BIOLOGICAL MOLECULES

Water and Proteins

Jorge Melo

Recap

How does the water goes up?

Transpiration pull (negative pressure)

Root pressure (positive pressure)

Capillarity (small plants)

2 important factors of the water: Cohesion: H2O molecules

tend to stick together Adhesion: H2O molecules

tend to stick to the inside of the xylem

xerophytes

Leaves Small to reduce the surface area Thick to reduce surface area

xerophytes Sunken Stomata

xerophyte

Thick waxy cuticles

reduce water loss through the epidermis

What am I?

My relative molecular mass is 18g/mol.

There is 1.26 million trillion tons of me on earth.

I can be found as a solid, liquid, or gas.

I make up 70% of human body.

Two hydrogen and one oxygen.

Aim: To explore the structures and functions of different macromolecules

Objectives by the end of this lesson SSBAT:

List the properties of water that make it essential to life.

Explain how the atomic structure of water affects its biological interactions.

Describe the properties of proteins and its structures

Aims and objectives

Biomolecules group task

Carbohydrates Functions

Proteins Importance

Lipids Sources

Introduction Human body

Many different types of molecules

Such as:

Biomolecules

Water

The most common is water

Water

Water structure 2 H atoms 1 O atom covalent bonds O (δ-) H (δ+) hydrogen bonds

Ice Vapour Liquid

Water Properties

High specific heat capacity. Temperature Kinetic energy 4.1 KJ/°C

High latent heat.

Water Properties

High density.

Surface tension and cohesion.

Water as a solvent Water can carry a wide range of

substances in solution.

Proteins

Enzymes

Amino acids

Genetic code

Structural/mechanical functions

Meat, dairy products, soya, fish, beans, eggs

Proteins also form some of the entrances and exits through the cell.

Proteins

4 elements C H O N

Basic unit: amino acid

Proteins

Amino group- NH2

R group

Carboxyl group -COOH

Condensation reaction

Proteins

Polypeptide chain

Condensation reaction

Loss of 2 H atoms

And loss of 1 O

Ribosome

Hydrolysis reaction

Recap

Hydrolysis

Condensation

Primary structure

Amino acid

Polypeptide chain

Primary structure

20 different AA

Polypeptide may contain hundreds

A change in one makes it a different protein

Secondary structure

Secondary structure

Secondary structure

Polypeptide chains do not lie in straight

Some parts of the chain may Coil into a regular pattern calledα-Helix

Hydrogen bonds

Tertiary structure

Disulphide bonds

Ionic bonds

Intermolecular interactions

Hydrophobic bonds

Quaternary

Heamoglobin

Globular protein

Fibrous protein

Colagen

Collagen

Fibrous Vs Globular

Fibrous proteins Globular proteins

Stable structure Relative unstable structure

Insoluble in water Soluble in water

Strength gives structural structures

Metabolic functions

Polypeptide chains from long strands

Polypeptide chains “roll up” into spherical shape

E.g. Collagen in bone and keratin in hair

E.g. all enzymes , antibodies, some hormones (e.g. insulin), heamoglobin

Review

1. Which of the following suspects is a protein component?

2. List some foods that provide proteins?

3. How does my body use proteins?

Task1

Aim: To explore the structures and functions of different macromolecules

Objectives by the end of this lesson SSBAT:

List the properties of water that make it essential to life.

Explain how the atomic structure of water affects its biological interactions.

Describe the properties of proteins and its structures

Aims and objectives