Answer:
1. Answer: (c) A virus
Explanation: 'A Virus'. Viruses are considered as the intermediates between living and non- living as they cannot metabolize or reproduce on their own. For all its processes virus requires a host. Viruses can be stored as crystal-like chemicals.
2. Answer: (c) DNA and protein
Explanation: Each chromosome is made up of two components (i) Deoxyribonucleic acid (DNA) (ii) Proteins (e.g.; his tones and acidic proteins) These consist of two (unreplicated) or four (duplicated) arms and a primary constriction or centromere which gives them a particular shape due to its position.
3. Answer: (c) Smooth endoplasmic reticulum
Explanation: Smooth endoplasmic reticulum(ER) is responsible for the detoxification of a number of organic chemicals.
4. Answer: (d) nucleoid
Explanation: The nucleoid (meaning nucleus-like) is an irregularly shaped region within the prokaryotic cell that contains all or most of the genetic material.
5. Answer: (b) endocytosis
Explanation: Amoeba is an unicellular organism. It shows the holozoic mode of nutrition where it engulfs the whole food and digests it using various digestive enzymes. This method of engulfing the food molecule is called endocytosis or phagocytosis.
6. Answer: (c) Osmosis
Explanation: Osmosis is the movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules, through a cell's partially permeable membrane.
7. Answer: (a) Chloroplasts change to chromosplasts
Explanation: The change in color of the fruits on ripening is a chemical change. ... An unripe fruit is green because it contains chloroplasts in its skin. Towards the ripening of the fruit, the chloroplasts are changed into chromoplasts which gives the fruit attractive non-green colour.
8. Answer: (b) Shrinkage of cytoplasm in hypertonic medium.
Explanation: Plasmolysis is the process of shrinkage or contraction of the protoplasm of a plant cell as a result of loss of water from the cell. Plasmolysis is one of the results of osmosis and occurs very rarely in nature, but it happens in some extreme conditions.
9.Answer: (d) Mycoplasma
Explanation: Mycoplasma (Kingdom-Monera) are the simplest and smallest free living prokaryotes which are devoid of a cell wall. Plasma membrane forms the outer boundary of the cell of mycoplasma. Nostoc is a cyanobacterium (Kingdom- Monera), in which cell wall comprises of peptidoglycans.
10. Answer: (a) Mitochondria and Plastids
Explanation: Chloroplast and mitochondria are the double membranous cell organelle. These two cell organelle, are the only one which contains their own genetic component that is the DNA.
11. Answer: (b) Chromosome
Explanation: An Animal cell lacking nuclei would also lack in chromosomes. The cells which lack chromosomes are Red blood cells and platelets. Chromosomes occur during cell division, and they are formed due to the coiling and folding of chromatin. If any animal cell lacks a nucleus then it will lack of chromosomes too.
12.Answer: (a) cellulose
Explanation: The cell wall is composed of cellulose, the most abundant and resistant polysaccharide on earth.
13. Answer: (b) golgi apparatus
Explanation: lysosomes which arise from the Golgi apparatus. Together with the Golgi apparatus, the endoplasmic reticulum is called the cell's protein machinery. Likewise, the lysosome proteins from the Golgi apparatus are marked and bundled with the late endosome in a specific vesicle to create a mature lysosome.
14. Answer: (a) Schleiden and Schwann
Explanation: The classical cell theory was proposed by Theodor Schwann in 1839.These parts were based on a conclusion made by Schwann and Matthias Schleiden in 1838, after comparing their observations of plant and animal cells.
15. Answer: (b) golgi apparatus
Explanation: Silver nitrate solution is used for studying the Golgi Apparatus. Golgi apparatus is an organelle that is present in eukaryotic cells which consists of a stack of flattened sacs.
16. Answer: (c) Isotonic solution
Explanation: If a cell is placed in an isotonic solution, there will be no net flow of water into or out of the cell, and the cell's volume will remain stable. If the solute concentration outside the cell is the same as inside the cell, and the solutes cannot cross the membrane, then that solution is isotonic to the cell.
17. Answer: (d) Chromosomes
Explanation: The rod-shaped structures in the cell nucleus that contain genes are called chromosomes.
18. Answer: (b) Genes
Explanation: Genes are the functional segments of DNA as they are capable of producing mRNA.
19. Answer: (d) Leucoplast
Explanation: Leucoplasts: colorless plastids for monoterpene synthesis; leucoplasts sometimes differentiate into more specialized plastids: Amyloplasts: for starch storage and detecting gravity (for geotropism).
20. Answer: (c) Mitosis
Explanation: Most of the time when people refer to “cell division,” they mean mitosis, the process of making new body cells. Mitosis is a fundamental process for life. During mitosis, a cell duplicates all of its contents, including its chromosomes, and splits to form two identical daughter cells.
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