Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Asexual reproduction is the process resulting in the production of genetically identical offspring from one parent, without the fusion of gametes or change in chromosome number ().
Sexual reproduction involves the fusion of two haploid () gamete nuclei to form a diploid () zygote, resulting in genetically diverse offspring.
The cellular mechanism for asexual reproduction is mitosis, whereas sexual reproduction relies on meiosis to produce haploid gametes () from diploid germ cells ().
Genetic variation in sexual reproduction is driven by three main factors: crossing over during Prophase I, independent assortment during Metaphase I, and random fertilization of gametes.
Advantages of asexual reproduction include rapid population growth and no requirement for a mate, while sexual reproduction allows for adaptation to changing environments through genetic diversity.
📐Formulae
💡Examples
Problem 1:
In a species of lily, the diploid chromosome number is . If a pollen grain (male gamete) fertilizes an egg cell, calculate the chromosome number of the resulting zygote and the number of chromosomes in a leaf cell produced by asexual vegetative propagation.
Solution:
Zygote chromosome number = ; Leaf cell chromosome number = .
Explanation:
The pollen and egg are haploid (). Their fusion restores the diploid state (). A leaf cell produced via asexual propagation is formed through mitosis, which maintains the original diploid number ().
Problem 2:
Calculate the total number of possible genetic combinations in the gametes of an organism where , assuming variation is only due to independent assortment.
Solution:
combinations.
Explanation:
The number of possible combinations due to independent assortment is calculated using the formula , where is the haploid number. Since , . Therefore, .