Click the following link for a Carbon and Functional Groups Student Learning Guide to accompany this tutorial.

1. Introduction

In the last tutorial, we saw how carbon can covalently bond with itself and atoms of other elements to form chains, rings, and branched molecules. Carbon’s versatility in forming bonds allows for the possibility of molecules that have the same number and types of atoms, but which have different structures. Consider, for example, the two molecules below. They’re both variations on the formula, C5H12. Molecules with the same number and types of atoms, but with different structures, are called isomers. Once we know a bit more chemistry, we’ll come back to isomers and look at some of their biological implications.

Chain Branched molecules
05_800px-N-Pentane 06_Isopentane

Molecules like the ones shown above, consisting solely of carbon and hydrogen, are called hydrocarbons. Fossil fuels (petroleum, natural gas, and coal) are hydrocarbons. These substances are rich in energy, a legacy of ancient sunlight that was captured by photosynthetic organisms in forests and oceans tens or hundreds of millions of years ago. Since the start of the industrial revolution (about 200 years ago), we humans have been burning these fossil fuels at a tremendous rate. This energy has, in many parts of the globe, altered human existence, enabling us to heat and light our homes, move ourselves in cars, trains, and planes, and power our industries. Though it varies from region to region in the United States, about 81% of our energy in 2015 came from burning fossil fuels (National Academy of SciencesNAS ). But this has come at a cost: fossil fuel emissions have altered the chemistry of our atmosphere, and caused various forms of pollution. And while understanding climate change is not part of the most introductory biology courses, it’s important for every human on planet Earth to know how fossil fuel emissions are disrupting the predictable climate patterns upon which our civilization depends: You can learn more about it from my Greenhouse Effect videos).

07_D-glucose-chain-2D-Fischer
Glucose

While hydrocarbons are essential fuels, they’re not particularly important in living things. Rather, the molecules that make up living things are typically organized like the molecule of glucose (a common sugar) shown to the right. What you see, in this case, is a chain of carbon atoms, with many of the carbons attached to small groups of other atoms. These small groups of atoms act as a unit, and are called functional groups.

Let’s continue using glucose as an example. If you look at carbon number 1, you can see that the carbon, in addition to sharing electrons with a hydrogen atom, is also double bonded to an oxygen. That carbon, with its double bond to an oxygen, is a functional group, and its presence (along with other functional groups) helps to determine the chemistry of whatever molecule it’s attached to. Similarly, Carbons 2 through six are bonded both to hydrogen and to an -OH. The “-OH” is another functional group.

Biology students need to know seven of these groups. Start by taking a few minutes to study the table below. If you are unfamiliar with the idea of polarity and its consequences, you can jump back to my tutorials on water, polarity, and hydrogen bonding.

Functional Groups
 Name Structure Key effect on molecules
Hydroxyl 01_hydroxyl Makes a molecule polar.
 Carbonyl 02_carbonyl Makes a molecule polar.
 Carboxyl 03_carboxyl Makes a molecule acidic (because it can donate H+ to a solution).
 Amino 04_amino Makes a molecule basic (because it picks up an H+ from the solution).
 Sulfhydryl 05_sulfhydryl Two sulfhydryls can form Sulfur-Sulfur bonds (also called “disulfide bridges”), which are important in protein structure.
 Phosphate 06_phosphate-corrected-ionized Important in energy transfer.
Methyl 07_methyl Makes a molecule non-polar. Can bind to DNA, affecting gene activity (usually turning genes “off”)
Acetyl A component of many organic molecules. Can bind to DNA-associated proteins, enhancing gene expression.

2. Quiz : Identifying Functional groups

[qwiz random = “true” qrecord_id=”sciencemusicvideosMeister1961-Functional Groups Quiz 1 (M5)”]

[h]Quiz: Identifying Functional Groups

[i]The following quiz will show you structural formulas of each of the functional groups. Some of the questions will ask you to write in the name, hangman style. Others questions will be multiple choice.

 

[!!!]Question 1, Hydroxyl [/!!!]
[q]This functional group is

[c*]hydroxyl    [c]carbonyl     [c]carboxyl   [c]amino

[c]sulfhydryl   [c]phosphate   [c]methyl [c]acetyl

[f]Yes. A hydroxyl group consists of an oxygen bonded to a hydrogen,

[f]No. A carbonyl group has a carbon that’s double bonded to an oxygen, as shown below.

