AP bio unit 1

Polarity

Differences in atomic electronegativity across an atom

Hydrogen bond

a weak bond between the negative and positive regions of 2 separate molecules

Cohesion

2 of the same molecule form hydrogen bonds with one another

Adhesion

2 different molecules form hydrogen bonds with one another

Surface tension

The ability of water closer to the surface to pack closer together due to cohesion. (increased hydrogen bonding at the surface)

How does water’s adhesion property make it an essential substance?

Adhesion gives it high solvency ability in its liquid state.

• because organisms need a variety of nutrients and are made up of water, the high solvency allows nutrients to be easily accessible for cells

Why is ice less dense than liquid water?

Due to the cohesive properties of water.

• the orientation of hydrogen bonds causes the water molecules to push out farther

How does water’s cohesive property related to thermal energy?

Its cohesive property allows it to absorb a lot of thermal energy before changing states, meaning it can resist sudden changes in temperature.

• helpful for organisms that rely on the water to regulate their body temperature.

Capillary Action

The result of adhesive and cohesive properties.

• plants utilize this to gather water through their roots

Law of the conservation of energy

Energy cannot be created or destroyed, only transformed

Why do living systems need a constant input of energy?

To grow, reproductive, and maintain organization

What are carbon skeletons and what are the 3 shapes they can form?

Multiple carbons bonded together, other atoms can attach

• chains

• Rings

• Branches

What is formed between 2 interacting monomers?

A covalent bond

Dehydration synthesis

• form covalent bonds

• Create macromolecules

• The sub components of water (H and OH) are removed and replaced by a covalent bond

• The H and OH form a water molecule separate from the macromolecule (byproduct)

Hydrolysis

• cleave covalent bonds

• Breaks a macromolecule into its monomers

• A water molecule is hydrolyzed (broken) into its sub components (H and OH) and each is added to a different monomer.

How are the properties of biological molecules determined?

By their structure and thus function.

Primary structure

The specific order of amino acids of a protein

R-groups

The atoms attached to the central carbon

• can be hydrophilic

• Hydrophobic

• Or ionic

Saturated fatty acid

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Unsaturated fatty acid

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Phospholipid: name the regions

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What are the 2 main molecules that make up membranes?

Phospholipids and proteins

What do hydrogen bonds between base pairs do in a DNA molecule?

Stabilize it

What connects nucleotides?

Covalent bonds

What is the directionality of the sub components of a protein?

Amino terminus and carboxyl terminus

Where are new amino acids added on a protein?

To the c (carboxyl) terminus

Secondary structure

Local folding of the amino acid chain (beta-sheets and alpha-helixes)

Tertiary structure

The overall 3d shape of the protein

Quaternary structure

The interactions between multiple polypeptides

Starch

Stored form of sugars and energy in plants

Glycogen

Stored form of energy and sugars in animals/vertebrates

Cellulose

Commonly provides strength in cell walls