Cellular Processes and Organelles Flashcards

Which organelle is correctly matched with its primary function in a eukaryotic cell?

Answer: Mitochondrion - Energy production through cellular respiration

The mitochondrion is known as the 'powerhouse' of the cell because it is the primary site of cellular respiration, a process that generates ATP, the main energy currency for the cell. Ribosomes are responsible for protein synthesis. The Golgi apparatus modifies, sorts, and packages proteins and lipids. The lysosome contains digestive enzymes to break down waste.

A scientist observes a cell transporting a large molecule from an area of low concentration to an area of high concentration across the cell membrane. Which cellular process is being observed, and what is its key requirement?

Answer: Active Transport - Requires energy in the form of ATP

The scenario describes the movement of a substance against its concentration gradient (from low to high concentration). This process is known as active transport and requires the cell to expend energy, typically in the form of ATP, to move the molecule. Osmosis, facilitated diffusion, and simple diffusion are all forms of passive transport, where molecules move down their concentration gradient without the cell expending energy.

A red blood cell is placed in a beaker of pure, distilled water. What is the most likely outcome for the cell?

Answer: The cell will swell and likely burst (lyse) because water will move into it.

Distilled water is a hypotonic solution compared to the cytoplasm of a red blood cell. This means the water has a higher water potential (lower solute concentration) than the inside of the cell. Due to osmosis, water will move from the area of higher water potential (the distilled water) to the area of lower water potential (inside the cell) across the semipermeable cell membrane. This influx of water will cause the cell to swell and, because animal cells lack a rigid cell wall, it will likely burst (a process called lysis or hemolysis).

Which of the following correctly describes the function of the nucleus within a eukaryotic cell?

Answer: It contains the cell's genetic material and controls cell activities.

The nucleus serves as the control center of the eukaryotic cell. Its main functions are to house and protect the cell's genetic material (DNA) and to control the cell's growth, metabolism, protein synthesis, and reproduction by regulating gene expression. ATP synthesis occurs in the mitochondria, protein packaging in the Golgi apparatus, and lipid synthesis in the smooth endoplasmic reticulum.

The process of cellular respiration involves several stages. In which location does the Krebs cycle (citric acid cycle) take place?

Answer: In the matrix of the mitochondria

Cellular respiration begins with glycolysis in the cytoplasm. The resulting pyruvate is then transported into the mitochondria. The Krebs cycle, also known as the citric acid cycle, occurs in the mitochondrial matrix, the innermost compartment of the mitochondria. The final stage, oxidative phosphorylation, takes place on the inner mitochondrial membrane. The stroma is part of the chloroplast and is involved in photosynthesis.

A cell needs to produce a protein that will be exported and used outside the cell. Which organelle is primarily responsible for synthesizing this protein?

Answer: Ribosomes bound to the rough endoplasmic reticulum

Ribosomes are the sites of protein synthesis. Ribosomes that are free in the cytoplasm typically make proteins that will function within the cytosol itself. However, proteins destined for secretion, insertion into membranes, or delivery to certain organelles are synthesized by ribosomes attached to the rough endoplasmic reticulum (RER). The RER then helps to fold and modify these proteins before they are sent to the Golgi apparatus for further processing and export.