Biology Answers

Phenylketonuria is a metabolic disease due to a single recessive gene. Number of Babies born detected with it are 8 out of 8000 babies. Find out % of Carriers among the Population.

Fill in the missing word:

3) The ________ structure of a protein refers to the conformation, or overall three dimensional shape of a polypeptide that has been folded into a functional protein

3) What is the name of an unbranched chain of β-glucose subunits which is the primary structural fibre in plant cell walls.

A male cardinals red color is an example of a tree effect by natural selection The females of the species choose meats based on the vibrant colors of the males features if females began using different criteria then feather color when they choose mates, what would most likely happen to the color of the male cardinals overtime?

2.6) The genotype of F1 individuals in a tetrahybrid cross is AaBbCcDd. Assuming independent assortment of these 4 genes what are the probabilities that F2 offspring will have the following genotypes?

• AABBCCDD
• AaBBccDd

2.6) In corn plants, a dominant allele I inhibits kernel colour, while the recessive allele i permits colour when homozygous. At a different locus, the dominant allele P causes purple kernel colour, while the homozygous recessive genotype pp causes red kernels. If plants heterozygous at both loci are crossed, what will the phenotypic and genotypic ration of the offspring be?

2.6) Red colour in wheat kernels is produced by the genotype R-B-, white by the double recessive genotype (rrbb). The genotypes R-bb and rrB- produce brown kernels. A homozygous red variety is crossed with a white variety. What phenotypic results are expected in the F1 and F2?

In butternut varieties, white fruit colour is governed by a dominant allele (W) and yellow fruit colour by the recessive (w). A dominant allele at another locus (S) produces disc shaped fruit and its recessive allele (s) yields sphere shaped fruit. If a homozygous white disc variety of genotype WWSS is crossed with a homozygous yellow sphere variety wwss, the F1 are all white disc dihybrids of genotype WwSs.

1. If the F1 is allowed to mate at random, what would be the phenotypic ratio expected in the F2 generation.
2. If a heterozygous white disc variety of genotype is crossed with a homozygous yellow sphere variety, what would be the phenotypic ratio expected in the F1 generation?

2.6) If two animals heterozygous for a single pair of alleles are mated and have 200 offspring, about how many would be expected to have the phenotype of the dominant allele?

2.6) Albino mice lack pigment in their fur and eyes, Hybrids between pure coloured and pure albino mice are coloured (heterozygotes). If coloured and albino are alternatives for the gene locus, then:

• Is the albino or coloured allele dominant?

• What frequency of albino progeny (offspring) is expected from the crosses between heterozygous coloured mice?

• What types of progeny are expected if albino mice are mated?

• Why can’t you make an exact prediction of the types of progeny if coloured mice are mated?