Proteins Chapter 3 pages 54-58

1
QUESTION 1
You are sitting by a lake, you drop a leaf on
the lake and notice that it floats on the top of
the water, which of the following properties of
water could help explain what you observe? A)
It is more dense when liquid than when frozen.
B) It can dissolve large quantities of solutes.
C) It has a high specific heat. D) It has a
strong surface tension. E) None of these can
explain what you observe.
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QUESTION 2
The formation of large, repetitive organic
molecules from small monomers is a __________
reaction. A) dehydration synthesis B)
reduction C) dehydrogenation D) hydrolysis
3
QUESTION 3

• Carbon is such an important molecule for life
  because
• it can form chemical bonds with a maximum of
  four other atoms.
• B) it is part of the water molecule.
• C) it can hydrogen bond to so many molecules.
• D) it can be bonded ionically.
• E) it can form isomers.

4
QUESTION 4

• Glycogen is a polysaccharide used for energy
  storage by
• monera
• fungi
• plants
• animals

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QUESTION 5

Which of the following solutions has the greatest
concentration of hydrogen ions (H)? A) gastric
juice at pH 2 B) black coffee at pH 5 C)
vinegar at pH 3 D) tomato juice at pH 4 E)
household bleach at pH 12
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Proteins and Nucleic Acids
KEY WORDSProtein Polypeptide Amino
Acid Essential Amino Acid Denature 1, 2, 3, 4
Structure Nucleic Acid Nucleotide DNA RNA
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Types of Proteins
See Table 5.1
Structural
Storage
Enzymes
Hormones
Transport
Antibodies
Receptor
Contractile
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Proteins
Subunit amino acid
Amino acids have three parts
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The 20 amino acids of proteins nonpolar
10
The 20 amino acids of proteins polar and
electrically charged
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Linking Amino Acids
Dehydration synthesis forms a covalent bond A
Peptide Bond
Creates a polypeptide
12
Making a polypeptide chain
13
How are proteins able to do so many things?
20 different kinds amino acids - different
R-groups
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Scrabble Analogy

• Carbohydrates Glucose
• Hard to make more than one word

• Proteins 20 amino acids
• Glutamine
• Isoleucine
• Asparagine
• Serine
• Threonine
• Lysine
• Arginine

E1
G1
G1
G1
I1
G1
G1
G1
N1
S1
T1
K5
R1
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Proteins Fold into Active Shape
Protein function depends on shape
Four Levels of Structure Primary 1 Secondary 2
Tertiary 3 Quaternary 4
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Primary (1) Structure
Sequence of amino acids in polypeptide
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The primary structure of a protein
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Secondary (2) Structure
Folds in part of amino acid chain Hydrogen bonds
b- pleated sheet
a-helix
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Tertiary (3) Structure
3D Packing of Polypeptides More hydrogen bonds
20
Examples of interactions contributing to the
tertiary structure of a protein
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Quaternary (4) Structure
Interactions between 2 polypeptides
22
The quaternary structure of proteins
23
Review the four levels of protein structure
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Conformation of a protein, the enzyme lysozyme
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A chaperonin in action
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Denatured Proteins

• Proteins can be unfolded denatured
• Can affect the behavior of the protein

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What can cause proteins to denature?
Chemicals
pH
Heat
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Shape is critical for protein interactions

• EXAMPLE
• Hemoglobin
• 4 Polypeptides
• Binds Iron
• Oxygen transport

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Protein Folding and Disease
Many diseases caused by incorrect protein folding
Mad Cow Disease Alzheimers Cystic
Fibrosis Parkinsons Disease Sickle Cell
Anemia Arthritis Marfan Syndrome ALS (Lou
Gehrigs Disease) Cancer Diabetes Insipidus
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A single amino acid substitution in a protein
causes sickle-cell disease
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Sickled cells
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Diet Essential Amino Acids

• 20 different amino acids
• All living things have protein
• 8 Essential Amino Acids can not be synthesized by
  our bodies - must be found in diet
• All 8 essential amino acids are present in animal
  protein and soy beans

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Essential Amino Acids
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QUESTION

• Which of the following is contains all 8
• essential amino acids?
• Wheat
• Soy beans
• Brown rice
• Corn
• None of these

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Lipoproteins Glycoproteins
LIPOPROTEINS-Lipid Protein -Used for transport
of fats throughout the body -Example HDL and LDL
Cholesterol GLYCOPROTEINS -Carbohydrate
Protein -Receptors on the surface of cells
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QUESTION

• The myoglobin protein, which carries oxygen in
  muscle cells, only has the first three levels of
  protein structure (it lacks a quaternary level).
  From this you can conclude that myglobin
• Is made of nucleic acids
• Is made of only one polypeptide chain
• Lacks hydrogen bonds
• Is not helical or pleated
• Is a fiber

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NUCLEIC ACIDS

• Nucleic acids include RNA and DNA
• Polymers made up of repeating monomers called
  nucleotides.

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James Watson and Francis Crick
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Rosalind Franklin
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X-ray crystallography
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NUCLEOTIDES
3 Main Components

• 5-Carbon Sugar (Pentose)
• RNA ribose,
• DNA deoxyribose
• Phosphate Group
• Nitrogen-containing base

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Nucleotides Important Energy Storage Molecules

• Adenosine Triphosphate (ATP) acts like cells
  battery, providing energy for most activities.

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RNA and DNA

• SIMILARITIES
• 5-carbon sugar
• Phosphate group
• DIFFERENCES
• Nucleotides
• DNA Adenine, Guanine, Cytosine, Thymine
• RNA Adenine, Guanine, Cytosine, Uracil
• Sugar
• DNA Deoxyribose
• RNA Ribose

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Nucleic Acid Synthesis

• Nucleotides joined by dehydration synthesis
• Covalent bond forms between PHOSPHATE GROUP and
  SUGAR

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Structure of DNA
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The components of nucleic acids
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The DNA double helix and its replication
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(No Transcript)
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Polypeptide Sequence as Evidence for Evolutionary
Relationships
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Nucleotides are to ____ as ____ are to proteins.

• Nucleic acids amino acids
• Amino acids polypeptides
• Glycosidic linkages polypeptide linkages
• Genes enzymes
• Polymers polypeptides

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The structural level of a protein least affected
by a disruption in hydrogen bonding is

• Primary
• Secondary
• Tertiary
• Quaternary
• All equally affected

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Which of the following is not a protein?

• Hemoglobin
• cholesterol
• An antibody
• An enzyme
• Insulin