Class 10 How do Organisms Reproduce? Mock Test (CBSE)

Topics in How do Organisms Reproduce?

• Do organisms create exact copies of themselves?
• Importance of variation
• Fission
• Fragmentation
• Regeneration
• Budding
• Vegetative propagation
• Spore formation
• Sexual reproduction in flowering plants
• Human male and female reproductive systems
• Reproductive health

How do Organisms Reproduce? practice questions with answers

1. Q1Multiple choice·1 mark
   An Amoeba divides by binary fission once every hour under ideal conditions. Starting with one Amoeba, how many Amoebae will be present after 4 hours?

   1. (a)$8$
   2. (b)$16$
   3. (c)$32$
   4. (d)$4$
   Show answer and step marks

   1. Correct option: (b) $16$+1

   Answer: (b)
2. Q2Multiple choice·1 mark
   Which statement correctly distinguishes budding in Hydra from binary fission in Amoeba?

   1. (a)Hydra divides into two equal halves; Amoeba forms a bud that detaches.
   2. (b)Hydra forms a bud that detaches; Amoeba divides into two nearly equal daughter cells.
   3. (c)Both organisms form buds that grow from the parent body.
   4. (d)Both organisms divide into many spores within a cyst.
   Show answer and step marks

   1. Correct option: (b) Hydra forms a bud that detaches; Amoeba divides into two nearly equal daughter cells.+1

   Answer: (b)
3. Q3Assertion and reason·1 mark
   Assertion (A): In human females, fertilisation normally takes place in the uterus. Reason (R): The fallopian tube (oviduct) is the site where the ovum is fertilised by a sperm.

   1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
   2. (b)Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
   3. (c)Assertion (A) is true but Reason (R) is false.
   4. (d)Assertion (A) is false but Reason (R) is true.
   Show answer and step marks

   1. Correct option: (d) Assertion (A) is false but Reason (R) is true.+1

   Answer: (d)
4. Q4Multiple choice·1 mark
   Spirogyra reproduces asexually by a process known as:

   1. (a)Budding
   2. (b)Fragmentation
   3. (c)Regeneration
   4. (d)Binary fission
   Show answer and step marks

   1. Correct option: (b) Fragmentation+1

   Answer: (b)
5. Q5Multiple choice·1 mark
   Under a microscope, a yeast cell is seen with a small outgrowth on its surface. The outgrowth grows and then detaches to form a new cell. This mode of reproduction is:

   1. (a)budding
   2. (b)fragmentation
   3. (c)regeneration
   4. (d)binary fission
   Show answer and step marks

   1. Correct option: (a) budding+1

   Answer: (a)
6. Q6Long answer·5 marks
   In a bakery, a baker keeps a culture of yeast cells in a warm sugar solution to make bread dough rise. Under a microscope, a yeast cell is seen with a small outgrowth on its surface, which grows and then separates to form a new cell. Answer the following. (a) Explain why the new cell formed from this outgrowth carries the same genetic information as the parent cell. [2] (b) Explain why a copying error in the DNA of one cell is passed on to all the cells formed from it by later divisions. [1] (c) Explain why a culture made up of nearly identical cells may be wiped out if the temperature of the bakery rises suddenly. [1] (d) Explain why most cells in the culture still look like the parent, even though DNA copying is not always perfect. [1]
   Show answer and step marks

   1. (a) The DNA of the parent yeast cell is copied before the outgrowth separates, so there are two copies of the genetic material.+1
   2. (a) One copy of the DNA moves into the outgrowth, so the new cell receives the same genetic information as the parent.+1
   3. (b) The changed DNA is copied in every division of the cell that carries it, so the error is inherited by all its descendant cells.+1
   4. (c) No cell in the culture carries a variant suited to the new temperature, so the whole population may not survive.+1
   5. (d) DNA copying is highly accurate and most errors are rare and small, so most daughter cells show no noticeable difference from the parent.+1

   Answer: (a) The parent's DNA is copied and one copy passes into the new cell, so the genetic information is the same. (b) The changed DNA is copied and inherited by all descendants of that cell. (c) All cells are nearly alike, so none is suited to the new temperature and the culture may be wiped out. (d) DNA copying is very accurate and most errors are small, so most cells look like the parent.

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