what ability allows carbon atoms to form larger

The Chemical Basis for Life

Carbon is the nigh important chemical element to living things because it tin course many different kinds of bonds and form essential compounds.

Learning Objectives

Explain the backdrop of carbon that let it to serve as a building cake for biomolecules

Key Takeaways

Cardinal Points

• All living things incorporate carbon in some form.
• Carbon is the primary component of macromolecules, including proteins, lipids, nucleic acids, and carbohydrates.
• Carbon's molecular construction allows it to bond in many dissimilar ways and with many dissimilar elements.
• The carbon wheel shows how carbon moves through the living and not-living parts of the environs.

Key Terms

• octet rule: A rule stating that atoms lose, gain, or share electrons in lodge to have a full valence shell of viii electrons (has some exceptions).
• carbon cycle: the physical cycle of carbon through the world'due south biosphere, geosphere, hydrosphere, and atmosphere; includes such processes as photosynthesis, decomposition, respiration and carbonification
• macromolecule: a very large molecule, especially used in reference to large biological polymers (e.grand., nucleic acids and proteins)

Carbon is the fourth most abundant element in the universe and is the building block of life on earth. On earth, carbon circulates through the land, ocean, and temper, creating what is known equally the Carbon Bike. This global carbon cycle tin be divided further into two dissever cycles: the geological carbon cycles takes identify over millions of years, whereas the biological or concrete carbon bicycle takes identify from days to thousands of years. In a nonliving environment, carbon can be every bit carbon dioxide (CO₂), carbonate rocks, coal, petroleum, natural gas, and expressionless organic thing. Plants and algae convert carbon dioxide to organic affair through the process of photosynthesis, the energy of calorie-free.

Carbon is present in all life: All living things contain carbon in some course, and carbon is the primary component of macromolecules, including proteins, lipids, nucleic acids, and carbohydrates. Carbon exists in many forms in this leafage, including in the cellulose to course the leafage's construction and in chlorophyll, the pigment which makes the leaf green.

Carbon is Of import to Life

In its metabolism of food and respiration, an fauna consumes glucose (C₆H₁₂O₆), which combines with oxygen (O₂) to produce carbon dioxide (CO_ii), water (H₂O), and energy, which is given off as estrus. The animal has no need for the carbon dioxide and releases information technology into the atmosphere. A plant, on the other manus, uses the opposite reaction of an animate being through photosynthesis. It intakes carbon dioxide, h2o, and energy from sunlight to make its own glucose and oxygen gas. The glucose is used for chemical energy, which the plant metabolizes in a similar style to an animal. The plant then emits the remaining oxygen into the environs.

Cells are made of many complex molecules called macromolecules, which include proteins, nucleic acids (RNA and DNA), carbohydrates, and lipids. The macromolecules are a subset of organic molecules (whatever carbon-containing liquid, solid, or gas) that are peculiarly of import for life. The fundamental component for all of these macromolecules is carbon. The carbon atom has unique properties that let it to form covalent bonds to as many as four different atoms, making this versatile element platonic to serve every bit the basic structural component, or "backbone," of the macromolecules.

Structure of Carbon

Private carbon atoms have an incomplete outermost electron shell. With an diminutive number of half dozen (six electrons and half-dozen protons), the first two electrons fill the inner beat, leaving iv in the second trounce. Therefore, carbon atoms tin form four covalent bonds with other atoms to satisfy the octet dominion. The marsh gas molecule provides an instance: it has the chemical formula CH_four. Each of its iv hydrogen atoms forms a single covalent bond with the carbon atom past sharing a pair of electrons. This results in a filled outermost shell.

Structure of Methane: Methane has a tetrahedral geometry, with each of the four hydrogen atoms spaced 109.v° apart.

Hydrocarbons

Hydrocarbons are important molecules that tin form chains and rings due to the bonding patterns of carbon atoms.

Learning Objectives

Discuss the role of hydrocarbons in biomacromolecules

Key Takeaways

Key Points

• Hydrocarbons are molecules that contain simply carbon and hydrogen.
• Due to carbon's unique bonding patterns, hydrocarbons can have unmarried, double, or triple bonds between the carbon atoms.
• The names of hydrocarbons with single bonds end in "-ane," those with double bonds end in "-ene," and those with triple bonds cease in "-yne".
• The bonding of hydrocarbons allows them to form rings or chains.

