Revision Guide
Explore the fascinating world of heredity, understanding how traits are passed from parents to offspring through genes and chromosomes.
Heredity - Quick Look Revision Guide
Your 1-page summary of the most exam-relevant takeaways from Science.
This compact guide covers 20 must-know concepts from Heredity aligned with Class X preparation for Science. Ideal for last-minute revision or daily review.
Key Points
Define heredity with an example.
Heredity is the transmission of traits from parents to offspring. For example, a child may inherit eye color from their parents.
Explain variation in heredity.
Variation refers to differences in traits among individuals of a species, caused by genetic differences and environmental factors.
State Mendel's law of dominance.
Mendel's law states that in a pair of contrasting traits, one will be dominant and the other recessive. Dominant traits are expressed in the F1 generation.
Describe Mendel's law of segregation.
This law states that alleles for a trait separate during gamete formation, so each gamete carries only one allele for each trait.
Explain Mendel's law of independent assortment.
Genes for different traits are inherited independently of each other, leading to new trait combinations in offspring.
Define dominant and recessive traits.
Dominant traits are expressed even if only one allele is present, while recessive traits require two alleles to be expressed.
What is a gene?
A gene is a segment of DNA that codes for a specific protein, determining a particular trait in an organism.
Explain the concept of alleles.
Alleles are different versions of the same gene that can result in variations of the trait controlled by that gene.
Describe the genotype and phenotype.
Genotype is the genetic makeup of an organism, while phenotype is the physical expression of those genes.
How is sex determined in humans?
Sex is determined by the sex chromosomes: XX for females and XY for males. The father's sperm determines the child's sex.
What are sex chromosomes?
Sex chromosomes are the X and Y chromosomes that determine the sex of an individual. Females have XX, and males have XY.
Explain the role of DNA in heredity.
DNA carries genetic information that is passed from parents to offspring, determining inherited traits.
What is a chromosome?
A chromosome is a long DNA molecule with part or all of the genetic material of an organism.
Describe the process of DNA copying.
DNA copying is the process by which DNA replicates itself, ensuring genetic information is passed accurately during cell division.
What causes genetic variation?
Genetic variation is caused by mutations, recombination during sexual reproduction, and random fertilization.
Explain the importance of variation.
Variation is crucial for the survival of species as it allows adaptation to changing environments and evolution.
What is a monohybrid cross?
A monohybrid cross is a genetic cross between individuals differing in one trait, used to study inheritance patterns.
What is a dihybrid cross?
A dihybrid cross is a genetic cross between individuals differing in two traits, showing independent assortment of genes.
How do traits get expressed?
Traits are expressed through proteins synthesized based on genetic instructions, influenced by dominant and recessive alleles.
What is the significance of Mendel's experiments?
Mendel's experiments laid the foundation for genetics, explaining how traits are inherited and predicting inheritance patterns.
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