[f]No. A Carboxyl group has a carbon that’s double bonded to an oxygen, and single bonded to a hydroxyl group (-OH)

[f]No. An amino group consists of a nitrogen atom with single bonds to two hydrogen atoms.

[f]No. A sulfhydryl group consists of a sulfur atom bonded to a hydrogen atom.

[f]No. A phosphate group consists of a phosphorus atom surrounded by four oxygens. The phosphorus shares a double bond with one of the oxygens, and a single bond with each of the other three. Two of the oxygens have a negative charge.

[f]No. A methyl group consists of a carbon single bonded with three hydrogens.

[f]No. An acetyl group consists of a methyl group connected to a carbonyl group.

[!!!]Question 2, CARBONYL [/!!!]
[q]This functional group is

[c]hydroxyl    [c*]carbonyl     [c]carboxyl   [c]amino

[c]sulfhydryl   [c]phosphate   [c]methyl   [c]acetyl

[f]No. A hydroxyl group consists of an oxygen bonded to a hydrogen,

[f]Yes. A carbonyl group has a carbon that’s double bonded to an oxygen, as shown below.

[f]No. A Carboxyl group has a carbon that’s double bonded to an oxygen, and single bonded to a hydroxyl group (-OH)

[f]No. An amino group consists of a nitrogen atom with single bonds to two hydrogen atoms.

[f]No. A sulfhydryl group consists of a sulfur atom bonded to a hydrogen atom.

[f]No. A phosphate group consists of a phosphorus atom surrounded by four oxygens. The phosphorus shares a double bond with one of the oxygens, and a single bond with each of the other three. Two of the oxygens have a negative charge.

[f]No. A methyl group consists of a carbon single bonded with three hydrogens.

[f]No. An acetyl group consists of a methyl group connected to a carbonyl group.

[!!!]Question 3, CARBoxyl [/!!!]
[q]This functional group is

[c]hydroxyl    [c]carbonyl     [c*]carboxyl   [c]amino

[c]sulfhydryl   [c]phosphate   [c]methyl [c]acetyl

[f]No. A hydroxyl group consists of an oxygen bonded to a hydrogen,

[f]No. A carbonyl group has a carbon that’s double bonded to an oxygen, as shown below.

[f]Yes. A Carboxyl group has a carbon that’s double bonded to an oxygen, and single bonded to a hydroxyl group (-OH)

[f]No. An amino group consists of a nitrogen atom with single bonds to two hydrogen atoms.

[f]No. A sulfhydryl group consists of a sulfur atom bonded to a hydrogen atom.

[f]No. A phosphate group consists of a phosphorus atom surrounded by four oxygens. The phosphorus shares a double bond with one of the oxygens, and a single bond with each of the other three. Two of the oxygens have a negative charge.

[f]No. A methyl group consists of a carbon single bonded with three hydrogens.

[f]No. An acetyl group consists of a methyl group connected to a carbonyl group.

[!!!]Question 4, AMINO [/!!!]
[q]This functional group is

[c]hydroxyl    [c]carbonyl     [c]carboxyl   [c*]amino

[c]sulfhydryl   [c]phosphate   [c]methyl [c]acetyl

[f]No. A hydroxyl group consists of an oxygen bonded to a hydrogen,

[f]No. A carbonyl group has a carbon that’s double bonded to an oxygen, as shown below.

[f]No. A Carboxyl group has a carbon that’s double bonded to an oxygen, and single bonded to a hydroxyl group (-OH)

[f]Yes. An amino group consists of a nitrogen atom with single bonds to two hydrogen atoms.

[f]No. A sulfhydryl group consists of a sulfur atom bonded to a hydrogen atom.

[f]No. A phosphate group consists of a phosphorus atom surrounded by four oxygens. The phosphorus shares a double bond with one of the oxygens, and a single bond with each of the other three. Two of the oxygens have a negative charge.

[f]No. A methyl group consists of a carbon single bonded with three hydrogens.

[f]No. An acetyl group consists of a methyl group connected to a carbonyl group.

[!!!]Question 5, SULFHYDRYL [/!!!]
[q]This functional group is

[c]hydroxyl    [c]carbonyl     [c]carboxyl   [c]amino

[c*]sulfhydryl   [c]phosphate   [c]methyl [c]acetyl

[f]No. A hydroxyl group consists of an oxygen bonded to a hydrogen,

[f]No. A carbonyl group has a carbon that’s double bonded to an oxygen, as shown below.

