Characteristics of Life
All living organisms maintain a stable internal environment despite external changes. What is the biological term for this balance?
Homeostasis
Which biomodule serves as the primary, immediate source of energy for cellular respiration?
Carbohydrates
Known as the "powerhouse of the cell," which organelle generates ATP energy through cellular respiration?
Mitochondrion (Mitochondria)
What type of cellular transport moves molecules from high concentration to low concentration without using energy?
Passive Transport(or Simple Diffusion)
What is the molecule called that binds to an enzyme's active site to undergo a chemical reaction?
Substrate
Which characteristic of life explains why plants lean toward a window or why you pull your hand back from a hot stove?
Response to Stimuli
What are the monomers (building blocks) that join together via peptide bonds to form proteins?
Amino Acids
Which cellular structure synthesizes proteins using instructions provided by mRNA?
Ribosome
What is the specific term for the diffusion of water molecules across a selectively permeable membrane?
Osmosis
What happens to an enzyme's shape and function when exposed to extreme temperatures or extreme pH levels?
It denatures (loses its specific 3D shape and can no longer bind its substrate).
What is the fundamental structural and functional unit of all living organisms?
The Cell
Which class of biomolecules includes fats, oils, and waxes, and forms the core structure of cell membranes?
Lipids
What organelle found exclusively in plant cells and algae conducts photosynthesis to convert solar energy into glucose?
Chloroplast
If a red blood cell is placed in a hypertonic solution (high salt concentration outside), what will happen to the cell and why?
The cell will shrink (crenate) because water leaves the cell to equalize solute concentration.
What biological molecule is known as the "energy currency" of the cell, releasing energy when its terminal phosphate bond is broken?
ATP (Adenosine Triphosphate
Viruses can mutate and contain genetic code, but why do biologists classify them as non-living?
They lack cellular structure and cannot reproduce or metabolize without a host cell.
Enzymes are biological catalysts. To which group of biomolecules do they belong, and how do they speed up reactions?
Proteins; they speed up reactions by lowering the activation energy.
How do the Endoplasmic Reticulum (ER) and the Golgi Apparatus work together to process and ship proteins?
Rough ER folds/assembles proteins; Golgi modifies, packages, and tags them in vesicles for transport.
Why does active transport require ATP energy, whereas facilitated diffusion does not?
Active transport moves substances against their concentration gradient (low to high); facilitated diffusion moves them down their gradient.
Compare the chemical equations of photosynthesis and cellular respiration in terms of reactants and products.
They are opposite
Keystone Challenge: Explain how a organism's need to maintain homeostasis relies on both metabolic energy and cellular transport.
Cells must actively transport molecules (like ions or nutrients) against gradients using ATP to maintain stable intracellular conditions.
Keystone Challenge: Compare DNA and RNA in terms of their nucleic acid structure, sugar group, and function in protein synthesis.
DNA is double-stranded with deoxyribose sugar (stores genetic info); RNA is single-stranded with ribose sugar (transfers code to make proteins).
Keystone Challenge: Contrast prokaryotic and eukaryotic cells in terms of membrane-bound organelles and genetic material organization.
Prokaryotes lack membrane-bound organelles and have free-floating circular DNA; Eukaryotes have membrane-bound organelles and nucleus-enclosed linear DNA.
Keystone Challenge: Describe how the phospholipid bilayer structure enables selective permeability for nonpolar vs. polar molecules.
Nonpolar/small molecules pass through the hydrophobic core easily; polar/large molecules require transport proteins to cross.
Keystone Challenge: Describe how a competitive inhibitor differs from a noncompetitive (allosteric) inhibitor in affecting enzyme rate and active site access.
A competitive inhibitor directly blocks the active site by mimicking the substrate; a noncompetitive inhibitor binds elsewhere, changing the active site's shape.