Transcript Organic

BIOCHEMISTRY
“All life is chemistry.”
Jan Baptist van Helmont (1648)
• Introduction
– Defn = chemistry of living organisms
– 98% is C, H, O (99% is CHNOPS)
– Organic chemistry deals mainly with ________.
– Why is carbon so versatile? Draw its Lewis Dot
structure.
How many
atoms of
each
element a
human
baby has.
KEY for Model Building
•
•
•
•
Black = ?
White = ?
Blue = ?
Red = ?
• What do the white tubes represent?
Try making methane = CH4
It’s 3-D shape is what you built.
Is it polar or Nonpolar?
Try building carbon dioxide=CO2
Is it polar or nonpolar?
Functional group, -COOH
(aka, carboxylic acid)
Why is it called an “acid?”
Organic Polymers that Life Requires
The BIG 4 Biomolecules
1.
2.
3.
4.
Carbohydrates
Lipids/Fats
Proteins
Nucleic Acids (DNA & RNA)
All made up of C,H, O, N
1. Carbohydrates
• Include mono- & polysaccharides
• Examples: glucose, fructose, sucrose,
deoxyribose, amylose
• Named “carbo” “hydrates” b/c …
each carbon is hydrated w/ H- and –OH.
• Formula = Cn(H2O)n where n = whole
number so carbs have 1C:2H:1O ratio.
A. Monosaccharides
• Building blocks of polysaccharides
• Means “single sugars”
• Examples include glucose, fructose,
galactose (all C6H12O6)>>isomers=same
chemical make-up, different arrangement
Glucose
Why is glucose so important?
It is the energy
molecule
made by
photosynthesis!
B. Disaccharides
• “double sugars”
• 2 monosacs joined together via dehydration
synthesis reaction
+ H0
2
• examples:
glucose + glucose = maltose + water (see above)
glucose + fructose = sucrose (table sugar) + H20
galactose + glucose = lactose (milk sugar) + H20
C. Polysaccharides
• “many sugar” polymer made up of
200+ monosacs (“bricks”) to make a
macromolecule “house”
• Usually long chains of glucoses
joined together via dehydration
synthesis
Examples of Polysaccharides
• I’ll provide 1 structural & 1 energy store
for both plants & animals
• Made out of the same “brick”=glucose
• How those glucoses are arranged is what
makes them different (structurally and
functionally)
• Can you see how in the following 4
examples?
#1=
-What monomer is repeated in this chain?
-What do you notice about how they are
positioned in the long chain?
-What kind of reaction occurred to join all
of them together?
Cellulose=structural polysac made up of αglucoses joined 14 alternating orientation
found in plant cell walls (tough& fibrous).
Can we humans digest it?
• Humans cannot digest cellulose (but it is a source of
good fiber)
• Neither can cows nor termites but their microbial
partners in their guts can
#2=STARCH (aka, Amylose) made up
of chains of glucoses w/ 14 rightside up linkages
How are these glucoses joined differently than those in
cellulose?
Can we animals digest starch?
YES! With Amylase =enzyme found in saliva that
digests amylose by breaking bonds betw. glucoses
Starch granules in plant cells
Photo by
David Webb
How do animals store carbohydrates?
#3=Glycogen (animals’ complex
storage carb)
Glycogen(use it all & you’ll hit the wall)
#4=Chitin (animal structural
polysac). What does it resemble?
Chitin (continued)
• Monomer=glucosamine (amine
group at the #2 carbon in the
glucose ring)
• Found in the exoskeleton cuticle
of insects and crustaceans
Chitin--found in the exoskeleton of
the cicada
Chitin is sometimes purified &
used in surgical wire
Indicator Tests for Carbs
1. Reducing (simple)
sugars: Benedict’s
Solution made up of a
Cupric ion (Cu 2+) which
is blue reacts with
reducing sugars that
donate electrons
resulting in Cuprous
Oxide (Cu 1+) which is
reddish in color.
2. Starch Test
• Lugol’s Iodine
solution is yelloworangish in color
but changes to
bluish-black in the
presence of the
complex carb,
starch.
2. Lipids
•
•
Include fats, oils, waxes, & steroids
Chemically different group classified
together b/c they are insoluable in water
(NONPOLAR).
A. Triglycerides = 3 fatty acids + glycerol
Saturated vs. Unsaturated Fats
• So named b/c each carbon is “saturated
with hydrogens”
• Found mainly in animals vs. plants
• Contain only single covalent bonds in long
hydrocarbon chain vs. double bonds
present in unsat. that lead to “kinks” in the
long chain.
