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Questions and Answers
Which trait is expressed in an organism when it has alternate forms of a gene?
Which trait is expressed in an organism when it has alternate forms of a gene?
The Law of Segregation states that offspring inherit two genetic alleles from each parent.
The Law of Segregation states that offspring inherit two genetic alleles from each parent.
False (B)
What is the phenotypic ratio of dominant to recessive traits in the F2 generation of pea plants?
What is the phenotypic ratio of dominant to recessive traits in the F2 generation of pea plants?
3:1
A trait that is masked and does not show itself in the organism is called a __________ trait.
A trait that is masked and does not show itself in the organism is called a __________ trait.
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Match the following terms with their definitions:
Match the following terms with their definitions:
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What is a key concept of Incomplete Dominance?
What is a key concept of Incomplete Dominance?
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Mendel's Law of Independent Assortment states that the inheritance of one trait depends on the inheritance of another.
Mendel's Law of Independent Assortment states that the inheritance of one trait depends on the inheritance of another.
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What ratio represents the dominant to recessive traits in the F2 generation of Mendel's experiments?
What ratio represents the dominant to recessive traits in the F2 generation of Mendel's experiments?
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What is the basic unit of heredity?
What is the basic unit of heredity?
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A DNA molecule is composed of two polypeptide chains that form a double helix.
A DNA molecule is composed of two polypeptide chains that form a double helix.
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Who is known as the father of genetics?
Who is known as the father of genetics?
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In genetics, ____ indicates a dominant trait and ____ indicates a recessive trait.
In genetics, ____ indicates a dominant trait and ____ indicates a recessive trait.
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Which of the following bases are found in DNA?
Which of the following bases are found in DNA?
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Mendel's experiments were conducted in a laboratory setting.
Mendel's experiments were conducted in a laboratory setting.
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What are chromosomes made of?
What are chromosomes made of?
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Study Notes
Genetics - Lesson 1
- Genetics is the branch of biology that studies genes, variation, and heredity.
- A gene is the basic unit of heredity, a sequence of nucleotides in DNA or RNA.
- Variation refers to diversity and differences among individuals or populations.
- Heredity is the genetic heritage passed down from biological parents.
Understanding DNA, Chromosomes, and Genes
- DNA (deoxyribonucleic acid) is a molecule composed of two polynucleotide chains forming a double helix.
- DNA carries genetic instructions for the development, functioning, growth, and reproduction of all known organisms and many viruses.
- Chromosomes are thread-like structures inside the nucleus of animal and plant cells, composed of protein and a single DNA molecule.
DNA Structure
- DNA is made of nucleotides, each containing a phosphate group, a pentose sugar (deoxyribose), and a nitrogenous base.
- Nitrogenous bases include Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
- These bases pair specifically (A with T, and C with G).
Types of Bases
- Adenine, Thymine, Cytosine, and Guanine are the four bases in DNA.
- The sequence of these bases codes for traits.
Father of Genetics
- Gregor Mendel conducted experiments with pea plants to understand inheritance patterns.
- His work formed the foundation for modern genetics.
Important Terms
- Allele: One of a pair of genes at a specific location on a chromosome, controlling a characteristic (e.g., blood type, color blindness).
- Dominant Trait: The trait that appears or is visibly expressed in an organism.
- Recessive Trait: The trait that is masked and does not show itself in the organism.
- Genotype: The combination of alleles an organism inherits (genetic code).
- Phenotype: The physical appearance of traits in an organism.
- Homozygous Dominant: Both alleles are dominant (e.g., AA).
- Heterozygous: One dominant allele and one recessive allele (e.g., Aa).
- Homozygous Recessive: Both alleles are recessive (e.g., aa).
Traits of Pea Plants
- Mendel studied seven traits in pea plants, each with two forms (e.g., round/wrinkled seeds, tall/short plants).
- He identified pure-breeding plants that consistently showed one form of a trait after generations of self-pollination.
Mendel's Experiments
- Mendel crossed different pea plant varieties.
- His experiments showed that traits are inherited as discrete units (genes).
- He found a 3:1 ratio of dominant to recessive traits in the second generation (F2).
Punnett Square
- A Punnett square is a tool to predict the probabilities of offspring traits.
Mendel's Laws of Heredity
- Law of Segregation: Parental genes separate randomly into sex cells; each offspring inherits one allele from each parent.
- Law of Independent Assortment: Genes for different traits are sorted separately, so inheritance of one trait doesn't depend on others.
- Law of Dominance: Organisms with alternate forms of a gene express the dominant form.
Other Inheritance Patterns
- Incomplete Dominance: Neither allele fully dominates, resulting in a new phenotype (e.g., a blend of traits in flower color).
- Codominance: Both alleles are expressed, resulting in both phenotypes being visible (e.g., spotted coat color in animals).
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Description
Explore the fundamentals of genetics in this quiz covering the basics of genes, variation, and heredity. Delve into the structure and function of DNA and its role in passing on genetic information. Perfect for anyone wanting to understand the building blocks of life.
