Proteins, Enzymes, & Nucleic Acids Flashcards
(35 cards)
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
