Chapter 4b

Carbon Compounds In Cells

Organic Compounds

Hydrogen and other elements covalently bonded to carbon

Carbohydrates

Lipids

Proteins

Nucleic Acids `

Carbon’s Bonding Behavior

• 1) Outer shell of carbon has 4 electrons; can hold 8

• 2) Each carbon atom can form covalent bonds with up to four atoms`

Structural Representations

Bonding Arrangements

• 1) Carbon atoms can form chains or rings

• 2) Other atoms project from the carbon backbone`

Functional Groups

• 1) Atoms or clusters of atoms that are covalently bonded to carbon backbone

– a) Give organic compounds their different properties`

Examples of Functional Groups

Hydroxyl group - OH

Amino group - NH3+

Carboxyl group - COOH

Phosphate group - PO3-

Sulfhydryl group - SH`

Functional Groups

Carbohydrates Monosaccharides

(simple sugars)

Oligosaccharides(short-chain carbohydrates)

Polysaccharides(complex carbohydrates) `

Monosaccharides

• 1) Simplest carbohydrates

• 2) Most are sweet tasting, water soluble

• 3) Most have 5- or 6-carbon backbone

Glucose (6 C) Fructose (6 C)

Ribose (5 C) Deoxyribose (5

C)`

Two Monosaccharides

glucose fructose

Monosaccharide

Disaccharides

• 1) Type of oligosaccharide

• 2) Two monosaccharides covalently bonded

• 3) Formed by condensation reaction`

+ H2O

glucose fructose

sucrose

Sucrose Formation

Polysaccharides

• 1) Straight or branched chains of many sugar monomers

• 2) Most common are composed entirely of glucose– a) Cellulose

– b) Starch (such as amylose)

– c) Glycogen`

Cellulose & Starch• 1) Differ in bonding patterns between

monomers

– a) Cellulose - tough, indigestible, structural material in plants

– b) Starch - easily digested, storage form in plants`

Cellulose and Starch

Starch Cellulose

Glycogen

• 1) Sugar storage form in animals

– a) Large stores in muscle and liver cells

• 1. When blood sugar decreases, liver cells degrade glycogen, release glucose`

Chitin

• 1) Polysaccharide

– a) Nitrogen-containing groups attached to glucose monomers

– b) Structural material for hard parts of invertebrates, cell walls of many fungi`

• 1) Most include fatty acids– a) Fats– b) Phospholipids– c) Waxes

• 2) Sterols and their derivatives have no fatty acids– a) Tend to be insoluble in water`

Lipids

Fatty Acids

• 1) Carboxyl group (-COOH) at one end

• 2) Carbon backbone (up to 36 C atoms)

– a) Saturated - Single bonds between

carbons

– b) Unsaturated - One or more double

bonds`

Three Fatty Acids

Fats

• 1) Fatty acid(s)

attached to

glycerol

– a) Triglycerides

are most

common`

Triglyceride

Phospholipids

• 1) Main components of cell

membranes`

Phospholipid

Sterols and Derivatives• 1) No fatty acids

• 2) Rigid

backbone of four

fused-together

carbon rings

• 3) Cholesterol -

most common

type in animals`

Cholesterol

Waxes

• 1) Long-chain fatty acids linked

to long chain alcohols or carbon

rings

– a) Firm consistency, repel water

– b) Important in water-proofing`

Amino Acid Structure

aminogroup

carboxylgroup

R group

Properties of Amino Acids

• 1) Determined by the “R group”

• 2) Amino acids may be:

– a) Non-polar

– b) Uncharged, polar

– c) Positively charged, polar

– d) Negatively charged, polar`

Amino Acids

Protein Synthesis

• 1) Protein is a chain of amino acids

linked by peptide bonds

– a) Peptide bond

• 1. Type of covalent bond

• 2. Links amino group of one amino

acid with carboxyl group of next

• 3. Forms through condensation

reaction`

Peptide Bond

Primary Structure

• 1) Sequence of amino acids

• 2) Unique for each protein

• 3) Two linked amino acids = dipeptide

• 4) Three or more = polypeptide

• 5) Backbone of polypeptide has N atoms:

-N-C-C-N-C-C-N-C-C-N-`

A Permanent Wave

hair wrapped around cuticles

differentbridges form

bridgesbroken

Primary Structure

Secondary/Tertiary

Quaternary

Studying Spider Silk

Enzyme Structure and Function

1) Enzymes are catalytic molecules

a) They speed the rate at which reactions approach equilibrium`

Four Features of Enzymes

1) Enzymes do not make anything happen that could not happen on its own. They just make it happen much faster

2) Reactions do not alter or use up enzyme molecules`

Four Features of Enzymes

3) The same enzyme usually works for

both the forward and reverse reactions

4) Each type of enzyme recognizes and binds to only certain substrates`

• 1) Sugar

– a) Ribose or deoxyribose

• 2) At least one phosphate group

• 3) Base

– a) Nitrogen-containing

– b) Single or double ring structure`

Nucleotide Structure

Nucleotide Functions

• Energy carriers

• Coenzymes

• Chemical messengers

• Building blocks for

nucleic acids`

ATP - A Nucleotide

three phosphate groups

sugar

base

ATP

• 1) Composed of nucleotides• 2) Single- or double-stranded• 3) Sugar-phosphate backbone`

Nucleic Acids

AdenineCytosine

DNA Subunits

DNA

• 1) Double-stranded

• 2) Consists of four types of nucleotides– a) A bound to T– b) C bound to G`

DNA Structure

RNA

• 1) Usually single strands

• 2) Four types of nucleotides– a) Unlike DNA, contains the base uracil

in place of thymine

• 3) Three types are key players in protein synthesis`

DNA/RNA