Biology 1113: Lecture 3 (carbohydrate) Flashcards
What are the primary components of carbohydrates?
Carbon (C), Hydrogen (H), and Oxygen (O), often in the ratio 1:2:1.
What is the general formula for carbohydrates?
(CH₂O)n.
Why are carbohydrates hydrophilic?
Due to their polar C=O and -OH functional groups.
What are the main functions of carbohydrates?
Energy storage, structural support, and serving as raw materials for other molecules.
What is a monosaccharide?
A simple sugar with one ring structure.
Name three common monosaccharides.
Glucose, fructose, and galactose.
Why are monosaccharides important?
They are the monomers of carbohydrates, essential for digestion, absorption, and cellular respiration.
How do monosaccharides differ?
By the number of carbons, position of the C=O group, and orientation of the -OH groups.
What are the two forms of glucose in ring structures?
Alpha (α) and beta (β) glucose, differing in the position of the -OH group.
What is a disaccharide?
Two monosaccharides covalently bonded together.
Give examples of disaccharides and their components.
Sucrose: Glucose + Fructose
Lactose: Glucose + Galactose
What causes lactose intolerance?
Inability to break the bond between glucose and galactose due to an enzyme deficiency.
What reaction forms disaccharides?
A condensation reaction forming a glycosidic linkage.
What is a polysaccharide?
Many monosaccharides linked together.
Name two energy-storing polysaccharides and where they are found.
Starch: Plants
Glycogen: Animals
Why does glycogen lead to ‘water weight’?
It is stored with a lot of water.
What structural polysaccharide is found in plants?
Cellulose.
Why can’t humans digest cellulose?
It consists of β-glucose, which humans lack the enzyme to break down.
What are the structural polysaccharides in fungi and bacteria?
Chitin: Fungi and insects
Peptidoglycan: Bacterial cell walls
What makes cellulose strong?
Linear parallel strands linked by hydrogen bonds.
What are ‘simple sugars’ on nutrition labels?
Monosaccharides and disaccharides.
How do complex carbohydrates affect blood sugar differently from simple sugars?
They take longer to digest, leading to a slower and more sustained energy release.
What roles do carbohydrates play in cell identity?
They act as markers on glycoproteins and glycolipids, aiding in cell-cell recognition and signaling.
What determines blood type in humans?
The specific oligosaccharides attached to membrane proteins or lipids.
Ionic Bonds
Bond formed by transfer of electrons between ions.
Charged Ions
Atoms with positive or negative charge due to electron transfer.
Nonpolar Covalent Bonds
Equal sharing of electrons between atoms.
Polar Covalent Bonds
Unequal sharing of electrons, creating partial charges.
Electronegativity
Tendency of an atom to attract electrons.
Hydrophilic Molecules
Substances that dissolve easily in water.
Hydrophobic Molecules
Substances that do not dissolve in water.
Hydrogen Bonds
Weak attractions between polar molecules involving hydrogen.
Solvent
Liquid that dissolves solutes, commonly water.
Solute
Substance dissolved in a solvent, e.g., NaCl.
pH Scale
Measure of hydrogen ion concentration in solutions.
Buffers
Substances that minimize changes in pH.
Macromolecules
Large biological molecules, including carbohydrates and proteins.
Monomers
Small units that link to form polymers.
Polymers
Large molecules formed from repeated monomer units.
Carbohydrates
Organic molecules primarily for energy storage, C, H, O.
Monosaccharides
Simple sugars, the basic building blocks of carbohydrates.
Glucose
Main energy source in cellular respiration.
Fructose
Simple sugar found in high-fructose corn syrup.
Galactose
Sugar found in dairy products.
Functional Groups
Specific groups of atoms that determine molecular behavior.
Acids
Substances that increase hydrogen ion concentration in solutions.
Bases
Substances that decrease hydrogen ion concentration in solutions.
Hydrophobic Interactions
Nonpolar molecules cluster together in aqueous solutions.
Carbon Skeleton
Framework of carbon atoms in organic molecules.
Silicon-based Life
Hypothetical life forms using silicon instead of carbon.
C-H Bonds
Nonpolar bonds that store significant energy.
C=O Bonds
Polar bonds that contribute to molecule hydrophilicity.
α-Glucose
Form of glucose with -OH group down.
β-Glucose
Form of glucose with -OH group up.
