A cell is a fundamental unit of life. Therefore, if we were to break an organism apart to the cellular level, the smallest independent component which would be found would be the cell.
A cell is the basic and smallest life’s unit which is responsible for all life's processes. Cells are the functional, structural, and biological units of all living beings. A cell can also be independently replicated. Thus, the cells are called the building blocks of life.
Each cell contains a fluid known as cytoplasm, enclosed by a membrane. Also, the cytoplasm contains several biomolecules such as nucleic acids, proteins, and lipids. Furthermore, the cellular structures known as cell organelles are suspended in the cytoplasm.
A cell structure is composed of individual components with specific functions important to carry out the processes of life. These components include cell membrane, cell wall, cytoplasm, nucleus, and also cell organelles.
The plasma/cell membrane is the outermost layer of a cell. It controls the entry and exit of the cell. The gases move in and out through diffusion and liquid travels through the process of osmosis.
The cell wall is present outside the plasma membrane. This cell wall is present in the plant cells to provide structural support and thus is rigid in nature. The cell wall is composed of cellulose.
The nucleus acts as a cell's command centre. It plays a very crucial role in the reproduction of a new cell. Nucleus contains Y shaped structures called chromosomes, which contain DNA or genes for the new cell's production.
The nucleus is covered with a thin layer called the nuclear membrane and is filled with nucleoplasm. It contains nuclear pores that regulate the passage of molecules between the nucleus and cytoplasm, permitting some to pass through the membrane, but not others.
The cytoplasm is a liquid component present in the cell. It is composed of water, salt and protein. All the important organelles of a cell including the nucleus are present in the cytoplasm.
Lysosomes are responsible for the digestion process in a cell. All the food and worn out parts in the cells are broken down through the digestive enzymes. It keeps the cell clean and free from any kind of bacteria. In abnormal cases, the lysosomes burst and end up digesting their own cell, which is why they are also called suicide bags.
Mitochondria is the powerhouse of a cell. It provides energy to the cell for various types of chemical reactions that happen inside it. The energy is provided in the form of ATP (Adenosine Triphosphate) molecules. These are the energy currency of the cell.
Importance of MCQs
In general, the Multiple Choice Questions (MCQs) are recognized as the most useful and widely applicable type of objective test elements. They could be used to measure the most important educational outcomes, such as understanding, knowledge, judgment, and problem-solving.
By preparing these MCQs once after completing every topic, we can able to attempt competitive exams like NEET easily and effectively.
Let us look at the MCQ on cell structure and function, including the cell structure and function MCQ with answers.
1. In the given list, which is the simplest amino acid?
Glycine is the simplest amino acid. It contains a single hydrogen atom as its side chain. It is also a proteinogenic amino acid.
2. Animal cells are interconnected by _______
b. Cell wall
d. Plasma membrane
Desmosomes are the structure by which adjacent cells are attached and formed from the protein plagues in cell membranes linked by the filaments.
3. Polythene chromosomes are found because of _____?
Endomitosis is the replication or duplication of the chromosome in the absence of nuclear division or cell, resulting in numerous copies within each cell, which occurs in the Drosophila salivary glands.
Polytene chromosomes are popularly called salivary chromosomes. They contain 1000- 16000 times DNA, as compared to ordinary somatic chromosomes and can reach a length of 2000 μm. During the interphase stage of the cell division in the nuclei of the salivary gland cells of the larvae of Drosophila melanogaster, polytene chromosomes are formed due to endoreduplication, duplication without separation and replication of DNA without cell division. These chromosomes undergo somatic pairing to form identical chromosomes which are joined along their length to one another.
4. The rRNA is synthesized by _________
a. Golgi body
A nucleolus is the small dense spherical structure in the cell nucleus. It acts as a site for active rRNA synthesis. Rough ER (absence of ribosomes)- helps in the synthesis of proteins.
5. Which of the following is known as mitoplast?
a. Mitochondria without outer membrane
b. Another name for mitochondria
c. Mitochondria without membranes
d. Mitochondria without inner membrane
Mitoplast is mitochondria where the outer membrane stripped in it has been removed, by keeping the inner membrane unchanged or intact.
6. The Lipid drugs’ detoxification including the other harmful compounds of various types in the ER is carried out by ______?
a. Cytochrome F
b. Cytochrome bf
c. Cytochrome P450
d. Cytochrome D
Cytochrome P450 enzymes function to metabolize the potentially toxic compounds. There exist 57 human genes coding for different cytochrome P450.
7. Sodium and potassium pumps are examples of __________
b. Active transport
c. Passive transport
Active transport is the movement of either ions or molecules across a cell membrane into a higher concentration region assisted by the enzymes and requiring energy. Sodium and potassium pumps are good examples of active transport.
8. The histone octamer contains __________?
a. 5 types of histones
b. 6 types of histones
c. 8 types of histones
d. 8 histones of four different types
Histone octamer is an 8 protein complex that is found at the centre of the core particles of the nucleosome. It contains 2 copies of 4 core histone proteins.
9. Centriole takes part in the formation of ________?
c. Cell plate
d. To start cell division
Centrioles are cylindrical structures that are composed of tubulin. These take part in the formation of a Spindle.
11. Which of the below option is/are examples of an organ that contain a smooth muscle?
a. Uterus only
b. Iris of eye
c. Bronchi only
d. All of the above
Smooth muscles are also called involuntary muscles, and these muscles contract slowly and automatically. Uterus, iris and bronchi are examples of smooth muscles.
12. The Major difference between the human cheek cells and onion peel cells is ______?
a. Presence of mitochondria in onion peel
b. Absence of plasma membrane in cheek cells
c. Cell wall presence in onion peel cells
d. Absence of endoplasmic reticulum in cheek cells
The major difference between an animal cell and a plant is that, unlike plant cells, animal cells are devoid of cell walls and chloroplast. Therefore, C is the answer above.
13. An organelle that mainly serves as a packaging area for molecules that are distributed across the cell and are called ____?
a. Golgi apparatus
Golgi apparatus, also known as the Golgi body, is a cell membrane that is a part of the endomembrane system in the cytoplasm. It is a 'membrane-bound organelle' of the eukaryotic cell which is made up of a series of 'flattened, stacked pouches’ called 'cisternae'. This organelle serves as a 'primary packaging area' for molecules that will be distributed throughout the cell. It packs the protein into membrane-bound vesicles inside the cell before sending it to its destination.
14. The cell theory is not applicable to-
Viruses are considered neither living nor non-living. The cell structure is not present in the viruses, and do not use cells in their reproduction. Thus, cell theory is not applicable to viruses.
15. In the below-given list, which one includes the blood tissue?
a. Muscle tissue
b. Connective tissue
c. Epithelial tissue
d. Nervous tissue
Blood is a type of connective tissue. Connective tissue has three main components: cells, fibres, and ground substance. Together the ground substance and fibres make up the extracellular matrix. Blood in the body has a network in our body through which it transports gases like oxygen and carbon dioxide, hormones, and required nutrients in the body.