Biochemistry of Cells

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They are variants of testosterone

Some athletes use them to build up their muscles quickly

They can pose serious health risks

Slide 49

Proteins

Proteins are polymers made of monomers called amino acids

All proteins are made of 20 different amino acids linked in different orders

Proteins are used to build cells, act as hormones & enzymes, and do much of the work in a cell

Slide 50

Four Types of Proteins

Structural

Contractile

Storage

Transport

Slide 51

20 Amino Acid Monomers

Slide 52

Structure of Amino Acids

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

Amino group –NH2

Carboxyl group -COOH

Hydrogen -H

Side group -R

Amino

group

Carboxyl

group

R group

Side groups

Leucine -hydrophobic

Serine-hydrophillic

Slide 53

Linking Amino Acids

Cells link amino acids together to make proteins

The process is called condensation or dehydration

Peptide bonds form to hold the amino acids together

Carboxyl

Amino

Side Group

Dehydration Synthesis

Peptide Bond

Slide 54

Proteins as Enzymes

Many proteins act as biological catalysts or enzymes

Thousands of different enzymes exist in the body

Enzymes control the rate of chemical reactions by weakening bonds, thus lowering the amount of activation energy needed for the reaction

Slide 55

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.

Slide 56

Enzyme + Substrate = Product

Slide 57

How the Enzyme Works

Enzymes are reusable!!!

Active site changes SHAPE

Called INDUCED FIT

Slide 58

Primary Protein Structure

The primary structure is the specific sequence of amino acids in a protein

Called polypeptide

Amino Acid

Slide 59

Protein Structures