1 Proteins & Enzymes Ms. Dunlap. DO NOW! 5 MIN SILENTLY! 1. What are the 4 Macromolecules? 2. Enzymes are a part of which macromolecules? 3. What do you.

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Proteins & Enzymes

Ms. Dunlap

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DO NOW! 5 MIN SILENTLY!1.What are the 4 Macromolecules?

2.Enzymes are a part of which macromolecules?

3.What do you know about Enzymes?

Copyright Cmassengale

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Carbon-based MoleculesAlthough a cell is mostly water, the rest of the cell consists mostly of carbon-based moleculesOrganic chemistry is the study of carbon compounds


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Carbon is a Versatile AtomIt has four electrons in an outer shell that holds eight

Carbon can share its electrons with other atoms to form up to four covalent bonds


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Giant Molecules - PolymersLarge molecules are called polymersPolymers are built from smaller molecules called monomersBiologists call them macromolecules


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Examples of PolymersProteins

Lipids

CarbohydratesNucleic

Acids


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Four Types of Proteins

Structural

Contractile

Storage

TransportCopyright Cmassengale

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20 Amino Acid Monomers


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Structure of Amino Acids

Amino acids have a central carbon with 4 things boded to it:Amino group –NH2

Carboxyl group -COOH

Hydrogen -HSide group -R

Amino

group

Carboxylgroup

R group

Side groups

Leucine -hydrophobic

Serine-hydrophillic


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Linking Amino AcidsCells link amino acids together to make proteinsThe process is called condensation or dehydrationPeptide bonds form to hold the amino acids together

Carboxyl

Amino Side

Group

Dehydration Synthesis

Peptide BondCopyright Cmassengale

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Proteins as EnzymesMany proteins act as biological

catalysts or enzymesThousands of different enzymes exist in the bodyEnzymes control the rate of chemical reactions by weakening bonds, thus lowering the amount of activation energy needed for the reaction


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Enzymes

Their folded conformation creates an area known as the active site.

Enzymes are globular proteins.

The nature and arrangement of amino acids in the active site make it specific for only one type of substrate.


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Enzyme + Substrate = Product


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How the Enzyme Works

Enzymes are reusable!!!Active site changes SHAPECalled INDUCED FIT


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Primary Protein StructureThe primary structure is the specific sequence of amino acids in a proteinCalled polypeptide

Amino Acid


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Protein Structures

Secondary protein structures occur when protein chains coil or foldWhen protein chains called

polypeptides join together, the tertiary structure forms because R groups interact with each otherIn the watery environment of a cell, proteins become globular in their quaternary structure


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Protein Structures or CONFORMATIONS

Hydrogen bond

Pleated sheet

Amino acid

(a) Primary structure

Hydrogen bond

Alpha helix

(b) Secondary structure

Polypeptide(single subunit)

(c) Tertiary structure

(d) Quaternary structure


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Denaturating ProteinsChanges in temperature & pH can denature (unfold) a protein so it

no longer worksCooking denatures protein in eggs

Milk protein separates into curds & whey when it denatures


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Take 5 min…

• If the enzyme LACTASE breaks down the sugar LACTOSE please write down what enzyme breaks down SUCROSE? What sugars are sucrose broken down too? What sugars are Lactose broken down too?


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Changing Amino Acid Sequence

Substitution of one amino acid for another in hemoglobin causes

sickle-cell disease

(a) Normal red blood cell Normal hemoglobin

1 2 34 5

6 7. . . 146

(b) Sickled red blood cell Sickle-cell hemoglobin

2 314 5

6 7. . . 146


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Other Important Proteins

•Blood sugar level is controlled by a protein called insulin

•Insulin causes the liver to uptake and store excess sugar as Glycogen

•The cell membrane also contains proteins

•Receptor proteins help cells recognize other cells


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INSULIN

Cell membrane with proteins & phospholipids


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• Get into groups of 2,3, or 4. There should be no more than 9 groups. Use the small dry erase boards to answer the following questions. Every group has to answer. Raise up your board so I can see you answers. Be Quick...other groups might steal your choices. You have 30 seconds to answer. GO!!!!!


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1.Where can we find structural proteins?

Answer: Hair


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2. The Specific sequence of amino acids in a protein can be found in which structure?

Answer: Primary Structure


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3. These two changes can denature proteins

Answer: Temperature and Ph


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4. Cells Linking Amino Acids to make proteins are called ______ or _______

Answer: Condensation or Dehydration


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5. What enzyme breaks down sucrose?

Answer: Sucrase


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End


1 Proteins & Enzymes Ms. Dunlap. DO NOW! 5 MIN SILENTLY! 1. What are the 4 Macromolecules? 2. Enzymes are a part of which macromolecules? 3. What do you.

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