How to study to get maximum score in genetics section

"To do it quickly without making mistakes, students must be proficient in the skills of writing cross-breeding diagrams, synthesizing cross-breeding formulas...", shared teacher Thinh Van Nam, a Biology teacher with nearly 20 years of experience teaching exam preparation.

In the Natural Science exam of the national high school exam, Biology only has 50 minutes to complete 40 multiple choice questions. This subject isIn theory (theoretical questions account for more than 60%), the exercises are usually on genetic laws.

So how will the general exam trends and the types of genetics exercises change with the multiple choice test format this year? This is a question that students need to have an answer to, thereby helping to orient their learning more focused.

In recent years, the exam has tended to favor short questions and exercises with quick solutions. The questions are subject-specific and many require practical knowledge to solve.

The recent trend of the exam questions on genetics has changed very quickly. From the heavy calculation type of exercises to the very light calculation type, but still testing a lot of knowledge.

Exercise 1: HStudents need to understand the nature of biological processes.

This is a high-level exercise, not heavy on calculations but still testscomprehensive from basic knowledge to students' analytical and synthesis skills.

Type 2: When doing exercises, if students want to do them quickly without making mistakes, they must master the skills of writing crossbreeding diagrams, synthesizing crossbreeding operations...

Example 2: In a plant species, flower shape is determined by the complementary interaction of two independently assorting non-allelic genes located on an autosomal chromosome. Knowing that the genotype (AB-) gives double flower phenotype, the remaining genotypes give single flower phenotype. Let the plant heterozygous for 2 pairs of genes self-pollinate to get F1 then let F1 freely crossbreed with each other to produce F2. How many crosses give F2 with phenotype segregation in a ratio of 3:1?

Type 3: When you encounter this type of question, immediately use the quick calculation formula.

Quick calculation formula is an indispensable tool if we want to save maximum time when doing exercises.

For example, when we encounter a cross between two individuals heterozygous for two pairs of genes and one gene determines a trait, the dominant is complete, then we do not need to pay attention to whether the two pairs of traits are inherited independently, linked, or permuted. The result of the cross always gives the phenotype of the next generation:

Individuals with two dominant traits have a ratio of: 50% + the ratio of phenotypes with two recessive traits;

Individuals with dominant and recessive phenotypes = Individuals with recessive and dominant phenotypes = 25% - the proportion of phenotypes with two recessive traits.

Through the 3 types of exercises above, it can be seen that when studying the types of exercises on the laws of heredity, students need to orient themselves towards exercises with neat topics, exercises that focus on using basic knowledge of Biology to solve. Each type of exercise requires a separate solution method.

Therefore, before each exercise, you need to read the question carefully, analyze the given data; the next step is to apply the skills you have to solve the problem as quickly as possible.

Note that when doing a multiple choice test, the 4 answer options are suggestions to help us solve the problem faster.

According to VNE