass it on to all his sons.

What is the chance and percentage that a child will be colorblind if one parent is a colorblind male and the other is a carrier female?

The chance and percentage that a child will be colorblind in this scenario is 50%.