BIOLOGY 1A03 Chapter Notes - Chapter 5: Peripheral Membrane Protein, Lipid Bilayer, Active Transport

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BIOLOGY 1A03 Full Course Notes

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Cell membranes are composed of two layers of lipids. The major type of lipid found in cell membranes are phospholipids, which are made up of a glycerol backbone attached to a phosphate group and two fatty acids. The phosphate head is a group is hydrophilic and forms hydrogen bonds with water. The two fatty acid tails are hydrophobic because they are non-polar and do not form hydrogen bonds with water. Molecules with both hydrophilic and hydrophobic regions in a single molecule are termed amphipathic. The shape of the structure is determined by the bulkiness of the head group relative to the hydrophobic tails. Lipids with bulky heads and a single hydrophobic fatty acid tail are wedge- shaped and pack into spherical structures called micelles. Lipids with less bulky head groups and two hydrophobic tails form a bilayer. If phospholipids are in an environment with neutral ph, they spontaneously form spherical bilayers called liposomes that can capture macromolecules during formation.

Related Questions

1. Use the following definitions and phrases to describe to which molecules of life and their subunits it belongs:

a. Energy-storing molecule, typically water soluble - b. Subunits are called monosaccharides â c. Used to speed chemical reactions - d. Subunits are joined to each other with peptide bonds - e. Most prevalent molecule in cell membranes - f. Some of them function as hormones - g. Used for storing, transmitting, and executing genetic information - h. Subunits are nucleotides

2. Weak hydrogen bonds between water molecules are responsible for the many properties of water. Acidity is expressed as pH. Buffers stabilize pH. a. What characteristics of water molecule makes it polar? Provide two examples why this property is important in microbiology. b. What is the role of buffers in living organisms, including microbes? c. What must be added to pure water to decrease OH- and/or H+ concentration, respectively

3. Carbohydrates serve as storage molecules and structural material. Lipids are hydrophobic molecules; phospholipids are main component of cell membranes. Protein has a complex structure based on identity and sequence of amino acids. Nucleic acids (DNA and RNA) are genetic station of storage information and for synthesis of proteins. ATP serve as the main energy source in the living cell. a. Name the subunits (building blocks) of carbs, simple lipids, proteins, and nucleic acids b. What level of protein structure is described as an alpha helix? c. If DNA is placed in boiling water, what and how the molecule would change?

Unit 2 Organic Chemistry

Organic compounds vs. Inorganic compounds

What makes a compound organic? Inorganic?

Functional groups (phosphate groups, amino groups, carboxyl groups)

Know the structure of each of these groups, and which organic compounds they are found in. You can draw them for your own use.

Hydrolysis

What is it? What is it used for?

Dehydration synthesis

What is it? What is it used for?

Carbohydrates (Monosaccharides, Disaccharides, Polysaccharides and examples)

Know the process of joining two monosaccharides together to create a disaccharide.

Be able to give examples of several monosaccharides, disaccharides and polysaccharides.

Monosaccharide examples (3)	Disaccharide examples (2)	Complex carbohydrates (3)

Lipids (Saturated vs. Unsaturated; Phospholipids, Steroids)

Define a saturated fatty acid.

Define an unsaturated fatty acid. Draw if it helps.

What process is used to put the fatty acid chain on a glycerol molecule?

Hydrophilic vs. hydrophobic

Define hydrophilic.

What part of the phospholipid is hydrophilic?

Define hydrophobic.

What part of the phospholipid is hydrophobic?

Proteins, types and functions

What is a protein composed of, and what does it do?

Amino acids

Name the three parts of the amino acid that come off the common Carbon.

Identify each of the three parts. (Amino Acid ID game)

Peptide Bonds

How are they formed?

What two parts of each amino acid do they join together?

Enzymes - define.

Levels of Protein structure

Complete the chart below.

Protein structure level	definition
Primary
Secondary
Tertiary
Quarternary

Protein Denaturation

What is it and how does it happen?

Define what a Solute is.

Define what a solvent is

Nucleic acids (DNA, RNA, ATP)

Nucleotide

Name its three parts and be able to identify each of them on a diagram. (Nucleotide ID game)

What are the two possible sugars used in a nucleotide?

Complete the Table below.

	DNA	RNA	ATP
What sugar does it have?
What nitrogen bases does it have?
Provide the pairings of the nitrogen bases of each nucleic acid			N/A
What is its structure?

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

BIOLOGY 1A03 Chapter Notes - Chapter 5: Peripheral Membrane Protein, Lipid Bilayer, Active Transport

BIOLOGY 1A03 Full Course Notes

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