Chapter 3: Nucleic Acids, Proteins, and Enzymes Flashcards
Nucleic Acids
Polymers that store, transmit, and express genetic information
Nucleic acids are made up of what type of monomers?
They are made of nucleotides
What are the two types of nucleic acids?
- Deoxyribonucleic acid (DNA)
2. Ribonucleic acid (RNA)
What does DNA do?
It stores and transmits genetic information
What does RNA do?
Carries information of amino acids from genes to where proteins are made
Nucleic acids and proteins encoded by DNA and RNA determine what?
They determine the metabolic functions of an organism
Nucleotides
Are monomers of nucleic acids
What are the three components of nucleotides?
- Nitrogen-containing base
- A pentose sugar (Ribose in RNA or deoxyribose in DNA)
- One to three phosphate groups
Nucleosides
Are molecules containing nitrogen base and a pentose sugar that doesn’t have phosphate groups
Pyrimidine
a 6 membered single-ringed structure
Purine
A fused double-ringed structure
What are nucleotide bonded in?
Condensation reaction to form phosphodiester linkages
Condensation reactions
A chemical reaction where 2 molecules are joined together by a covalent bond to make a larger, more complex molecule, with the loss of a small molecule
Phosphodiester linkages
linkage between the 3’(prime) carbon aton of 1 sugar molecule and the 5’ (prime) carbon atom of another
What are the 4 bases of DNA?
- Adenine (A)
- Cytosine (C)
- Guanine (G)
- Thymine (T)
What are the 4 bases of RNA?
- Adenine (A)
- Cytosine (C)
- Guanine (G)
- Uracil (U)
DNA is composed of what?
They are composed of 2 polynucleotide strands (double-stranded)
What is RNA structure?
It is single-stranded and can fold upon itself, forming a variety of structures
Complementary Base Pairing
Nitrogenous bases (A, C, G, and T/U) of the DNA and RNA molecules bond with one another and are held together by hydrogen bonds
Transcription
When DNA sequence can be copied into RNA
Translation
When RNA specifies the amino acid sequence of a protein from transcription
What are the function of proteins?
- Enzyme
- Defense proteins
- Hormonal and regulatory proteins
- Receptor proteins
- Storage proteins
- Structural proteins
- Transport proteins
- Genetic Regulatory protein
Amino Acids
Are the building blocks of proteins and are monomers that make up polymers in protein
What are the 2 functional groups in amino acids?
- Nitrogen-containing amino acid group (base)
2. the (acidic) carboxyl group
What are the following structural properties of amino acids?
They have an alpha carbon, a hydrogen atom, and a R group (side chain)
R Group
is the fourth bonding electron that is shared with a group that differs in each amino acid
What number of amino acids occur in proteins of all living organism?
There are 20 amino acids
What are the 4 different types of R-Group?
- Amino acids with electrically charged hydrophilic side chains
- Amino acids with uncharged side chains (hydrophilic)
- Special cases (Cysteine, Glycine, proline)
- Amino acids with nonpolar hydrophobic side chains
Amino acids are linked by what?
Linked in a condensation reaction to form peptide bonds
Peptide Bond
Is a chemical bond formed between 2 molecules when the carboxyl group of one molecule react with the amino acid group of the other molecule, releasing a water molecule
Where does polymerization take place?
It takes place in the amino to carboxyl direction
Primary structure of a protein
Established by covalent bonds and is the sequence of amino acids in the linear polypeptide chain
Secondary structure of a protein
It consists of repeated spatial patterns in different regions of polypeptide chain
What are the 2 types of second structure of a protein that are determined by hydrogen bonding?
- alpha helix, which is a right-handed coil that turns the same direction
- Beta pleated sheet, which is formed from 2 or more sequences of amino acids that are extended and aligned
Tertiary Structure of a Protein
Is a three-dimensional shape of a protein that has a singular polypeptide chain (Backbone) made from the combination of alpha-helix and beta-pleated sheet
Quaternary structure of a protein
have 2 or more polypeptide chains (subunits) bind together by hydrophobic and ionic interactions and hydrogen bonds. (basically means proteins interact with each other)
Protein structure can change by what factors?
- Temperature
- Alterations in pH
- A high concentration of polar substances
- nonpolar substances
- molecule interactions that disrupt the interaction between R groups
Free Energy Equation
Describes the energy change associated with a chemical reaction
Catalysts
Are substances that speed up reactions without being permanently altered
Enzymes
Are biological catalysts that are mostly protein, except RNA molecules, called ribozymes
What is E_a?
is the activation energy required for a reaction to begin?
Substrate
Are reactants that bind to a specific site on the enzyme
Active Site
A specific site on the enzyme where the reaction occurs
Enzyme-substrate complex (ES)
The binding of a substrate to the active site of an enzyme that are held together by H-bonding, electrical attraction, or temporary covalent bond
Cofactors in Enzymes
Are molecules that some enzymes require to function
Coenzymes
Have a carbon-containing (organic) molecule that is required for the action of 1 or more enzymes
Prosthetic groups
non-amino acid groups such as heme, flavin, retinal. Are organic molecules that are permanently bound to their enzymes
Substrate concentration affects what?
It affects the rate of an enzyme-catalyzed reaction
What is the protein tertiary structure sensitive to?
It is sensitive to the concentration of H^+ (pH) in the environment
What affects enzymes speed?
- Warming increases rates of chemical reactions, but if the temperature is too high, non-covalent bonds can break and inactivate enzymes
- pH levels
What can enzymes be regulated by?
Inhibitors
Chemical inhibitors
They bind to enzymes and slow reaction rates
Natural inhibitors
Regulates metabolism
Artificial Inhibitors
Are used to treat diseases, kill pests, and help study enzyme function
Irreversible Inhibition
Inhibitor covalently binds to an amino acid side chain at the active site of an enzyme and it permanently blocks the active site
Reversible Inhibition
The inhibitor can separate from the enzyme, allowing the enzyme to function fully as before
Competitive inhibitor
Competes with a natural substrate for the active site, meaning that natural substrate can’t enter the active site
Noncompetitive inhibitor
Binds at a site distinct from the active site which changes the shape of enzyme and function
Allosteric Regulation
The non-substrate molecule binds or modifies other than the active site (the allosteric site, causing a change in enzyme shape and active site shape) and alters enzyme activity
Allosteric regulation can do what?
They can activate/ inactivate enzymes and can be modified by covalent/noncovalent bonding
Feedback Inhibition
inactivates the enzyme and is a widespread type of enzyme regulation and prevents a cell from making excess products it doesn’t need