[f]No. A Carboxyl group has a carbon that’s double bonded to an oxygen, and single bonded to a hydroxyl group (-OH)

[f]No. An amino group consists of a nitrogen atom with single bonds to two hydrogen atoms.

[f]Yes. A sulfhydryl group consists of a sulfur atom bonded to a hydrogen atom.

[f]No. A phosphate group consists of a phosphorus atom surrounded by four oxygens. The phosphorus shares a double bond with one of the oxygens, and a single bond with each of the other three. Two of the oxygens have a negative charge.

[f]No. A methyl group consists of a carbon single bonded with three hydrogens.

[f]No. An acetyl group consists of a methyl group connected to a carbonyl group.

[!!!]Question 6, PHOSPHATE [/!!!]
[q]This functional group is

[c]hydroxyl    [c]carbonyl     [c]carboxyl   [c]amino

[c]sulfhydryl   [c*]phosphate   [c]methyl [c]acetyl

[f]No. A hydroxyl group consists of an oxygen bonded to a hydrogen,

[f]No. A carbonyl group has a carbon that’s double bonded to an oxygen, as shown below.

[f]No. A Carboxyl group has a carbon that’s double bonded to an oxygen, and single bonded to a hydroxyl group (-OH)

[f]No. An amino group consists of a nitrogen atom with single bonds to two hydrogen atoms.

[f]No. A sulfhydryl group consists of a sulfur atom bonded to a hydrogen atom.

[f]Yes. A phosphate group consists of a phosphorus atom surrounded by four oxygens. The phosphorus shares a double bond with one of the oxygens, and a single bond with each of the other three. Two of the oxygens have a negative charge.

[f]No. A methyl group consists of a carbon single bonded with three hydrogens.

[f]No. An acetyl group consists of a methyl group connected to a carbonyl group.

[!!!]Question 7, METHYL [/!!!]
[q]This functional group is

[c]hydroxyl    [c]carbonyl     [c]carboxyl   [c]amino

[c]sulfhydryl   [c]phosphate   [c*]methyl [c]acetyl

[f]Yes. A hydroxyl group consists of an oxygen bonded to a hydrogen,

[f]No. A carbonyl group has a carbon that’s double bonded to an oxygen, as shown below.

[f]No. A Carboxyl group has a carbon that’s double bonded to an oxygen, and single bonded to a hydroxyl group (-OH)

[f]No. An amino group consists of a nitrogen atom with single bonds to two hydrogen atoms.

[f]No. A sulfhydryl group consists of a sulfur atom bonded to a hydrogen atom.

[f]No. A phosphate group consists of a phosphorus atom surrounded by four oxygens. The phosphorus shares a double bond with one of the oxygens, and a single bond with each of the other three. Two of the oxygens have a negative charge.

[f]Yes. A methyl group consists of a carbon single bonded with three hydrogens.

[f]No. An acetyl group consists of a methyl group connected to a carbonyl group.

[!!!]Question 8, acetyl [/!!!]
[q]This functional group is

[c]hydroxyl    [c]carbonyl     [c]carboxyl   [c]amino

[c]sulfhydryl   [c]phosphate   [c]methyl [c*]acetyl

[f]Yes. A hydroxyl group consists of an oxygen bonded to a hydrogen,

[f]No. A carbonyl group has a carbon that’s double bonded to an oxygen, as shown below.

[f]No. A Carboxyl group has a carbon that’s double bonded to an oxygen, and single bonded to a hydroxyl group (-OH)

[f]No. An amino group consists of a nitrogen atom with single bonds to two hydrogen atoms.

[f]No. A sulfhydryl group consists of a sulfur atom bonded to a hydrogen atom.

[f]No. A phosphate group consists of a phosphorus atom surrounded by four oxygens. The phosphorus shares a double bond with one of the oxygens, and a single bond with each of the other three. Two of the oxygens have a negative charge.

[f]Yes. A methyl group consists of a carbon single bonded with three hydrogens.

[f]Fabulous. An acetyl group consists of a methyl group connected to a carbonyl group.

[!!!]Question 1b, Hydroxyl [/!!!]
[q]This functional group is

[hangman]

[c*]hydroxyl

[f]Yes. The name of this functional group is hydroxyl.

[!!!]Question 2b, carbonyl [/!!!]
[q]This functional group is

[hangman]

[c*]carbonyl

[f]Yes. The name of this functional group is carbonyl.

