Cell Structure and Function| Exam 2|
Updated Questions and Answers|
Verified| Passed
**Describe the process by which proteins are synthesized and exported from the cell, starting
from DNA transcription.**
Proteins are synthesized in a process that begins with DNA transcription in the nucleus,
where mRNA is formed. The mRNA exits the nucleus and is translated by ribosomes in the
cytoplasm or on the rough ER. The protein is then modified in the Golgi apparatus and packaged
into vesicles for export through exocytosis.
**Explain how the plasma membrane maintains selective permeability.**
The plasma membrane maintains selective permeability by allowing only certain molecules
to pass through. Small, non-polar molecules diffuse through the lipid bilayer, while larger or
charged molecules require specific transport proteins or channels.
**How do lysosomes protect the cell from damage?**
Lysosomes protect the cell by digesting damaged organelles, pathogens, and waste materials
using hydrolytic enzymes. This prevents the accumulation of cellular debris and maintains
homeostasis.
**Describe the role of mitochondria in ATP production.**
1
, Mitochondria generate ATP through oxidative phosphorylation in the electron transport
chain. Electrons are transferred through protein complexes, driving the production of ATP via
ATP synthase as protons flow across the inner membrane.
**How does the structure of the endoplasmic reticulum (ER) relate to its function?**
The rough ER, studded with ribosomes, is involved in protein synthesis and modification,
while the smooth ER lacks ribosomes and is responsible for lipid synthesis, detoxification, and
calcium storage.
**What is the role of peroxisomes in lipid metabolism and detoxification?**
Peroxisomes break down fatty acids via beta-oxidation and neutralize harmful substances
like hydrogen peroxide through catalase. They also play a role in the synthesis of cholesterol and
bile acids.
**Explain the function of the cytoskeleton in maintaining cell shape and enabling movement.**
The cytoskeleton, composed of microtubules, microfilaments, and intermediate filaments,
maintains the cell's shape, anchors organelles, and facilitates movement through structures like
cilia, flagella, and motor proteins.
**What is the function of glycoproteins in cell-cell communication?**
Glycoproteins, found on the cell surface, act as receptors or markers in cell recognition and
communication, allowing cells to interact with each other and their environment, such as in
immune responses.
2
Updated Questions and Answers|
Verified| Passed
**Describe the process by which proteins are synthesized and exported from the cell, starting
from DNA transcription.**
Proteins are synthesized in a process that begins with DNA transcription in the nucleus,
where mRNA is formed. The mRNA exits the nucleus and is translated by ribosomes in the
cytoplasm or on the rough ER. The protein is then modified in the Golgi apparatus and packaged
into vesicles for export through exocytosis.
**Explain how the plasma membrane maintains selective permeability.**
The plasma membrane maintains selective permeability by allowing only certain molecules
to pass through. Small, non-polar molecules diffuse through the lipid bilayer, while larger or
charged molecules require specific transport proteins or channels.
**How do lysosomes protect the cell from damage?**
Lysosomes protect the cell by digesting damaged organelles, pathogens, and waste materials
using hydrolytic enzymes. This prevents the accumulation of cellular debris and maintains
homeostasis.
**Describe the role of mitochondria in ATP production.**
1
, Mitochondria generate ATP through oxidative phosphorylation in the electron transport
chain. Electrons are transferred through protein complexes, driving the production of ATP via
ATP synthase as protons flow across the inner membrane.
**How does the structure of the endoplasmic reticulum (ER) relate to its function?**
The rough ER, studded with ribosomes, is involved in protein synthesis and modification,
while the smooth ER lacks ribosomes and is responsible for lipid synthesis, detoxification, and
calcium storage.
**What is the role of peroxisomes in lipid metabolism and detoxification?**
Peroxisomes break down fatty acids via beta-oxidation and neutralize harmful substances
like hydrogen peroxide through catalase. They also play a role in the synthesis of cholesterol and
bile acids.
**Explain the function of the cytoskeleton in maintaining cell shape and enabling movement.**
The cytoskeleton, composed of microtubules, microfilaments, and intermediate filaments,
maintains the cell's shape, anchors organelles, and facilitates movement through structures like
cilia, flagella, and motor proteins.
**What is the function of glycoproteins in cell-cell communication?**
Glycoproteins, found on the cell surface, act as receptors or markers in cell recognition and
communication, allowing cells to interact with each other and their environment, such as in
immune responses.
2
