Transcript You Light Up My Life

Carbon
&
Molecules of Life
Organic Compounds
Hydrogen and other elements
covalently bonded to carbon
Carbohydrates
 Lipids
 Proteins
 Nucleic Acids

Organic Compounds
carbon (C)
calcium (Ca)
sodium (Na)
oxygen (O)
phosphorous (P)
chlorine (Cl)
hydrogen (H)
potassium (K)
magnesium (Mg)
nitrogen (N)
sulfur (S)
iron (Fe)
p.34a
Organic Compounds
structural formula
for methane
ball-and-stick model
space-filling model
p.34b
Carbon’s Bonding Behavior

Outer shell of carbon
has 4 electrons; can
hold 8

Each carbon atom can
form covalent bonds
with up to four atoms
Bonding Arrangements

Carbon atoms can
form chains or rings

Other atoms project
from the carbon
backbone
Organic Compounds
or
Simplified structural formula
for a six-carbon ring
icon for a six-carbon ring
p.34e
Organic Compounds
Fig. 3-2, p.35
Isomers
Structural isomers – differ in the arrangement
of their atoms
 Geometric isomers – differ in the
arrangement of atoms around a double bond
 Enantiomers – Chiral Molecules –

◦ Molecules are mirror images of each other
◦ Cells can tell the two apart
◦ Usually one is biologically active while the other is
not
Polymers
Large molecules made by linking many
individual building blocks together in long
chains
 The building block subunits are called
monomers
 Subunits are linked by a reaction called
dehydration synthesis
 Can be cleaved by a reaction called
hydrolysis

Functional Groups

Atoms or clusters of atoms that are
covalently bonded to carbon backbone

Give organic compounds their different
properties
Examples of Functional Groups
Hydroxyl group
- OH
Amino group
- NH3+
Carboxyl group
- COOH
Phosphate group
Sulfhydryl group
- PO3-
- SH
Common
Functional
Groups in
Biological
Molecules
Fig. 3-4, p.36
Functional Groups in Hormones

Estrogen and testosterone are hormones responsible for observable differences in
traits between male and female wood ducks

Differences in position of functional groups attached to ring structure (pg 63)
An Estrogen
Testosterone
Fig. 3-5b, p.36
Dehydration Synthesis Reactions

Form polymers from subunits

Enzymes remove -OH from one molecule,
H from another, form bond between two
molecules
Discarded atoms can join to form water
 Also called condensation reactions

Dehydration Synthesis
Fig. 3-6a, p.38
Hydrolysis

A type of cleavage reaction

Breaks polymers into smaller units

Enzymes split molecules into two or
more parts

An -OH group and an H atom derived
from water are attached at exposed sites
Hydrolysis
Fig. 3-6b, p.38
Carbohydrates
Monosaccharides
(simple sugars)
Oligosaccharides
(short-chain carbohydrates)
Polysaccharides
(complex carbohydrates)
Monosaccharides

Simplest carbohydrates

Most are sweet tasting, water soluble

Most have 5- or 6-carbon backbone
Glucose (6 C)
Fructose (6 C)
Ribose (5 C)
Deoxyribose (5 C)
Two Monosaccharides
glucose
fructose
Fig. 3-7, p.38
Disaccharides
Type of oligosaccharide
 Two monosaccharides
covalently bonded
 Formed by
condensation reaction

glucose
fructose
+ H2O
sucrose
Fig. 3-7b, p.38
Polysaccharides

Straight or branched chains of many sugar
monomers

Most common are composed entirely of
glucose
◦ Cellulose
◦ Starch (such as amylose)
◦ Glycogen
Cellulose & Starch

Differ in bonding patterns between
monomers

Cellulose - tough, indigestible, structural
material in plants

Starch - easily digested, storage form in
plants
Cellulose and Starch
Fig. 3-8, p.38
Glycogen

Sugar storage form in animals

Large stores in muscle and liver
cells

When blood sugar decreases, liver
cells degrade glycogen, release
glucose
Fig. 3-9, p.38
Chitin

Polysaccharide

Nitrogen-containing groups attached to
glucose monomers

Structural material for hard parts of
invertebrates, cell walls of many fungi
Chitin

