Chemical Reactions in Living Cells

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Chemical Reactions in Living Cells
Biochemistry Chemical Reactions in Living Cells

• Chemical Reaction
• Involves the making and breaking of chemical
  bonds
• Represented as a short statement

H2O H2 O2
2
2
How would you balance this?
Does this happen on its own?

• Activation Energy The amount of energy
  needed to initiate a reaction

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Biochemistry The unique properties of water
d
d
d -
Water molecules are polar covalent bonds.
They are attracted to other water molecules
through relatively weak Hydrogen bonds.
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Biochemistry The unique properties of water
Can water form ions?
Yes, at a very small rate (1 out of 500,000,000!)

-
H
OH-

H2O
How would you quantify (count) this ionic
disassociation?
The pH scale
pH
The power of Hydrogen scale
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ltH gtOH-
Stomach Acid, lemon juice
Increasingly Acidic ?
Vinegar, cola
Tomato juice
Black coffee Rainwater
Urine
H OH-
Pure water Human blood
Neutral
Seawater
Milk of magnesia
? Increasingly Basic
Household ammonia
gtH ltOH-
Household bleach
Oven cleaner
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Besides water, what elements and compounds are
essential to life?
Organic Compounds An Overview

• Organic compounds
• Mostly contain Carbon, Hydrogen, Oxygen,
  Nitrogen, Phosphorus and Sulfur

Carbon
C
C
C
C
C
C
For Homework Left Side IntNB Assignment
Write an Acrostic Poem for the six elements often
found in organic compounds
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Organic Compounds Carbohydrates
Can you believe that each of your cells contains
about 2 meters of me?
Hurry up, Lipids! You should have more energy
stored up than this!

• Organic compounds (continued)
• Four categories of organic compounds
• Carbohydrates
• Lipids
• Proteins
• Nucleic Acids
• All formed and separated in similar ways
• Formation (Polymerization) Dehydration Synthesis
• Separation Hydrolysis

Hi there! My name is Polly Peptide.
Hey Sugar, I sure am happy that youre a
Carbohydrate like me.
Awww, how sweet!
Does this bond structure make me look fat?
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Polymerization
Bonding Polymerization

• Polymerization (definition)
• Forming of large organic macromolecules by the
  joining of smaller repeating units called monomers

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Dehydration Synthesis
Bonding Polymerization Dehydration Synthesis

• Dehydration Synthesis is the removal of a water
  molecule to form a new bond.

1
2
3
HO
H
HO
H
Short Polymer
Monomer
H2O
Dehydration removes a water molecule forming a
new bond
1
2
3
4
H
HO
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Hydrolysis
Bonding Polymerization Hydrolysis

• Polymers are broken by adding water.
• Literally, Water Splitting

H2O
1
2
3
4
H
HO
Hydrolysis adds a water molecule to break a bond
1
2
3
H
HO
HO
H
Monomer
Short Polymer
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Carbon The element of life
Bonding Carbon

• Carbons Valence has ____ electrons
• Can bond with ____ elements
• Can form chains, rings, branches, isomers

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4
What biological impact do you think isomers have
on living systems?
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Thalidomide an optical isomer
Bonding The importance of chemical structure
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Bond energy
Bonding Bond Energy

• When bonds are made, energy (E) is stored.

• When bonds are broken, energy (E) is released for
  use.

Glucose A Monosaccharide
Fructose A Monosaccharide
Sucrose A Disaccharide
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Carbohydrates
Organic Compounds Carbohydrates

• Carbohydrates are
• an important energy (E) source
• Cellular structures
• Carbon, Hydrogen and Oxygen in a ratio of 121
• General Formula (CH2O)n

C
H2O
hydrate
Water hydrate
Carbon
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Carbohydrates
Organic Compounds Carbohydrates Monomers

• Monosaccharides (simple sugars)
• Contain 3-7 Carbons each
• Examples Glucose, Galactose, Fructose

Glucose
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Carbohydrates
Organic Compounds Carbohydrates Dimers

• Disaccharides (two sugars)
• Examples Sucrose, Maltose, Lactose
• Maltose Glucose Glucose
• Lactose Glucose Galactose

Sucrose
Glucose
Fructose
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Carbohydrates
Organic Compounds Carbohydrates Polymers

• Polysaccharides (many sugars)
• Examples Starch, Glycogen, Cellulose

Starch
Cellulose
Chloroplast
Starch
Liver Cell
Cellulose
Plant Cells
Glycogen
Plant Cells
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Lipids
Organic Compounds Lipids