Key Terms

• covalent bond: A type of chemical bond where two atoms are connected to each other past the sharing of ii or more electrons.
• aliphatic: Of a class of organic compounds in which the carbon atoms are arranged in an open chain.
• effluvious: Having a closed ring of alternating unmarried and double bonds with delocalized electrons.

Hydrocarbons

Hydrocarbons are organic molecules consisting entirely of carbon and hydrogen, such every bit methane (CH₄). Hydrocarbons are often used as fuels: the propane in a gas grill or the butane in a lighter. The many covalent bonds between the atoms in hydrocarbons store a corking corporeality of energy, which is released when these molecules are burned (oxidized). Methane, an excellent fuel, is the simplest hydrocarbon molecule, with a central carbon atom bonded to iv different hydrogen atoms. The geometry of the methane molecule, where the atoms reside in 3 dimensions, is adamant by the shape of its electron orbitals. The carbon and the four hydrogen atoms form a shape known as a tetrahedron, with four triangular faces; for this reason, methane is described as having tetrahedral geometry.

Methane: Methyl hydride has a tetrahedral geometry, with each of the four hydrogen atoms spaced 109.5° apart.

Equally the backbone of the large molecules of living things, hydrocarbons may exist as linear carbon chains, carbon rings, or combinations of both. Furthermore, private carbon-to-carbon bonds may be unmarried, double, or triple covalent bonds; each blazon of bond affects the geometry of the molecule in a specific mode. This iii-dimensional shape or conformation of the big molecules of life (macromolecules) is critical to how they office.

Hydrocarbon Bondage

Hydrocarbon chains are formed past successive bonds between carbon atoms and may be branched or unbranched. The overall geometry of the molecule is contradistinct by the different geometries of single, double, and triple covalent bonds. The hydrocarbons ethane, ethene, and ethyne serve as examples of how different carbon-to-carbon bonds affect the geometry of the molecule. The names of all iii molecules first with the prefix "eth-," which is the prefix for two carbon hydrocarbons. The suffixes "-ane," "-ene," and "-yne" refer to the presence of unmarried, double, or triple carbon-carbon bonds, respectively. Thus, propane, propene, and propyne follow the same pattern with three carbon molecules, butane, butene, and butyne for 4 carbon molecules, and so on. Double and triple bonds change the geometry of the molecule: single bonds allow rotation along the axis of the bond, whereas double bonds atomic number 82 to a planar configuration and triple bonds to a linear one. These geometries have a significant touch on the shape a particular molecule tin can assume.

Hydrocarbon Chains: When carbon forms single bonds with other atoms, the shape is tetrahedral. When two carbon atoms form a double bail, the shape is planar, or flat. Single bonds, like those plant in ethane, are able to rotate. Double bonds, like those found in ethene cannot rotate, so the atoms on either side are locked in place.

Hydrocarbon Rings

The hydrocarbons discussed so far accept been aliphatic hydrocarbons, which consist of linear chains of carbon atoms. Another blazon of hydrocarbon, aromatic hydrocarbons, consists of closed rings of carbon atoms. Ring structures are found in hydrocarbons, sometimes with the presence of double bonds, which can exist seen by comparing the construction of cyclohexane to benzene. The benzene ring is present in many biological molecules including some amino acids and near steroids, which includes cholesterol and the hormones estrogen and testosterone. The benzene band is too found in the herbicide ii,four-D. Benzene is a natural component of crude oil and has been classified equally a carcinogen. Some hydrocarbons have both aliphatic and effluvious portions; beta-carotene is an example of such a hydrocarbon.

Hydrocarbon Rings: Carbon can grade five-and six membered rings. Single or double bonds may connect the carbons in the ring, and nitrogen may be substituted for carbon.

Organic Isomers

Isomers are molecules with the same chemic formula but have different structures, which creates unlike properties in the molecules.

Learning Objectives

Give examples of isomers

Key Takeaways

Cardinal Points

• Isomers are molecules with the aforementioned chemical formula but have different structures.
• Isomers differ in how their bonds are positioned to surrounding atoms.
• When the carbons are bound on the same side of the double bond, this is the cis configuration; if they are on opposite sides of the double bond, it is a trans configuration.
• Triglycerides, which prove both cis and trans configurations, can occur every bit either saturated or unsaturated, depending upon how many hydrogen atoms they have attached to them.

Key Terms

• fatty acid: Whatever of a class of aliphatic carboxylic acids, of general formula CnH2n+1COOH, that occur combined with glycerol as brute or vegetable oils and fats.
• isomer: Any of two or more compounds with the aforementioned molecular formula merely with different structure.

