Transcript Biochemistry PPT - Kenston Local Schools

Biochemistry
pH
Paul Anderson / Bozeman Science
https://www.youtube.com/watch?v=Xeuyc
55LqiY
Physical Vs Chemical Change
Organic Chemistry
Organic = it contains carbon, or was once
alive.
Organic Chemistry
Carbon can covalently bond with up
to four other atoms.
Organic Compounds
1.
2.
3.
4.
Carbohydrates
Lipids
Proteins
Nucleic Acids
Carbohydrates
Contain: Carbon / Hydrogen & Oxygen
Provide energy for the organism
Ratio: 1:2:1
Monosaccharides = 1 sugar
Disaccharides = 2 sugars
Polysaccharides = 3 sugars
Monosaccharides = C6H12O6
= “one sugar”
Glucose
Fructose
Galactose
These are ISOMERS
= same chemical
formula different
structural formula
Monosaccharides
Disaccharides
Polysaccharides
How do monosaccharides make a
disaccharide or polysaccharide?
It’s “dehydrated” – a
WATER molecule is
removed – often
called condensation
or dehydration
synthesis.
Glycogen
Consists of glucose monomers
 Is the major storage form of glucose
in animals

Mitochondria
Giycogen granules
0.5 m
Glycogen
Figure 5.6
17
(b) Glycogen: an animal polysaccharide
Structural Polysaccharides
Cellulose

Is a polymer of glucose
18

Has different glycosidic linkages than starch
H
O
C
CH2OH
H
4
O
H
OH H
OH
HO
H
C
H
H
OH
 glucose
CH2OH
OH
HO
C
H
H
C
OH
H
C
OH
H
C
OH
H
O
H
OH
4
HO
OH
1
H
H
H
OH
 glucose
(a)  and  glucose ring structures
CH2OH
CH2OH
O
HO
O
4
1
OH
O
O
O
1
OH
4
O
1
OH
OH
OH
CH2OH
CH2OH
O
4
1
OH
O
OH
OH
(b) Starch: 1– 4 linkage of  glucose monomers
CH2OH
O
HO
O
OH
1
4
OH
OH
CH2OH
O
O
O
OH
OH
O
O
OH
Figure 5.7 A–C
OH
CH2OH
OH
(c) Cellulose: 1– 4 linkage of  glucose monomers
19
CH2OH
OH

Is a major component of the tough walls that
enclose plant cells
Cell walls
Cellulose microfibrils
in a plant cell wall
Microfibril
About 80 cellulose
molecules associate
to form a microfibril, the
main architectural unit
of the plant cell wall.
0.5 m
Plant cells
Parallel cellulose molecules are
held together by hydrogen
bonds between hydroxyl
groups attached to carbon
atoms 3 and 6.
Figure 5.8
OH CH2OH
OH
CH2OH
O O
O O
OH
OH
OH
OH
O
O O
O O
O CH OH
OH
CH2OH
2
H
CH2OH
OH CH2OH
OH
O O
O O
OH
OH
OH
OH
O
O O
O O
O CH OH
OH CH2OH
2
H
CH2OH
OH
OH CH2OH
O O
O O
OH
OH
OH O
O OH
O O
O
O CH OH
OH CH2OH
2
H
 Glucose
monomer
20
Cellulose
molecules
A cellulose molecule
is an unbranched 
glucose polymer.
Cellulose is difficult to digest

Cows have microbes in their stomachs to
facilitate this process
Figure 5.9
21
Chitin, another important structural
polysaccharide


Is found in the exoskeleton of arthropods
Can be used as surgical thread
CH2O
H
O OH
H
H
OH H
OH
H
H
NH
C
O
CH3
(a) The structure of the (b) Chitin forms the exoskeleton
of arthropods. This cicada
chitin monomer.
is molting, shedding its old
exoskeleton and emerging
Figure 5.10 A–C
in adult form.
22
(c) Chitin is used to make a
strong and flexible surgical
thread that decomposes after
the wound or incision heals.
Polysaccharides
Hydrolysis
In a reaction opposite to dehydration, a
water molecule can be added to split a
polymer in two: Hydrolysis
Think of chewing a Saltine cracker
Basic Chemistry
https://www.youtube.com/watch?v=MYuh5
yErdfA (Part 1)
https://www.youtube.com/watch?v=Juw7H
Bg0zZs (Part 2)
Animations: Campbell
LIPIDS
Lipids
Lipids are molecules that have a Glycerol
molecule…
Connected to three fatty acid chains
hydrocarbon chains.
Lipids are NON polar.
Glycerol
LIPIDS
Three Fatty Acids
Saturated vs. Unsaturated Fat
Phospholipids