• Solid vs. liquid at room temp.
Importance of Fats
• Great source of long-term energy storage
(each gram of fat produces 2X as much
energy as carbs/protein)
• Insulation (esp. needed in first 3 years of
brain development of humans to insulate
your brain nerve cells)
• Lubrication (keeps organs from tearing
each other apart)
B. Phospholipids=make up the
bilayer of the cell membrane
OUTSIDE
Inside of Cell Membrane
INSIDES of a CELL
C. Steroids->all made from cholesterol =
a set of 4 hydrocarbon rings
1.) Sex Steroids are hormones that
use cholesterol as backbone
Figure 2: Estradiol
2.) Fat-soluble vitamins
like Vitamin D
Formed from cholesterol.
Important in maintaining
strong bones and
boosting immune system.
Lipid Indicator test: Sudan stain.
Sudan IV is not soluble in
water; it is, however, soluble
in lipids. Red Sudan IV is
added to a solution along
with ethanol to dissolve any
possible lipids. If lipids are
present the Sudan IV will
stain them reddish-orange,
giving a positive test, usu.
Forming a layer on top.
Sleep-Fat Study
• ttp://www.npr.org/blogs/health/2012/10/17/
163018568/poor-sleep-may-lead-to-toomuch-stored-fat-and-disease
3. PROTEINS
• Means “first place”
• Monomer = amino acids: central carbon w/
1. Amino group
2. Carboxylic acid grp.
3. A Hydrogen
4. R group
What is an R group?
• R = Replacement Group
• Could be anything but only 20 that life
uses (see p. 367 for a list of them).
• Build yours and attach (see index cards).
• Gives each amino acid its uniqueness &
specificity (dictates how the amino acid
interacts w/ others)
• Either nonpolar, polar, or charged
AA1 + AA2 Dipeptide + H20
Left=remove –OH from carboxyl / Right =remove H
from amine. Connect 2 aa with peptide bond
+ H2O
Polypeptide
= many amino acids joined together to create
long amino acids chain.
Smallest human one = gastric peptide (10aa)
Largest human protein = TITAN (>27,000 aa)
• For each peptide bond formed, a water
molecule is lost thru dehydration synthesis.
• How that polypeptide folds and takes on a
3-D shape is determined by its R groups
and how they interact w/ each other.
Roles that Proteins Play
1.) Speed up chemical reactions (catalysts)
= ENZYMES
Ex: amylase: starts breaking down starch
Pepsin: starts breaking down proteins
ATP Synthase: helps make ATP
2.) Structural / supportive
Ex: collagen in tendons
Does this look like anything we’ve seen
before?
3.) Transport Ex: hemoglobin in red
blood cells moves O2 throughout the body
4.) Communication
Hormones = messenger molecules
that are secreted one place but have
their effect elsewhere
(Ex: insulin : secreted from pancreas &
tells body cells to remove glucose from
bloodstream)
Honors
+ Neurotransmitters (serotonin)
insulin
5.) Energy storage—egg whites
contain albumin
6.) Defense—antibodies that help
immune system destroy invaders
7.) Movement—actin & myosin in
muscle fibers
4. Nucleic Acids
• Named so because they are found mainly
in the nucleus of cells.
• Include DNA & RNA.
• Monomer = nucleotide
A. Structure– the nucleotide is
made up of 3 parts
1.) 5-carbon sugar = Deoxyribose or Ribose
2.) Nitrogen-Carbon Ringed Base
• DNA has 4 = A, C, G, or T
• RNA has 4 = A, C, G, or U
3.) Phosphate Group
NUCLEOTIDE: all 3 parts together
• See p. 48, Fig 2-16
• See class model
-Red pentagon = sugar
-Purple = phosphate
-Middle colored “stairs”
= adenine, thymine,
cytosine, guanine
B. Function of NAs
• The “code of life”
• Specifically they code for proteins
• Each NA’s role:
 DNA—stores the info (w/in chromosomes) for all
of life’s processes (growth, metabolism,
reproduction, etc.)
 RNA—messenger that carries the info out
Nucleic Acid Polymer Structure
A. DNA = double helix
wound w/in large
chromosomes
`
B. RNA = single
stranded, much
shorter nucleotide
sequences, comes in
many different forms
to perform different
jobs in the decoding
process