[!!!]Question 3b, carboxyl [/!!!]
[q]This functional group is

[hangman]

[c*]carboxyl

[f]Yes. The name of this functional group is carboxyl.

[!!!]Question 4b, amino [/!!!]
[q]This functional group is

[hangman]

[c*]amino

[f]Yes. The name of this functional group is amino.

[!!!]Question 5b, sulfhydryl [/!!!]
[q]This functional group is

[hangman]

[c*]sulfhydryl

[f]Yes. The name of this functional group is sulfhydryl.

[!!!]Question 6b, phosphate [/!!!]
[q]This functional group is

[hangman]

[c*]phosphate

[f]Yes. The name of this functional group is phosphate.

[!!!]Question 7b, methyl [/!!!]
[q]This functional group is

[hangman]

[c*]methyl

[f]Yes. The name of this functional group is methyl.

[!!!]Question 8b, acetyl [/!!!]
[q]This functional group is

[hangman]

[c*]acetyl

[f]Yes. The name of this functional group is acetyl.

[x]

[restart]

[/qwiz]

3. Ionized functional groups

Three of the functional groups, carboxyl, amino, and phosphate can be shown in an ionized or an unionized form. You should be able to recognize both forms when you see them attached to molecules. Study the table below.

Functional Groups
 Name Non-ionized form Ionized form
 Carboxyl 03_carboxyl 03a_carboxyl-ionized
 Amino 04_amino 04a_amino-group-ionized
 Phosphate 06a_phosphate-unionized 06_phosphate-corrected-ionized

4. More about Isomers

At the beginning of this tutorial, I described how molecules with the same number and types of atoms, but different arrangements of those atoms, are called isomers. There are three types of isomers to know about.

Structural isomers are the kind we looked at above (and shown again below for your convenience).

Chain Branched molecules
05_800px-N-Pentane 06_Isopentane

Both of these molecules have the same molecular formula (C5H12), but their structural arrangement differs. The different arrangement can have the effect of giving these molecules different physical and chemical properties.

A second type of isomer is a cis-trans isomer. Cis-trans isomers are result of the fact that double bonds (two shared pairs of electrons) are geometrically fixed, and don’t allow the atoms they join to rotate around the bond axis. Take a look at these two molecules, both of which have the formula C4H8.

C4H8, cis configuration C4H8, trans configuration
08_220px-cis-2-butene-svg 09_220px-trans-2-butene-svg

They are obviously isomers, with a different geometry. Note how the two methyl groups in the molecule on the left are on the same side of the double bond, which is referred to as a cis configuration. In the molecule on the right, the two methyl groups are on opposite sides of the double bond, which is referred to as a trans configuration. As with structural isomers, the different location of the methyl groups can alter the chemical and physical properties of these molecules.

You might have heard about trans-fats, and how they’re bad for your heart. That’s correct, and you’ll learn more about them in my videos and interactive tutorials about biochemistry. Click here if you want to jump ahead to that topic now.

The last type of isomers are molecules that are non-superimposable mirror images of one another. That sounds abstract, but it’s actually simple. Hold your hands out in front of you. Your hands are analogous to enantiomers: same bones, same digits, with a mirror image structure. If you made a mold that perfectly fit your right hand, your left hand wouldn’t be able to fit into it. These types of isomers are called called enantiomers.

The two molecules below are both chemical relatives of the neurotransmitter dopamine.

D-dopa (biologically inactive) L-dopa (biologically active)
10_d-dopa 11_l-dopa-290px-34-dihydroxy-l-phenylalanin_levodopa-svg

10a_d-dopa-from-campbell
D-dopa

11b-l_dopa-from-campbell
L-dopa

Neurotransmitters are the chemicals used to send signals from one nerve cell to the next. Dopamine works in the brains of animals (including humans) in processes including pleasurable reward to stimuli, attention, memory, and learning.

D-dopa and L-dopa look pretty similar, right? Let’s focus on the structural formulas. Remember that in this type of structural formula, every angle vertex indicates a carbon atom. Note that the amino group in D-dopa is shown as being attached to its carbon with a dashed wedge. That dashed wedge means that the amino group is below the plane of the molecule. In L-dopa, there’s a solid wedge connecting the amino group to its carbon. That solid wedge indicates that the amino group is above the plane of the molecule.

