Proteins Flashcards
What is bone composed of?
- Hydroxyapatite(mineral)
- Collagen (protein)
- Non-collagen proteins
- Lipids
- Water
What are proteins?
• polymers with 3D structures that promote functions including enzymatic activity and formation of essential structures
• The linkage between amino acids in a protein is an _____
amide linkage
A sequence of peptide linkages are known as a ______
polypeptide
How long are most proteins?
50-2000 amino acids
What are the 3 types of interactions that hold a protein together?
hydrogen bond, van der walls interactions, electrostatic attractions (salt bridges between positively and negatively charged parts of proteins)
What is the primary structure of a protein?
sequence of amino acids
The type of bond between 2 amino acids is a ____
peptide bond
Primary structure goes from ___ to ____ terminus
N to C
Rotation around peptide bond restricted by _____
resonance
What are the 2 secondary structures?
alpha helix, beta sheet
Where do hydrogen bonds form in alpha helix?
1,4 hydrogen bond
How many steps per turn in alpha helix?
3.6 or interact every 4 steps
what is the distance between neighboring residues in alpha helix? beta sheet?
.15 nm, .35nm
B strands can align both _____ and _____ to form B-sheets. what does each mean?
parallel, antiparallel–>C to N interacts with N to C, for parallel theyre the same
Which beta sheet is more stable?
antiparallel
Examples of all beta sheet proteins?
silk fibroin, amyloid of alzheimer disease
example of all alpha helix?
@ keratin, myosin
Most proteins are ____ of secondary structures
mixtures
Variations of Beta sheet?
B helix, B-Hairpin, Greek-key
The collagen triple helix is composed of ____
1/3 glycine
To denature a protein is to ______
unravel its secondary and tertiary structure
Tertiary structure is :
3 dimensional structure of the entire polypeptide chain
What is the Anfinsen hypothesis?
tertiary structure is determined by primary structure
is the anfinsen hypothesis true?
for some, but not all proteins
How did they denature protein? S-S bonds?
urea, B-mercaptoethanol
What is quaternary structure?
arrangement of protein subunits in a complex (group of several proteins
How are tertiary structures stabilized?
hydrogen bonds, electrostatic/hydrophobic interactions, sometimes disulfide linkages
what are some roles proteins play?
increase rate of reaction 2) protect DNA 3) shuttle nutrients and waste across membrane
