BIOL 115 Lecture Notes - Lecture 5: Hydrophile, Carboxylic Acid, Sodium Hydroxide

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23 Jan 2018

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The 3 big are oxygen (o), carbon (c), and hydrogen (h) Covalent bonds are much harder to break than ionic bonds or hydrogen bonds; other interactions, such as hydrophobic and van der waals interactions, are based on molecular attraction and repulsion. Has a carbon backbone with covalent bonds. At least one bond to hydrogen (h) May also contain oxygen (o) and/or nitrogen (n) Car(cid:271)o(cid:374) is the (cid:271)asis of the (cid:862)orga(cid:374)i(cid:272) (cid:373)ole(cid:272)ules(cid:863) that are asso(cid:272)iated with life. Car(cid:271)o(cid:374) is also fou(cid:374)d i(cid:374) (cid:862)i(cid:374)orga(cid:374)i(cid:272) (cid:373)ole(cid:272)ules(cid:863) su(cid:272)h as co2. Form when electrons are transferred between two atoms. Are weaker (easier to break) than covalent bonds. As a liquid, the h-bonds between h2o molecules break continuously but randomly. Fluidity over a large temp range, mixes molecules for chemical reactions, moderates temperature, surface tension (cohesion) Shared electron pairs (covalent bond) are not. This is because o is electronegative relative to h equidistant between o and h atoms.

Related Questions

The type of macromolecule found in highest concentration on a weight basis in a HeLa cell is

protein.

lipid.

polysaccharide.

nucleic acid.

water

Co and Zn ions are required by humans in

microgram amounts.

gram or near gram amounts.

kilogram amounts.

d. milligram amounts.

Which description best characterizes the length of a hydrogen bond between water molecules?

About the same length as the calculated van der Waals distance for two water molecules.

About the same length as a covalent O----H bond.

Shorter than a covalent O---H bond.

Longer than a covalent O---H bond, but shorter than the calculated van der Waals distance between water molecules.

Which of the following statements about water is not true?

Water will hydrogen bond into highly ordered structures or "cages" around non-polar molecules.

The electron-rich oxygen atom of one water molecule can interact with an electron-poor hydrogen on another water molecule to form a hydrogen bond.

Water is a key player in the energetics of the hydrophobic effect.

In an ice crystal water molecules pack into open lattices consisting of five-membered oxygen rings.

At 25 degrees celsius liquid water is about 85% as hydrogen bonded as the water in ice, with each molecule in an average of 3.4 hydrogen bonds.

Which of the following is the strongest?

Ionic interactions

Permanent dipole - permanent dipole interactions

London dispersion forces

Co-linear hydrogen bonds

Which of the following is the best explanation for the hydrophobic effect?

It is caused by the attraction of hydrophobic groups for each other.

It is an entropic effect caused by the tendency of hydrophobic groups to increase their entropy by associating with other hydrophobic groups.

It is an entropic effect, caused by the tendency of water molecules to increase their entropy by excluding hydrophobic groups, which they must otherwise surround with highly ordered structures.

It is caused by the attraction of water for hydrophobic groups.

It is an entropic effect, caused by the tendency of water molecules to increase their entropy by forming highly ordered structures around the hydrophobic groups.

Which of the following is NOT defined as a buffer? (pKa PIPES-H⁺ = 6.76; pKa MOPS-H⁺ = 7.15; pKa HEPES-H⁺ = 7.47)

0.15 M MOPS, pH 6.50

0.05 M HEPES-H⁺ / 0.04 M HEPES

0.20 M PIPES, pH 7.97

0.01 M HEPES, pH 7.30

1. The level of protein structure that is stabilized primarilyby non-covalent interactions between the side chains within asingle polypeptide chain is refered to as its:

A) primary structure

B) secondary structure

C) tertiary structure

D) quaternary structure

E) none of the above

2. Collagen, a strong fibrous protein found in connectivetissue, bone, and the extracellular matrix, has a structure inwhich three left-handed helices wind around each other to form aright-handed triple helix. The primary structure of collagen has arepeat unit of -(Gly-X-Pro)- Which of the following bonds stabilizethe collagen triple helix? (mark all that apply)

A) Hydrogen bonds between hydroxyproline residues

B) Hydrogen bonds between N-H and C=O

C) Ionic bonds between amino acid side chains

D) Hydrogen bonds between charged amino acids

3. The non-covalent forces that stabilize the Beta-strandconformation of peptides include:

A) H-bonds between amide C=O and amide NH

B) Van der Waals packing between the peptide backbone atoms

C) Van der Waals packing due to side chain interdigitation

D) Only A and B above

E) None of the above

4. What is the approximate length difference of a 22-kDasingle-stranded ?-helical protein segment vs. a 22-kDasingle-stranded ?-strand protein segment? Assume a mean residuemass of 110 Da. Show work.

5. Circular dichroism measurements have shown that the peptidebackbone of poly-l-lysine (KKKKKKK) adopts a random coilconformation at pH 7.0, but becomes ?-helical as the pH is raisedabove 10. This observation is known as the

magentaotter572

Nitrogen and phosphorus are in the same column of the periodic table. They have similar properties in bonding with other molecules because they have the same number of:

We cannot answer this question definitively because there is not enough information.

What I choose are wrong.

BIOL 115 Lecture Notes - Lecture 5: Hydrophile, Carboxylic Acid, Sodium Hydroxide

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