Biology

Proteins and Enzymes

Unit 3, Notes #3

Review

• Organic Compound contain __________

• Examples: carbohydrates, lipids, proteins

Carbon!

Review- Carbs• Carbohydrates are sugars (immediate NRG)

– C:H:O is 1:2:1– Building blocks = monosacharides

• Single saccharride molecules• Glucose, fructose, ribose, etc

– Disaccharides – 2 monos combined• Sucrose (table sugar), lactose (in milk)

– Block Tower = polysaccarhides• Starch (created by plants), cellulose, • Glycogen – made by muscles and liver from cellulose

Review - Lipids• Lipids (Fats)

• Monomer: Fatty Acid

• Polymer: Lipid

• Structure: Fatty Acids

• bonded to compounds

• such as glycerol

• (carbon, hydrogen and oxygen!)

• Most Common lipids: Fats,

• Oils, Cholesterol, Waxes

Glycerol molecule

Review - Lipids• Fats and Oils = long term energy storage

• Carbs can be turned into lipids to be stored as energy for much later use

• Overall, they yield less energy than carbs• Saturated – animal fats, all single C-C bonds• Unsaturated – plants, at least one double C=C bond

– Waxes – repel water (plants and animals can produce this)

– Phospholipids – cell membranes– Cholesterol – too much is BAD

Proteins

Protein Basics

• Used in variety of cellular functions

• Made of smaller amino acids– Monomer: Amino acid

– Polymer: Protein, held together by peptide bonds

• Only 20 amino acids… but thousands of proteins– Exact arrangement of amino acids determines the protein

leucine valine glycine alanine leucine leucinehisti-dine

aspara-gine

serine proline = protein A

leucinevaline glycine alanine leucine leucinehisti-dine

aspara-gine

serine proline = protein B

leucine valine glycine alanine leucine leucine = protein C

Amino acid (monomer)

Amino Acid Structure

• 5 basic parts

1) Central C atom

2) Amino group (NH2)

3) H

4) Carboxyl group (COOH)

5) R group

Only 20 amino acids…

Each has different R group

..

What differs between these 6 amino acids?

Each “R” group is different

Proteins

• C, H, O, N, Sulfur and Phosphorous• “building blocks” of organisms• Functions of proteins:

– Movement- Muscle fibers – Structure- cartilage, bones, tendons– Regulation-control chemical reactions– Transport- hemoglobin carries O2 – Defense – antibodies are proteins that fight off

bacteria and viruses

Review1) What are the smaller monomers that make proteins

called?

2) How many different amino acids exist?

3) How does each amino acid differ?

4) The NH2 part of the amino acid is called the ____ group.

5) The COOH part of the amino acid is called the ____ group.

Chemical Reactions

• Change substances into different ones by breaking and forming chemical bonds– Reactants are the substances changed during a

chemical reaction.– Products are the substances made by a chemical

reaction

ProductsReactants

Type of Protein - enzyme

• Enzyme:

– Increases the speed of specific chemical reactions so they happen faster! Does this by lowering the energy it takes for the rxn to happen

• Breaking down food

• Build needed molecules

• “catalyst” – something that speeds up a reaction

• They can work inside cells and outside cells

• Sensitive to pH and temperature

– ex: If high fever: enzymes lose ability to work

– Ex. Cooking “denatures” enzymes

• Reusable

• Helps to maintain homeostasis

Type of Protein - enzyme

• Vocab:• Catalyst – anything that speeds up a rxn• Enzyme – proteins that lower the energy it

takes for a chemical rxn to happen• Substrate – compounds put together

(synthesized) OR broken down by enzymes• Coenzyme – a 2nd enzyme needed to help

do the job

Another Enzyme Structure

Review1. Given the following chemical formula list the products

and reactants: 6O2 + C6H12O6 6CO2 + 6H2O

2. Which group of proteins help to start chemical reactions?

3. What are the molecules called that react with enzymes?

4. What are the substances that are changed during a chemical reaction called?

5. What is another term for a catalyst?

6. What can cause an enzyme to stop functioning?

7. What do enzymes weaken between molecules?