Question

Select the correct statements.
a. Endomembrane system includes plasma membrane, ER, Golgi complex, lysosomes, and vacuoles.
b. ER helps in transport of substances, synthesis of proteins, lipoproteins, and glycogen.
c. Ribosomes are involved in protein synthesis.
d. Mitochondria helps in oxidative phosphorylation and generation of ATP.

(I) b, c, and d are correct
(II) a alone is correct
(III) b alone is correct
(IV) c alone is correct

Answer 1

Hint: mRNA translation takes place in the ribosomes. Mitochondria are known as the powerhouse of the cell.

Complete answer:
- ER (endoplasmic reticulum), ribosomes, and mitochondria to answer this question. The endomembrane structure consists of multiple membranes that are located within a eukaryotic cell in the cytoplasm. The cell is separated by these membranes into structural and functional organelles or compartments.
- The endoplasmic reticulum (ER) consists of two subunits- RER (rough endoplasmic reticulum) and SER (smooth endoplasmic reticulum). In most eukaryotic cells, the ER is seen which creates an interconnected flattened network, membrane-enclosed sacs called cisternae present in the RER and in SER tubular structures are seen.
- Complex particles formed from special rRNA (ribosomal RNA) and various proteins are said as ribosomes. A semi-autonomous double-membrane-bound organelle present in most eukaryotic species is the mitochondrion.

Now, let us find the solution from the options-
- The nuclear membrane, the ER, the Golgi apparatus, the lysosomes, the endosomes, the vesicles, and the cell membrane form the endomembrane system in eukaryotes. Thus, the statement a is incorrect.
- The smooth and rough endoplasmic reticulum is an integrated flattened network, cisternae or tube-like structures responsible for lipid and steroid hormone (SER) and protein (RER) synthesis. Thus, the statement b is correct.
- Ribosomes are classified as protein factories because it is the primary site of protein synthesis, and consist of proteins and ribonucleic acids. Thus, the statement c is correct.
- Mitochondria, recognized as the powerhouse of the cell and the location of the electron transport chain in aerobic respiration and oxidative phosphorylation means ATP production. Thus, the statement d is correct.

Thus, the correct answer is option (I) b,c, and d are correct.

Note: All eukaryotic and prokaryotic cells contain ribosomes. A membrane does not envelop the ribosomes. A mitochondrion which is present in most eukaryotic cells is a membrane-enclosed organelle.