What explains how the parents in a family both have the same eye color, but some of their children have a different eye color? Assume for this example that eye color is determined by a single gene.
Responses
One parent is homozygous dominant, and the other homozygous recessive for a gene that controls eye color allowing some of the children to express a different trait.
One parent is homozygous dominant, and the other homozygous recessive for a gene that controls eye color allowing some of the children to express a different trait.
The parents are both homozygous dominant for a gene that controls eye color allowing some of the children to get two recessive alleles.
The parents are both homozygous dominant for a gene that controls eye color allowing some of the children to get two recessive alleles.
The parents are both heterozygous for a gene that controls eye color allowing some of the children to get two recessive alleles.
The parents are both heterozygous for a gene that controls eye color allowing some of the children to get two recessive alleles.
One parent is homozygous dominant, and the other heterozygous for a gene that controls eye color allowing some of the children to express a different trait.
One parent is homozygous dominant, and the other heterozygous for a gene that controls eye color allowing some of the children to express a different trait. In this case, the homozygous dominant parent passes on the dominant allele for eye color to all their children, while the heterozygous parent has a 50% chance of passing on the dominant allele and a 50% chance of passing on the recessive allele. This results in some of the children inheriting two dominant alleles and having the same eye color as their parents, while others inherit one dominant and one recessive allele, leading to a different eye color.
Which of the following disorders describes cystic fibrosis?
Responses
mitochondrially inherited
mitochondrially inherited
autosomal dominant
autosomal dominant
autosomal recessive
autosomal recessive
sex linked
sex linked
The correct answer is autosomal recessive. Cystic fibrosis is an autosomal recessive disorder, meaning that it is caused by inheriting two recessive alleles for the gene associated with the disorder.
Scientists are studying a genetic disorder. They discover that when both parents are carriers, and do not express the disorder themselves, their children have a 25% chance of developing the disorder. If only one parent is a carrier, none of the children express the disorder. What type of disorder are they most likely studying?
Responses
autosomal dominant
autosomal dominant
mitochondrially inherited
mitochondrially inherited
sex linked
sex linked
autosomal recessive
autosomal recessive
The disorder that is most likely being studied in this scenario is autosomal recessive. Autosomal recessive disorders typically require the inheritance of two copies of the recessive allele, one from each parent, in order for the disorder to be expressed. When both parents are carriers (heterozygous), each child has a 25% chance of receiving two copies of the recessive allele and developing the disorder. If only one parent is a carrier, none of the children will have a chance of receiving two copies of the recessive allele and therefore will not express the disorder.
What molecule forms a double helix structure composed of two complimentary strands of nucleotides?
The molecule that forms a double helix structure composed of two complimentary strands of nucleotides is deoxyribonucleic acid (DNA).
An ecosystem contains more individuals of a certain species than it can support. Which of the following describes if natural selection will occur and why?
Responses
Natural selection will not occur because there is no competition
Natural selection will not occur because there is no competition
Natural selection will not occur because there is no mutation
Natural selection will not occur because there is no mutation
Natural selection will occur because there is competition
Natural selection will occur because there is competition
Natural selection will occur because there is lowered fitness.
The correct answer is "Natural selection will occur because there is competition." When an ecosystem contains more individuals of a certain species than it can support, it results in competition for limited resources such as food, water, and space. This competition will lead to differential survival and reproduction, where individuals with advantageous traits that allow them to access and utilize resources more effectively will have higher fitness and a better chance of passing on their genes to the next generation. As a result, natural selection will occur, favoring traits that improve survival and reproductive success in the given environment.
A piece of DNA from a gene found in a deer is compared to the same gene in four other species of mammals.
Comparison
Total Nucleotides Compared
Number of Identical Nucleotides
Deer and chimpanzee 300 297
Deer and rabbit 300 295
Deer and kangaroo 300 278
Deer and anteater 300 290
Based on this analysis, which animal is the closest relative of the deer?
Responses
chimpanzee
chimpanzee
kangaroo
kangaroo
anteater
anteater
deer