Biology Chapter 12: Gregor Mendel Flashcards

Questions and Answers

Which organisms did Mendel use as his 'model system' in developing his principles of heredity?

Peas

What is genetics?

The study of heredity and the variation of inherited characteristics.

Are 'true breeding' plants homozygous or heterozygous?

True

What are 3 traits that Mendel observed during his experiments?

Flower color (purple/white), Plant height (tall/short), Pod shapes (smooth/constricted) Signup and view all the answers

When 2 true breeding parents were crossed, Mendel found that the offspring (F1) were ______________?

heterozygous Signup and view all the answers

Name the male parts of a flower.

Anther and filament Signup and view all the answers

Name the female parts of a flower.

Stigma, style, pollen tube, ovary, ovule Signup and view all the answers

What is pollination?

Transfer of pollen from anther to stigma Signup and view all the answers

What is cross pollination?

Pollen of a flower transmits to another flower and enters the stigma Signup and view all the answers

What is Mendel's First Principle of Inheritance?

Inheritance is determined by units called genes, which are passed from parents to offspring. Signup and view all the answers

What are alleles?

Different forms of a gene Signup and view all the answers

What is Mendel's Second Principle of Inheritance?

Where more than one form of a gene for a single trait exists, some alleles may be dominant and others recessive. Signup and view all the answers

What is a dominant allele?

A form of a gene that is fully expressed, even when two different alleles are present; HH or Hh Signup and view all the answers

What is a recessive allele?

A form of a gene that is not expressed when paired with a dominant allele; aa or aA Signup and view all the answers

What is Mendel's Third Principle of Inheritance?

Each adult has two copies of each gene—one from each parent. These genes segregate from each other when gametes are formed. Signup and view all the answers

What is a gamete?

Sex cell Signup and view all the answers

What does homozygous mean?

Having two identical alleles for a trait Signup and view all the answers

What does heterozygous mean?

Having two different alleles for a trait Signup and view all the answers

What is a genotype?

Genetic makeup Signup and view all the answers

What is a phenotype?

An organism's physical appearance, or visible traits. Signup and view all the answers

What is probability?

Likelihood that a particular event will occur Signup and view all the answers

What is a Punnett Square?

A diagram that is used to predict an outcome of a particular cross or breeding experiment Signup and view all the answers

What are the probabilities in percentages of the offspring having brown eyes? Blue eyes?

Brown Eyes (75%) and Blue Eyes (25%) Signup and view all the answers

What is Mendel's Fourth Principle of Inheritance?

Alleles for different genes usually segregate independently of each other. Signup and view all the answers

What are Non-Mendelian traits?

Traits that do not follow the normal way that traits are created. Signup and view all the answers

What is incomplete dominance?

One allele is not completely dominant over another. Signup and view all the answers

What is codominance?

The phenotypes for both alleles are clearly expressed. Signup and view all the answers

What are multiple alleles?

Many genes exist in more than two forms. Signup and view all the answers

What are polygenic traits?

Many traits produced by the interaction of several genes. Signup and view all the answers

In addition to genes, what other factors might affect gene expression?

Environmental conditions Signup and view all the answers

Study Notes

Mendel's Experiments and Key Concepts

Gregor Mendel utilized pea plants as his model system for studying heredity.
Genetics is defined as the study of heredity and variation in inherited characteristics.
True breeding plants are homozygous, having identical alleles for a trait.

Observed Traits and Terms

Mendel's key traits included flower color (purple/white), plant height (tall/short), and pod shapes (smooth/constricted).
When true breeding parents were crossed, the first generation (F1) offspring were heterozygous.

Flower Anatomy and Pollination

The male parts of a flower are called the anther and filament.
Female flower parts include stigma, style, pollen tube, ovary, and ovule.
Pollination involves the transfer of pollen from the anther to the stigma.
Cross pollination occurs when pollen from one flower is transferred to another flower.

Principles of Inheritance

Mendel's First Principle states that inheritance involves genes passed from parents to offspring.
Alleles are different forms of a gene, with dominant alleles expressed fully, and recessive alleles only expressed when paired with another recessive allele.
Mendel's Second Principle highlights that some alleles are dominant while others are recessive.
His Third Principle explains that each adult has two gene copies, one from each parent, which segregate during gamete formation.
A gamete is defined as a sex cell.

Genetic Terminology

Homozygous refers to having two identical alleles for a trait.
Heterozygous indicates having two different alleles for a trait.
Genotype is the genetic makeup of an organism, while phenotype describes its physical appearance or visible traits.
Probability refers to the likelihood of a particular event occurring.

Predictive Tools in Genetics

A Punnett Square is a diagram used to predict the outcome of a breeding experiment.
In a typical cross, probabilities for offspring traits such as brown eyes (75%) and blue eyes (25%) can be calculated.

Additional Principles and Advanced Concepts

Mendel's Fourth Principle establishes that alleles for different genes usually segregate independently.
Non-Mendelian traits do not follow traditional inheritance patterns, indicating complex genetics.
Incomplete dominance occurs when one allele is not completely dominant over another.
Codominance involves the clear expression of both alleles' phenotypes.
Multiple alleles refer to genes existing in more than two forms.
Polygenic traits result from the interaction of several genes impacting a single trait.
Environmental conditions can influence gene expression alongside genetic factors.

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Description

Explore the foundational principles of genetics through this quiz focused on Gregor Mendel's experiments. Test your knowledge on key concepts such as heredity, true breeding plants, and the significance of Mendel's model system. Perfect for biology students and anyone interested in the science of inheritance.