Question

bonus
challenge problems:

1. after being exposed to a toxic substance, an animal cell could no longer produce its own proteins. what cell structures could have been damaged? use evidence to support your claim.
2. cystic fibrosis is caused by a defect in a channel that regulates the passage of certain molecules out of the cell. this results in excess fluids in the space outside of the cells within the lungs. what cell structure is malfunctioning? use evidence to support your claim.
3. below are two cells: a normal cell and a damaged cell. compare the 2 cells and identify the organelles that are malfunctioning in the damaged cell. use data to support your answer.

characteristics of normal cell	characteristics of damaged cell
58 proteins produced by cell in 1 hour	50 proteins produced by cell in 1 hour
140 molecules of atp produced	4 molecules of atp produced

organelle malfunctioning and support:

Explanation:

Step1: Analyze protein - production cell structures

Ribosomes are the sites of protein synthesis in a cell. If an animal cell can no longer produce its own proteins after exposure to a toxic substance, ribosomes could be damaged. Evidence: Proteins are synthesized on ribosomes according to the genetic information carried by mRNA. If ribosomes are damaged, the translation process of protein - synthesis cannot occur properly.

Step2: Identify the cell structure in cystic fibrosis

The cell membrane contains channels (such as ion channels) that regulate the passage of molecules in and out of the cell. In cystic fibrosis, the defective channel is part of the cell membrane. Evidence: The problem states that there is a defect in a channel regulating molecule passage out of the cell, and cell membranes have such regulatory channels.

Step3: Analyze the malfunctioning organelles in the damaged cell

• For the nucleus - related data: The number of messages sent from the nucleus has increased slightly (from 54 in 5 minutes in normal cell to 63 in 5 minutes in damaged cell), so the nucleus may not be the main malfunctioning organelle.
• For protein - production: The normal cell produces 58 proteins in 1 hour while the damaged cell produces 50 proteins in 1 hour. Since ribosomes are responsible for protein synthesis, ribosomes may be malfunctioning.
• For ATP - production: The normal cell produces 140 molecules of ATP while the damaged cell produces only 4 molecules of ATP. Mitochondria are the power - houses of the cell and are responsible for ATP production. So mitochondria are likely malfunctioning. Evidence: ATP production is a key function of mitochondria, and the significant decrease in ATP production in the damaged cell indicates mitochondrial malfunction.

Answer:

1. Ribosomes could be damaged. Evidence: Ribosomes are the sites of protein synthesis.
2. The cell membrane is malfunctioning. Evidence: The defective channel regulating molecule passage is part of the cell membrane.
3. Ribosomes and mitochondria are malfunctioning. Evidence: Decrease in protein production (ribosome - related) and significant decrease in ATP production (mitochondria - related).