CH3 | Proteins (1/2) COPY Flashcards
Amino acids are the building blocks of…
proteins.
How many naturally occurring amino acids are there?
20.
The common structural features of amino acids are…
amino group (-NH2), carboxylate (-COOH) and hydrogen bonded to the same carbon atom.
Amino acids differ in their…
R group.
In the amino acid, the amino group is..
basic.
In the amino acid, the carboxylate group is…
acidic.
Protein primary structure is the exact order of…
amino acids in the chain.
The primary sequence determines the protein’s…
final fold and function.
Any change in primary sequence changes the…
entire protein.
What type of bond maintains the primary structure of a protein?
Covalent, peptide bonds.
Peptide bonds occur between which two groups of adjacent amino acids?
Amino and carboxyl.
Intramolecular bonding refers to…
bonds that occur within the atoms of the SAME molecule.
Intermolecular bonding refers to…
bonds that occur between ADJACENT MOLECULES.
Secondary structure refers to local folded structures within a polypeptide due to interactions between…
atoms of the backbone (without R group).
The most common secondary structures are…
α helix and β pleated sheet.
The α helix is stabilized by what type of bonds?
Hydrogen bonds.
Hydrogen bonds in α helix occur between which groups?
Amide (>N-H) and carbonyl (>C=O) groups.
An amide and carbonyl group that are hydrogen-bonded are how far apart on the amino acid chain?
4 amino acids.
How many amino acids are there in every twist of the α-helix?
3.6 amino acids.
Naturally occurring α-helices in proteins are…
right-handed.
An α-helix can be formed from how many polypeptide chains?
One (single chain).
Hydrogen bonds in α-helix are… (intermolecular or intramolecular)
intramolecular.
β-sheets are formed when two (or more) different regions of the polypeptide (____ amino acids long) lie side-by-side.
usually 3-10.
In β-sheets, hydrogen bonds form between which groups?
(C=O) and amino H groups of the backbone.
In β-sheets, the R groups extend…
above and below the plane of the sheet.
The strands of a β pleated sheet may be…
parallel or antiparallel.
How many beta-strands are necessary to make a β-sheet?
two or more.
In β pleated sheet, hydrogen bonds are… (intermolecular or intramolecular)
intermolecular.
Tertiary structure is the overall…
3D structure of a polypeptide.
Tertiary structure involves interactions between which groups?
R groups.
Tertiary structure is made up of combinations of…
alpha helices and beta pleated sheets.
The tertiary structure may be the…
final structure.
Proteins consisting of only one polypeptide chain have their ___ structure as their final structure.
tertiary.
Only those proteins that are made of multiple polypeptide chains have a ___ structure.
quaternary.
Proteins with quaternary structure are known as…
oligomeric.
Quaternary structures are bonded together through…
hydrogen bonds and Van der Waals forces.
Hydrogen bonds in quaternary structures exist between different…
subunits.
Van der Waals forces in quaternary structures exist between…
nonpolar side chains.
What is meant by “conformational changes” in quaternary protein structure?
Change in shape and/or orientation of subunits.
Quaternary structure proteins play an important role in…
functionality and structure of cellular membranes, mediating transport of ions and macromolecules.
Which protein has quaternary structure, made up of 2 alpha subunits and 2 beta subunits?
Haemoglobin.
Proteins are involved in almost every…
biochemical reaction inside biological systems.
Actin and myosin are involved in which function of proteins?
Mobility.
Collagen, Keratin, and elastin are involved in which function of proteins?
Structure.
Lysozyme and antibodies are involved in which function of proteins?
Immunity.
Amylases and pepsin are involved in which function of proteins?
Enzymes.
Insulin and growth hormones are involved in which function of proteins?
Hormones.
Blood proteins maintain…
fluid balance.
Haemoglobin and albumin regulate…
acid-base.
Transferrin and haemoglobin are involved in which function of proteins?
Transport.
Laminin and nerve growth factors are involved in which function of proteins?
Central nervous system.
Proteins are also involved in… (in terms of damage)
wound healing, regeneration, energy, and satiation.
A protein in native conformation is…
active and functional.
Native conformation occurs due to which type of forces?
inter- and intramolecular forces.
Denaturation changes protein…
shape and causes loss of functionality.
Which two factors affect protein shape?
temperature and pH.
Proteins in living organisms function optimally within…
specific conditions.
Human proteins require what temperature to maintain native conformation?
37°C.
Human proteins maintain their native conformation through which forces?
electrostatic interactions and hydrogen bonding.
Above 37°C, what happens to proteins?
Critical inter- and intramolecular forces are disrupted, leading to denaturation.
Denaturation leads to loss of…
protein function.
As temperature increases (below the optimum), what happens to the reaction velocity of a protein?
It increases.
What happens to the reaction velocity when the temperature rises above the optimum?
Denaturation takes place, decreasing velocity.
pH levels must be maintained within a ___ in living organisms.
narrow range.
As pH levels increase or decrease, the environment becomes more…
basic or acidic.
Changes in pH can cause what to happen to bonds holding proteins together?
Break down (leading to denaturation).
Denaturation leads to a loss of…
protein function.
The optimal pH for pepsin (stomach enzyme) is approximately…
2.
The optimal pH for trypsin (intestinal enzyme) is approximately…
8.
Therapeutic proteins are genetically engineered versions of…
naturally occurring human proteins.
Therapeutic proteins with enzymatic activity can…
replace a deficient protein, amplify an existing pathway, or have a new functional role.
Therapeutic proteins with targeting activity can…
interfere with another target molecule or deliver other compounds.
Therapeutic proteins can…
- be used as vaccines.
- interfere with a target molecule,
- develop immunity to foreign organisms,
- manage autoimmune diseases,
- or manage various cancers.
How can therapeutic proteins be used in diagnostics?
As purified and recombinant compounds.
