Genetics

Question 1

Allele

Answer 1

A letter representing the version of a trait that one parent passes down through one of their gametes to their offspring.

Question 2

Carrier

Answer 2

An organism that has the recessive allele for a trait but does not show the trait (often a mother who is heterozygous for a sex-linked trait).

Question 3

Dominant

Answer 3

The version of an allele that is always expressed.

Question 4

Gene

Answer 4

A section on a chromosome/a unit of heredity that codes for a certain trait.

Question 5

Codominance

Answer 5

A pattern of inheritance that has three phenotypes: two extremes and one where both extremes are expressed on the same organism.

Question 6

Monohybrid vs. Dihybrid

Answer 6

Monohybrid crosses determine the inheritance of one trait at a time, while dihybrid crosses determine the inheritance of two traits at a time.

Question 7

Heterozygous

Answer 7

A trait where the alleles are different, one dominant and one recessive. For example, Tt in plants where tall is dominant and short is recessive.

Question 8

Homozygous

Answer 8

A trait where the alleles are the same, both dominant or both recessive. For example, TT or tt in plants where tall is dominant and short is recessive.

Question 9

Incomplete Dominance

Answer 9

A pattern of inheritance that has three phenotypes: two extremes and one where the two extremes are mixed/blended. An example is crossing a red flower and a white flower to produce pink flowers.

Question 10

Karyotype

Answer 10

A visual representation showing the number and appearance of the chromosomes in the nucleus of a cell, as well as the gender of the organism.

Question 11

Genetic Variation

Answer 11

The varying or combinations of different DNA to produce genetically unique organisms.

Question 12

Law of Independent Assortment

Answer 12

Chromosomes line up independently on the metaphase plate during meiosis, so different alleles for different traits are passed down to offspring independently of each other.

Question 13

Law of Segregation

Answer 13

Each parent of an offspring passes down exactly one allele for each trait in each gamete.

Question 14

Genotype

Answer 14

The pair of alleles (genetic makeup) that codes for a trait in an organism. Example: Tt in plants.

Question 15

Phenotype

Answer 15

The physical expression/appearance of the genotype in an organism. Example: Tall matching a genotype of Tt.

Question 16

Punnett Square

Answer 16

A diagram that shows the heredity in a certain pattern of inheritance between generations, allowing likelihoods for the expression of certain genotypes and phenotypes to be calculated. Example Punnett Squares are drawn in my Genetic Review Packet.

Question 17

Polygenic

Answer 17

A problem or trait in genetic that involves multiple genes controlling one physical appearance. Example: skin color.

Question 18

Gregor Mendel

Answer 18

A monk and scientist who studied heredity and genetic in pea plants to determine how Punnett Squares can be used to track the passing down of a trait or multiple traits.

Question 19

Trait

Answer 19

A certain characteristic of an organism.

Question 20

Autosomal Dominant

Answer 20

A trait that is autosomal and is expressed by the dominant allele.

Question 21

Autosomal Recessive

Answer 21

A trait that is autosomal and is expressed by the pairing of recessive alleles.

Question 22

Sex-Linked

Answer 22

A trait that is passed down determined by genes on the X chromosomes of the parents.

Question 23

Sex-Linked Traits

Answer 23

Traits that are passed down according to the genetic makeups of the parents’ X chromosomes.

Question 24

Monohybrid

Answer 24

A cross that determines the heredity of one trait.

Question 25

Recessive

Answer 25

A trait that is expressed when both alleles in an organism for that trait are recessive.

Question 26

Multiple Alleles

Answer 26

A problem/trait in genetics where several different alleles (3-4) are available to choose from. Each trait still contains only 2 alleles, like normal, so some alleles are incomplete dominant or codominant with each other. Example: human blood type. Punnett Square example shown in Genetic Review packet.

Question 27

Rules of Pedigrees

Answer 27

If the trait can skip generations (unaffected parents have affected children), then the trait is autosomal recessive. If every affected child has an affected parent, then the trait is autosomal dominant. If the trait is much more common in males than females and every affected female’s son is affected, then the trait in question is sex-linked. If none of these rules fit, go back and look through each stage again.