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:

Figure 5.15 The 20 amino acids of proteins: nonpolar

Figure 5.15 The 20 amino acids of proteins: polar and electrically charged

Linking Amino AcidsDehydration synthesis: forms a covalent bond – A Peptide Bond

Creates a polypeptide

Figure 5.16 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

Figure 5.18 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

Figure 5.22 Examples of interactions contributing to the tertiary structure of a protein

Interactions between 2+ polypeptides

Quaternary (4°) Structure

Figure 5.23 The quaternary structure of proteins

Figure 5.24 Review: the four levels of protein structure

Figure 5.17 Conformation of a protein, the enzyme lysozyme

Figure 5.26 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

Figure 5.19 A single amino acid substitution in a protein causes sickle-cell disease

Figure 5.19x 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

Dietary Protein Consumption

Recommended Daily Allowances

Adult ManAdult Woman

(0.9g/kg)(0.8g/kg)

pounds/2.2 = kgTypical American Diet

Adult ManAdult Woman

92 g/ day60 g/ day

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

Figure 5.x3 James Watson and Francis Crick

Figure 5.x4 Rosalind Franklin

Figure 5.27 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

Figure 5.29 The components of nucleic acids

Figure 5.30 The DNA double helix and its replication

Figure 5.28 DNA RNA protein: a diagrammatic overview of information flow in a cell

Table 5.2 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