Tag: structure and functions of living organisms -ii

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Questions Related to structure and functions of living organisms -ii

Multiple choice biology the life cycle of animals how do animals reproduce? excretory, nervous and reproductive system structure and functions of living organisms -ii

Which of the following cells are present in mammalian testes and help to nourish sperms 

  1. Leydig cells

  2. Oxyntic cells

  3. Interstitial cells

  4. Sertoli cells
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sertoli cells are non-gametic cells in the seminiferous tubules which provide nourishment for developing sperms.

Multiple choice biology the life cycle of animals how do animals reproduce? excretory, nervous and reproductive system structure and functions of living organisms -ii

Assertion : There is generally monospermy in most of animals.

Reason : Vitelline membrane of ovum checks polyspermy.

  1. Both Assertion and Reason are true and Reason is a correct explanation of Assertion

  2. Both Assertion and Reason are true but Reason is not a correct explanation of Assertion

  3. Assertion is true but Reason is false

  4. Both Assertion and Reason are false

  5. Assertion is false but reason is true.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Entrance of a single sperm into an oocytes called monospermy generally monospermy is found in most of the animals. Cortical granules are extruded in the perivitelline space by exocytosis and some of these are attached along the inner surface of vitelline membrane which now thickens and becomes impervious to any other sperm entry. It is now called fertilization membrane. It prevents the polyspermy.

Multiple choice biology the life cycle of animals how do animals reproduce? excretory, nervous and reproductive system structure and functions of living organisms -ii

In most of the mammals the testes are situated outside the abdominal cavity because 

  1. Sperms produced in scrotal sac are more in number

  2. Sperms produced in abdominal cavity are provided with less motility

  3. Sperms produced in scrotal sac require lesser temperature for their best fertilization capacity

  4. Sperms produced in scrotal sac are bigger
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Testes in mammals are present out side the abdominal cavity because maturation of sperm needs low temperature. The temperature of scrotum is below (2 to 4$^{o}C$) than abdominal cavity.

Multiple choice biology the life cycle of animals how do animals reproduce? excretory, nervous and reproductive system structure and functions of living organisms -ii

Assertion : In morula stage, cells divide without increase in size.

Reason : Zona pellucida remain undivided till cleavage is complete.

  1. Both Assertion and Reason are true and Reason is a correct explanation of Assertion

  2. Both Assertion and Reason are true but Reason is not a correct explanation of Assertion

  3. Assertion is true but Reason is false

  4. Both Assertion and Reason are false

  5. Assertion is false but reason is true.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Zygote divide vertically to form two blastomeres. This is followed by a vertical division and a horizontal division. Now, several divisions occur forming equal sized blastomeres called morula. There is no increase in size of cells. Zona pellucida is a transparent non cellular layer surrounding egg cell. It remains undivided till the cleavage is complete.

Multiple choice biology the life cycle of animals how do animals reproduce? excretory, nervous and reproductive system structure and functions of living organisms -ii

In crocodiles male sex is predominant at

  1. Low temperature

  2. Intermediate temperature

  3. High temperature

  4. Ratio is genetically determined.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In crocodilians, sex determination is temperature-dependent. Males are typically produced at higher temperatures, while females are produced at lower temperatures.

Multiple choice biology the life cycle of animals how do animals reproduce? excretory, nervous and reproductive system structure and functions of living organisms -ii

Choose the correct answers from the alternatives given. 
Reproduction

  1. is a universal feature of all living organisms

  2. produces genetic variation that is important in survival of a species

  3. enables a species to persist over long periods of time

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Reproduction is a biological process by which new individual organism is produced from their parents. Reproduction is a fundamental feature of all life. Reproduction helps the species to live a long period of life. Sexual reproduction also links with a variation in species which help in them for survival. 

Hence, the correct answer is 'all of the above'

Multiple choice biology the life cycle of animals how do animals reproduce? excretory, nervous and reproductive system structure and functions of living organisms -ii

State whether the following statements are true or false.
Humans have greater reproductive potential than bacteria

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • A human being a complex eukaryotic organism with a well developed reproductive system have greater reproductive potential and since the variation is seen in the offspring chances of survival are most.
  • Bacteria being a simple prokaryotic organism with a not so developed reproductive system. Their reproduction is limited by the availability of resources.

Hence, the correct answer is 'True'.

Multiple choice biology the life cycle of animals how do animals reproduce? excretory, nervous and reproductive system structure and functions of living organisms -ii

In mammals the testes lies in scrotal sacs due to-

  1. Presence of urinary bladder.

  2. Presence of rectum.

  3. Long vas-deferens.

  4. Requirement of low temperature for spermatogenesis.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The testes in mammals are located outside the body cavity in the scrotum because spermatogenesis requires a temperature slightly lower than the core body temperature.

Multiple choice biology the life cycle of animals how do animals reproduce? excretory, nervous and reproductive system structure and functions of living organisms -ii

Consider the following effects of genetic engineering:
1. Disease resistance
2. Growth promotion
3. Cloning
4. Longevity
Of these effects, those that have been tried out with a certain amounts of success include

  1. 1, 2 and 4

  2. 2, 3 and 4

  3. 1, 3 and 4

  4. 1, 2 and 3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Genetic engineering allows of plants or animals to be modified so their maturity can occur at a quicker pace. Engineering can allow this maturity to occur outside of the normal growth conditions that are favorable without genetic changes as well. Even if there is higher levels of heat or lower levels of light, it becomes possible to expand what can be grown in those conditions. Genetic modification can help to create resistance to common forms of organism death. Pest resistance can be included into the genetic profiles of plants so they can mature as a crop without any further additives. Animals can have their genetic profiles modified to reduce the risks of common health concerns that may affect the breed or species. This creates the potential for an extended lifespan for each organism. With genetic engineering, new products can be created by adding or combining different profiles together. This process is called cloning. This makes it possible for more people to get what they need nutritionally, even if their food access is limited, and this could potentially reduce global food insecurity.

So the correct option is '1, 2 and 3'.