Proteins, Enzymes, & Nucleic Acids Flashcards
What is competitive inhibition?
- inhibitors that compete with the substrate molecules for the active site
- action is proportional to its concentration; when more inhibitor is present compared to substrate, it will out-compete the substrate for the active site
- resembles the substrate structure closely
- no induced fit and no catalyze
How many hydrogen bonds are between DNA?
2 hydrogen bonds between A-T
3 hydrogen bonds between G-C
What is a phosphodiester bond
~the covalent bond between nucleotides
~ a result of the condensation reaction between the phosphate group of one nucleotide and a hydroxyl group on the sugar of the next nucleotide in the strand
~ one water molecule is produced
What is the tertiary structure of proteins?
the helixes and sheets in a polypeptide arrange themselves according to hydrophobic ness/ hydrophilic ness, H-bonding, and electrostatic charges
~ Most of tertiary structure is determined by the hydrophobic effect; polar groups face towards the aqueous environment and non-polar groups towards the interior
What is the active site of the enzyme?
region on the protein/enzyme where reactions happen
How is a peptide bond formed?
2 amino acids bond, creating 1 water molecule (an oxygen from the carboxyl group and 2 H from the amino group) and a peptide bond which links a carbonyl group to N that is bonded to H
Whats the quaternary structure of proteins?
various polypeptides can join together forming multi polypeptide proteins (ex. enzymes)
~ 2 or more large polypeptides interact to create a final shape that gives a protein its function
What are nucleic acids made up of?
nucleotide monomers bonded together with a phosphodiester bond which creates a sugar-phosphate backbone
Describe the lock and key mechanism regarding enzymes.
The enzyme is the lock and the substrate is the key
~ substrate binds to the enzyme (this is called Enzyme-substrate complex) and after the reaction is done, 2 products are produced
What are enzymes
proteins that act as biological catalysts, increasing the rate of certain reactions
What is the catalytic cycle for enzymes?
once the reaction is complete, the enzyme can go back to work on a new substrate molecule
What is non-competitive inhibition?
- binds to a different site on the enzyme called the allosteric site, which regulates enzyme activity (they prevent the enzyme from working but do not bind to the active site)
- decreases enzyme activity
For every 2 amino acids, how many water molecules are produced
1 water molecule
What are proteins made up of?
amino acid monomers that are bonded together with a peptide bond forming a polypeptide
What are the 4 different Nitrogenous bases?
Adenine, Thymine, Guanine, Cytosine
~ (A pairs with T, C pairs with G)
In RNA, all are the same except Thyme (Thymine) is replaced by Uracil
What are the two types of nucleic acids? Describe.
DNA (deoxyribonucleic acid)
~ contains the genetic info of an organism which is decoded into particular amino acid sequences of proteins
~ contains a modified 5-carbon sugar which only has 4 oxygen atoms instead of 5 (this gives it its name of deoxy)
RNA (ribonucleic acid)
~ contains the genetic information of some virus particles and assists DNA to make proteins
~ is a large polymer that is composed of nucleotides which contain the sugar ribose (a normal 5-carbon sugar containing 5 oxygen atoms
What are the 4 levels of protein structure?
Primary Structure
Secondary Structure
Tertiary Structure
- Quaternary Structure
What are some factors that cause protein denaturation?
- changes in pH
- heat
- exposure to alcohol
- high salt concentrations
What are some factors that affect enzyme activity? explain each.
- temperature (at high temps, proteins denature; at cold temps, the bonds are not flexible enough to allow the substrate to bind)
- pH (extreme pH levels cause protein denaturation)
- concentration of substrate & enzyme
- inhibitors (chemicals that reduce the rate of enzymatic reactions; reduce the enzyme’s ability to interact with its substrate)
How do enzymes provide new reaction pathways?
by lowering the activation energy required
What types of nitrogenous bases are pyrimidines and purines? Give examples.
PYRIMIDINES: single-ringed bases (Thymine & Cytosine)
PURINES: double-ringed bases (Adenine & Guanine)
What is the secondary structure of proteins?
the amino acids hydrogen bond with neighbors, creating coils (alpha helix) or folds (beta-pleated sheets)
~ FOLDING: B sheets created when H-bonds form between 2 parts of the polypeptide chain layered on each other
~ COILING: alpha helix created by H-bonding between every 4th amino acid within a strand
What does the structure of a nucleotide include
PSN
Phosphate Group
Sugar
Nitrogenous base
Are enzymes recyclable?
Yes, they can be reused with every subsequent reaction
What is the amino acid structure?
Ionized amino group on the left bonded to a C (with H bond at top and R bond at bottom) and ionized carboxyl group on the right
What is an enzyme’s specificity determined by? What is the active site determined by?
the active site; active site is determined by the folding
What are enzyme cofactors?
a metal ion or mineral needed by some enzymes to help the reaction
~ ex. iron, zinc
What is induced fit for enzymes?
induced fit is when enzymes adjust their shapes so that the substrate fits perfectly
the enzymes “hug” the substrate
What is protein denaturation? Give examples.
the breaking of many bonds within a protein molecule that disrupts its shape & stabilizes the highly ordered structure
short & simple: the breaking of bonds
ex: curling/straightening hair, curing meat, cooking
What types of reactions can enzymes catalyze?
both ANABOLIC (synthesis/condensation) and CATABOLIC (hydrolysis) reactions
What is the primary structure of proteins?
the linear sequence/order of amino acids
~ amino acid monomers are joined by peptide linkages, forming polypeptide strands
What determines function when talking about proteins?
shape determines function
What are hydrolase enzymes?
enzymes that catalyze hydrolysis reactions
What’s the difference between RNA and DNA in terms of structure?
DNA has a missing oxygen on carbon 2 (hence it has 4 oxygens) and RNA has all 5 oxygens
What are coenzymes?
organic molecules that assist the reaction (many vitamins are coenzymes)
