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Transcript of You are sitting by a lake, you drop a leaf on the lake and notice that it floats on the top of the
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.
QUESTION 1
The formation of large, repetitive organic molecules from small monomers is a __________ reaction.
A) dehydration synthesis B) reduction C) dehydrogenation D) hydrolysis
QUESTION 2
Carbon is such an important molecule for life because:
A)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.
QUESTION 3
Glycogen is a polysaccharide used for energy storage by:
A)moneraB)fungiC)plantsD)animals
QUESTION 4
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
Proteins and Nucleic Acids
KEY WORDS:ProteinPolypeptideAmino AcidEssential Amino AcidDenature1°, 2°, 3°, 4° StructureNucleic AcidNucleotideDNARNA
Types of Proteins
Structural
Enzymes
Hormones
Antibodies
Contractile
Receptor
Transport
Storage
See Table 5.1
ProteinsSubunit = amino acid
1. Amino group 3. Carboxyl group2. R group
Amino acids have three parts:
The 20 amino acids of proteins: nonpolar
The 20 amino acids of proteins: polar and electrically charged
Linking Amino AcidsDehydration synthesis: forms a covalent bond – A Peptide Bond
Creates a polypeptide
Making a polypeptide chain
How are proteins able to do so many things?
20 different kinds amino acids - different R-groups
Non-polar Polar Charged
O-
Carbohydrates: Glucose
Hard to make more than one word
Scrabble Analogy
Proteins: 20 amino acids
• Glutamine
• Isoleucine
• Asparagine
• Serine
• Threonine
• Lysine
• Arginine
G1
G1
G1
G1
G1
G1
G1
G1
G1
G1
G1
G1
E1
E1
I1I1
N1
N1
S1
S1
T1
T1
K5
K5
R1
R1
Proteins Fold into Active ShapeProtein function depends on shape
Four Levels of Structure:
Primary 1°Secondary 2°Tertiary 3°Quaternary 4°
Primary (1°) StructureSequence of amino acids in polypeptide
The primary structure of a protein
Secondary (2°) StructureFolds in part of amino acid chain: Hydrogen
bonds
- pleated sheet -helix
Tertiary (3°) Structure3D Packing of Polypeptides: More hydrogen
bonds
Examples of interactions contributing to the tertiary structure of a protein
Interactions between 2+ polypeptides
Quaternary (4°) Structure
The quaternary structure of proteins
Review: the four levels of protein structure
Conformation of a protein, the enzyme lysozyme
A chaperonin in action
•Proteins can be unfolded = denatured•Can affect the behavior of the protein
Denatured Proteins
pH
Heat
Chemicals
What can cause proteins to denature?
Shape is critical for protein interactions
EXAMPLE:
Hemoglobin•4 Polypeptides•Binds Iron•Oxygen transport
Protein Folding and DiseaseMany diseases caused by incorrect protein
folding
Mad Cow DiseaseAlzheimersCystic FibrosisParkinson’s DiseaseSickle Cell AnemiaArthritisMarfan SyndromeALS (Lou Gehrig’s Disease)CancerDiabetes Insipidus
A single amino acid substitution in a protein causes sickle-cell disease
Sickled cells
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
Essential Amino Acids
Which of the following is contains all 8
essential amino acids?
1. Wheat2. Soy beans 3. Brown rice4. Corn5. None of these
QUESTION
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
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:
a)Is made of nucleic acidsb)Is made of only one polypeptide chainc)Lacks hydrogen bondsd)Is not helical or pleatede)Is a fiber
• Nucleic acids include RNA and DNA
• Polymers made up of repeating monomers called nucleotides.
NUCLEIC ACIDS
James Watson and Francis Crick
Rosalind Franklin
X-ray crystallography
• 5-Carbon Sugar (Pentose): RNA ribose, DNA deoxyribose
• Phosphate Group
• Nitrogen-containing base
NUCLEOTIDES3 Main Components:
Nucleotides: Important Energy Storage Molecules
• Adenosine Triphosphate (ATP): acts like cell’s battery, providing energy for most activities.
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
Nucleic Acid Synthesis
• Nucleotides joined by dehydration synthesis
• Covalent bond forms between PHOSPHATE GROUP and SUGAR
Structure of DNA
The components of nucleic acids
The DNA double helix and its replication
Polypeptide Sequence as Evidence for Evolutionary Relationships
Nucleotides are to ____ as ____ are to proteins.
• Nucleic acids; amino acids• Amino acids; polypeptides• Glycosidic linkages; polypeptide
linkages• Genes; enzymes• Polymers; polypeptides
The structural level of a protein least affected by a disruption in hydrogen bonding is
• Primary• Secondary• Tertiary• Quaternary• All equally affected
Which of the following is not a protein?
• Hemoglobin• cholesterol• An antibody• An enzyme• Insulin