Chitin occurs in protective body coverings
of many animals, including ticks
Fig. 3-10a, p.39
Fig. 3-10b, p.39
Lipids

Most include fatty acids
◦ Fats
◦ Phospholipids
◦ Waxes
Sterols and their derivatives have no fatty
acids
 Tend to be insoluble in water

Fats

Fatty acid(s)
attached to
glycerol

Triglycerides are
most common
Fig. 3-12, p.40
Fatty Acids

Carboxyl group (-COOH) at one end

Carbon backbone (up to 36 C atoms)
◦ Saturated - Single bonds between carbons
◦ Unsaturated - One or more double bonds
Three Fatty Acids
Fig. 3-11, p.40
Phospholipids

Main components of cell
membranes
Waxes

Long-chain fatty acids linked to long
chain alcohols or carbon rings

Firm consistency, repel water

Important in water-proofing
Waxes

Bees construct honeycombs from their own
waxy secretions
Fig. 3-14, p.41
Sterols and Derivatives

No fatty acids

Rigid backbone of four
fused-together carbon
rings

Cholesterol - most
common type in
animals
Fig. 3-14, p.41
Amino Acid Structure
carboxyl
group
amino
group
R group
Properties of Amino Acids

Determined by the “R group”

Amino acids may be:
◦ Non-polar
◦ Uncharged, polar
◦ Positively charged, polar
◦ Negatively charged, polar
Protein Synthesis

Protein is a chain of amino acids linked by
peptide bonds

Peptide bond
◦ Type of covalent bond
◦ Links amino group of one amino acid with
carboxyl group of next
◦ Forms through condensation reaction
Fig. 3-15b, p.42
Fig. 3-15c, p.42
Fig. 3-15d, p.42
Fig. 3-15e, p.42
Primary Structure

Sequence of amino acids

Unique for each protein

Two linked amino acids = dipeptide

Three or more = polypeptide

Backbone of polypeptide has N atoms:
-N-C-C-N-C-C-N-C-C-None
peptide
group
Protein Shapes

Fibrous proteins
◦ Polypeptide chains arranged as strands or
sheets

Globular proteins
◦ Polypeptide chains folded into compact,
rounded shapes
Primary Structure
& Protein Shape

Primary structure influences shape in two
main ways:
◦ Allows hydrogen bonds to form between
different amino acids along length of chain
◦ Puts R groups in positions that allow them to
interact
Secondary Structure

Hydrogen bonds form between different
parts of polypeptide chain

These bonds give rise to coiled or
extended pattern

Helix or pleated sheet
Examples of Secondary Structure
Tertiary Structure
heme group
Folding as a
result
of interactions
between R
groups
coiled and twisted polypeptide
chain of one globin molecule
Quaternary Structure
Some proteins are
made up of more
than one
polypeptide chain
Hemoglobin
heme
alpha globin
beta globin
alpha globin
beta globin
Fig. 3-17, p.44
Polypeptides with Attached Organic
Compounds

Lipoproteins
◦ Proteins combined with cholesterol,
triglycerides, phospholipids

Glycoproteins
◦ Proteins combined with oligosaccharides
Denaturation

Disruption of three-dimensional shape

Breakage of weak bonds

Causes of denaturation:
◦ pH
◦ Temperature

Destroying protein shape disrupts function
Nucleotide Structure

Sugar
◦ Ribose or deoxyribose

At least one phosphate group

Base
◦ Nitrogen-containing
◦ Single or double ring structure
Nucleotide Functions

Energy carriers

Coenzymes

Chemical messengers

Building blocks for nucleic
acids
ATP - A Nucleotide
base
three phosphate groups
sugar
Nucleic Acids
Cytosine
Composed of nucleotides
 Single- or double-stranded
 Sugar-phosphate backbone

Adenine
Bonding Between Bases in Nucleic
Acids
THYMINE
(T)
base with a
single-ring
structure
CYTOSINE
(C)
base with a
single-ring
structure
Fig. 3-20, p.46
DNA
Double-stranded
 Consists of four
types of nucleotides
 A bound to T
 C bound to G

RNA

Usually single strands

Four types of nucleotides

Unlike DNA, contains the base uracil in place
of thymine

Three types are key players in protein
synthesis