Have only two fatty acids
Have a phosphate group instead of a
third fatty acid
39
Phospholipid structure
 Consists of a hydrophilic “head” and
hydrophobic “tails”
CH2
+
N(CH )
3 3
Choline
CH2
O
O
P
O–
Phosphate
O
CH2
CH
O
O
C
O C
CH2
Glycerol
O
Fatty acids
Hydrophilic
head
Hydrophobic
tails
Figure 5.13
(b) Space-filling model
(a) Structural formula
40
(c) Phospholipid
symbol
LAB:
Organic
Compounds
Carbs, Proteins, Lipids
Constructed in similar way
Organic
Compounds
Lab Tests
BENEDICT’S TEST
test for monosaccharide
(simple sugar)
IODINE TEST – DO NOT HEAT!!
TEST for STARCH/Polysaccharide
Proteins
Amino Acids are building blocks of
Proteins
A peptide bond forms between amino
acids by dehydration synthesis.
They contain: C, H, O & N (Nitrogen)
BIURET’S TEST:
Test for PROTEIN
https://www.youtube.com/watch?v=lijQ3a8
yUYQ
What Determines Protein
Shape?
Protein shape (conformation)
depends on the physical and
chemical conditions of the protein’s
environment
Temperature, pH, etc. affect protein
structure
58
•Denaturation is when a protein
unravels and loses its native
conformation
(shape)
Denaturation
Normal protein
Figure 5.22
Denatured protein
Renaturation
59
The Protein-Folding Problem
Most proteins
Probably go through several
intermediate states on their
way to a stable shape
 Denaturated proteins no
longer work in their unfolded
condition

60
Nucleic Acids: DNA & RNA
(the fourth type of Organic Compound)
Most cells contain DNA /RNA
Nucleic Acids are made up of long chain of
nucleotides
Nucleotides are made up of three parts:



Sugar
Base
Phosphate group
RNA molecule
Each polynucleotide


Consists of monomers called nucleotides
Sugar + phosphate + nitrogen base
64
DNA Vs RNA
DNA:



Remains in the nucleus
Has four bases (A,C,T,G)
Double Stranded
RNA:



Can go from nucleus to cytoplasm
Has four bases (A,C,U,G)
Single Stranded
Enzymes
ENZYMES: End in - ase
EXAMPLES: (do not copy this!) 
Catalase
Reductase
Ligase
Nuclease
Maltase
Primase
Helicase
ENZYMES
Enzymes are “CATALYSTS” = They
speed up a reaction
All enzymes are PROTEINS
BUT: not all proteins are ENZYMES
Chaperonins

Are protein molecules that assist in the proper
folding of other proteins
75
X-ray crystallography

Is used to determine a protein’s threedimensional structure
Figure 5.24
76
Proteosome
Once a protein has completed its
job
It is disposed of
It recycles it’s amino acids

(in a type of mini trash compactor /
recycler)
HHMI Proteosome
http://www.hhmi.org/biointeractive/proteas
ome
http://www.youtube.com/watch?v=iaHHgE
oa2c8
ATP = Adenosine triphosphate
A high energy molecule
“ENERGY CURRENCY” of cells
When food is broken down – it is
converted to ENERGY = ATP
pH – measures the concentration
of H+ ions in solution
Acid Vs Base
Acid – pH value of: 0 - 6.9 (red litmus)
Base – pH value of: 7.1 – 14 (blue litmus)
Neutral = 7
Buffer: a substance that resists changes
in pH when an acid or base is added
Protein Structure
Level
Primary
Secondary
Description
The amino acid
sequence
Helices and Sheets
Disulfide bridges
Tertiary
Quaternary
Multiple polypeptides
connect
Animations
Carbs:
http://www.youtube.com/watch?v=QckfYvIl
Vu4
Lipids:
http://www.youtube.com/watch?v=3xF_LK
9pnL0&feature=channel
Proteins:
http://www.youtube.com/watch?v=wctkPUUpUc&feature=relmfu