How do Organisms Reproduce?: Class 10 Science Q&A · Page 2
112 free answers on How do Organisms Reproduce? (Science) for Class 10 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- ScienceClass 10CBSE
1. Colonies of yeast fail to multiply in water, but multiply in sugar solution. Give one reason for this.
Yeast requires energy for its growth and cell division. Water does not provide required energy whereas sugar provide energy hence yeast multiplies in sugar solution.
- ScienceClass 10CBSE
1. Explain how, offspring and parents of organisms reproducing sexually have the same number of chromosomes?
Because of halving of chromosome during gamete formation number of chromosome remain same as somatic cell of an organism. Halving of gametes in a chromosomes is called diploid number of chromosomes.
- ScienceClass 10CBSE
1. What is a clone? Why do offsprings formed by asexual reproduction exhibit remarkable similarity?
Clone are the aggregate of cell or organisms which are produced asexually. Asexual reproduction involve single parent and there will be no exchange of gametes hence offspring looks similar to their parent.
- ScienceClass 10CBSE
1. Can you consider cell division as a type of reproduction in unicellular organism? Give one reason.
Reproduction is creation of new individual. In unicellular organism cell division leads to formation of new individuals. Hence cell division is a type of reproduction in unicellular organisms.
- ScienceClass 10CBSE
1. In a bisexual flower inspite of the young stamens being removed artificially, the flower produces fruit. Provide a suitable explanation for the above situation.
When stamens of a bisexual flower are removed. Cross pollination can take place which results in fertilization and production of fruit.
- ScienceClass 10CBSE
1. Which among the following diseases is not sexually transmitted? (a) Syphillis (b) Hepatitis (c) HIV - AIDS Gonorrhoea
Soln: Answer is (b) Hepatitis Explanation: Hepatitis spread through contaminated water and food.
- ScienceClass 10CBSE
1. The correct sequence of organs in the male reproductive system for transport of sperms is (a) testis → vasdeferens → urethra (b) testis → ureter → urethra (c) testis → urethra → ureter testis → vasdeferens → ureter
Soln: Answer is (a) testis → vasdeferens → urethra Explanation: Testis produces sperm which is transferred into epididymis through vasdeferns. From vasdeferens sperm is taken to urethra.
- ScienceClass 10CBSE
1. Which among the following is not the function of testes at puberty? (i) formation of germ cells (ii) secretion of testosterone (iii) development of placenta (iv) secretion of estrogen (a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (i) and (iv)
Explanation: Testis is a male reproductive organ but estrogen is produced in females. Placenta is formed in females during pregnancy.
- ScienceClass 10CBSE
1. In human males, the testes lie in the scrotum, because it helps in the (a) process of mating (b) formation of sperm (c) easy transfer of gametes all the above
Answer is (b) formation of sperm Explanation: Testes lying in the scrotum ensures the temperature of the testes remain lower than the body temperature. This helps in sperm production.
- ScienceClass 10CBSE
1. In human females, an event that reflects onset of reproductive phase is (a) growth of body (b) changes in hair pattern (c) change in voice menstruation
Soln: Answer is (d) menstruation Explanation: During adolescence Following changes occur in boys Growth of hairs in new parts of the body such as armpits, between thighs near genital organ thin hairs on face, legs and on arms. Start menstruation Skin becomes oily and pimples will start appearing Breast size will increase
- ScienceClass 10CBSE
1. During adolescence, several changes occur in the human body. Mark one change associated with sexual maturation in boys (a) loss of milk teeth (b) increase in height (c) cracking of voice weight gain
Answer is (c) cracking of voice Explanation: During adolescence Following changes occur in boys Growth of hairs in new parts of the body such as armpits, on chest and between thighs near genital organ face, legs and on arms. Creaking of voice Skin becomes oily and pimples will start appearing Occasionally penis will erect especially while
- ScienceClass 10CBSE
1. Reproduction is essential for living organisms in order to (a) keep the individual organism alive (b) fulfill their energy requirement (c) maintain growth continue the species generation after generation
Soln: Answer is (d) continue the species generation after generation Explanation: Reproduction is essential to the lineage of the species whereas other life processes are essential to keep the organism alive.
