All Free Biology MCQs with Answers

• A. Endoplasmic reticulum
• B. Lysosomes
• C. Mitochondria
• D. Glucose and salts

Explanation: Endoplasmic reticulum is a network of membranes that is found in the cytoplasm of cells. It is not attached to actin filaments or myosin motor proteins, so it does not move during cytoplasmic streaming.

• A. Ribosomes
• B. SER
• C. RER
• D. Golgi bodies

Explanation: The smooth endoplasmic reticulum (SER) is involved in various functions, including lipid metabolism, calcium storage, and detoxification. In particular, the SER plays a significant role in the detoxification of harmful drugs and toxins in cells.

• A. Outer membrane-Smooth
• B. Inner membrane-F1 particles
• C. Outer membrane-Chemiosmosis
• D. Inner membrane-Increases surface arca

Explanation: Chemiosmosis occurs through inner mitochondrial membrane because of the presence of ATP synthase enzyme.

• A. The 60S and 40S
• B. The 80S and 70S
• C. The 70S and 80S
• D. The 80S and 80S

Explanation: Eukaryotic cells only consist of 70S and 80S ribosomes. 80S ribosomes are present in the cytosol and 70S ribosomes are present on the organelles. They do not have 60S and 40S ribosomes.

• A. I and II only
• B. I and III only
• C. III and IV only
• D. II and III only

Explanation: Plasma B cells would be there as they are proteins so they would be secreted by the RER and packaged by the Golgi bodies. Islets of Langerhans cells would be taking help from the Golgi body as they need to be packaged and modified since they are hormones and are produced by the SER. Adipose tissue has no relations with ER and Golgi Body, as it simply has to store fat, there is no need of packaging or modification or even proteins. Red blood cells do no need ER or golgi body.

• A. Cell wall
• B. Protoplasm
• C. Cellulose
• D. Nuclei

Explanation: In bacteria, the cell wall is made of peptidoglycan, which is a very strong in complex compound that helps in maintaining its structure and turgidity. Nuclei and protoplasm play no protective function. Cellulose is present in plants as their cell wall is made of it.

• A. Mycoplasma
• B. Protists
• C. Virus
• D. Algae

Explanation: Mycoplasma is a group of bacteria that are unicellular in nature. They are some of the smallest known free-living organisms and lack a cell wall which distinguishes them from most other bacterial groups.

• A. Osmosis
• B. Facilitated diffusion
• C. Active transport
• D. Endocytosis

Explanation: Glucose is transported by transporter proteins which act as channels or transporters that facilitate the movement of glucose across the cell membrane. Facilitated diffusion is a passive transport mechanism that does not require the expenditure of energy. It relies on the concentration gradient and the presence of specific transport proteins to move molecules across the cell membrane.

• A. Leucoplast-Carotene
• B. Elaioplast-Oils
• C. Amyloplast-Starch
• D. Aleuroplasts-Proteins

Explanation: In context of leucoplasts, carotenes are not typically present because leucoplast are non-pigment organelles, and carotenes on the other hand are pigment organelles which show red, yellow or orange colour in fruits. The rest of the plastids have been correctly matched to what they store.

• A. Thylakoids
• B. Cristae
• C. Oxysomes
• D. Cisternae

Explanation: Option D is correct because cisternae are the functional unit of golgi body which is repsonsible for the processing, sorting an modification of lipids and proteins synthesized in the ER. It is composed of a series of stacked membrane-bound components known as cisternae.