Biochemistry Basics and Biomolecules

Biochemistry Basics and Biomolecules

Reviewing chemistry concepts that are helpful in studying macromolecules in biology.

Amino acids are the monomers (single subunits) that build protein polymers (larger molecules made up of 2 or more monomers). The functional groups -COOH and -NH₂ gives amino acids their properties and function. Acidic amino acids will have more -COOH groups. Whereas neutral amino acids will have only one -COOH for every -NH₂ .

Polar Acidic Molecules
Amino Acids

Multiple Choice

What is the monomer for proteins?

• fatty acids

• monosaccharides

• amino acids

• nucleotides

Multiple Choice

Which type of amino acids are shown in the image?

• acidic

• neutral

• basic

Hotspot

Identify the carboxylic acid on the molecule.

Hotspot

Identify the amino functional group.

The functional groups -COOH and -NH₂ gives amino acids their properties and function. Basic amino acids will have more

-NH₂ or amine groups than -COOH groups. Whereas neutral amino acids will have only one -COOH for every -NH₂ .

Polar Basic Molecules
Amino Acids

Neutral amino acids will have only one -COOH for every -NH₂ such as Alanine, Valine, Leucine, Serine, & Cysteine. To identify whether an amino acid is polar, non-polar, or charged, you will have examine their side chains highlighted in blue to the left.

Polar & Non-Polar Neutral Amino Acids

Dropdown

Acidic amino acids have more___than amino groups.

Select answer

Categorize

Options (6)

Organize the following amino acids into their correct category.

Acidic

Basic

Neutral

The formation and removal of water between the amino functional group and carboxylic acid functional group allows for the formation of a peptide bond that holds the amino acids together in dipeptides and polypeptides.

Condensation/Dehydration Synthesis

Reorder

Reorder the following with 1 being the smallest

• Amino acid

• Dipeptide

• Polypeptide

• Protein

1

2

3

4

• 1
• 2
• 3
• 4

Multiple Choice

The process of removing water in order to form a bond between monomers is called....

• Dehydration Synthesis
• Hydrolysis

Properties of Water Review

The bonds of water are polar because oxygen is more electronegative than hydrogen.

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A single water molecules is held together by two covalent bonds, but the slight positivity of the hydrogen atoms attract other water molecules and a hydrogen bond forms between an oxygen and hydrogen molecule.

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Negative bonding to positive = weak hydrogen bond.​

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Life depends on the properties of water.

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Cohesion: water molecules stick to each other.

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Adhesion: Water molecules stick to other things.

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Cohesion creates surface tension.​

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Cohesion, Adhesion & Surface Tension

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Surface tension is the measure of difficulty of breaking the surface of a liquid.

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Water has the highest surface tension of common liquids.​ Water's strong tension allows objects to float like leaves to float on top.

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Animals such as the water strider "walk on water" because of it's high surface tension.​

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Surface Tension

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Hydrogen bonding accounts for the 3 states of water.

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Ice - a solid state has many Hydrogen bonds creating a crystal structure.

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Water - a liquid state with a lot of hydrogen bonds, but less than ice. The water molecules continuously make and break hydrogen bonds.

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Water Vapor - a gas ​molecules move too rapidly preventing most hydrogen bonding.

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​Structure of Water

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Cells and organisms are mostly water, ~70%, and live in an aqueous environment.

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Water is a good solvent​ (dissolver) for polar or charges molecules (hydrophilic)

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Nonpolar molecules​ (hydrophobic) have few positive or negative charges and will mostly avoid water.

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​Solvent properties of water.

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The O and H molecules in water can dissociate into two molecules. OH^- (hydroxide) and H⁺. This happens when Oxygen takes an electron from one Hydrogen.

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The presence of OH^- and H⁺ affects how water interacts with other ions and molecules.

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Acids donate H⁺ ions and Bases (Alkaline) accept H⁺.​

​Some text here about the topic of discussion.

Water dissociation and pH

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When water is removed from two or more molecules, it allows a new covalent bond to form between them, forming a new molecule, or adding a new subunit to an existing molecule.

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Dehydration synthesis builds molecules.

Hydrolysis reactions break the covalent bonds by adding water across the bond.

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Hydrolysis means to break using water.

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Hydrolysis is the reverse reaction of dehydration synthesis. ​

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​Hydrolysis reactions break larger molecules down.

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Multiple Choice

Which reaction will create a macromolecule?

• Dehydration Synthesis

• Hydrolysis

Multiple Choice

The dominant type of intermolecular attractions between molecules with a hydrogen atom bonded directly to a oxygen atom

• Hydrogen bonding

• Covalent bonding

• Van Der Waals forces

• Dipole-dipole forces

• Ionic bonding

Multiple Choice

Macromolecules are made of repeating subunits called

• monomers

• monosaccharides

• polymers

• polysaccharides

Multiple Choice

A __________ consists of many monomers bonded together.

• monomer

• hydrocarbon

• peptide

• polymer

Multiple Choice

A _________ reaction removes a molecule of water to bond molecules together to create a polymer.

• hydrolysis

• water

• dehydration synthesis

• magical

Multiple Choice

In order to break apart a polymer ________ must be added.

• carbon

• water

• oxygen

• hydrogen

Multiple Choice

Breaks up polymers, forming monomers

• dehydration synthesis
• hydrolysis

Multiple Choice

Surface tension of water is the cohesive force between water molecules and other molecules.

• True

• False

Multiple Choice

Cohesive force between water molecules and adhesive force between water molecules and other molecules enable this phenomenon to occur.

• Surface tension

• Capillary action

• Float on water

• Photosynthesis

Multiple Choice

Which end of the water molecule has a slightly positive charge?

• The hydrogen end

• The oxygen end

• Both ends are slightly positive

• Neither end is positive

Multiple Choice

What word describes when water is attracted to other substances?

• Cohesion

• Adhesion

• Capillary action

• Surface tension

Multiple Choice

When water molecules stick easily to other water molecules, this is called what?

• Cohesion

• Adhesion

• Solution

• Polar molecule

Multiple Choice

The tightness across the surface of water that enables insects to walk on it is

• Adhesion

• Capillary action

• Surface tension

• Polarity

Multiple Choice

Which statement explains why water molecules stick together?

• Both sides are negative

• One side has a positive charge and the other side has a negative charge

• One side has a negative charge and the other side has a neutral charge

• Both sides are positive