That difference might seem trivial, but it makes these molecules as different (and as non-interchangeable) as your left and right hands. That’s because enzymes, the proteins which carry out the chemical reactions inside your cells and body compartments (like your stomach) work by binding with the molecules they interact with. In the same way that you can’t put a right handed glove on your left hand, an enzyme that can fit with L-dopa can’t fit with D-dopa. The consequence is that L-dopa can serve as a medicine for people with Parkinson’s disease, a condition where the brain produces insufficient amounts of dopamine. D-dopa has no pharmacological use.

5. Another Quiz : Functional groups and isomers

That’s about all you need to know about carbon and functional groups to succeed in a first-year, introductory biology course. When we study proteins (as well as other key biological molecules) in the next module of our course, you’ll see that it will be useful to be able to identify functional groups, and to hold in mind which ones are polar, non-polar, acidic, basic, and so on. In the quiz that follows, just to keep you on your toes, some of the functional groups shown below are in their ionized form, but others are not. Enjoy!

[qwiz qrecord_id=”sciencemusicvideosMeister1961-Functional Groups Quiz 2 (M5)”]

[h]Functional groups and isomers

[i]

[!]++++question 1++++[/!!]

[q]In the diagram below, a hydroxyl group is shown at

[textentry single_char=”true”]

[c*] 5

[f] Nice job: a hydroxyl group is at “5.”

[c]*

[f]No, but here’s a hint. The hydroxyl group is like a water molecule, but it’s missing a hydrogen.

[!]++++question 2++++[/!!]

[q]In the diagram below, a methyl group is shown at

[textentry single_char=”true”]

[c*] 2

[f] Nice job: a methyl group is at “2.”

[c]*

[f]No, but here’s a hint. The methyl group is like a methane molecule, (CH4), but it’s missing a hydrogen.

[!]++++question 3++++[/!!]

[q]In the diagram below, a phosphate group is shown at

[textentry single_char=”true”]

[c*] 1

[f] Nice job: a phosphate group is at “1.”

[c]*

[f]No, but here’s a hint. The phosphate group is the only one with phosphorus.

[!]++++question 4++++[/!!]

[q]In the diagram below, a sulfhydryl group is shown at

[textentry single_char=”true”]

[c*] 6

[f] Nice job: a sulfhydryl group is at “6.”

[c]*

[f]No, but here’s a hint. Look at the name of this functional group (“sulfhydryl”). The first syllable tells you which element to look for.

[!]++++question 5++++[/!!]

[q]In the diagram below, a carboxyl group is shown at

[textentry single_char=”true”]

[c*] 3

[f] Nice job: a carboxyl group is at “3.”

[c]*

[f]No, but here’s two hints. 1) The name “carboxyl” indicates one of the key elements in this group. 2) The carboxyl group is one of the functional groups that can be in an ionized form (meaning that it will have a charge (indicated by a “plus” or a “minus” sign). So, look for the element I’ve hinted at, and a charge.

[!]++++question 6++++[/!!]

[q]In the diagram below, a carbonyl group is shown at

[textentry single_char=”true”]

[c*] 7

[f] Nice job: a carbonyl group is at “7.”

[c]*

[f]No, but here’s a hint. The carbonyl group’s name indicates one of its most important elements.

[!]++++question 7++++[/!!]

[q]In the diagram below, an amino group is shown at

[textentry single_char=”true”]

[c*] 4

[f] Nice job: an amino group is at “4.”

[c]*

[f]No, but here’s a hint. The fourth letter in the word “amino” indicates a key element in this functional group.

[!]++++question 7++++[/!!]

[q]In the diagram below, an acetyl is shown at

[textentry single_char=”true”]

[c*] 8

[f] Nice job: an acetyl group is at “8.”

[c]*

[f]No, but here’s a hint. Acetyl groups have a methyl groups and a carbonyl group.

[!]++++question 8++++[/!!]

[q]In the diagram below, the functional group that’s used to deactivate stretches of DNA (turning genes off) is at

[textentry single_char=”true”]

[c*] 2

[f] Nice job: a methyl group is at “2.” These groups are often used in gene inactivation.

[c]*

[f]No, but here’s a hint. This process of turning genes off by adding a functional group is called “methylation.”

[!]++++question 9++++[/!!]

[q]In the diagram below, the functional group that’s often used in energy transfer is at

[textentry single_char=”true”]

[c*] 1

[f] Nice job: a phosphate group is shown at “1.” These are often used in energy transfer (as in the molecule adenosine triphosphate, ATP).

[c]*

[f]No, but here’s a hint. These type of energy transfers are referred to as phosphorylations.

[!]++++question 10++++[/!!]

