TLS Online TPP Program

#Question id: 12078


Following ejaculation, arterial blood flow into the corpora cavernosa decreases back to the normal resting level resulting in the flaccid state. What is the best explanation for this decrease in blood flow?

#Unit 7. System Physiology – Animal
  1. Systemic arterial pressure decreases due to absence of sexual stimulation
  2. The level of sympathetic stimulation to the arterioles supplying the corpora cavernosa decreases
  3. Resistance of the arterioles supplying the corpora cavernosa increases
  4. Formation of nitric oxide in the endothelial cells of the arterioles supplying the corpora cavernosa is stimulated by the increase in parasympathetic nervous system activity
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TLS Online TPP Program

#Question id: 4767

#Unit 8. Inheritance Biology

Neurofibromatosis is a condition in humans which is generally inherited in a dominant fashion. Assuming this disorder is 90% penetrant, what is the chance that a single child born to a father with neurofibromatosis and a mother known not to carry the mutation will have the disorder?

TLS Online TPP Program

#Question id: 4768

#Unit 8. Inheritance Biology

A trait that appears to be dominant in one sex but recessive in the other is called:

TLS Online TPP Program

#Question id: 4769

#Unit 8. Inheritance Biology

In some sheep, the presence of horns is produced by an autosomal allele that is dominant in males and recessive in females. A horned female is crossed with a hornless male. One of the resulting F1 females is crossed with a hornless male. What proportion of the male and female progeny from this cross will have horns?

TLS Online TPP Program

#Question id: 4770

#Unit 8. Inheritance Biology

When two independent pure lines of pea with white flowers are crossed, the F1 progeny has purple flowers. The F2 progeny obtained on selfing shows both pruple and white flower in a ratio of 15:1. The following conclusions were made

A. Two different genes are involved, mutation in which lead to formation of white flower.

B. These two genes does not show independent assortment

C. This is an example of complementary gene action

D. The is an example of duplicate genes

Which of the following conclusions are correct?

TLS Online TPP Program

#Question id: 4771

#Unit 8. Inheritance Biology

The normal eye color of Drosophila is red, but strains in which all flies have brown eyes are available. Similarly, wings are normally long, but there are strains with short wings. A female from a pure line with brown eyes and short wings is crossed with a male from a normal pure line. The F1 consists of normal females and short-winged males. An F2 is then produced by intercrossing the F1. Both sexes of F2 flies show phenotypes as follows:

Are genes for eye color and wing length x link or autosome? 

TLS Online TPP Program

#Question id: 4772

#Unit 8. Inheritance Biology

A black Labrador, Three phenotype of black, brown and yellow is control by non allelic gene interaction. Following some genotype

 The following conclusions were made

A. The 9:3:4 ratio obtained upon selfing of AaBb here indicates recessive epistasis

B. This is a recessive epistasis where homozygous bb is epistatic to A and a.

C. When Gene A and B incompletely link, It will be produced all phenotype black, brown and yellow upon selfing of AaBb

D. When Gene A and B incompletely link, test cross of AaBb will be produced all phenotype black, brown and yellow in ratio 1:1:2 respectively

Which of the following conclusions are correct?