Biology Chapter 11 Genetics Study Guide

The study of heredity

Who is known as the father of genetics?
Gregor Mendel

What did Mendel work with in his experiments of genetics?
Garden peas

Why did Mendel pick pea plants to use in his experiments?
This was because these plants reproduce

What does the male part of the pea plant contain?
This part contains the pollen

What does the female part of the pea plant contain?
This part consists of the egg cells

In order to perform his experiments, what did Mendel have to do?
Mendel selected the pea plants he would mate with each other. He then cut the male parts of the flower off and dusted them with pollen from a second flower

A trait is a specific characteristic that varies from one individual to another

What did Mendel do when he crossed the plants?
Mendel crossed plants with each of the 7 contrasting characters and studied their offspring (homozygous)

The offspring of crosses between parents with different traits (heterozygous)

What conclusions did Mendel come up with after his experiments?
Mendel found that biological inheritance is determined by factors that are passed on from one generation to the next

The likelihood that a particular event will occur

Why are the principles of probability important to genetics?
They can be used to predict the outcomes of genetic crossings

Punnet Squares
Are used in genetics to help determine what gene combinations might result from a genetic cross

What letters represent dominant alleles?
Capital letters

What letters represent recessive alleles?
Lowercase letters

Two identical alleles for a particular trait

What is an example of homozygous?
TT, tt

Two different alleles for the same trait

Physical characteristics

Genetic makeup

One trait is crossed at a time

Two traits are crossed at a time

Law of Dominance
The inheritance of biological characteristics is determined by individual units known as genes. In organisms that reproduce sexually, genes are passed from parent to their own offspring

Law of Segregation
In most sexually reproducing organisms, each adult has 2 copies of each gene, one from each parent. These genes are usually segregated from each other when gametes are formed

Law of Independent Assortment
The alleles for different genes usually segregate separately of one another

Incomplete Dominance
Cases in which one allele is not completely dominant over another

What is the intermediate phenotype in incomplete dominance?
This is the phenotype somewhere in between the 2 main phenotypes

Homologous Chromosomes
Are chromosomes that each have a corresponding chromosome from the opposite sex parent

Means two sets and is used to describe both sets of homologous chromosomes

When there is only a single set of chromosomes

The process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell

What two states does meiosis have?

A structure formed when each chromosome pairs with its corresponding homologous chromosome

Crossing Over
A process by which homologous chromosomes can also exchange parts of their chromatids

What does meiosis 1 result in?
This results in two haploid daughter cells, each with 1/2 the number of chromosomes as the original cell

What does meiosis II result in?
This results in 4 haploid daughter cells

What does meiosis create?
Meiosis creates gametes with half the number of body cells

Why is Thomas Hunt Morgan important to genetic studies?
His research with fruit flies led to “Principle of Linkage”

Principle of Linkage
When many genes appear to be linked

Gene Linkage
Genes located on same chromosomes are genetically inherited together

How does gene linkage affect the usual ratios found when working punnet squares?
They can alter usual ratios

What is a gene map?
Diagram showing relative locations of genes on chromosomes

How are the locations of genes determined on a gene map?
Look at the rate at which genes were separated and recombined to figure out the distances between genes

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