Bio Chapter 3: Carbon and the Molecular Diversity of Life

Carbon and the Molecular Diversity of Life

Carbohydrates, Lipids, Proteins, Nucleic Acids

The 4 important classes of biological molecules

Electron configuration

The key to an atom’s chemical characteristics is its __ __

4

With four valence electrons, carbon can form __ covalent bonds with a variety of atoms

Tetrahedral

In molecules with multiple carbons, each carbon bonded to four other atoms has a ___ shape

Double

When two carbon atoms are joined by a double/single bond, the atoms joined to the carbons are in the same plane as the carbons

Valence

The number of covalent bonds an atom can form

Covalent

The electron configuration of carbon gives it ___ compatibility with many different elements

Chains

A carbon atom can also form covalent bonds to other carbon atoms, linking the atoms into ___

Carbon __ form the skeletons of most organic molecules, vary in length and shape

Some have double bonds which vary in number and location

Length, Double bond position, branching, presence of rings

What 4 ways can carbon skeletons vary

Hydrocarbons

Organic molecules consisting of only carbon and hydrogen, hydrocarbons can undergo reactions that release a large amount of energy

Fats

Many organic molecules, such as __, have hydrocarbon components

Isomers

Compounds that have the same number of atoms of the same elements but different structures and properties

Structural isomers

Isomers that differ in the covalent arrangement of

their atoms

Increases

The number of possible isomers ___ as carbon skeletons increase in size

Single

__ bonds allow the atoms of structural isomers to rotate freely about the bond axis

Cis-trans isomers

Carbons have covalent bonds to the same atoms, but the atoms differ in their spatial arrangement due to inflexibility of double bonds

Shape

The subtle differences in ___ between cis-trans isomers can greatly affect the activities of organic molecules

Enantiomers

Isomers that are mirror images of one another (left-handed and right-handed versions of the same molecule)

Differ in shape due to the presence of an asymmetric carbon, usually only one isomer is biologically active

Structural, enantiomers, cis-trans

The 3 types of isomers

Geometric isomers

Another name for cis-trans isomers

Functional groups

The chemical groups that affect molecular function by being directly involved in chemical reactions

Replace

Chemical groups can ___ one or more of the hydrogens bonded to the carbon skeleton of a hydrocarbon

Characteristic

Each functional group participates in chemical reactions in a ___ way

They have different functional groups

Why do estradiol and testosterone produce different physical traits despite having nearly identical four-ring carbon backbones

HO

What extra group does estradiol have that testosterone doesn’t

O, CH3

What extra groups does testosterone have that Estradiol doesn’t

7

There are __ functional groups that are most important in the chemistry of life

Hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, methyl

What are the functional groups (know these!)

Alcohol

Compound name for Hydroxyl group (-OH/HO-)

Ketone (within) Aldehyde (at end)

Compound name for Carbonyl group (>C=O) (depending on where in skeleton)

Carboxylic Acid (or organic acid)

Compound name for carboxyl group (-COOH)

Amine

Compound name for Amino group (-NH₂)

Thiol

Compound name for Sulfhydryl group (-SH or HS-)

Organic phosphate

Compound name for phosphate group (-OPO₃^2-)

Methylated compound

Compound name for methyl group (-CH₃)

Acetone Propanal

Textbook example for Carbonyl group

Acetic acid

Textbook example for Carboxyl group

Glycine

Textbook example for Amino group

Cysteine

Textbook example for Sulfhydryl group

Glycerol phosphate

Textbook example for Phosphate group

5-Methylcytosine

Textbook example for Methyl group

Ethanol

Textbook example for Hydroxyl group

Adenosine triphosphate (ATP)

An organic phosphate molecule, consists of an organic molecule called adenosine

Attached to a string of three phosphate groups

Stores the potential to react with water, releasing energy that can be used by the cell

An important source of energy for cellular processes

ATP

What is this an image of

Polymer

A long molecule consisting of many similar or identical building blocks

Monomers

Small building-block molecules that create polymers

Functions

Some molecules that serve as monomers also have ___ of their own

Macromolecules

Polymers, built from Monomers

Similar

The process of making and breaking down polymers is __ for all classes of large biomolecules

Enzymes

Facilitate the process of making and breaking down polymers, speed up chemical reactions

Condensation

In a ___ reaction two molecules are covalently bonded to each other with the loss of a small molecule

Dehydration reaction

Reaction that occurs when two monomers bond together through the loss of a water molecule

Hydrolysis

Polymers are disassembled to monomers by ___, a reaction that is essentially the reverse of the dehydration reaction.

