AP Biology Biomolecules

Biomolecule

Organic, carbon-based macromolecules (Needed by all living organisms)

Four Main Types of Biomolecules

• Carbohydrates

• Lipids

• Proteins

• Nucleic Acids

Monomer

Individual subunit (building block) of a biomolecule

Dimer

Two monomers covalently bonded together

Polymer

Many monomers covalently bonded together

Biomolecule Metabolism

Combination of chemical reactions that synthesize and hydrolyze biomolecules for energy storage and release in an organism

Free Energy

Energy that is actually available for a cell to use for metabolic processes

Catabolic Reactions (Exergonic Reactions)

• Breaks down biological polymers into monomers to help generate ATP

• Exergonic - There is a net release of free energy

• Exergonic reactions release free energy that is used by endergonic reactions so they can occur. This is called reaction coupling

Anabolic Reactions (Endergonic Reactions)

• Builds up monomers into biological polymers for energy storage

• Endergonic - Requires a net investment of free energy

Dehydration Synthesis

• Process where monomers are covalently bonded together into polymers

• Anabolic process - Synthesizes polymers for energy storage and/or structure

• Requires the assistance of enzymes

• Removal of water to make a bond between monomers

• Water is formed as a byproduct

Hydrolysis

• Process where polymers are broken down into monomers

• Catabolic process - Breaks down polymers to release energy 

• Requires the assistance of enzymes and the breakdown of water to occur

• Uses water to break the bonds between monomers

Carbohydrates (Sugars)

• Monomers: Monosaccharides (Glucose)

• Polymers: Polysaccharides (Starches/Cellulose)

• Structure: Hexamer Rings

• Main Functions: Short term energy source, Energy storage, Structure

• Elemental Compositions: Carbon, Hydrogen, Oxygen (1C: 2H: 1O ratio)

• Found in small amounts on the cell membrane and helps cell types recognize each other

Energy Storing Carbohydrates

• Have a branched structure

• More branches means more monomers can be broken off at once, allowing for cellular respiration to happen faster to make more ATP energy

Structural Carbohydrates

• Have a linear structure and are able to stack

• Stacking gives the carbohydrates stability, allowing for the formation of tough structures that allow for structural support (Ex: Plant cell walls and chitin shells in crabs)

Lipids (Fats/Oils)

• Monomers: Fatty Acid

• Polymers are lipids

• Structure: Long hydrocarbon chains

• Main Functions: Long term energy storage, Insulation and protection of body parts

• Elemental Composition: Carbon, Hydrogen, Oxygen (1C: 2H: very little oxygen ratio)

• Phospholipids are a special type of lipid that make up the main part of the cell membrane

• Hydrophobic

Saturated Fats (Bad Fats)

• Do not have double bonds in their molecular structure

• Linear - They can stack and form solids at room temperature. This can lead to lipid build up in blood vessels

Unsaturated Fats (Good Fats)

• Do have double bonds in their molecular structure

• Double bonds prevents them from stacking, so they are liquid at room temperature. They are less likely to clog your arteries and veins

Proteins (Meats/Muscles)

• Monomers: Amino Acids

• Polymers: Polypeptides

• Structure: Very complex with four levels

• Main Functions: Wounds and tissue repair, Catalyzing chemical reaction, Cell signaling

• Elemental Composition: Carbon, Hydrogen, Oxygen, Nitrogen and Sulfur (CHONS)

• Enzymes are specialized proteins that speed up (catalyze) chemical reactions in cells to help maintain homeostasis

• Some proteins are embedded in the cell membrane and helps with transporting materials into and out of the cell

Nucleic Acids (Genetic Material)

• Monomers: Nucleotides

  • 3 Parts of a Nucleotide

    • Sugar

    • Phosphate

    • Nitrogenous Base

  • 3 parts linked by covalent bonds

• Polymers: Nucleic Acids

• Main Functions: Storage of genetic material, Coding for an organism’s physical characteristics (traits)

• Elemental Composition: Carbon, Hydrogen, Oxygen, Nitrogen and Phosphorus (CHONP)

• There are two main types of nucleic acids: DNA and RNA

• DNA and RNA have directionality

  • 5’ end and 3’ end

DNA

• Structure

  • Eukaryotes: Linear, double stranded double helix

  • Prokaryotes: Circular, double stranded double helix

• Stores the genetic code

• 4 nucleotides

  • Adenine

  • Thymine

  • Cytosine

  • Guanine

• Nucleotides have a deoxyribose sugar

• More stable than RNA

• Location

  • Eukaryotes: Nucleus

  • Prokaryotes: Floating in the cytoplasm of the cell

RNA

• Single stranded

• 3 Types of RNA

  • Messenger RNA (mRNA)

  • Transfer RNA (tRNA)

  • Ribosomal RNA (rRNA)

• Used for protein synthesis

• 4 nucleotides

  • Adenine

  • Uracil

  • Cytosine

  • Guanine

• Nucleotides have a ribose sugar in them

• Less stable than DNA

• Made in the nucleus and transported to the cytoplasm