_________ are known as the protein factory of the cell.

The correct answer is Ribosomes.

Key Points

• Ribosomes are known as the protein factories of the cell because they are responsible for synthesizing proteins by translating messenger RNA (mRNA).
• They are found in both prokaryotic and eukaryotic cells, either floating freely in the cytoplasm or attached to the endoplasmic reticulum.
• Ribosomes are composed of ribosomal RNA (rRNA) and proteins, forming two subunits: one small and one large.
• Ribosomes attached to the rough endoplasmic reticulum specialize in producing proteins for secretion or membrane integration, while free ribosomes synthesize proteins used within the cell.
• Protein synthesis in ribosomes is an essential process for cell growth, repair, and enzymatic function.

Additional Information

• Endoplasmic Reticulum (ER):
  • The ER is classified into two types: Rough ER (with ribosomes attached) and Smooth ER (without ribosomes).
  • Rough ER is involved in protein synthesis, while Smooth ER is associated with lipid synthesis and detoxification processes.
• Nucleus:
  • The nucleus is the control center of the cell, containing the cell’s genetic material (DNA).
  • It regulates cellular activities by controlling gene expression and coordinating cell division.
• Mitochondria:
  • Known as the powerhouses of the cell, mitochondria are responsible for producing energy in the form of ATP through cellular respiration.
  • They have their own DNA and are believed to have originated from endosymbiotic bacteria.
• Protein Synthesis:
  • Protein synthesis occurs in two main stages: transcription (DNA to mRNA) and translation (mRNA to protein).
  • Ribosomes play a crucial role in the translation process by decoding the mRNA sequence and assembling amino acids into polypeptide chains.