Introduction to Genetics and Mendel
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Questions and Answers

What did Gregor Mendel primarily study in his experiments?

  • Microbial genetics
  • Human genetics
  • Animal genetics
  • Pea plant hybridization (correct)

Mendel's work was widely recognized and celebrated during his lifetime.

False (B)

What are the two types of alleles related to a particular characteristic?

Homozygous and Heterozygous

A _______ is a fixed location on a strand of DNA where a gene or one of its alleles is located.

<p>locus</p> Signup and view all the answers

Match the following genetic terms with their definitions:

<p>Gene = A unit of heredity encoding a single protein Genome = The entire set of genes in an organism Alleles = Two genes at the same locus covering the same trait Homozygous = Identical genes for a particular characteristic</p> Signup and view all the answers

Which process is described as new combinations of genes in sexual reproduction?

<p>Fertilization (A)</p> Signup and view all the answers

Homologous chromosomes contain unique genes that do not pair with each other.

<p>False (B)</p> Signup and view all the answers

What was the name of Mendel's published work?

<p>Experiments in Plant Hybridization</p> Signup and view all the answers

What is the principle of independent assortment?

<p>Members of one gene pair segregate independently from other gene pairs (D)</p> Signup and view all the answers

Incomplete dominance results in a phenotype that is either dominant or recessive.

<p>False (B)</p> Signup and view all the answers

What phenotypic ratio is observed in the F2 generation when pink snapdragons are self-pollinated?

<p>1:2:1</p> Signup and view all the answers

The principle of _____ states that genes become separated during gamete formation.

<p>segregation</p> Signup and view all the answers

Match the following concepts with their definitions:

<p>Dominance = One allele masks another Segregation = Genes separate during gamete formation Independent Assortment = Gene pairs segregate independently Incomplete Dominance = Intermediate heterozygous phenotype</p> Signup and view all the answers

What is the term for the allele that masks the expression of an alternate allele?

<p>Dominant (A)</p> Signup and view all the answers

A recessive allele appears in the phenotype when in a heterozygous condition.

<p>False (B)</p> Signup and view all the answers

What does the term 'phenotype' refer to?

<p>The physical appearance of an organism</p> Signup and view all the answers

In a monohybrid cross, parents differ by a single ______.

<p>trait</p> Signup and view all the answers

Match the following terms with their definitions:

<p>Dominant = Allele that masks another allele Recessive = Allele that is masked by a dominant allele Genotype = The genetic makeup of an organism Phenotype = The physical appearance of an organism</p> Signup and view all the answers

What would the genotype of a homozygous tall plant be?

<p>TT (D)</p> Signup and view all the answers

All offspring from the cross PP × pp will be heterozygous.

<p>True (A)</p> Signup and view all the answers

Using a Punnett square allows you to predict the ______ and ______ of the offspring.

<p>genotypes, phenotypes</p> Signup and view all the answers

Flashcards

Genetics

The study of heredity and variation in organisms.It's about how traits are passed from parents to offspring.

Gregor Mendel

An Austrian monk who studied pea plants and discovered the basic principles of inheritance through experiments.

Gene

A unit of heredity. A segment of DNA that contains the information for a specific trait.

Alleles

Different forms of a gene occupying the same position on homologous chromosomes.

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Homozygous

Having two identical alleles for a specific gene.

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Heterozygous

Having two different alleles for a specific gene.

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Monohybrid cross

A genetic cross involving a single trait.

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Genome

All the genes in an organism.

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Principle of Segregation

During gamete formation, gene pairs separate, ensuring each gamete receives only one gene from each pair.

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Principle of Independent Assortment

Different gene pairs independently separate during gamete formation, leading to new gene combinations.

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Incomplete Dominance

A cross where the heterozygous phenotype is a blend of the homozygous phenotypes.

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Hereditary Factors

The genes located on chromosomes, that dictate traits or characteristics.

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Monohybrid vs. Dihybrid cross

A monohybrid cross follows only one trait, while a dihybrid cross follows two traits.

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Dominant allele

A type of allele that masks or suppresses the expression of another allele.

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Recessive allele

An allele only expressed when present in a homozygous state (both alleles matching).

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Phenotype

The visible or measurable characteristic(s) of an organism, influenced by both genotype and the environment.

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Punnett Square

A diagram used to predict the possible genotypes of offspring from a cross.

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Study Notes

Introduction to Genetics

  • Genetics is the branch of biology studying heredity and variation in organisms.
  • Chromosomes contain hereditary information in the form of genes.
  • Genes are sequences of DNA that encode proteins.
  • Chromosomes (and genes) exist in pairs.
  • New combinations of genes occur during sexual reproduction through fertilization from two parents.

Gregor Mendel

  • Gregor Mendel, an Austrian monk, studied heredity using pea plants.
  • Mendel's work involved controlled crosses of pea plants to study inheritance patterns.
  • Mendel showed that heredity is not a "blending" process but follows specific patterns.
  • He experimented with seven traits of pea plants.
  • In 1866, Mendel published his findings.
  • His work was initially overlooked, but later rediscovered and recognized as seminal work in genetics.

Mendel's Principles

  • Principle of Dominance: One allele can mask the expression of another.
  • Principle of Segregation: During gamete formation, the paired hereditary factors (genes) separate, ensuring each sex cell receives only one gene.
  • Principle of Independent Assortment: Members of one gene pair separate independently from other pairs during gamete formation. This leads to various combinations of traits in offspring.

Monohybrid and Dihybrid Crosses

  • Monohybrid crosses investigate the inheritance of a single trait.
  • Dihybrid crosses explore the inheritance of two separate traits.
  • These crosses support the principles of segregation and independent assortment.
  • Monohybrid crosses often involve parental generations (P generation) and first, or filial generation (F1 generation).

Punnett Square

  • A Punnett square is a tool to predict genotypes and phenotypes of offspring.
  • It visually represents the possible combinations of alleles in offspring resulting from a genetic cross.

Beyond Mendelian Genetics – Incomplete Dominance

  • Incomplete dominance occurs when the heterozygous phenotype is intermediate between the two homozygous phenotypes.
  • For example, in snapdragons, a cross between a red flower and a white flower produces pink flowers. This shows incomplete dominance.
  • The F1 generation consists of offspring exhibiting an intermediate phenotype (e.g., pink flowers).
  • When the F1 generation is self-pollinated, the F2 generation displays a 1:2:1 ratio of red, pink, and white flowers.

Genetic Terms

  • Gene: A unit of heredity, a section of DNA encoding a single protein.
  • Genome: The complete set of genes in an organism.
  • Alleles: Different versions of a gene.
  • Homozygous: Having identical alleles for a particular gene.
  • Heterozygous: Having different alleles for a particular gene.
  • Dominant: An allele that masks the expression of another.
  • Recessive: An allele whose expression is masked by another.
  • Genotype: The genetic makeup of an organism, describing the specific alleles present.
  • Phenotype: The physical appearance of an organism, resulting from the interaction between genotype and environment.
  • Locus: The specific fixed location of a gene or allele on a chromosome.

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Mendelian Genetics PDF

Description

This quiz covers the foundational concepts of genetics, focusing on heredity and variation in organisms. You'll explore Gregor Mendel's groundbreaking work with pea plants and understand his principles of inheritance. Test your knowledge on essential genetic terms and Mendel's contributions to the field.

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