UC Berkeley - Biology 1A - Jim Baxter - Quiz 2 questions and answers

What are the eight functions of proteins, plus cell type examples of each?

Structure - Silk, keratin

Storage - Ovalbumin

Transport - Hemoglobin

Cell Communication - Hormones, receptors

Movement - Myosin, actin

Regulation - Protein kinase

Protection - Antibodies

Enzymes - Bio catalysts

Describe the form of an amino acid

A central carbon connected to a/an:

Amine group

Carboxyl group

Hydrogen

R group

Side note: the amine group can hold a positive charge (an extra H) and the carboxyl group can hold a negative charge (carbonate)

What causes the difference in amino acids

The R group

How do you tell the difference between a polar and a non-polar molecule (generally)?

Non-polar molecules are just generally made up of hydrocarbons, while polar molecules contain higher atomic number atoms

What is the term for protein bond?

A peptide bond

Explain directionality of a protein

It goes from N-terminus to C-terminus

How are peptide bonds made?

Dehydration synthesis

Explain protein primary structure

Linear chain of amino acids

What are the shapes of secondary protein structure?

Alpha Helix

Beta Pleated Sheets

Explain the types of bonds in a secondary structure protein

Hydrogen bonds between the the double bonded oxygen of the former carboxyl group and the hydrogen of the amine group

Explain directionality of beta pleated sheets

If they're going in the same direction then they're parallel. If they're going in opposite directions then they're ant-parallel

What are the molecular interactions of a tertiary structure

Disulfide bridge

Hydrogen bonds

Ionic bonds

Hydrophobic interactions

Native Conformation

Conformation normally assumed by a functional protein

Denaturation

Changes in conformation of a protein

What causes denaturation?

Increase in temperature -> increase in thermal vibration -> breakage of hydrogen bonds

Lowering pH -> adding hydrogens

Multermieric

Made up of multiple polypeptide

What makes up a lipid?

Glycerol + fatty acids

What is the structure of glycerol?

Three carbon alcohol

What are the structures of fatty acids?

Made up of a hydrocarbon tail with a and a carboxyl head

Saturated fatty acids

No C=C bonds

Unsaturated fatty acids

Has C=C bonds

Cis fats

Contain a bent

Naturally occurring

Trans fat

Straight

Processed

What are the roles of fats?

Long term storage of energy

Cushioning

Insulation

Explain the long term storage energy of fats

We store glycogen in the liver (some in skeletal muscle)

When we don't eat, this glycogen in released

When we use all of our carbohydrate reserves, we use our fat sorage

Solid fats

Tend to be saturated fats, lard in animals

They tend to be cis, so they're more tightly packed causing solid

Liquid fats

Are unsaturated fats, (oils in plants)

They can be bent, so they're less tightly packed causing liquids

Phospholipids

Replace one of the fatty acids of the lipid with a phosphate

A polar head and a non-polar tail

What are the structures of phospholipids?

Micelle - A sphere

Liposome - A sphere with a hollow center

Phospholipid Bilayer - Two connected layers of phospholipids

Used in membranes

Steroids

Made up of 4 hydrocarbon rings

Very hydrophobic, non-polar

Ex. Cholesterol

What are the functions of steroids?

Membrane structure

Some are hormones

Robert Hooke

1665 - He noticed little boxes in living things using a primitive microscope

Gave the name cells

Schleiden and Schwann

1839 - Came up with Cell Theory

4 Principles of Cell Theory

1. All living things consist of cells

2. Cells arise from other cells

3. Chemical rxns occur in cells

4. Cells contain hereditary information

What are some problems with size

Volume increases faster than surface area when you increase size

Transportation vs Consumption

Prokaryotic Cells

DNA singular circular molecule

No nucleus

Usually few or no organelles

Typically smaller

Domain Eubacteria

Domain Archaea

Eukaryotic Cells

DNA linear chromosomes (many) + protein (histones)

Huge DNA molecules thats tightly packages and folded

Present nucleus

Many organelles

Phospholipid bilayer

Typically larger

Domain Eukarya

Gram Positive v Gram Negative

Gram negative has a thinner cell wall covered in another phospholipid bilayer. They're usually more difficult to enter. They have proteins on the outside and a reverse polarity.