حل مراجعة عامة حسب الهيكل في العلوم باللغة الإنجليزية للصف السادس انسبير (2)

Al Dannah School C2&3 Girl’s

Principal; Amina Almulla

Teacher: Nour Bany Yaseen

MCQ

Genes, sections of chromosomes carrying genetic information for specific traits, are passed to offspring from both parents. Asa result, offspring often, at least to some extent, look like their parents, although variation occurs among individuals.

trait characteristics like skin, hair, or eye color that are inherited from

parents، genetics

the study of how traits are passed from parents to their offspring

dominant

a genetic trait that is observable dominant allele is expressed

in، an، organism، when

Hybrid: traits came from true –breeding parent plants with different forms of the same trait

recessive a genetic trait that is masked (hidden) in an organism by the

presence of a dominant allele

First-Generation Crosses Crossing two true-breeding plants with purple flowers gave plants with just purple flowers. Crossing two true-breeding plants with white flowers gave plants with just white flowers. Crossing truebreeding plants with purple flowers and true-breeding plants with white flowers unexpectedly gave plants with just purple flowers. Second-Generation (Hybrid) Crosses The first-generation purpleflowering plants are hybrids that were bred from true-breeding plants with different forms of the same trait. Crossing two purpleflowering hybrid plants gave purple and white flowers.

: What do you think Mendel observed when he crossed a true-breeding plant with purple flowers with a true-bleeding plant with white flowers? All the offspring had purple flowers.

ASK: Are the results of the two crosses the same?

Yes. They are arranged differently in the figure,

but the number (and ratio) of purple and white

flowers is the same.

ASK: Why do you think some white flowers

appeared in Mendel's hybrid crosses?

.Some may realize that something from the white

true-breeding plant was hidden and reappeared

in the next generation.

In Mendel's second-generation

cross, the trait for white flowers reappeared. This may have

What is the approximate trait ratio in the Second-Generation occurred because the parents were hybrids and contained

Cross?

some part of the white flower trait.

Purple (hybrid) x Purple (hybrid)

A) 100% dominant trait B) 50% dominant, 50% recessive C) 3:1 (75% dominant, 25% recessive) D) 100% recessive trait

2. C-Correct. A, B, and D are incorrect because traits must be passed to the grandmother's and mother's generation to reappear in the brother.

3. C-Correct. A and B are incorrect because the white flowers have a homozygous recessive genotype. The white allele is not expressed in the offspring because the dominant purple allele is present. D is incorrect because the term does not apply to this question.