Genetics

Question 1

What is genetics?

Answer 1

The study of heredity and how traits are passed from parents to offspring

Question 2

What is heredity?

Answer 2

The transmission of genetic material from one generation to the next

Gene : A segment of DNA that codes for a protein , determining a particular trait

Question 3

What is a gene?

Answer 3

A segment of DNA that codes for a protein , determining a particular trait

Question 4

What is an allele?

Answer 4

Different versions of a gene that exist ( e . g ., dominant and recessive alleles

Important Vocabulary : Chromosomes : Structures within the nucleus made of DNA , containing many genes

Question 5

What are chromosomes?

Answer 5

Structures within the nucleus made of DNA , containing many genes

Question 6

What does homozygous mean?

Answer 6

Having two identical alleles for a gene ( e . g ., AA or aa

Heterozygous : Having two different alleles for a gene ( e

Question 7

What does heterozygous mean?

Answer 7

Having two different alleles for a gene ( e

Question 8

Who is Gregor Mendel and what did he discover?

Answer 8

The scientist who discovered the basic laws of inheritance using pea plants

Question 9

What is the Law of Segregation?

Answer 9

Each individual has two alleles for each gene , which segregate ( separate ) during gamete formation

Law of Independent Assortment : Genes for different traits are inherited independently of each other ( for traits located on different chromosomes )

Question 10

What is the Law of Independent Assortment?

Answer 10

Genes for different traits are inherited independently of each other ( for traits located on different chromosomes )

Question 11

What is an allele?

Answer 11

An allele that only expresses its trait when two copies are present ( e

Question 12

What is a Punnett Square used for?

Answer 12

A tool used to predict the possible genotypes of offspring from a cross between two individuals

Important Vocabulary : Dominant Allele : An allele that expresses its trait even when only one copy is present ( e . g ., A Recessive Allele : An allele that only expresses its trait when two copies are present ( e

Question 13

What is a dominant allele?

Answer 13

An allele that expresses its trait even when only one copy is present ( e . g ., A

Recessive Allele : An allele that only expresses its trait when two copies are present ( e

Question 14

What is a recessive allele?

Answer 14

An allele that only expresses its trait when two copies are present ( e

Question 15

What is a genotype?

Answer 15

The genetic makeup of an organism ( e . g ., AA , Aa , or aa

Phenotype : The physical appearance or traits of an organism ( e

Question 16

What is a phenotype?

Answer 16

The physical appearance or traits of an organism ( e

Question 17

What is incomplete dominance?

Answer 17

A situation where neither allele is completely dominant , and the heterozygous phenotype is a blend of the two alleles ( e . g ., red + white = pink

Codominance : A situation where both alleles are expressed equally in the heterozygous phenotype ( e

Question 18

What is codominance?

Answer 18

A situation where both alleles are expressed equally in the heterozygous phenotype ( e

Question 19

What are multiple alleles?

Answer 19

Some traits are determined by more than two alleles ( e . g ., blood types : A , B , O

Polygenic Inheritance : Traits controlled by two or more genes , leading to a range of phenotypes ( e

Question 20

What is polygenic inheritance?

Answer 20

Traits controlled by two or more genes , leading to a range of phenotypes ( e

Question 21

What is epistasis?

Answer 21

When one gene influences the expression of another gene

Question 22

What is pleiotropy?

Answer 22

When one gene affects multiple traits

Question 23

What are sex chromosomes?

Answer 23

The chromosomes that determine an organism ‘ s sex ( X and Y in humans )

Question 24

What is a mutation?

Answer 24

A change in the DNA sequence , which can lead to changes in proteins and traits

Types of Mutations : Point Mutation A change in a single nucleotide ( e

Question 25

What is a silent mutation?

Answer 25

A mutation that does not affect the protein due to redundancy in the genetic code

Question 26

What is a missense mutation?

Answer 26

A mutation that results in a different amino acid being incorporated into a protein ## Footnote Nonsense Mutation : A mutation that causes an early stop codon , potentially leading to a nonfunctional protein

Question 27

What is a nonsense mutation?

Answer 27

A mutation that causes an early stop codon , potentially leading to a nonfunctional protein

Question 28

What are autosomal dominant disorders?

Answer 28

Disorders caused by a dominant allele on a non - sex chromosome ( e

Question 29

What are autosomal recessive disorders?

Answer 29

Disorders caused by a recessive allele on a non - sex chromosome ( e . g ., cystic fibrosis ## Footnote X - linked Disorders : Disorders caused by mutations in genes located on the X chromosome ( e

Question 30

What is a carrier?

Answer 30

An individual who has one copy of a recessive allele for a disorder but does not express the disorder

Question 31

What is a pedigree?

Answer 31

A diagram that shows the inheritance pattern of a trait across generations ## Footnote Study Tips-360 Review key vocabulary and make sure you understand the meanings of terms like genotype , phenotype , allele , dominant , and recessive