The three-dimensional placement of atoms and chemical bonds within organic molecules is central to understanding their chemistry. Molecules that share the same chemical formula only differ in the placement (construction) of their atoms and/or chemic bonds are known equally isomers.

Structural Isomers

Structural isomers (such as butane and isobutane ) differ in the placement of their covalent bonds. Both molecules have four carbons and ten hydrogens (C₄H_x), merely the different organisation of the atoms within the molecules leads to differences in their chemical properties. For example, due to their different chemical backdrop, butane is suited for use as a fuel for cigarette lighters and torches, whereas isobutane is suited for utilize as a refrigerant and a propellant in spray cans.

Geometric Isomers

Geometric isomers, on the other hand, accept similar placements of their covalent bonds but differ in how these bonds are made to the surrounding atoms, particularly in carbon-to-carbon double bonds. In the unproblematic molecule butene (C_ivH₈), the ii methyl groups (CH₃) can be on either side of the double covalent bond central to the molecule. When the carbons are jump on the same side of the double bond, this is the cis configuration; if they are on contrary sides of the double bond, it is a trans configuration. In the trans configuration, the carbons class a more than or less linear structure, whereas the carbons in the cis configuration brand a bend (change in direction) of the carbon courage.

Isomers: Molecules that have the same number and type of atoms arranged differently are chosen isomers. (a) Structural isomers have a dissimilar covalent arrangement of atoms. (b) Geometric isomers have a different system of atoms around a double bail. (c) Enantiomers are mirror images of each other.

Cis or Trans Configurations

Cis and Trans Fatty Acids: These space-filling models prove a cis (oleic acid) and a trans (eliadic acrid) fatty acrid. Observe the bend in the molecule cause by the cis configuration.

In triglycerides (fats and oils), long carbon chains known every bit fatty acids may contain double bonds, which can be in either the cis or trans configuration. Fats with at to the lowest degree one double bond between carbon atoms are unsaturated fats. When some of these bonds are in the cis configuration, the resulting bend in the carbon backbone of the concatenation means that triglyceride molecules cannot pack tightly, then they remain liquid (oil) at room temperature. On the other hand, triglycerides with trans double bonds (popularly called trans fats), have relatively linear fatty acids that are able to pack tightly together at room temperature and class solid fats.

In the human diet, trans fats are linked to an increased risk of cardiovascular affliction, and so many food manufacturers accept reduced or eliminated their use in recent years. In dissimilarity to unsaturated fats, triglycerides without double bonds between carbon atoms are called saturated fats, significant that they contain all the hydrogen atoms available. Saturated fats are a solid at room temperature and usually of animal origin.

Organic Enantiomers

Enantiomers share the same chemical construction and bonds but differ in the placement of atoms such that they are mirror images of each other.

Learning Objectives

Give examples of enantiomers

Key Takeaways

Key Points

• Enantiomers are stereoisomers, a blazon of isomer where the lodge of the atoms in the two molecules is the same but their arrangement in infinite is dissimilar.
• Many molecules in the bodies of living beings are enantiomers; there is sometimes a large difference in the effects of ii enantiomers on organisms.
• Enantiopure compounds refer to samples having, within the limits of detection, molecules of only 1 chirality.
• Compounds that are enantiomers of each other have the same concrete backdrop except for the direction in which they rotate polarized calorie-free and how they collaborate with different optical isomers of other compounds.

Primal Terms

• enantiomer: One of a pair of stereoisomers that is the mirror paradigm of the other, but may not be superimposed on this other stereoisomer.
• chirality: The phenomenon in chemical science, physics, and mathematics in which objects are mirror images of each other, but are not identical.
• stereoisomer: ane of a set of the isomers of a compound in which atoms are arranged differently about a chiral eye; they exhibit optical activity

Enantiomers

Stereoisomers are a blazon of isomer where the order of the atoms in the two molecules is the same simply their arrangement in infinite is different. The two main types of stereoisomerism are diastereomerism (including 'cis-trans isomerism') and optical isomerism (likewise known as 'enantiomerism' and 'chirality'). Optical isomers are stereoisomers formed when disproportionate centers are nowadays; for example, a carbon with four different groups bonded to it. Enantiomers are two optical isomers (i.eastward. isomers that are reflections of each other). Every stereocenter in one isomer has the opposite configuration in the other. They share the aforementioned chemical construction and chemic bonds, just differ in the iii-dimensional placement of atoms then that they are mirror images, much as a person'due south left and right hands are. Compounds that are enantiomers of each other take the same concrete properties except for the direction in which they rotate polarized light and how they collaborate with different optical isomers of other compounds.

