Chapter 5 Flashcards
Macromolecules
Carbohydrates
Lipids
Proteins
Nucleus acids
Polymer
Is a long molecule consisting of many similar or identical building blocks linked by covalent bonds.
Monomers
Are the repeating units that serve as the building blocks of a polymer. (Are smaller molecules)
Chain-like macromolecules
Carbohydrates
Proteins
Nucleic Acid
Enzymes
Specialized macromolecules that speed up chemical reactions.
Dehydration reaction
A reaction in which two molecules are covalently bonded to each other, with the loss of a water molecule. This is how monomers are connected to each other.
Hydrolysis
The bond between monomers is broken by the addition of a water molecule, with a hydrogen from water attaching to one monomer and the hydroxyl group attaching to the other.
Carbohydrates
Include sugars and polymers of sugars.
Monosaccharides, disaccharides, and polysaccharides.
Monosaccharides’ general molecular formula
CH2O
Glucose structure
C6H12O6. Has a carbonyl group and multiple hydroxyl groups. Is an aldose (aldehyde sugar). Forms rings.
Most common monosaccharide
Glucose
Carbohydrate carbon skeleton size
Three to seven carbons long
Trioses
Three-carbon sugars.
Pentoses
Five-carbon sugars. Form rings.
Asymmetric carbon
A carbon attached to four different atoms or groups of atoms.
Glycosidic linkage
A covalent bond formed between two monosaccharides by a dehydration reaction.
Maltose
Disaccharide formed by two molecules of glucose. Present in beer.
Sucrose
Disaccharide made of glucose and fructose. Known as table sugar.
Lactose
Disaccharide made of glucose and galactose. Present in milk.
Polysaccharides
Are macromolecules, polymers with a few hundred to a few thousand monosaccharides joined by glycosidic linkages.
Architecture and function of a polysaccharide is determined by…
It’s sugar monomers and the position of its glycosidic linkages.
Starch
Plants use starch to store excess glucose. Starch represents stored energy.
Glycogen
A polymer of glucose that is like amylopectin (complex starch) but more extensively branched. Animals use glycogen to store sugar mainly in muscle and liver cells.
Cellulose
Polysaccharide present in cell walls. The most abundant organic compound on Earth.
Two rings that form glucose
Alpha and beta
Chitin
Carbohydrate used by arthropods to build their exoskeletons.
Lipids
They mix poorly, if at all, with water. Generally not big enough to be considered macromolecules.
Lipids consist of mostly…
Hydrocarbon regions.
Lipids most biologically important molecules
Fats, phospholipids, and steroids
Fats
A fat is constructed from glycerol and fatty acids.
Glycerol
Is an alcohol. (Each of its 3 carbons carries a hydroxyl group)
Fatty acid
A fatty acid has a long carbon skeleton, usually 16 or 18 carbon atoms in length. The carbon at one end is part of a Carboxyl group (acid). The rest of the skeleton is a hydrocarbon chain (hydrophobic).
Triacylglycerol
Three fatty acid molecules are each joined to glycerol by an ester linkage, a bond formed via dehydration reaction between a hydroxyl group and a carboxyl group.
Saturated fatty acid
Has a carbon skeleton without double bonds, only single bonds.
Unsaturated fatty acid
Has one or more double bonds. Nearly all of these double bonds are cis double bonds.
Saturated fats are solid at room temperature
True
Unsaturated fats are liquid at room temperature
True
Trans fats
Have trans double bonds resulting from hydrogenating unsaturated fats.
Major Function of fats
Energy Storage
A gram of fat stores more than twice as much energy as a gram of polysaccharide
True
Phospholipid
Has only two fatty acids attached to glycerol. The third hydroxyl group of glycerol is joined to a phosphate group, which has a negative charge.
A phospholipid’s phosphate group and its attachments form a…
Hydrophilic head
When phospholipids are added to water
They for a bilayer, shielding their hydrophobic tail from water.
Steroids
Are lipids characterized by a carbon skeleton consisting of four fused rings.
Cholesterol
A type of steroid. It is a common component in animal cell membranes and is the precursor form from which other steroids are synthesized.
Proteins account for more than 50% of the dry mass of most cells, and they are instrumental in almost everything organisms do.
True
Different protein functions
Speed up chemical reactions
Defense
Storage
Transport
Cellular communication
Movement
Structural support
Catalysts
Chemical agents that selectively speed up chemical reactions without being consumed by the reaction.
Proteins are the most structurally sophisticated molecules known
True