Chapter 2 Lecture Flashcards
(34 cards)
What are the four big groups of organic macromolecules found in all life?
Carbohydrates, lipids, proteins, and nucleic acids.
Why does the structure of a macromolecule matter?
Shape and bonding determine the molecule’s job in the cell (e.g., storage vs. structure).
What is the simple definition of a carbohydrate?
A molecule made of carbon, hydrogen, and oxygen in a CH₂O ratio.
Describe one glucose molecule in a few words.
Six-carbon sugar that forms a ring in water and is the main fuel for cells.
Give two other monosaccharides besides glucose.
Ribose and fructose.
What bond links sugars in di- and polysaccharides?
A glycosidic linkage (covalent bond).
Match each sugar with its type: sucrose, lactose, glucose.
Sucrose – disaccharide; lactose – disaccharide; glucose – monosaccharide.
Name the storage polysaccharide in plants.
Starch.
What structural polysaccharide builds plant cell walls?
Cellulose.
Where is chitin found and what is its role?
Exoskeletons of arthropods and fungal cell walls; gives strength and protection.
Main job of monosaccharides?
Quick energy for cells.
Main job of disaccharides?
Transportable or short-term energy (e.g., sucrose in plants, lactose in milk).
Main jobs of polysaccharides?
Long-term energy storage (starch, glycogen) or structure (cellulose, chitin).
What one trait unites all lipids?
They are hydrophobic (water-fearing).
List three major lipid types.
Fats -energy- (triglycerides), phospholipids -cell membrane-, and steroids -signalling molecules-
What two building blocks make a fat?
One glycerol plus three fatty acids.
What bond links fatty acids to glycerol?
An ester linkage.
Difference between saturated and unsaturated fatty acids?
Saturated have no double bonds; unsaturated have one or more double bonds.
Physical state of saturated vs. unsaturated fats at room temp?
Saturated – solid (e.g., butter); unsaturated – liquid (e.g., olive oil).
Define essential fatty acid.
A fatty acid humans cannot make and must get from food (e.g., omega-3).
Sketch the basic parts of a phospholipid in words.
Glycerol + two fatty acids (tails) + phosphate head (often with a small charged group).
Why do phospholipids form bilayers in water?
Hydrophilic heads face water; hydrophobic tails hide inside, creating a membrane.
What is the core structure of every steroid?
Four fused carbon rings.
Give two examples of biologically important steroids.
Cholesterol (membrane component) and steroid hormones like testosterone or estrogen.
