Chemical Components of Cells Flashcards
Covalent Bonds
When atoms share electron(s)
Non-covalent bonds
Ionic bonds and Hydrogen bonds
Ionic bonds
When an atom gains or donates an electron leading to atoms with positive or negative charges.
Gain electron –> negative charge
Lose electron –> positive charge
Hydrogen Bonds
weak electrostatic interactions with single hydrogen shared between 2 electronegative atoms
Hydrophobic interactions
Water fearing interactions, interactions between groups insoluble in water, groups tend to group together to minimize exposure to water.
Van der Walls interaction- very weak interactions
Life supporting properties of H2O
About 70% of cell’s weight, good solvent, ice is solid form, less dense than liquid from, important to aquatic ecosystems
Acids
A molecule that is capable of donating a hydrogen atom
Base
A molecule that is capable of receiving a hydrogen atom
Amphoteric Molecule
A molecule that can serve as an acid or a base
Buffer
Solution that minimizes the fluctuation in pH; binds/ releases hydrogen
The nature of biological Molecules
Organic Chem. centers around the chemistry of carbon:
Carbon binds up to 4 other atoms since it has 4 outer shell electrons (8 are needed to fill the outer shell, octet rule)
Functional groups of biological molecules
Grouping of atoms with often behaves as a unit, responsible for physical and chemical properties:
OH- hydroxyl group
COOH- carboxyl group
SH- sulhydryl group
NH2- Amino Group
Macromolecules
Form structures and carry out cellular activities, usually huge and highly organized polymers.
Carbohydrates, lipids, proteins, and nucleic acids
Monomers
Sugars—> polysaccharides (carbohydrates)
Amino Acids–> proteins
Nucleotides–> nucleic acids
Fatty acids–> lipids
Other important molecules
Metabolites- Metabolic intermediate, a compound formed along chemical pathways leading to end product
Vitamins- usually, small molecules adjunct to proteins
ATP- molecules for energy storage
Urea- metabolic waste product
Hormones
Steroids: progesteron, estradiol, cortisol, testosterone
Protein hormones: insulin, growth hormone
Carbohydrates
Chemical energy storehouse, durable building material for biological construction
General Formula: (CH2O)n
Glycosidic bond: linking sugars
Disaccharide: 2 monosaccharides covalently bonded together by condensation reaction
Oligosaccharide: small chain of sugars; usually attached to lipids and proteins outside of the plasma membrane (glycolipids and glycoproteins)
Polysaccharides: many sugars linked together to form long chains; Glycogen: animal tissues (liver)- principle animal energy storage, especially in liver and muscles
Starch- plants (rice)
Cellulose- plants (cotton fibers)
Chitin- Shells of insects (shrimps and crabs)
Lipids
Primarily composed of C, H, O; insoluble in water (but soluble in organic solvent); fuel molecules (contain more energy than carbohydrates); structural components; include: fat and oil
Saturated chains of fatty acids
Do not contain double bonds, meaning they are straight and tightly packed
Unsaturated chains of fatty acids
Contains of 1 or a few double bonds, making them unable to be packed tightly
Fatty acids
Long hydrocarbon chain
Amphipathic: have hydrogen and hydrophilic character (e.g. Phospholipids from bilayer membrane)
Differ in chain length (usually 14-20 carbons)
Triglyceride (neutral lipid)
Formed by 3 condensation reaction which form ester linkages (-C-O-C-) between glycerol and 3 fatty acids
Fatty acids chains of triglycerides do not need to be identical but may be. Glycerol is polar
Storage from of lipids for fuel (e.g., in adipocytes)
Steroids
Complex rings structures: 4 joined rings, number and positions of double bonds and functional groups differ
Sex hormones: testosterone, estradiol, ect.
Phospholipids
Glycerol + 2 fatty acid + phosphate group
Highly charged at physiological pH
1 saturated and 1 unsaturated fatty acid chain
Length and degree of unsaturation affect membrane fluidity
Glycolipids
Lipids + sugars residues (e.g. galactose)
