6. Genetics and Heredity

Question 0

True- Breeding

Answer 0

Organisms that produce offspring identical to themselves if allowed to self-pollinate

Ex. Mendel’s pea plants would true-breed and create offspring identical to themselves because essentially the plant would have 1 parent

Question 1

Fertilization

Answer 1

Process in sexual reproduction in which make and female reproductive cells join to form a new cell

Ex. The flower was fertilized when it’s male sperm joined with the female egg.

Question 2

Trait

Answer 2

Specific characteristic that varies from one individual to another

Ex. Mendel used pea plant breeding to determine which traits were dominant and recessive in the plants.

Question 3

Hybrid

Answer 3

Offspring of crosses between parents with different traits

Ex. The hybrid pea plant had 1 purple parent and 1 pink parent so it’s a pink-purple hybrid.

Question 4

Gene

Answer 4

Sequence of DNA that codes for a protein and thus determines a trait

Ex. I have a gene for fiery red hair.

Question 5

Allele

Answer 5

One of a number of different forms of a gene

Ex. The pea plant’s great height was determined by the dominant allele it carried.

Question 6

Segregation

Answer 6

Segregation of alleles during gamete formation

Ex. When Tt and Tt plants breed, there are 4 gametes. There are 2 T’s and 2 t’s. When the gametes come together the they are the variations of these alleles.

Question 7

Probability

Answer 7

Likelihood that a particular event will occur

Ex. The probability of Pea plants having tall characteristics is increased when both parents have the tall Gene.

Question 8

Punnett square

Answer 8

Diagram showing the gene combinations that might result from a genetic cross.

Ex. A punnet square shows the gene combinations that might result from a genetic cross.

Question 9

Homozygous

Answer 9

Term used to refer to an organism that has two identical alleles for a particular trait

Ex. The pea plants with two tt (recessive genes and TT genes are homozygous.

Question 10

Heterozygous

Answer 10

Term used to refer to an organism that has two different alleles for the same trait.

Ex. Tt (one dominant and one recessive)

Question 11

Phenotype

Answer 11

Physical characteristics of an organism

Ex. My phenotype is blue eyes and blonde haired.

Question 12

Genotype

Answer 12

Genetic makeup of an organism

Ex. My genotype is my genes

Question 13

Independent assortment

Answer 13

Independent segregation of genes during the formation of gametes.

Ex.

Question 14

Independent assortment

Answer 14

Independent segregation of genes during the formation of gametes

Ex. Variations in phenotype are caused by independent assortment of genes during gamete formation.

Question 15

Incomplete dominance

Answer 15

Situation in which one allele isn’t completely dominant over another

Ex. There is an allele for red petals of a flower and an allele for white petals. Incomplete dominance results in a white flower

Question 16

Codominance

Answer 16

Situation in which both alleles of a gene contribute to the phenotype of the organism.

Ex. The cow has black and white spots

Question 17

Multiple alleles

Answer 17

Three or more alleles of the same gene

Ex. Aaa

Question 18

Gene map

Answer 18

Diagram showing the relative locations of each known gene on a particular chromosome

Ex. A gene map shows where certain genes are located on a specific chromosome

Question 19

Polygenic traits

Answer 19

Trait controlled by two or more traits

Ex. Your fat earlobes are a polygenic trait because they are caused by a gene for fatness and a gene for detached earlobes

Question 20

Karyotype

Answer 20

Set of photos of chromosomes grouped and ordered in pairs

Ex. The normal diploid somatic cell of a human has 46 chromosomes

Question 21

Sex chromosome

Answer 21

One of two chromosomes that determine an individual’s sex; females have two x’s and males have one x and one Y chromosome

Ex. You are a boy because you have the teeny Y chromosome

Question 22

Autosome

Answer 22

Autosomal chromosome ; chromosome that is not a sex chromosome

Ex. All the chromosomes other than the last 2 (usually) on a karyotype are autosomes

Question 23

Pedigree

Answer 23

Chart that shows relationships in a family

Ex. My mom made me do a mediated chart when we learned about family hx in church

Question 24

Sex-linked gene

Answer 24

Gene located on the X or Y chromosome

Ex. A sex linked gene is a gene linked to sex, found on your sex cells that make you a girl or a guy

Question 25

Nondisjunction

Answer 25

Error in meiosis in which homologous chromosomes fail to separate

Ex. When homologous chromosomes just stick together and don’t divide during meiosis (making of gametes)

Question 26

Crossing over

Answer 26

Process in which homologous chromosomes exchange portions of their chromatids during meiosis

Ex. When, during meiosis, the homologous chromosomes cross their chromatids and switch them out.

Question 27

Genetics

Answer 27

Scientific study of heredity