Adds a water molecule, breaking a bond

Thousands

Each cell has ___ of different macromolecules

Vary

Macromolecules __ among cells of an organism, _ more within a species, and __ even more between species

Small

An immense variety of polymers can be built from a __ set of monomers

Carbohydrates

Include sugars and the polymers of sugars

Serve as fuel and building material

Monosaccharides

The simplest carbohydrates are ___, or simple sugars

Have molecular formulas that are usually multiples of CH₂O

Polysaccharides

Carbohydrate macromolecules are ___, polymers composed of many sugar building blocks

Glucose

The most common monosaccharide (C₆H₁₂O₆)

Classified

Monosaccharides are ___ by the number of carbons in the carbon skeleton and the placement of the carbonyl group

Rings

Though often drawn as linear skeletons, in aqueous

solutions, many sugars form ___

Glucose

Monosaccharides, especially ___, are major nutrients for cells and as raw material for building molecules

Disaccharide

Formed when a dehydration reaction joins two monosaccharides

Glycosidic linkage

What is a disaccharide’s covalent bond called

Table sugar

The most prevalent disaccharide is sucrose, which is ___ ___

Dissaccharide synthesis

Ex: Glucose and fructose combining together to form sucrose through a dehydration synthesis reaction. Joining a -OH with -H from the hydroxyl groups of both sugars to make H₂O

Polysaccharides

The polymers of sugars, have storage and structural roles

The structure and function are determined by its sugar monomers and the positions of its glycosidic linkages

Granules

Plants store surplus starch as __

Starch

A storage polysaccharide of plants, consists entirely of glucose monomers

Hydrolyze

Most animals have enzymes that can __ plant starch, making glucose available as a nutrient

Glycogen

A storage polysaccharide in animals

Humans and other vertebrates store ___ mainly in liver and muscle cells, this stored fuel cannot sustain an animal for long

ok

Understand this

Cellulose

The polysaccharide ___ is a major component of the tough walls that enclose plant cells

Like starch, ___ is a polymer of glucose, but the glycosidic linkages in these two differ, based on the two ring structures for ___

beta

In cellulose, the monomers are arranged in the __ conformation, making each monomer “upside down” with respect to its neighbors

alpha

In starch, the glucose monomers are arranged in the __ conformation

Helical

Certain starch molecules are largely __

Unbranched

Cellulose molecules are relatively straight and are___

Parallel

In cellulose, some hydroxyl groups on its glucose monomers can hydrogen-bond with hydroxyl groups of other cellulose molecules many ___ cellulose molecules are held together this way

Microfibrils

Parallel cellulose molecules held together this way are grouped into ___, which form strong building materials for plants

Cellulose strands forming hydrogen bonds

What is this an image of

Can’t

Enzymes that digest starch by hydrolyzing alpha linkages can/can’t hydrolyze the beta linkages in cellulose

Fiber

Cellulose in human food passes through the digestive tract as insoluble ___

Enzymes

Some microbes use ___ to digest cellulose

Symbiotic

Many herbivores, such as cows and termites, have ___ relationships with these microbes

Fungi

___ can digest cellulose, helping to recycle the elements in Earth’s ecosystems

Chitin

Structural polysaccharide, is found in the exoskeleton of arthropods

Also provides structural support for the cell walls of many fungi

Lipids

Do not form true polymers and are usually too small to be considered macromolecules

The unifying feature is having little or no affinity for water

Hydrophobic because they consist mostly of hydrocarbons, which form nonpolar covalent bonds

Fats, phospholipids, steroids

The most biologically important lipids are __ __ and _

Fats

Assembled from two types of smaller molecules: glycerol and fatty acids

Glycerol

___ is a three-carbon alcohol with a hydroxyl group attached to each carbon

Fatty acid

Consists of a carboxyl group attached to a long carbon skeleton

1 glycerol backbone + 3 fatty acids

Components of a fat molecule (triacylglycerol)

Hydration synthesis, 3(H2O)

Reaction type of synthesis of fat and water molecules released

Separate

Fats ___ from water because water molecules hydrogen-bond to each other and exclude the fats

Dehydration

In a fat, three fatty acids are joined to glycerol by ___ reaction

Ester linkage

What’s the name of the bond linking glycerol to fatty acids, creating a triacylglycerol or triglyceride

Length

Fatty acids vary in ___ (number of carbons) and in the number and locations of double bonds

Saturated fatty acids

Fatty acids that have the maximum number of hydrogen atoms possible and no double bonds

Unsaturated fatty acids

Fatty acids that have one or more double bonds