Virtual Science Teachers

Bell-Ringers: Inheritance and Variation of Traits

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Genetics and Traits

Use the arrows located at the bottom of the presentation to navigate through all the bell ringer questions.

  1. All genes determine visible traits. While many genes determine traits we can see (like eye color), others might influence things we can’t easily observe (like metabolism rate).

  2. Dominant genes are more common in populations. Just because a gene is dominant does not mean it’s more frequent in a population.

  3. If parents don’t show a trait, their children can’t have it. Recessive traits can be carried without being expressed and can appear in future generations.

  4. Mutations are always harmful. While some mutations can be harmful, others can be beneficial or neutral.

  5. A mutation in a gene will always result in a noticeable change in the organism. Many mutations have no noticeable effect.

  6. Genes work in isolation. In reality, multiple genes often work together to determine a trait.

  7. Every cell contains different DNA. With few exceptions (like mature red blood cells), every cell in an organism contains the same DNA.

  8. Traits that are beneficial will eventually appear in all individuals of a species. This is not necessarily true due to genetic drift, gene flow, and other evolutionary forces.

  9. Mutations are the result of external damage only (e.g., radiation). While external factors can cause mutations, they can also occur naturally during DNA replication.

  10. Genes and proteins have a one-to-one relationship. One gene can give rise to multiple protein variants through processes like alternative splicing.

Genetic Diversity: Inheritance & Variation

Use the arrows located at the bottom of the presentation to navigate through all the bell ringer questions.

  1. All Traits are Inherited from Parents: Some people might think that every trait an organism has is directly inherited from its parents. However, some traits arise from interactions between genes and the environment.

  2. Equal Contribution from Each Parent: The misconception that every trait is a 50-50 mix from each parent. In reality, dominant and recessive alleles can influence the appearance of a trait.

  3. Males and Females Contribute the Same Chromosomes: A common misconception is that males and females contribute the same type of sex chromosome to their offspring. In reality, females contribute an X chromosome while males can contribute either an X or a Y chromosome, determining the offspring’s sex.

  4. All Offspring from the Same Parents are Genetically Identical: Some believe that siblings should have identical genes since they have the same parents. However, due to the random assortment of chromosomes, each offspring is genetically unique, barring identical twins.

  5. Genes Dictate Only Physical Traits: There’s a misconception that genes only influence physical appearance. Genes can also influence behavior, susceptibility to certain diseases, and more.

  6. Dominant Traits are More Common: Just because a trait is dominant doesn’t mean it’s more common in a population. For instance, having six fingers is dominant over having five, but it’s rarer.

  7. If Parents Don’t Show a Trait, Offspring Won’t Either: Recessive traits can be carried without being expressed. Two carriers of a recessive allele can produce offspring that express the recessive trait.

  8. The Misunderstanding of Random: “Genes acquired at random” might be misconstrued to mean any possible genetic combination can occur. However, the “random” aspect refers to the way alleles separate during gamete formation — it doesn’t mean offspring can have genes that aren’t present in either parent.

  9. Two Alleles, One from Each Parent: While it’s true that individuals inherit two alleles (one from each parent) for a given gene, some might mistakenly think this means they inherit two versions of each gene. In reality, they inherit one gene with two possible alleles that can influence the expression of a trait.

  10. All Genetic Differences are Visible: Some might think that all genetic differences result in observable traits. However, many genetic differences are “silent” or don’t result in any noticeable change in the organism.