Topic 2.1: Cell Structure and Function
This organelle is responsible for synthesizing proteins by translating messenger RNA.
Answer: What are ribosomes?
This ratio describes the relationship between a cell's outer membrane area and its internal volume.
Answer: What is the surface area-to-volume ratio?
These molecules form the bilayer that makes up the primary structure of the plasma membrane.
Answer: What are phospholipids?
This process describes the passive movement of water across a selectively permeable membrane.
Answer: What is osmosis?
This type of membrane transport requires energy to move substances against their concentration gradient.
Answer: What is active transport?
This organelle modifies, sorts, and packages proteins and lipids into vesicles for transport.
Answer: What is the Golgi apparatus?
Compared with larger cells of the same shape, smaller cells have this type of surface area-to-volume ratio.
Answer: What is a higher surface area-to-volume ratio?
This model describes the plasma membrane as a flexible phospholipid bilayer containing proteins, lipids, and carbohydrates.
Answer: What is the fluid mosaic model?
A red blood cell placed in this type of solution will lose water and shrink because the surrounding solution has a higher concentration of nonpenetrating solutes.
Answer: What is a hypertonic solution?
This process occurs when a vesicle fuses with the plasma membrane to release materials outside the cell.
Answer: What is exocytosis?
This organelle contains hydrolytic enzymes that digest macromolecules, helps complete apoptosis, and recycle damaged cellular components.
Answer: What is a lysosome?
Cells can increase their surface area without significantly increasing their volume by adding these structures to their plasma membrane.
Answer: What are folds or projections of the plasma membrane?
This type of passive transport allows large or charged molecules to cross the plasma membrane through channel or carrier proteins.
Answer: What is facilitated diffusion?
A plant cell placed in a hypotonic solution gains water, generating this pressure against its cell wall.
Answer: What is turgor pressure?
This protein uses ATP to move three sodium ions out of a cell and two potassium ions into the cell.
What is the sodium-potassium pump?
A cell that produces large quantities of proteins for secretion would be expected to have an abundance of this membrane-bound organelle, which contains attached ribosomes.
Answer: What is the rough endoplasmic reticulum?
A cube-shaped cell has sides measuring 2 µm. Using the formulas SA = 6s² and V = s³, calculate its surface area-to-volume ratio.
Answer: What is 3:1?
These specialized membrane channel proteins increase the rate at which water crosses the plasma membrane.
Answer: What are aquaporins?
A plant cell is placed in a solution with a lower water potential than the cell. Net water movement will occur in this direction.
Answer: What is out of the cell?
This cellular feature allows different metabolic processes to occur in separate membrane-bound spaces, increasing efficiency and preventing interfering reactions.
Answer: What is compartmentalization?
A scientist observes that a muscle cell contains significantly more of this organelle than a skin cell because muscle cells require large amounts of ATP for contraction.
Answer: What are mitochondria?
A cube-shaped cell doubles its side length from 2 µm to 4 µm. Its surface area-to-volume ratio decreases from 3:1 to this value.
Answer: What is 1.5:1?
A scientist observes that glucose enters a cell through a membrane protein, moving from high to low concentration without ATP. The protein binds glucose and changes shape to move it across the membrane. This type of transport protein is responsible.
Answer: What is a carrier protein?
A plant cell has a solute potential of −0.8 MPa and a pressure potential of +0.3 MPa. Calculate the cell's total water potential.
What is −0.5 MPa?
Mitochondria and chloroplasts contain circular DNA, bacterial-like ribosomes, and reproduce through binary fission. These characteristics provide evidence supporting this theory about the evolution of eukaryotic cells.
Answer: What is the endosymbiotic theory?