Genes are segments of DNA that control hereditary traits in organisms. Genes contain genetic information and can be dominant, recessive, or semi-dominant. Alleles are gene variants that appear at corresponding locations on homologous chromosomes. A monohybrid cross involves breeding organisms with homozygous dominant and recessive genotypes for a trait to determine the dominant allele and inheritance patterns. It can also involve breeding heterozygous individuals to confirm allele dominance.

2. are the smallest units of genetic material that control the hereditary traits of organisms.
Genes consist of DNA that is spun by histone proteins and arranged in a linear and regular sequence in
loci on chromosomes.
1. Dominant gene with a strong expression denoted by capital letters.
2. Semi-dominant gene with expression between dominant and recessive genes.
3. A recessive gene with a weak expression denoted by lowercase letters.
1. As a separate particle in the chromosome.
2. Carrying genetic information from generation to generation.
3. Regulate metabolic processes and development in organisms.
1. Contains genetic material and can duplicate itself.
2. Each gene has a different function.
3. Determined by the combination of nitrogenous bases.

3. Alleles are pairs of genes located in the corresponding locus on homologous
chromosomes. The arrangement of genes and their alleles on homologous
chromosomes is called a genotype.
 The genotype is homozygous dominant, with the allele pair consisting of two
dominant genes.
Example: AA
 The genotype is homozygous recessive, with the allele pair consisting of two
recessive genes.
Example: aa
 Heterozygous genotype, with allele pairs consisting of two different genes, one
dominant with one recessive.
Example: Aa

4. Related Biology Terms

5. A monohybrid cross is a genetic mix between two individuals who have
homozygous genotypes, or genotypes that have completely dominant or
completely recessive alleles, which result in opposite phenotypes for a certain
genetic trait.
Monohybrid crosses are used by geneticists to observe how the offspring of
homozygous individuals express the heterozygous genotypes they inherit from their
parents. Typically, this mix determines the dominant genotype.
A monohybrid cross can also signify a genetic mix between two individuals who
have heterozygous genotypes. These crosses confirm the dominance of an allele

6. Quiz
1. A monohybrid cross breeds one parent with a __________ ___________ genotype with another parent with a
_________ __________ genotype to determine the ________ ______.
A. Homozygous dominant, homozygous retrograde, dominant allele
B. Heterozygous dominatrix, homozygous dominant, dominant allele
C. Homozygous dominant, homozygous recessive, dominant allele
D. Homoromantic dominant, homosexual recessive, dominant allele
2. A monohybrid cross between two parents that have heterozygous genotypes for a specific trait confirms the
dominance of a specific allele because …
A. It produces offspring in which the dominant allele occurs more often.
B. It produces offspring that only have the dominant allele.
C. Both parents die if the hypothesis is true.
D. It produces offspring that know if they have the recessive allele.
3. A monohybrid cross CANNOT predict:
A. Your hair color
B. Whether you will inherit a genetic condition
C. Whether you will have a shellfish allergy
D. Whether the sun will come out tomorrow

7. C is correct. A monohybrid cross breeds a parent that has a homozygous dominant genotype for a specific trait, with a
parent that has a homozygous recessive genotype for a specific trait. In this way, it predicts the dominant allele.
A is correct. In ideal conditions, a second monohybrid cross, in which both parents have heterozygous genotypes, will
yield offspring of which the majority have the dominant trait.
D is correct. A monohybrid cross can predict things as benign as hair color, or it can alert parents to potentially life-
threatening conditions in their own children. However, it cannot predict traits, events, or patterns outside of the
organism on which it is conducted.

8. P (Parent)
Genotype : X rr
Phenotype : X White
X r r
R r r
r
F1 (Filial 1 = Keturunan 1)
Rr

9. R
P2 (Parent)
Genotype : r X r
Phenotype : X Red
r X r
F1 (Filial 1 = Keturunan 1)
r, r
rr

10. P (Parent)
Genotype : X rr
Phenotype : X White
X r r
R r r
r
F1 (Filial 1 = Keturunan 1)
Rr

11. R
P2 (Parent)
Genotype : r X r
Phenotype : X
r X r
F1 (Filial 1 = Keturunan 1)
r, r
rr

12. R r
R RR
(Red)
Rr
(Pink)
r Rr
(pink)
rr
(white)
Genotype : r X r
Phenotype : X