Course Guide Chapter 13: Introduction to Genetics

Question 1

Define genes

Answer 1

the unit of heredity

Question 2

Define allele

Answer 2

alternate forms of a gene

Question 3

Define locus

Answer 3

the location of a gene or a few genes on a chromosome

Question 4

Define genotyoe

Answer 4

the assorted collection of various genes in the chromosome

Question 5

Define phenotype

Answer 5

a physical trait, physiological condition or biochemical aspect determined by the genes at the molecular level according to its genotype

Question 6

Define homozygous

Answer 6

an organism with a pair of identical alleles for a particular gene in both the homologous chromosomes

Question 7

Define heterozygous

Answer 7

an organism with mixed allele pairs for a particular gene

Question 8

Define dominant allele

Answer 8

the allele of a gene that is expressed under both homozygous and heterozygous condition

Question 9

Define recessive allele

Answer 9

the allele of a gene that is expressed only under homozygous condition

Question 10

What does the Law of Segregation state?

Answer 10

Allele pairs segregate during gamete formation and the paired condition is restored by the random fusion of gametes at fertilization

Question 11

What does the Law of Independent Assortment state?

Answer 11

the segregation of each allele pair is independent of other allele pairs

Question 12

Define incomplete dominance

Answer 12

the homozygotes have a particular phenotype, and the heterozygotes have an intermediate phenotype meaning that no single gene is completely dominant

Question 13

Define codominance

Answer 13

both phenotypes are expressed at about equal levels by the expression of two types of proteins by two alleles

Question 14

Define pleiotropy

Answer 14

one gene or allele codes for more than one phenotype

Question 15

Define epistasis

Answer 15

one gene interferes with the expression of another gene