Question

the twenty amino acids differ in structure by having unique ____ groups.
amino
hydroxyl
carboxyl
r
phosphate

the rna pol ii protein has quaternary structure. this means that rna pol ii
has four - fold symmetry.
changes over time.
forms part of a quadruple complex.
is composed of multiple polypeptide subunits.
binds to the surface of membranes.

the secondary structure of a protein is determined by its *
interactions among r groups.
right - handed coil.
hydrogen bonding between atoms of the polypeptide backbone.
peptide bonds.
glycosidic linkages.

the ability of proteins to be in motion while embedded in the lipid bilayer may be restricted by being tethered to
glycolipids and glycoproteins.
phospholipids.
the cytoskeleton.
channel proteins.
peripheral membrane proteins.

osmosis occurs when water moves through biological membranes down its concentration gradient. which of the following statements about osmosis is true?
water will move across a membrane to a region with less solute.
water will move across a membrane to a region with more solute.
the direction of osm
if the membrane does not allow solutes to pass, water will be equal

Explanation:

1. Amino acids have a common structure with an amino group, a carboxyl group, and a hydrogen atom attached to a central carbon. The R - group is what makes each of the twenty amino acids unique.
2. Quaternary structure of a protein refers to the arrangement of multiple polypeptide subunits into a single functional complex. RNA Pol II having quaternary structure means it is composed of multiple polypeptide subunits.
3. Protein secondary structure is formed by hydrogen - bonding between atoms of the polypeptide backbone, such as the carbonyl oxygen and the amide hydrogen.
4. Proteins embedded in the lipid bilayer can have their movement restricted by being tethered to the cytoskeleton, which provides a fixed framework.
5. Osmosis is the movement of water across a semi - permeable membrane from an area of lower solute concentration (higher water concentration) to an area of higher solute concentration (lower water concentration). So water will move across a membrane to a region with more solute.

Answer:

1. R
2. is composed of multiple polypeptide subunits.
3. hydrogen bonding between atoms of the polypeptide backbone.
4. the cytoskeleton.
5. Water will move across a membrane to a region with more solute.