7.1 Study Guide Flashcards
What are the monomers of Proteins?
Amino Acids
What bond joins amino acids together?
Peptide Bond (O=C-N-H)
Proteins can be one or more ________folded and bonded together?
Polypeptide Chains
Protein functions depends on what?
Protein Structure.
The repeated sequence of -N-C-C (with attached -H and =O, but not the -R (functional groups) in a polypeptide is called what?
The polypeptide backbone
What is the primary structure of a protein?
The specific sequence (order) of amino acids in a polypeptide chain. Determined by the DNA of the gene that encodes the protein. Covalent Peptide bonds hold amino acids together.
What is the secondary structure of a protein?
Local folded structures that form within a polypeptide due to interactions between atoms of the backbone. The most common types of secondary structures are the α helix and the β pleated sheet.
How are alpha helix and beta pleated sheets held together?
By hydrogen bonds which form between the carbonyl O of one amino acid and the amino H of another.
What is the tertiary structure of a protein?
The overall three-dimensional structure of a polypeptide. The tertiary structure is primarily due to interactions between the R groups of the amino acids that make up the protein forming hydrogen bonds ionic bonds and disulfide bridges between hydrophilic R- groups.
What is the quaternary structure of a protein?
When multiple polypeptide subunits (tertiary structures) join together.
What level of protein structure is described? “formed by interactions of side chains, hydrophobic and hydrophilic interactions, attraction between acidic (-) and basic (+), and covalent bonds between cysteines?”
Tertiary Protein Structure
What level of protein structure is described? “formed by hydrogen bonds between backbone amino and carboxyl groups of different amino acids?”
Secondary Protein Structure
What level of protein structure is described? “formed when multiple polypeptides are joined together”
Quaternary Protein Structure
What level of protein structure is described? “formed by covalent bonds that link amino acids together”
Primary Protein Structure
How can changes in amino acid affect protein structure?
Amino Acids have different properties -> Amino Acid properties influence protein folding -> Protein folding creates a unique shape -> Shape/ protein structure is critical to its function
Mutations can change __________ of proteins?
the primary structure
What is protein denaturation?
Unfolding of a protein that results in the protein no longer being able to perform its original function.
What can cause protein denaturation?
Changes in temperature, PH, salinity
Can proteins return to their functional shape after denaturation?
Some can but most cant
What is the Function of the Protein Type: Antibodies?
engaging in constant battle in the bloodstream; they recognize foreign molecules (pathogens) in the bloodstream and defend the body against them as part of the immune system that protects from infection
What is the Function of the Protein Type: Infrastructure?
supporting and moving cells; give support / shape to the cell, hold and provide scaffolding for tissues and organs
What is the Function of the Protein Type: Pumps, Channels and Receptors (Transport)?
getting back and forth across the membrane; control movement of materials in and out of the cell
What is the Function of the Protein Type: Hormones?
carrying molecular messages through the blood; chemical messenger that trigger cell responses
What is the Function of the Protein Type: Enzymes?
cutting and joining the molecules of life (perform chemical reactions)
Carboxypeptidase cuts apart a specific bond in polypeptides. It would be classified as which type of protein?
Enzyme
About 1/4 of the protein in your body is collagen. Its many different roles include forming molecular cables that strengthen tendons, forming sheets that support the skin and organs, and forming scaffolding for bones and teeth. It would be classified as which type of protein?
Infrastructure
Epidermal growth factor is a protein message telling cells that they have permission to grow. It would be classified as which protein type?
Hormone
What do digestive enzymes do?
break food into small nutrient molecules
Does the following enzyme synthesize or break down (hydrolyze? What does is make or break? “Fatty Acid Synthase”
Synthesis, Fatty Acids
Does the following enzyme synthesize or break down (hydrolyze? What does is make or break? “Tryptophan Synthase”
Synthesis, Tryptophan
Does the following enzyme synthesize or break down (hydrolyze? What does is make or break? “RuBisCo”
Synthesis, Captures carbon dioxide and builds sugar molecules
Does the following enzyme synthesize or break down (hydrolyze? What does is make or break? “Pepsin”
Hydrolyze, Breaks proteins from the foods organisms eat
Does the following enzyme synthesize or break down (hydrolyze? What does is make or break? “Amylase”
Hydrolyze, Starch
What is the function of the following structural protein/ filament? “Collagen”
A structural protein in connective tissue
What is the function of the following structural protein/ filament? “Microtubule”
Provides support and tracks for the motion of two types of protein motors: Kinesin and Dynein
What is the function of the following structural protein/ filament? “Actin”
Forms filaments that are important for cell structure and mobility
What is the function of the following structural protein/ filament? “Myosin”
The molecular motor that powers muscle contractions
What is the function of the following transport structure? “Calcium Pump”?
Transport calcium ions across the cell membrane
What is the function of the following transport structure? “Potassium Channel”
Allows potassium to pass through the membrane
What is the function of the following transport structure? “Acetylcholine Receptor”
Binds the neurotransmitter acetylcholine and opens a channel as part of the process of signaling across nerve synapses
Why do antibodies have several flexible arms with binding sites at the end of each arm?
The arms with binding sites work together to grab targets of different shapes
What are the binding sites of antibodies composed of?
Several loops in the protein chain that have different lengths and amino acid composition allowing the antibody to bind to different targets.
Why are antibodies very flexible?
To allow the arms to reach neighboring targets.
How do mutations and denaturation effect proteins differently?
Mutations change the primary structure potentially affecting function and the effect is a performance difference. Denaturation changes secondary, tertiary and quaternary levels of structure effecting multiple functions in the cell.
Why and how would the structure and function of a protein change if a hydrophobic amino acid was substituted for a hydrophilic one?
The protein structure might change due to the new hydrophilic side chain being attracted to water instead of repelled by water. The hydrophilic side chain may pull/push the structure into a different shape trying to bond with nearby water molecules. The change in shape / structure could change the function of the protein.
Similarities and differences in amino acid structure
All amino acids have an animo (H3N+) and Carbonyl (=O-C-O); the side chain (R) differs between amino acids
How is the tertiary structure formed?
Hydrophobic interactions - hydrophobic side chains clump together in the middle
Hydrophilic interactions- fold to outside and form hydrogen bonds
Acidic and Basic side chains -form ionic attractions
Cysteine side chains (contain S-H) - form covalent disulfide bonds with each other
What four types of side chains (-R) do amino acids have?
- Nonpolar (C-H; contain mainly Carbon and Hydrogen)
- Polar (-OH, 0=C-NH2; contain polar functional groups)
- Acidic (-, O=C-O~, contain charged carbonyl)
- Basic (+, C-NH3+, contain charged amino)
