Lesson 4 Flashcards
3 categories of amino acids are…
charged polar
uncharged polar
non polar
3 unique amino acids are…
glycine
proline
cysteine
… hydrogen bond with the…
carbonyl oxygens of one peptide…amino hydrogens of another peptide
hydrogen bond on a beta sheet is…
between two regions of the same polypeptide
- happens in regions with adjacent, and parallel or anti-parallel backbones
a hydrogen bond in an alpha-helix is…
within the same region of a polypeptide
- 4 amino acids away
tertiary structure often determined by …
NMR that uses magnetic fields to orient them (?)
fibrous proteins are…
elongated, structural, and found outside the cells (ex. collagens, keratins)
globular proteins are …
compact shape and found inside the cell
what is a quaternary structure?
multiple polypeptides associated to work as one functional protein ex. hemoglobin
protein domains are…
protein segments with a distinct structure and predictable functions. each domain works in a semi-independent manner
- there can be multiple domains of ONE protein
the primary structure of a protein is a…
sequence of amino acids linked together by peptide bonds, forming a polypeptide
the secondary structure is formed by…
local regions of the resulting polypeptide can then be coiled in to a helix
who was christian anfinsen
in 1956, he found that adding urea and mercaptoethanol to a protein while allow for unfolding, when these elements were taken away again, the protein refolded back to native state
what are molecular chaperones?
to prevent inappropriate interactions ***
membranes are…and they do…
they are 5-10nm thick and their functions are
- compartmentalization
- scaffolding for biochemical activities
- selectively permeable barrier
- energy production
- signaling
what is the composition of membranes
- proteins
- lipids : phospholipids (phosphoglycerides and sphingolipids) , sterols (cholesterol), glycolipids
- carbohydrates
phosphoglycerides, a type of phospholipid are…
amphipathic! which means they are both hydrophobic and hydrophylic
sphingolipids are…
similar to phosphoglycerides. it has a fatty acid attached to a sphingosine with no glycerol backbone (sphingosine instead) and longer fatty acid tails than phosphoglycerides
lipids in the membrane of erythrocytes is an example of
asymmetric distribution where there is an uneven distribution between the leaflets
who are gorter and grendel
in 1925 they found that in a natural state the lipids must be in a bilayer ***
how can lipids move?
- rotation
- lateral diffusion - moving spots on one layer
- transverse diffusion - moving from one layer to another (flipflop) – this never happens
how does fatty acid saturation affect membrane fluidity?
unsaturated fatty acids = increased fluidity
saturated fatty acids = decreased fluidity
how does cholesterol affect membrane fluidity
it increases whatever the natural state is - if it is a solid membrane fluid it makes it more fluid and vice versa
temperature and cholesterol?
at warmer temps - it increases membrane rigidity, it acts as walls to prevent movement
at cooler temps - it increases membrane fluidity, its bumpy shape makes gaps and prevents tight packing