• Lipids function in
• Energy (E) storage,
• forming cell membranes,
• and as chemical messengers (e.g., hormones)
• Nonpolar (hydrophobic)
• Made up mostly of Carbon and Hydrogen (with a few
  Oxygen)

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Lipids
Organic Compounds Lipids Fats

• Fats (Triglycerides)
• Glycerol 3 Fatty Acids
• Saturated No Double Bonds (solid)
• Unsaturated Double Bonds (liquid)

OH
Ester Bonds
OH
OH
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Lipids
Organic Compounds Lipids Phospholipids

• Phospholipids
• Glycerol with Phosphate Head 2 Fatty Acid
  Chains
• Amphiphilic (Both lover)
• Hydrophilic head
• Hydrophobic tail
• Forms 2 layers in water
• Makes up cell membranes

Phosphate
Glycerol
Fatty Acids
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Organic Compounds Lipids Sterols
Lipids

• Sterols
• Lipids whose Carbon Skeleton consists of 4 fused
  rings
• Includes
• Hormones
• Cholesterol
• Cortisol
• Makes up cell membranes

OH
O
OH
O
OH
HO
O
HO
O
Testosterone
Estrogen
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Proteins
Organic Compounds Proteins

• Made up of Carbon, Hydrogen, Oxygen and Nitrogen
  (and some Sulfur)
• Many functions represented through different
  types of proteins

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Proteins
Organic Compounds Proteins Functions
I am completely unchanged, and ready for some
more sucrose!
I am an enzyme. I am going to try to convert you.

• Enzymes Catalysts that speed up the rate of a
  chemical reaction
• Build up or break down substrate
• Fit together like a lock and a key
• Not used up in the reaction
• Work in a very specific biological range
• Usually end with -ase

Hi sweeties, Do you remember me?
I am the active site. The substrate binds to me.
I am a product, too. I am a fructose now.
I am now a product. I am a glucose now.
In addition to what you know. I am a substrate.
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Proteins
Organic Compounds Proteins Functions

• Structural Proteins
• Provides mechanical support to cells and tissues
• Transport Proteins
• Transports small ions or molecules
• Motor Proteins
• Enables structures to move

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Proteins
Organic Compounds Proteins Functions

• Hormones (signaling proteins)
• Carries signals from cell-to-cell
• e.g., insulin
• Storage
• Stores small molecules or ions
• e.g., iron is stored in the liver in ferritin
• Other specialized functions
• Defense (antibodies),
• Receptor proteins (in eyes and muscles to detect
  stimulus)

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Proteins
Organic Compounds Proteins Monomers

• Monomers Amino Acids
• Peptide Bond Bond between 2 Amino Acids
  Amino end (NH2) and the Carboxyl end (COOH)

Amino end
Carboxyl end
R Group
Side Chains
Backbone
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Proteins
Organic Compounds Proteins Monomers

• R Groups (Side chains)
• Differ in
• Size
• Charge
• Polarity
• There are 20 protein-building Amino Acids
• 9 Essential Amino Acids
• Cant be synthesized by the body, but are
  necessary for life

Hydrophilic Amino Acid
Hydrophobic Amino Acid
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Proteins
Organic Compounds Proteins Polymers
Poly
peptides

• Polymers Polypeptides
• Many Peptides
• Four Levels of Structure
• Primary (1)
• Secondary (2) H bonds
• Tertiary (3)
• Quaternary (4) several polypeptides
• These specific shapes allow proteins to function

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Organic Compounds Proteins Denaturation
Proteins

• Denaturation
• When the protein loses its shape, and becomes
  non-functional due to
• Changes in
• temperature
• pH
• salinity (salt concentration)
• alcohol concentration

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Nucleic Acids
Organic Compounds Nucleic Acids

• Nucleic Acids
• Informational Polymers Code for all of the
  proteins in an organism
• Monomers Nucleotides
• Phosphate Group
• 5-Carbon Sugar
• Nitrogenous base

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Nucleic Acids
Organic Compounds Nucleic Acids
Deoxyribo

• DNA (Deoxyribonucleic Acid)
• Backbone sugar Deoxyribose
• Four Bases
• Adenine (A)
• Guanine (G)
• Thymine (T)
• Cytosine (C)
• RNA (Ribonucleic Acid)
• Messenger RNA mRNA conveys the instructions to
  build proteins from the genetic information in
  DNA
• Differences from DNA
• Backbone sugar Ribose
• Uracil in place of Thymine

Thymine
Cytosine
Uracil
Adenine
Guanine
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Flow of Information
Organic Compounds Nucleic Acids and Proteins

• DNA
• RNA
• Protein