Properties of water
What type of bond forms between two water molecules?
Hydrogen bond
What organelle is known as the “powerhouse of the cell”?
Mitochondria
What are the four major classes of biological macromolecules?
Carbohydrates, lipids, proteins, and nucleic acids.
What is the main component of the cell membrane?
Phospholipids arranged in a bilayer.
Why is water considered a polar molecule?
Because oxygen is more electronegative and pulls shared electrons closer, creating partial charges.
What organelle is responsible for packaging and modifying proteins before export?
Golgi apparatus
What type of reaction links monomers together to form polymers?
Dehydration synthesis (condensation reaction).
What does “selectively permeable” mean?
The membrane allows some substances to pass while restricting others.
What property of water allows it to move upward through plant stems?
Cohesion and adhesion (capillary action).
What organelle contains digestive enzymes that break down waste?
Lysosome
What type of bond connects amino acids in a protein?
Peptide bond.
How do diffusion and facilitated diffusion differ?
Facilitated diffusion uses transport proteins; simple diffusion does not.
Why does ice float on liquid water?
Hydrogen bonds form a crystalline structure that makes ice less dense than liquid water.
What is the function of the rough endoplasmic reticulum (RER)?
Synthesizes and folds proteins using attached ribosomes.
What is the difference between saturated and unsaturated fatty acids?
Saturated fats have no double bonds; unsaturated fats have one or more double bonds in their hydrocarbon chains.
What is active transport?
Movement of molecules against their concentration gradient using energy (ATP).
How does water’s high specific heat benefit living organisms?
It helps regulate temperature in organisms and the environment by absorbing heat without large temperature changes.
How do plant and animal cells differ in their organelles?
Plant cells have a cell wall, chloroplasts, and a large central vacuole; animal cells do not.
How do DNA and RNA differ?
DNA contains deoxyribose and thymine; RNA contains ribose and uracil and is usually single-stranded.
What happens to an animal cell placed in a hypertonic solution?
Water leaves the cell, causing it to shrink (crenation).