Question

Creating a transgenic organism

A. is the result of deleting DNA from specific genes of an organism.

B. is a form of natural selection.

C. is the result of adding DNA to an organism from another species.

D. happens spontaneously.

E. benefits all organisms.

How are artificial selection and natural selection similar?

A. Both require human intervention.

B. Both work to create a new species.

C. Both select for a specific trait(s) within a population.

D. Both processes only affect animals.

E. All of the above are correct.

Most commercial insecticides are effective for only a few years. This is because:

A. not enough is used.

B. natural selection for insecticide resistance occurs.

C. of artificial selection by farmers.

D. of genetic engineering creating new insects.

E. None of the above is correct.

Traits controlled by X-linked recessive genes appear more often in males than in females because:

A. the male inherits X-linked genes from his father.

B. the male inherits Y-linked genes from his mother.

C. the male needs only one copy of the gene for the trait to appear in his phenotype.

D. the male inherits more copies of the gene than does a female.

E. the male needs two copies of the gene for the trait to appear in his phenotype.

Answer 1

1.C. is the result of adding DNA to an organism from another species

Transgenic organisms are created by inserting genes of other species into their genome.They are created by microinjection of DNA into the fertilised egg which is then implanted into the oviduct of a pseudopregnant surrogate mother. This has various applications including in the area of drug and industrial production.

2.C. both select for a specific trait(s) within a population

Natural selection which occurs naturally acts on heritable traits of the population. They select for beneficial alleles and increase their frequency in the population and they decrease the frequency of deleterious alleles and this process is known as adaptive evolution.

Artificial selection (selective breeding ) is the process done by humans to selectively develop some particular phenotypic traits. Two purebred animals of different breeds are crossed to produce a cross breed, and cross bred plants are called hybrids which have the desired traits. Artificial selection is used in agriculture to produce animals and crops with desirable traits.

3.B. natural selection for insecticide resistance occurs

When same type of insecticide is used for a long time insect evolve insecticide resistance via natural selection. There will be some insects that are resistant to insecticide. They survive and pass their acquired heritable changes traits to their offspring.

4.C. the male needs only one copy of the gene for the trait to appear in his phenotype.

X linked recessive genes are common in males than females. This is because male has only one X chromosome ( male sex chromosomes are XY). If this has the recessive mutation the trait will appear in his phenotype. Females have two X chromosomes and the trait will appear in her phenotype only when both X chromosomes have recessive mutation. And this have less chance than males.