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1: Life Molecules

Students categorize biomolecules into major classes (proteins, carbohydrates, lipids, nucleic acids) and distinguish hydrophobic from hydrophilic molecules.

LibreTexts reference: Unit 1, Chapter 1: Molecules of Life LibreTexts

Matching Biochemical Functional Groups to Descriptions

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Match each of the following seven biochemical functional groups with their corresponding descriptions.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. Phosphate
Drop Your Choice Here 2. Carbonyl
Drop Your Choice Here 3. Sulfhydryl
Drop Your Choice Here 4. Hydroxl

Drag one of the choices below:

  • A. Compound name: Thiol
  • B. Compound name: Ketone or aldehyde
  • C. Compound name: Alcohol
  • D. —H2PO4–
 

Matching Chemical Bond Types to Characteristics

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Match each of the following types of chemical bonds with their corresponding examples.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. polar covalent bond
Drop Your Choice Here 2. ionic bond
Drop Your Choice Here 3. non-polar covalent bond
Drop Your Choice Here 4. hydrogen bond

Drag one of the choices below:

  • A. Mg2+ • 2× Cl- (magnesium chloride)
  • B. O-H ···· O (bond represented by the dots)
  • C. N - H (in an amide group)
  • D. N ≡ N (nitrogen gas)
 

Matching Macromolecule Types to Descriptions (Reduced Set)

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Match each of the following types of macromolecules with their corresponding macromolecules.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. nucleic acids
Drop Your Choice Here 2. carbohydrates
Drop Your Choice Here 3. lipids
Drop Your Choice Here 4. proteins

Drag one of the choices below:

  • A. nitrogenous bases
  • B. triglycerides or fat
  • C. polypeptides
  • D. ketose
 

Matching Macromolecule Types to Descriptions (Full Set)

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Match each of the following types of macromolecules with their corresponding macromolecules.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. carbohydrates
Drop Your Choice Here 2. lipids
Drop Your Choice Here 3. nucleic acids
Drop Your Choice Here 4. proteins

Drag one of the choices below:

  • A. phenylalanine
  • B. agarose – a heteropolysaccharide extracted from certain red seaweed
  • C. guanosine
  • D. monoglycerides
 

Biochemical Functional Groups from Descriptions

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Which one of the following seven biochemical functional groups correspond to the description '—COOH'.

 

Types of Chemical Bonds from Examples

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Which one of the following types of chemical bonds correspond to the example 'N-H ···· N (bond represented by the dots)'.

 

Macromolecule Types from Descriptions (Reduced Set)

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Which one of the following types of macromolecules correspond to the macromolecule 'lactose'.

 

Macromolecule Types from Examples (Full Set)

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Which one of the following types of macromolecules correspond to the macromolecule 'fatty acids'.

 

Hydrophobic Compounds from Molecular Formulas

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Based on their molecular formula, which one of the following compounds is most likely hydrophobic?

 

Macromolecule Types from Chemical Structures

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Guide to Identifying the Chemical Structures of Macromolecules
Carbohydrates (monosaccharides)
  • Should have about the same number of oxygens as carbons.
  • Look for hydroxyl groups (–OH) attached to the carbon atoms.
  • Carbonyl groups (C=O) are often present as well.
  • Look for the base unit of CH2O.
  • Larger carbohydrates will form hexagon or pentagon ring-like structures.
Lipids (fatty acids)
  • Contain mostly carbon and hydrogen.
  • Very few oxygens and often no nitrogens.
  • Fats and oils will have carboxyl groups (–COOH) and ester bonds
  • Look for long chains or ring structures of only carbon and hydrogen.
  • Steroids have four interconnected carbon rings.
Proteins (amino acids and dipeptides)
  • Always have a nitrogen/amino group (–NH2 or –NH3+)
  • Always have a carboxyl group (–COOH or –COO-)
  • Identify the central Cα (alpha-carbon) attached to an amino group and a carboxyl group
  • Larger protein macromolecules will have a characteristic peptide bond (C–N)
  • Try to identify common side chains (R groups).
Nucleic acids (nucleobases)
  • Must have a nucleobase, rings containing carbon and nitrogen.
  • Larger nucleic acids will have a sugar backbone and phosphate groups.
Phosphate groups (–PO42-)
  • Found in all of the macromolecule types.
  • It is best to ignore them to not let them confuse you.
  • The breakdown of carbohydrates involves add phosphates.
  • Membrane lipids have phosphate head groups.
  • Many proteins are phosphorylated for regulatory purposes.
  • DNA has a phosphate backbone.
Molecule Information
Full name theophylline
Molecular formula C7 H8 N4 O2
Molecular weight 180.16 g/mol
Image link link to static image
Partition coefficient 0.0 logP
C/(O+N) ratio 1.2

Which one of the four main types of macromolecules is represented by the chemical structure of theophylline shown above?