CLEP - Biology Cell Organelle Structure/Function Questions and Answers — Questions and Answers
Question 1: A cell actively engaged in breaking down and recycling damaged organelles and foreign particles would be expected to have a high concentration of which organelle?
- Ribosomes
- Golgi apparatus
- Lysosomes (Correct answer)
- Mitochondria
Correct answer: Lysosomes
Lysosomes are membrane-bound organelles that contain hydrolytic enzymes. Their primary function is to break down waste materials, foreign particles, and cellular debris, a process known as phagocytosis. Therefore, a cell with high metabolic activity involving degradation would be rich in lysosomes.
Question 2: A scientist is studying a plant cell and observes an organelle with a double membrane, containing stacks of flattened sacs called grana. What is the primary function of this organelle?
- Synthesizing lipids and steroids
- Modifying, sorting, and packaging proteins
- Generating ATP through cellular respiration
- Converting light energy into chemical energy (Correct answer)
Correct answer: Converting light energy into chemical energy
The described organelle is a chloroplast. Chloroplasts are the site of photosynthesis in plant cells. They contain thylakoids arranged in stacks called grana, which house the chlorophyll pigments necessary for capturing light energy and converting it into chemical energy in the form of glucose.
Question 3: Which of the following correctly outlines the path of a protein destined for secretion from a eukaryotic cell?
- Golgi apparatus → Rough ER → Ribosome → Plasma membrane
- Ribosome → Rough ER → Golgi apparatus → Plasma membrane (Correct answer)
- Nucleus → Ribosome → Smooth ER → Lysosome
- Ribosome → Golgi apparatus → Rough ER → Plasma membrane
Correct answer: Ribosome → Rough ER → Golgi apparatus → Plasma membrane
The synthesis of proteins for export begins on ribosomes attached to the rough endoplasmic reticulum (RER). The protein then moves into the RER for folding, travels to the Golgi apparatus for further modification and packaging into vesicles, and is finally transported to the plasma membrane for secretion (exocytosis).
Question 4: Liver cells are heavily involved in detoxifying harmful substances like alcohol and drugs. Which organelle would you expect to be particularly abundant in these cells to perform this function?
- Nucleolus
- Smooth Endoplasmic Reticulum (Correct answer)
- Peroxisome
- Vacuole
Correct answer: Smooth Endoplasmic Reticulum
The smooth endoplasmic reticulum (SER) has several functions, including lipid synthesis and, notably, the detoxification of drugs and poisons. Liver cells have an extensive SER to break down toxic substances into less harmful, water-soluble molecules that can be excreted from the body.
Question 5: The inner membrane of a mitochondrion is highly folded into structures called cristae. This structural feature is critical because it:
- provides a large surface area for the attachment of ribosomes.
- houses the genetic material (mtDNA) of the mitochondrion.
- increases the surface area for the reactions of the electron transport chain. (Correct answer)
- allows for the storage of water, nutrients, and waste products.
Correct answer: increases the surface area for the reactions of the electron transport chain.
The electron transport chain and ATP synthase, key components of aerobic cellular respiration, are embedded in the inner mitochondrial membrane. The folding of this membrane into cristae dramatically increases the available surface area, allowing for a greater number of these components and thus maximizing ATP production.
Question 6: Which organelle is considered the primary site of ATP synthesis during aerobic cellular respiration in eukaryotes?
- Chloroplast
- Ribosome
- Nucleus
- Mitochondrion (Correct answer)
Correct answer: Mitochondrion
The mitochondrion is often called the 'powerhouse' of the cell because it is where the Krebs cycle and oxidative phosphorylation (electron transport chain) occur. These processes of aerobic cellular respiration generate the vast majority of the cell's adenosine triphosphate (ATP).
CLEP - Biology Cell Organelle Structure/Function Questions and Answers
A cell actively engaged in breaking down and recycling damaged organelles and foreign particles would be expected to have a high concentration of which organelle?