1) “Melopsittacus undulatus” (leia-se os dois nomes em itálico), conhecido popularmente como periquito-australiano, pode apresentar plumagem nas cores azul, amarela, branca e verde. Essa característica é condicionada por dois pares de genes, com segregação independente, que têm interação entre si. A cor branca é condicionada por genes homozigotos recessivos. Indivíduos que apresentam em ambos os Ioci pelo menos um dos alelos dominantes são verdes. Quando apresentam um um Ioci com genes recessivos e o outro com, pelo menos, um alelo dominante, são azuis ou amarelo. Do cruzamento de dois indivíduos duplamente heterozigotos, espera-se encontrar:

It is expected to observe individuals exhibiting green, yellow, blue, and white colors in a phenotypic ratio of 9:3:3:1, respectively.

Explanation:

This example is a classic case of a dihybrid cross involving two unlinked genes that differ in the same observed trait. In this case, the genotype double homozygous recessive is white, while the presence of one dominant allele in one of these genes results in individuals with either blue or yellow color. Finally, the presence of two dominant alleles results in individuals with blue color.

Phenotypic and genotypic ratios:

gene 1 two alleles U u

gene 2 two alleles N n

Cross:  

UuNn x UuNn

uunn: white color (1/16)

U_nn: yellow color (3/16)

uuN_: blue color (3/16)

U_N_: green color (9/16)

1. amino acid refers to the fundamental building block of proteins, comprising of an amino group and a carboxyl group.

2. catalyst refers to any substance, which increases the rate of chemical reaction without being used up in the reaction.

3. a complex molecule containing he genetic code is dna or deoxyribonucleic acid.

4. an enzyme refers to a molecule of protein, which is unique in accelerating up a particular chemical reaction in the biological systems.

5. nucleic acid refers to an sequence of sugars, phosphates, and nitrogenous bases, for example, dna and rna.

6. a protein refers to a large, composite organic molecule comprising of a huge number of amino acids associated together with the of peptide bonds.

7. rna refers to a nucleic acid that takes part in the production of proteins.

8. substrate refers to a compound, which takes part in a chemical reaction, and is chemically modified by the reaction.