Lipid Bilayer & Proteins

Question 1

Phospholipid Structure

Answer 1

Modified triglyceride
Contains an R group
Has amphipathic properties

Question 2

Micelle

Answer 2

Single-layer lipid sphere made of hydrogen bonds

Question 3

Liposomes

Answer 3

Lipid bilayer sphere, with a more stable organization of phospholipids in water

Question 4

Planar Lipid Bilayer

Answer 4

Takes about 30,000 phospholipid molecules lying side by side to cover the cell
0.012 degrees of curvature between adjacent phospholipid molecules

Question 5

Lipid Mosaic Model: Lipid Bilayer

Answer 5

Punctuated by proteins that span the bilayer

Question 6

Lipid Mosaic Model: Integral Membrane Proteins

Answer 6

In cellular communication
Ionic pathways
Maintain ion concentrations

Question 7

Lipid Mosaic Model: Glycosylation Status

Answer 7

Attachment to the extracellular matrix
Protein stability

Question 8

Primary Protein Structure

Answer 8

Sequence of a chain of amino acids (peptide bond)

Question 9

Secondary Protein Structure

Answer 9

Local folding of the polypeptide chain into helices or sheets mediated through hydrogen bonds

Question 10

Tertiary Protein Structure

Answer 10

The 3-dimensional folding pattern of a protein due to side-chain interactions
Formed mainly by hydrophobic interactions between amino acid side chains

Question 11

Quaternary Protein Structure

Answer 11

Protein consisting of more than one amino acid chain

Question 12

Amino Acids

Answer 12

Proteins are constructed by long chains of amino acids
All amino acids contain a carboxyl group and an amino group linked by a carbon with an R group attached to this carbon

Question 13

R Group

Answer 13

Characteristics for each of the 20 amino acids
Some R groups are hydrophobic while others are hydrophilic

Question 14

Peptide Bonds

Answer 14

Form when the carbon on the carboxyl group forms a covalent bond with the nitrogen in the amine group in the adjacent amino acid

Question 15

a-helices

Answer 15

Polypeptide backbone forms a very compact corkscrew
Each peptide bond (C-O) is hydrogen bonded to the peptide bond (N-H) four amino acid residues ahead of it

Question 16

B- sheets

Answer 16

Hydrogen bonds are formed between the peptide bond (C-O) and N-H groups of polypeptides that lie side by side

Question 17

Determinants of Shape

Answer 17

Type of amino acids
Order of amino acids
The bond between amino acids
Environmental Factors- temp, pH, etc.

Question 18

Bad Proteins (Prions)

Answer 18

Animals: Scrapie- a degenerative disease affecting the nervous systems of sheep and goats, Mad Cow Disease- Affects CNS
Humans: Creutzfeldt-Jakob Disease- transmitted by contact with infected tissue, such as during a transplant or from eating contaminated meat, Kuru- transmissible spongiform encephalopathy, is a disease of the nervous system that causes physiological and neurological effects that ultimately lead to death

Question 19

Amyloidosis

Answer 19

Deposit of abnormal proteins