How do organisms reproduce MCQ

Ans. (c) Yeast 

Explanation: Yeast is a unicellular organism that is known to reproduce by the process of budding. These cells exist in two major forms known as the haploid and diploid. They form groups and colonies through sexual or asexual reproduction. Both types of cells can reproduce asexually with the help of budding. In this process, a small bud known as the daughter cell comes out of the mother cell, starts to enlarge and reaches up to a certain extent, then it separates itself from the mother cell. Yeast cells rapidly divide once every 90 minutes when observed in the laboratory.

Ans. (a) Penicillium 

Explanation: The Penicillium fungus does not reproduce by spore formation. It is a saprophytic fungus by nature and is commonly known as blue or green mould. They are found extensively in vegetables, soil, air, meat, etc. They reproduce in three ways named as vegetative, sexual, and asexual reproduction. In the case of asexual reproduction of penicillium, they do it by unicellular, uninucleate, and spores that aren’t motile called conidia.

Ans. (a)i and iii

Explanation: This phenomenon takes place because of the innumerable spores present in the air. Moisture present in the air also acts as a great factor behind this. The fungi also get attracted to the essential nutrients which are present in the bread. As they are saprophytes, immense growth happens in an environment that makes all these conditions come true. 

Ans. (b) Cell division resulting into multiple cells

Explanation: Also known as water silk, Spirogyra is a kind of green algae, which is known to grow underwater. They reproduce asexually by the process called fragmentation. This takes place with the formation of aplanospores, akinetes, and azygospore. Aplanospores are formed under very unfavourable conditions where the protoplast seems to shrink and a wall is formed. Akinetes are formed when they develop into a fresh filament after undergoing the decay of the parent filament. They have a strong and thick cell wall. Lastly, azygospores are formed when they mature into a new filament by asexual reproduction. Therefore, this process involved the division of cells into many cells or segments. 

Ans. (d) i and iv. 

Explanation: The major reason is that asexual reproduction involves only one parent, and they don’t involve gametes. The reason behind this is, when sexual reproduction takes place among offspring, there is a fusion of both male and female gametes. On the other hand, in the case of asexual production, there is no such fusion and offspring have a single parent. Due to this, the offspring is identical or a copy of the parent and shares the same traits. 

Ans. (c ) Multiple fission

Explanation: The process of the division of cells into several cells during reproduction in Plasmodium has been coined as multiple fission. There are many forms of asexual reproduction, in budding, a new bud or organism develops into a separate bud because of cell division. Fragmentation is asexual reproduction where the new individual splits into fragments. Multiple fission witnesses the regular division of the nucleus into multiple daughter cells. This is commonly found in the case of Plasmodium. Each daughter nuclei takes away a portion of the cytoplasm. 

Ans. (b) Halving of chromosomes during gamete formation

Explanation: This phenomenon takes place because of the halving of the chromosomes after the formation of gametes. This occurs in meiosis. In meiosis, a single cell divides two times and leads to the formation of four daughter cells which consist of half of the original genetic material in the mother cell. These sex cells are usually sperms in males and eggs in females. 

Ans. (d) p, q, r, s

Explanation: All the parts, that is p, q, r, and s in a planaria, are capable enough to develop or regenerate into separate fully grown and healthy individuals. Planaria are a type of flatworm and the most simplest kind of multicellular organisms. Cells located at the point where the planarian is cut start to increase forming a blastema. This blastoma helps distinguish new tissues formed and thereby help in the growth of the cut parts. The process of regeneration usually fluctuates between a week and up to ten days. 

Ans. (d)Y creates sperms and V makes seminal fluid. 

Explanation: The point Y represents the male testes which are the primary reproductive organs of a male. They are solely associated with the function of producing sperms. Point V in the diagram denotes the prostate gland. The main function of this gland is to produce seminal fluid which helps in transporting the sperm and nourishing them. 

Ans. (b) Hydra

Explanation: Just like yeast, reproduce asexually by the process called budding. The buds start to originate at the base of the body. Upon being fed gradually they start growing into adults, develop individual tentacles and break away from the parent. It becomes a new individual. The production of bud depends on how fast it is fed by nutrition. It also reproduces asexually by binary fission which is similar to the reproduction process of planaria. 

Ans. (c)i, ii, and iv. 

Explanation: Flowers reproduce by the process of pollination. In the case of sexual reproduction of flowering plants, both male and female reproductive parts are found in the same plant. The male gametes are found in the pollen grains, while the female gametes are present in the ovules. The former is found in the anthers whereas the latter is found in the ovary of the flowering plant. From the anther, the pollen grains get transferred to the stigma. This results in seed production. Therefore, the answer is c. Fertilisation is a compulsory event, it always results in a zygote, and two kinds of gametes are required. 

Ans. (d) Both iii and iv

Explanation: The development of the placenta and the secretion of oestrogen are not associated with testes during puberty. The testes are male oval-shaped organs surrounded by a layer of skin called the scrotum. It is located just outside the abdomen. The organ is endocrine in nature and is the main reproductive organ found in males. The main function of this organ is to produce sperms and also the male hormone known as testosterone. The testis consists of various segments of skin which consist of seminiferous tubules. 

Ans.(a)Fertilisation

Explanation: It is quite evident that fertilisation does not lead to the formation of clones. The process of fertilisation can be defined as the fusion between two gametes which result in giving rise to a new offspring or individual and thereby enhance its growth. This happens in the case of sexual reproduction. Clones are usually formed in the case of asexual reproduction. 

Ans. (a) 2:1

Explanation: The human sperm and the egg cells are haploid. This is because they are germ cells, they possess 23 chromosomes. When fertilisation takes place, the sperm cells and germ cells come together to fuse. They form into a zygote. The zygote is different and has a diploid nature. Hence, 

Sperm cells(n) + egg cells(n) = 46 chromosomes

23 + 23 = 46 chromosomes 

It can also be called as 23 pairs of chromosomes or 2n simply. 

Therefore, the ratio of the number of chromosomes in a human zygote and a human sperm is (a) 2:1. 

Ans. (d)Androecium

Explanation: The androecium is a male reproductive part of a flowering plant. It consists of an elongated filament. At the tip of the androecium, an anther is attached. The anther has two lobes, and each of them consists of two sacs. The sacs contain pollen grains inside them.