Genetics and Human Inheritance Chapter 20

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Questions and Answers

What is the study of how traits are passed from parent to offspring?

Genetics (correct)

Evolution

Heredity

Genomics

What is the term for the transmission of traits from one generation to the next?

Heredity (correct)

Genetics

Inheritance

Traits

What are the segments of DNA that code for a specific protein?

Traits

Alleles

Genes (correct)

Chromosomes

What is a characteristic produced by the actions of one or more gene-directed proteins?

Trait Signup and view all the answers

What are different forms of a gene that produce different versions of the trait they determine?

Alleles Signup and view all the answers

How many chromosomes are received from each parent?

23 Signup and view all the answers

What is the purpose of a pedigree chart?

To study the genetic connections among individuals in a family Signup and view all the answers

What is a carrier in the context of genetics?

Someone who displays the dominant phenotype but is heterozygous for a trait Signup and view all the answers

What is the purpose of chorionic villus sampling (CVS)?

To confirm if the baby has a genetic disorder or chromosome condition Signup and view all the answers

What is the correct term for a trait that is not visible in the heterozygote?

Recessive trait Signup and view all the answers

What is the main goal of CRISPR technology?

To edit genes and treat genetic disorders Signup and view all the answers

What is the genotype of an offspring with freckles in a cross between two parents heterozygous for the freckle trait?

Ff Signup and view all the answers

What is the phenotypic ratio of offspring in a monohybrid cross?

3:1 Signup and view all the answers

What is the purpose of a dihybrid cross?

To study the inheritance of two traits Signup and view all the answers

What is the law of independent assortment?

The law that states that alleles of a pair segregate independently of other allele pairs during gamete formation Signup and view all the answers

What is the term for one gene having multiple effects on the body?

Pleiotropy Signup and view all the answers

What is the genotypic ratio of offspring in a monohybrid cross?

1:2:1 Signup and view all the answers

What is the result of having two copies of the sickle-cell allele?

All hemoglobin is the sickle-cell variety Signup and view all the answers

What happens to the sickled red blood cells in the body?

They break down and clog blood vessels Signup and view all the answers

What is the effect of sickle-cell anemia on the body's organs?

Multiple organs are affected, including the heart, brain, lungs, kidneys, and muscles and joints Signup and view all the answers

What is the probability of getting either a one or a six on a single roll of a fair six-sided die?

1/3 Signup and view all the answers

What is the term for the condition where an individual has one copy of the sickle-cell allele and one copy of the normal allele?

Sickle-cell trait Signup and view all the answers

Which rule is applied when finding the probability of an outcome that requires either event X or event Y to occur?

Rule of addition Signup and view all the answers

What is the result of the abnormal hemoglobin in sickle-cell anemia?

Red blood cells become sickle-shaped when oxygen content is low Signup and view all the answers

In an Aa x Aa cross, how many events can lead to a dominant phenotype?

3 Signup and view all the answers

Why can we apply the rule of addition in an Aa x Aa cross?

Because the events are mutually exclusive Signup and view all the answers

What is the type of situation where the rule of addition is applied?

Or situation Signup and view all the answers

Study Notes

Genetics Overview

The study of how traits are passed from parent to offspring is known as genetics.
The transmission of traits from one generation to the next is termed heredity.
Genes are segments of DNA that code for specific proteins, influencing traits in organisms.
A phenotype is a characteristic produced by the actions of gene-directed proteins.
Alleles are different forms of a gene that lead to various versions of a trait.

Chromosomes and Inheritance

Each parent contributes 23 chromosomes, resulting in a total of 46 for their offspring.
Pedigree charts are used to track the inheritance of traits and can illustrate genetic disorders in families.
A carrier in genetics refers to an individual who possesses one allele for a recessive trait but does not express the trait.

Genetic Testing and Techniques

Chorionic villus sampling (CVS) is a prenatal test used to detect genetic abnormalities in a fetus by sampling placental tissue.
A trait that is not visible in the heterozygote is classified as recessive.
The main goal of CRISPR technology is to enable precise editing of genes to modify genetic sequences.

Genetic Crosses and Ratios

In a cross between two heterozygous parents (Ff), the genotype of an offspring with freckles could be either FF or Ff.
The phenotypic ratio in a monohybrid cross is typically 3:1 for dominant to recessive traits.
A dihybrid cross assesses the inheritance of two different traits simultaneously.
The law of independent assortment states that alleles for different traits are distributed to gametes independently.

Genetic Conditions

Pleiotropy refers to one gene causing multiple effects on the body.
The genotypic ratio of offspring in a monohybrid cross is 1:2:1 (homozygous dominant : heterozygous : homozygous recessive).
Having two copies of the sickle-cell allele (HbS) leads to sickle-cell anemia.
Sickled red blood cells can lead to blockages in blood vessels, causing pain and organ damage.

Probability in Genetics

The probability of rolling either a one or a six on a fair six-sided die is 2 out of 6 or simplified to 1/3.
An individual with one sickle-cell allele and one normal allele is said to have the condition sickle-cell trait.
The addition rule is applied when determining the probability of an outcome that requires either event X or event Y to occur simultaneously.
Abnormal hemoglobin in sickle-cell anemia causes the red blood cells to deform and decrease oxygen transport efficiency.
In the Aa x Aa cross, three combinations lead to a dominant phenotype (AA and Aa), allowing the use of the addition rule in calculations.
The rule of addition is applicable in situations where multiple pathways can lead to a particular outcome.

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Description

Understand the principles of inheritance, breaks in chromosomes, and detecting genetic disorders. Learn how genetic information is carried on chromosomes and how traits are passed down from parents to offspring.