[q]In the diagram below, the functional group that plays a key role in protein structure through the formation of disulfide bridges is

[textentry single_char=”true”]

[c*] 6

[f] Nice job: a sulfhydryl group is shown at “6.” Two sulfhydryl groups can form a structure called a “disulfide” bridge, which can bend a protein into a particular shape (which helps to determine the protein’s shape, which in turn helps determine its function).

[c]*

[f]No, but here’s a hint. The structure is called a “disulfide bridge.” What element name do you see in “disulfide.” Which functional group has that element?

[!]++++question 11++++[/!!]

[q]Note that in this question, the diagram is just for reference. The two functional groups that can make the molecule they’re attached to an acid are

[c]methyl and carbonyl

[f]No, but here’s a hint. Look for the two functional groups that, in their ionized form, have negative charges. They’re negative because they lost a hydrogen ion, which has dissolved into the surrounding solution, making that solution more acidic.

[c] phosphate and amino

[f]No, but here’s a hint. Look for the two functional groups that, in their ionized form, have negative charges. They’re negative because they lost a hydrogen ion, which has dissolved into the surrounding solution, making that solution more acidic.

[c]sulfhydryl and carboxyl

[f]No, but here’s a hint. Look for the two functional groups that, in their ionized form, have negative charges. They’re negative because they lost a hydrogen ion, which has dissolved into the surrounding solution, making that solution more acidic.

[c*]carboxyl and phosphate

[f] Nice job: The two functional groups that make the molecule they’re attached to an acid are phosphate and carboxyl

 

[!]++++question 12++++[/!!]

[q]In the diagram below, the functional group can make the molecule it’s attached to a base is

[textentry single_char=”true”]

[c*] 4

[f] Nice job: the amino group, at 4, can absorb a hydrogen ion from the solution it’s in, making the solution more basic.

[c]*

[f]No, but here’s a hint. Ammonia is a base that has a structure related to this functional group. Ammonia’s fifth letter has an element that will lead you right to this functional group.

[!]++++question 13++++[/!!]

[q]A general term for two or more molecules with the same molecular formula but a different arrangement of the atoms in these molecules is

[hangman]

[c*]isomer

[f]A general term for two or more molecules with the same molecular formula but a different arrangement of the atoms in these molecules is isomer.

[!]++++question 14++++[/!!]

[q]Two molecules that are non-superimposable mirror images of one another are known as

[hangman]

[c*]enantiomers

[f]Two molecules that are non superimposable mirror images of one another are known as enantiomers. 

[!]++++question 15++++[/!!]

[q]Cis-trans isomers are molecules with the same number and type of atoms, but with different arrangement of these atoms around a __________ bond.

[hangman]

[c*]double

[f]Cis-trans isomers are molecules with the same number and type of atoms, but with different arrangement of these atoms around a double bond.

[!]++++question 16++++[/!!]

[q]In the molecule below, the functional group attached to carbon number 1 is a _________ group.

[hangman]

[c*]carbonyl

[f]Excellent. The functional group attached to carbon number 1 is a carbonyl group.

[!]++++question 17++++[/!!]

[q]In the molecule below, the functional group attached to carbon number 4 is a _________ group.

[hangman]

[c*]hydroxyl

[f]Nice. The functional group attached to carbon number 4 is a hydroxyl group.

[!]++++question 18++++[/!!]

[q]In the molecule below, the functional group attached to the left side of the central carbon is a(n) _________ group (note: the central carbon has the R1 hanging below it: you’ll learn what that is very soon).

[hangman]

[c*]amino

[f]Awesome. The functional group to the left of the central carbon is an amino group.

[!]++++question 19++++[/!!]

[q]In the molecule below, the functional group attached to the right side of the central carbon is a(n) _________ group (note: the central carbon has the R1 hanging below it: you’ll learn what that is very soon).

[hangman]

[c*]carboxyl

[f]Awesome. The functional group to the right of the central carbon is an carboxyl group.

[!]++++question 20++++[/!!]

[q]In the molecule below, there are three of the same functional groups in a row, indicated by letters “A,” “B,” and “C.” This is a ______________ group.

[hangman]

[c*]phosphate

[f]Terrific. The thrice repeated functional group is a  phosphate group.

[/qwiz]

6. What now?

Link to

  1. Proceed to Biochemistry (Carbohydrates, Lipids, Proteins, and Nucleic Acids)
  2. return to the Carbon and functional groups menu