The amino acid alanine is example of an entantiomer. The two structures, D-alanine and L-alanine, are non-superimposable. In nature, just the L-forms of amino acids are used to brand proteins. Some D forms of amino acids are seen in the cell walls of bacteria, just never in their proteins. Similarly, the D-form of glucose is the main product of photosynthesis and the L-course of the molecule is rarely seen in nature.

Enantiomers: D-alanine and L-alanine are examples of enantiomers or mirror images. Just the L-forms of amino acids are used to make proteins.

Organic compounds that comprise a chiral carbon usually have two not-superposable structures. These two structures are mirror images of each other and are, thus, ordinarily called enantiomorphs; hence, this structural property is now ordinarily referred to as enantiomerism. Enantiopure compounds refer to samples having, within the limits of detection, molecules of but ane chirality.

Enantiomers of each other often show different chemical reactions with other substances that are also enantiomers. Since many molecules in the bodies of living beings are enantiomers themselves, in that location is sometimes a marked difference in the effects of two enantiomers on living beings. In drugs, for example, often merely one of a drug's enantiomers is responsible for the desired physiologic effects, while the other enantiomer is less agile, inactive, or sometimes even responsible for agin effects. Owing to this discovery, drugs composed of only one enantiomer ("enantiopure") can be developed to raise the pharmacological efficacy and sometimes do away with some side furnishings.

Organic Molecules and Functional Groups

Functional groups are groups of molecules attached to organic molecules and give them specific identities or functions.

Learning Objectives

Depict the importance of functional groups to organic molecules

Key Takeaways

Key Points

• Functional groups are collections of atoms that attach the carbon skeleton of an organic molecule and confer specific backdrop.
• Each type of organic molecule has its own specific type of functional group.
• Functional groups in biological molecules play an important role in the germination of molecules like DNA, proteins, carbohydrates, and lipids.
• Functional groups include: hydroxyl, methyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl.

Fundamental Terms

• hydrophobic: lacking an affinity for h2o; unable to absorb, or be wetted by h2o
• hydrophilic: having an affinity for water; able to absorb, or be wetted past water

Location of Functional Groups

Functional groups are groups of atoms that occur within organic molecules and confer specific chemic backdrop to those molecules. When functional groups are shown, the organic molecule is sometimes denoted as "R." Functional groups are found along the "carbon backbone" of macromolecules which is formed by chains and/or rings of carbon atoms with the occasional substitution of an chemical element such as nitrogen or oxygen. Molecules with other elements in their carbon backbone are substituted hydrocarbons. Each of the four types of macromolecules—proteins, lipids, carbohydrates, and nucleic acids—has its own feature set of functional groups that contributes profoundly to its differing chemic properties and its function in living organisms.

Properties of Functional Groups

A functional grouping can participate in specific chemic reactions. Some of the of import functional groups in biological molecules include: hydroxyl, methyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl groups. These groups play an important part in the formation of molecules similar DNA, proteins, carbohydrates, and lipids.

Classifying Functional Groups

Functional groups are commonly classified as hydrophobic or hydrophilic depending on their accuse or polarity. An example of a hydrophobic grouping is the non-polar methane molecule. Among the hydrophilic functional groups is the carboxyl group institute in amino acids, some amino acrid side chains, and the fatty acid heads that form triglycerides and phospholipids. This carboxyl grouping ionizes to release hydrogen ions (H⁺) from the COOH group resulting in the negatively charged COO^– group; this contributes to the hydrophilic nature of whatever molecule it is establish on. Other functional groups, such as the carbonyl group, accept a partially negatively charged oxygen cantlet that may form hydrogen bonds with water molecules, again making the molecule more hydrophilic.

Examples of functional groups: The functional groups shown here are establish in many dissimilar biological molecules, where "R" is the organic molecule.

Hydrogen Bonds between Functional Groups

Hydrogen bonds between functional groups (within the same molecule or betwixt different molecules) are of import to the function of many macromolecules and assistance them to fold properly and maintain the appropriate shape needed to role correctly. Hydrogen bonds are also involved in various recognition processes, such as DNA complementary base of operations pairing and the binding of an enzyme to its substrate.

Hydrogen bonds in DNA: Hydrogen bonds connect two strands of DNA together to create the double-helix structure.

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Source: https://courses.lumenlearning.com/boundless-biology/chapter/carbon/

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