- ScienceClass 10CBSE
1. Offspring formed as a result of sexual reproduction exhibit more variations because (a) sexual reproduction is a lengthy process (b) genetic material comes from two parents of the same species (c) genetic material comes from two parents of different species genetic material comes from many parents
Soln: Answer is (b) genetic material comes from two parents of the same species Explanation: In sexual reproduction zygote is formed by gametes produces by a male and a female. A male and a female gamete fuse to form a zygote which fertilizes to produce new offspring. Because of contribution of two parents off-springs incur more variations.
- ScienceClass 10CBSE
1. Which among the following statements are true for sexual reproduction in flowering plants? (i) It requires two types of gametes (ii) Fertilisation is a compulsory event (iii) It always results in formation of zygote (iv) Offspring formed are clones (a) (i) and (iv) (b) (i), (ii) and (iv) (c) (i), (ii) and (iii) (i), (ii) and (iv)
Soln: Answer is (c) (i), (ii) and (iii) Explanation: Off-springs produced from sexual reproduction cannot be clones hence statement iv) is wrong.
- ScienceClass 10CBSE
1. Which among the following statements are true for unisexual flowers? (i) They possess both stamen and pistil (ii) They possess either stamen or pistil (iii) They exhibit cross pollination (iv) Unisexual flowers possessing only stamens cannot produce fruits (a) (i) and (iv) (b) (ii), (iii) and (iv) (c) (iii) and (iv) (i), (iii) and (iv)
Soln: Answer is (b) (ii), (iii) and (iv) Explanation: Cross pollination is necessary is unisexual flowers as they possess either stamen or pistil. Flowers possessing only stamens cannot produce fruits because fruit is a mature ovary.
- ScienceClass 10CBSE
1. Which of the following statements are true for flowers? (i) Flowers are always bisexual (ii) They are the sexual reproductive organs (iii) They are produced in all groups of plants (iv) After fertilisation they give rise to fruits (a) (i) and (iv) (b) (ii) and (iii) (c) (i) and (iii) (ii) and (iv)
Soln: Answer is (d) (ii) and (iv) Explanation: Flowers are not always bisexual hence statement i) is wrong. Only angiosperms produces flowers hence statement iii) is wrong.
- ScienceClass 10CBSE
1. Length of pollen tube depends on the distance between (a) pollen grain and upper surface of stigma (b) pollen grain on upper surface of stigma and ovule (c) pollen grain in anther and upper surface of stigma upper surface of stigma and lower part of style
Soln: Answer is (d) upper surface of stigma and lower part of style Explanation: Length of pollen tube ensures pollens reach the stigma to conduct pollination.
- ScienceClass 10CBSE
1. Factors responsible for the rapid spread of bread mould on slices of bread are (i) large number of spores (ii) availability of moisture and nutrients in bread (iii) presence of tubular branched hyphae (iv) formation of round shaped sporangia (a) (i) and (iii) (b) (ii) and iv) (c) (i) and (ii) (iii) and (iv)
Answer is (c) (i) and (ii) Explanation: Large number of spores ensure a few spore survive even in adverse conditions. Availability of moisture and nutrients in the bread provides necessary environment for spore to grow into mould.
- ScienceClass 10CBSE
1. Vegetative propagation refers to formation of new plants from (a) stem, roots and flowers (b) stem, roots and leaves (c) stem, flowers and fruits stem, leaves and flowers
Soln: Answer is (b) stem, roots and leaves Explanation: Vegetative propagation is a type of asexual reproduction occur in plants. In vegetative reproduction new plant is produced from vegetative parts of the plants such as roots, stem, leaf and buds. In vegetative reproduction plants produced are genetically similar enough to the parent plant to have all its characteristics.
- ScienceClass 10CBSE
1. In Rhizopus, tubular thread-like structures bearing sporangia at their tips are called (a) filaments (b) hyphae (c) rhizoids roots
Answer is (b) hyphae Explanation: Tiny blob-on-a-stick like structures involved in reproduction are called hyphae. The blobs are called sporangia, which contain cells, or spores, that can eventually develop into new Rhizopus individuals.