BILD 1 Lecture Notes - Lecture 3: Hydrogen Bond

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byzantiumfly635

26 Apr 2016

School

UCSD

Department

Biology/Lower Division

Course

BILD 1

Professor

Stephanie Mel

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Document Summary

Covalent bonds (shared electrons but not necessarily equal) are strong, sturdy, stable, and form more permanent bonds. Non-covalent bonds (not shared electrons) are much weaker, reversible, and do not involve shared electrons. Only 2 types of bonds: hydrogen bonds and ionic bonds/interactions. A hydrogen bond is an interaction between a hydrogen that is partially positively charged and another electronegative atom. Ionic interaction is a positive attracted to a negative atom (in biological systems, the environment affects the bond strength; in water, molecules are weaker) Water: the molecule that supports all of life. All living organisms require water more than any other substance. Most cells are surrounded by water, and cells themselves are about 70-95% water. A solution is a liquid that is homogeneous mixture of substances. A solvent is the dissolving agent of a solution. The solute is the substance that is dissolved. An aqueous solution is one in which water is the solvent.

Related Questions

Fill in the following chart with the appropriate subatomic particle and state whether each is located in the nucleus of the orbital

Particle	Charge	Location (Nucleus or Orbital)
	Positive (+)
	Negative (-)
	Neutral Charge

Fill in the following chart using the lowercase letter of the statements below. Please be aware that some letters should be used more than once because they are true for more than one type of bond.

Covalent Bonds	Ionic Bonds	Hydrogen Bonds

Electrons are transferred from one atom to another atom

Valance electrons are shared between atoms

Involves positive and negative ions

A weak bond between 2 or more polar molecules

A bond between 2 or more atoms

The type of bond used to make NaCl (table salt)

The type of bond used to make CH₄ (Methane)

What does it mean when a molecule is described as âpolar?â Be detailed in your answer.

State and explain two reasons that water molecules are essential to life because of their hydrogen bonds.

Fill in the chart with the missing information about macromolecules

Macromolecule	Dietary source	Function	Example	Defining Characteristics
Carbohydrate			Cellulose and glucose
Lipid	Fats, Oils
Protein
Nucleic Acid	Sardines, beans, spinach			Made of nucleotides (contain a base, sugar and phosphate)

greydinosaur410

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

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.

BILD 1 Lecture Notes - Lecture 3: Hydrogen Bond

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