Exam 1 Flashcards
What are the four small, organic molecules that are contained in all living species?
Sugars, fatty acids, amino acids, and nucleotides
What bonds contribute to the ability of a molecule to be hydrophilic?
Polar covalent and hydrogen
What bonds contribute to preventability of a molecule to be hydrophobic?
Non polar covalent
What are acids?
Substances that release protons when they dissolve in water
What are bases?
Substances that accept protons when they dissolve in water
What combinations of atoms occur repeatedly in organic molecules?
Methyl (CH3), hydroxyl (OH), carboxyl (COOH), carbonyl (C=O), phosphoryl (PO3^2-), and amino (NH2)
What are the primary source of chemical energy for cells?
Sugars
What are monosaccharides?
The smallest sugars with the general formula (CH2O)n
What are oligosaccharides?
2-10 monosaccharides
How do monosaccharides join together?
By linking their covalent bonds called glycosidic bonds to form larger carbohydrates
What is a condensation reaction?
A bond is formed between OH groups between sugars and a water molecule is expelled
What is hydrolysis?
A bond is broken between OH groups and a water molecule is consumed
What are some polysaccharides?
Glycogen and starch (used as energy store), cellulose (used as support), and chitins (used as exoskeletons and fungal cell walls)
How can oligosaccharides be linked?
To proteins to form glycoproteins or to lipids to form glycolipids
What are an even richer (but not more prevalent) energy source for cells than sugars?
Fatty acids
What is the essential function of fatty acids?
To form lipid molecules that assemble into cell membranes
What are the two chemically distance parts of fatty acids and what are their characteristics?
Long hydrocarbon chain (hydrophobic, not reactive) and the carboxyl group that behaves as an acid because in aqueous solution it is (ionized, hydrophilic, and chemically reactive)
What are amphipathic molecules?
Molecules that have hydrophilic and hydrophobic regions
How are fatty acid molecules linked?
Covalently by their carboxyl regions
What is a saturated fat?
No double bonds between carbons and the maximum number of hydrogens
What is an unsaturated fat?
One or more double bonds that creates kinks in the hydrocarbon tails and interferes with its ability to pack together
What are lipids?
Found in the long hydrocarbon chains of fatty acids and multiple linked aromatic rings in steroids that are insoluble in water but soluble in fat and other organic solvents
What are phospholipids?
Type of fatty acid that forms a lipid bilayer due to its amphipathic nature
Which bonds are non polar?
C-H, C-C
What are the three non covalent bonds?
Ionic, hydrogen, and van der waals forces
What are sugars used for?
Energy, structure, component of nucleic acids, component of exterior plasma membrane
Which functional group found in fatty acids is most chemically reactive?
Carboxyl
What is the name of the reaction that takes place between two sugars to form polymers of sugars?
Condensation
Lipids include which of the following?
Fatty acids, steroids, and oils
Glycogen, starch and cellulose are formed from simple sugars. What are two general names for glycogen, starch and cellulose?
Polysaccharides and carbohydrates
Which of the following pairs of functional groups might form hydrogen bonds with one another in water?
Carbonyl and hydroxyl
Which of the following functional groups are present in all sugars (monosaccharides, not in aqueous solution)?
Hydroxyl and carbonyl
What is a sugar in general?
A chain of carbons (at least 3) that has OH groups on each carbon except one which has a C=O
What is a fatty acid?
A hydrocarbon chain with a carboxyl group on one end
How are phospholipids and triacylglycerides related to fatty acids?
They’re formed by binding 2 (phospholipid) or 3 (triacylglycerides) fatty acids to a glycerol molecule through reactions between the carboxyl group on the fatty acid and the hydroxyl group on the glycerol
What is the general name for phospholipids, triglycerides, and other molecules?
Lipids
What are saturated fats solid and unsaturated fats liquid at room temperature?
Saturated fats have straight fatty acid chains that allow them to fit together more closely and have more van der waals forces and greater affinity whereas unsaturated fats have kinks where there are double bonds that doesn’t create enough attraction between molecules to make it solid
What are amino acids?
Building blocks of proteins that have a carboxylic acid and an amino group; they are distinguishable by their side chains
What are the long chains that amino acids make up called?
Proteins or polypeptides
What is the bond between two amino acids and how is it formed?
Peptide bond; condensation reaction
What are nucleotides?
Subunits of DNA and RNA composed of a nitrogen-containing ring compound linked to a 5-carbon sugar where there are one or more phosphate groups attached
What are pyrimidine bases?
One six-membered ring (i.e. cytosine, thymine, and uracil)
What are purine bases?
One six-membered ring attached to a 5-membered ring (i.e. guanine and cytosine)
What do nucleotides do?
Serve as storage and retrieval of biological information and building blocks for the construction of nucleic acids
What are nucleic acids?
Long polymers in which nucleotide subunits are linked by the formation of covalent phosphodiester bonds by a condensation reaction between the phosphate group attached to the sugar of one nucleotide and a hydroxyl group on another
What is metabolism?
The sum total of all the chemical reactions it needs to carry out to survive, grow, and reproduce
What are catabolic pathways?
Break down foodstuffs into smaller molecules, thereby generating both a useful form of energy for the cell and some of the small molecules that the cell needs as building blocks
What are anabolic or biosynthetic pathways?
Use the energy harnessed by catabolism to drive the synthesis of the many molecules that form the cell
What is the second law of thermodynamics?
States that, in the universe or in any isolated system, the degree of disorder can only increase
What is the first law of thermodynamics?
Energy cannot be created or destroyed but it can be converted from one form to another
What is catalysis?
The acceleration of the specific chemical reactions needed to sustain life
What do enzymes do?
Increase activation energy so molecules can be converted to a lower energy state
What are substrates?
Where the enzyme binds
What is a catalyst?
Type of enzyme that lowers the activation energy of a reaction by increasing the rate of the chemical reactions (they allow a much larger proportion of the random collisions with surrounding molecules to kick the substrates over the energy barrier)
When does disorder increase?
When useful energy that can be harnessed is dissipated as heat
What do all amino acids contain?
Carboxyl and amino groups
What varies among different amino acids?
Side chains
As a strand of DNA is replicated, a polymer of nucleotides is made by forming covalent bonds between the phosphoryl group on one nucleotide and the _______________ group on the next.
Hydroxyl
What type of bond links the two antiparallel polynucleotide chains to each other in a double helix of DNA?
Hydrogen
What is the covalent linkage called between two adjacent amino acids in a protein?
Peptide bond