Railway Science (Biology-Reproduction in Animals)

Total Questions: 50

1. During adolescence, several changes occur in the human body. Which of the following changes is associated with sexual maturation only in girls? [RRC Group D 17/08/2022 (Afternoon)]

Correct Answer: (a) Growth of mammary glands
Solution:

Puberty tends to take place around the ages of 12 to 16 (in boys) and 10 to 14 (in girls). The changes occurred during sexual maturation - The growth of hair, The consciousness of their appearance, Pimples, An upsurge in hormones, The growth of mammary glands (only in girls).

2. Which of the following is NOT an example of asexual reproduction? [RRC Group D 17/08/2022 (Afternoon)]

Correct Answer: (b) Pollination
Solution:

Pollination is part of the sexual reproduction process of flowering plants, which results in seeds that will grow into new plants. Grafting is a kind of horticulture technique whereby tissues of plants are joined so as to continue their growth.
Fragmentation - An organism simply breaks into individual pieces at maturity. Binary Fission - An organism divides into two, each part carrying one copy of genetic material. Budding - A new organism develops from a bud of an existing organism.

3. In which organism sex is not determined genetically? [RRC Group D 17/08/2022 (Evening)]

Correct Answer: (c) Snail
Solution:

The process of sex determination in snails is not genetically determined (this means sex of the child is not determined by the genes inherited from the parent). In humans and some animals (like sparrows and butterflies) sex is determined by genes and chromosomes inherited from parents.
Humans have 23 pairs of chromosomes. Father of Genetics - Gregor Johann Mendel. Sex Determination Techniques - include Chromosomal analysis, Ultrasonography, and Other Genetic Method (for example DNA Testing). Statutory Status - The Pre-Conception and Pre-Natal Diagnostic Techniques( Prohibition of Sex Selection) Act 1994, as amended in 2003, prohibits misuse of prenatal diagnostic techniques for determination and disclosure of sex of foetus.

4. Some reasons highlighting the importance of delivering sex education in schools are mentioned below. Choose the incorrect option. [RRC Group D 18/08/2022 (Morning)]

Correct Answer: (a) Knowing about their body changes, teenagers start making fun of each other
Solution:

Importance of delivering Sex Education - To raise awareness about sexually transmitted diseases and safe sex practices, to inform students about reproductive health, related organs, adolescence and to raise awareness in order to protect people from misconceptions about various sex-related issues.

5. Oral contraceptive pills work by stopping _____. [RRC Group D 18/08/2022 (Afternoon)]

Correct Answer: (b) ovulation and fertilization
Solution:

Ovulation is the process in which a mature egg is released from the ovary. Fertilization occurs when a sperm fuses with the female egg during intercourse and further forms an zygote that gets implanted in the uterus of the female. Implantation is the first trigger for the body to start producing HCG (human chorionic gonadotropin, also known as the pregnancy hormone).

6. How many autosomes will be present in a sexually reproducing organism with the chromosome number 2n = 18? [RRC Group D 18/08/2022 (Afternoon)]

Correct Answer: (c) 16
Solution:

Autosomes - They are numbered chromosomes that contain genes for anything that does not relate to sex determination. Sexually reproducing organisms have two of each sex chromosome in their cells because they received one set of chromosomes from each parent during the process of reproduction. Humans have 22 pairs of autosomes and one pair of sex chromosomes (XX or XY).

7. Some features of genes are mentioned below. Which option states the INCORRECT feature of genes? [RRC Group D 18/08/2022 (Evening)]

Correct Answer: (a) They do not undergo any change.
Solution:

Features of Genes : Genes are functional units of heredity (made of DNA), every gene comprises a particular set of instructions for a particular function or protein coding. For example, The HBB (Hemoglobin Subunit Beta) gene provides instructions for making a protein called beta-globin. Danish botanist Wilhelm Johannsen coined the word gene in 1909.

8. Two types of cell divisions, A and B, are shown in the figure below. Which option provides the correct answer for: [RRC Group D 22/08/2022 (Morning)]

i. Types of cell division
ii. When and where does division B take place?

Correct Answer: (b) i. A-Mitosis, B - Meiosis ii.Meiosis takes place in reproductive cells for the formation of gametes
Solution:

Meiosis (cell division creates egg or sperm) is a type of cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes. Mitosis (making new body cells) is a type of cell division in which one cell (Mother cell) divides to produce two new cells (daughter cells) that are genetically identical to itself.

9. In some women, oviducts are blocked. These women are unable to bear babies because sperms cannot reach the egg for fertilization. The doctors advise IVF (in vitro fertilization) in such cases. Below are given some steps of the procedure. Select the INCORRECT step. [RRC Group D 22/08/2022 (Evening)]

Correct Answer: (a) Zygote is kept outside and development takes place in a test tube
Solution:

In vitro fertilization (IVF) is a complex series of procedures used to help with fertility or prevent genetic problems and assist with the conception of a child. In such cases, the fertilization is done outside the uterus in a glass vessel by combining a female egg with a sperm.
IVF and test-tube babies are the same with no difference at all. During IVF, mature eggs are collected (retrieved) from ovaries and fertilized by sperm in a lab. Then the fertilized egg (embryo) or eggs (embryos) are transferred to a uterus.

10. In human males, why are testes present outside the abdominal cavity in a pouch called scrotum? [RRC Group D 22/08/2022 (Evening)]

Correct Answer: (c) It helps in maintaining temperature 2-3 degrees lower than the body for sperm formation
Solution:

Testes - A pair of male reproductive organs covered by the structure called the scrotum. It is associated with the function of production of a male gamete that is sperm and hormones such as testosterone which bring secondary sexual characteristics in males. The temperature of the testicles needs to be cooler than the inside of the body. So, the scrotum is located outside of the body.