PIGMENTS, PERFUMES AND POISONS

1

• Today
• Quiz 3 Discussion
• My office hours Tu 10 -11, Th 1 - 2 in Science
  106 C
• Family Science Night, Wednesday, Oct. 22, 6 - 9pm
  at Oak Grove Middle School in Concord!
• Primary Metabolites
• Carbohydrates
• Fats and Oils
• Amino acids and proteins

2
Quiz 3 Answers High 22 Low 8 Average 18.2

• Write the formula for
• calcium hydroxide (OH-) Ca(OH)2
• magnesium nitrate (NO3- ) Mg(NO3)2
• calcium carbonate (CO32- ) CaCO3
• potassium phosphate (PO43- ) K3PO4
• sodium sulfate (SO42- ) Na2SO4

3

• Draw the structures for two (three?) isomers of
  C5H12 /of C4H8
• a) Name two signs that a chemical reaction must
  have occurred (anywhere, in a lab or in a living
  organism).
• b) What is special about chemical reactions in
  plants? Mention at least two aspects.
• a) Which two products are always formed in a
  complete combustion of hydrocarbons (i.e. in the
  presence of plenty of oxygen)?
• b) Which two products are always formed during a
  fermentation?
• b) Which two products are always formed as a
  result of photosynthesis?

4
Primary and Secondary Metabolites
Primary metabolites Organic metabolites that are
found in all plants (and all animals) Sugars,
carbohydrates Provide energy ( have other
functions, too...) Functional groups, more on
isomers Fats and oils Provide protection and
energy Amino acids Building blocks of
proteins (More about these when we address
Plants and Foods.) Secondary metabolites
unique to some plants Plant odors. Pigments.
Defensive compounds.
5
Primary MetabolitesCarbohydrates
Cx(H2O)xglucose, sucrose, fructose, lactose,
cellulose.

• Carbohydrates (Sugars)
• are composed of C, H, O
• are organic compounds with lots of O-H
  functional groups
• Functional groups are attachments to the carbon
  skeleton. They have typical chemical reactions.

6
Glucose
has other molecular shapes as well
7
Chiral (or asymmetric) carbons in this molecule!





8
Molecules that can be left-handed or
right-handed
Asymmetric Molecules Chiral
MoleculesOptical Isomers

A
CH
CH
3
3
H
H
B
C
C
C
COOH
OH
OH
HOOC
D
E
a chiral molecule
Lactic acid
mirror image
Enantiomers Mirror images
9

Many Functions of Glucose in Plants!

• can be broken down during aerobic respiration to
  provide energy and highenergy compounds, such as
  ATP, to do further chemical work.
•      

10

Functions of Glucose

•   can be converted into starch for later use
  (bulbs in Mediterranean climate!)
•     

11
Functions of Glucose

• Is needed to compose cellulose in plants
•      

12
a section of a cellulose molecule     
13

Functions of Glucose

•     Required for the biosynthesis
• of other carbohydrates (like starch and
  cellulose)
• of fats and oils
• of amino acids (building blocks of proteins)
• Involved in the biosynthesis of all organic
  compounds in plants!

14

Functions of Glucose

• Molecules that are poorly soluble in water can
  become better soluble
• if glucose is bonded to them
• making them Glycosides

Examples
Cardiac Glycosides in Milkweed, Digitalis
In conclusion Glucose has many functions in
plants!
15
Summary of functions of carbohydrates in plants
(glucose and others)

• Required for biosynthesis of all other organic
  plant molecules
• Storage of energy (starch, other sugars)
• Provide structure (cellulose)
• Make other molecules water-soluble (glycosides)
• Sweeten ripe fruit
• Freeze-protection
• Sticky gums as defense
• Attract pollinators with sweet nectar

16
PracticeCan you find any chiral carbons in the
molecules below? Mark them with
CH4
OH

C -
H
C -
COOH
3
H
Lactic acid
17
Next class

• More on Primary Metabolites
• Lipids. Fats and Oils