Chapter 9: Problem 8
The RNA components of ribosomes are synthesized in the ________. a. cytoplasm b. nucleus C. nucleolus d. endoplasmic reticulum
Short Answer
Expert verified
The RNA components of ribosomes are synthesized in the \( \underline{\text{c. nucleolus}} \).
Step by step solution
01
Understand the organelles and their functions
First, go over the functions of each organelle mentioned in the exercise: cytoplasm, nucleus, nucleolus, and endoplasmic reticulum. Familiarize yourself with their roles in the cell.
02
Recall the role of ribosomes
Next, think about the function of ribosomes in cells. Ribosomes play an essential role in protein synthesis by translating the mRNA into a sequence of amino acids in a process called translation.
03
Match ribosome synthesis location with organelle's functions
Compare the functions of the organelles listed in the exercise with the role of ribosomes. Determine which organelle is responsible for synthesizing RNA components by matching the location where this process occurs with the organelle's function.
04
Choose the correct answer
After identifying the organelle responsible for ribosome RNA synthesis, choose the corresponding letter from the given options: a. cytoplasm, b. nucleus, c. nucleolus, or d. endoplasmic reticulum.
05
Verify your answer
Make sure your chosen answer is correct by revisiting the functions of all the organelles and confirming that the selected organelle is indeed where ribosome RNA components are synthesized.
06
Answer
Based on the analysis, the correct answer is c. nucleolus. The RNA components of ribosomes are synthesized in the nucleolus, which is a part of the nucleus and is primarily responsible for the production of ribosomes and ribosomal RNA.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Nucleolus Function
The nucleolus plays a pivotal role within the nucleus of eukaryotic cells. Its primary function is to oversee the production and assembly of ribosomal RNA (rRNA), a critical component of ribosomes, which are the cellular machinery responsible for protein synthesis. The nucleolus is also involved in the formation of signal recognition particles and the modulation of the cell's response to stress.
The process begins with the transcription of rRNA genes into precursor rRNA. These precursors are then processed and assembled with ribosomal proteins, which are imported from the cytoplasm, to form the subunits of ribosomes. This assembly occurs within the nucleolus. After assembly, these subunits exit the nucleus through the nuclear pores to the cytoplasm, where they will fully assemble into functional ribosomes.
In summary, the nucleolus is crucial for creating the components necessary for the cell's protein manufacturing centers. Without it, cells would lack the machinery to translate genetic instructions into the proteins necessary for life.
The process begins with the transcription of rRNA genes into precursor rRNA. These precursors are then processed and assembled with ribosomal proteins, which are imported from the cytoplasm, to form the subunits of ribosomes. This assembly occurs within the nucleolus. After assembly, these subunits exit the nucleus through the nuclear pores to the cytoplasm, where they will fully assemble into functional ribosomes.
In summary, the nucleolus is crucial for creating the components necessary for the cell's protein manufacturing centers. Without it, cells would lack the machinery to translate genetic instructions into the proteins necessary for life.
Ribosomal RNA
Ribosomal RNA, or rRNA, is a type of RNA that, together with ribosomal proteins, makes up the ribosomes, the 'workbenches' of protein synthesis. Ribosomes are found both floating freely within the cytoplasm and attached to the endoplasmic reticulum, but rRNA is synthesized and initially processed within the nucleolus.
rRNA has multiple roles within the ribosome, such as ensuring the proper alignment of mRNA and ribosomal subunits, catalyzing the formation of peptide bonds between amino acids during protein synthesis, and acting as a structural scaffold for the ribosome. In eukaryotes, there are four types of rRNA: 5S, 5.8S, 18S, and 28S, which come together to form the two major ribosome subunits. The larger subunit consists of 5S, 5.8S, and 28S rRNA, while the smaller subunit contains the 18S rRNA.
rRNA genes are highly conserved and are repeated dozens to hundreds of times in the genome, which reflects the high demand for rRNA in rapidly dividing cells where protein synthesis is robust.
rRNA has multiple roles within the ribosome, such as ensuring the proper alignment of mRNA and ribosomal subunits, catalyzing the formation of peptide bonds between amino acids during protein synthesis, and acting as a structural scaffold for the ribosome. In eukaryotes, there are four types of rRNA: 5S, 5.8S, 18S, and 28S, which come together to form the two major ribosome subunits. The larger subunit consists of 5S, 5.8S, and 28S rRNA, while the smaller subunit contains the 18S rRNA.
rRNA genes are highly conserved and are repeated dozens to hundreds of times in the genome, which reflects the high demand for rRNA in rapidly dividing cells where protein synthesis is robust.
Protein Synthesis
Protein synthesis is a fundamental cellular process that converts the genetic code into functional proteins. This intricate process is divided into two main stages: transcription and translation. During transcription, the DNA sequence of a gene is copied into messenger RNA (mRNA), which then leaves the nucleus and enters the cytoplasm.
In translation, which occurs within the ribosomes, the sequence of the mRNA is read, and transfer RNA (tRNA) molecules bring the appropriate amino acids to the ribosome. The rRNA in the ribosome's large subunit catalyzes the linkage of the amino acids, forming polypeptide chains, which fold into functional proteins.
It's critical to understand that protein synthesis is a highly regulated process, allowing cells to respond to their environment and maintain homeostasis. Factors influencing protein synthesis include gene expression regulation, availability of amino acids, and the presence of initiation factors that facilitate the starting point of translation. The complexities of protein synthesis underscore the intricate design of cellular machinery working harmoniously to sustain life.
In translation, which occurs within the ribosomes, the sequence of the mRNA is read, and transfer RNA (tRNA) molecules bring the appropriate amino acids to the ribosome. The rRNA in the ribosome's large subunit catalyzes the linkage of the amino acids, forming polypeptide chains, which fold into functional proteins.
It's critical to understand that protein synthesis is a highly regulated process, allowing cells to respond to their environment and maintain homeostasis. Factors influencing protein synthesis include gene expression regulation, availability of amino acids, and the presence of initiation factors that facilitate the starting point of translation. The complexities of protein synthesis underscore the intricate design of cellular machinery working harmoniously to sustain life.
