Homeostasis+3A_Biomolecules

Wiki definition: Homeostasis refers to a system regulating its internal environment to maintain a stable, constant condition.

__Homeostasis (keywords):__
 * Living system
 * Change & balance (or equilibrium)

__Homeostasis examples:__
 * Osmosis
 * Active and passive transport
 * Diffusion

CELL STRUCTURES LIKE THE CELL MEMBRANE AID IN HOMEOSTASIS

**ENERGY, MATTER & ORGANISATION -** BIOMOLECULES //** Living systems are complex and highly organized, and they require matter and energy to maintain this organization. **//
 * **Energy** is stored in the organization of matter:

Note: Energy cannot be created or destroyed (not lost - along the food chain, energy is lost through heat and excretion). When ATP is generated from glucose, it is conversion of energy from one form to another, not creation (from nothing to something).


 * Living organisms use matter and energy to build and maintain body structures: Energy is required to generate new cells (new exoskeleton) and moult.

We eat to get energy from our food. The mitochondria in our cells are like the power houses of the cell and they produce energy in the form of ATP for us humans to use.(process)
 * Living organisms obtain and process matter and energy:

For example, phospholipids have hydrophobic as well as hydrophilic ends and therefore, the characteristics are able to dictate their functions. This shows that the phospholipids molecules have heads and tails which dictate its function(which forms the selectively permeable membrane.)
 * The structure of a molecule always dictates its function:
 * The structure and function of biological living systems obeys the laws of thermodynamics:


 * Communities of organisms depend on the cycling of matter and the flow of energy:


 * The constant flow of energy and cycling of matter in the biosphere leads to a balanced or steady state: Energy flow through a system, not a cycle.

In order for us to understand this better, we will start by looking at biomolecules. The questions we ask about ourselves and the world around us:

Important: What are they made up of? What is its strcture
 * 1) Are we just chemicals?
 * 2) Are we what we eat?
 * 3) Why is the carbon molecule suitable for life as we know it: It has 4 free valence electrons that allow it to bond to 4 atoms, which include itself. By bonding with itself, it is able to form a long chain consisting of both double and single covalent bonds - "carbon chain of backbone". One of the few elements that can form a long chain.
 * 4) Why is the chemistry of water suitable for life: Limitless: water exists in 3 states, properties of water, special properties of water in solid state: solid floats unlike other solids which sink given they are supposedly supposed to have a higher density.

In this unit you will need to know:
 * Understand and describe the properties of some important biological molecules; understand their roles, recall, recognize and identify the general formulae and structure of these molecules.
 * **Water**: understand its dipolar nature; understand formation of hydrogen bonds; understand the importance of water as a solvent; understand other roles of water related to its high latent heat of vapourisation, specific heat capacity, density and surface tension.
 * **Lipids**: understand the general nature of lipids as fats, oils and waxes; describe the roles of lipids as energy stores, and, in protection, waterproofing, insulation and buoyancy.
 * **Proteins**: understand the nature of amino acids as monomers in the formation of polypeptides and proteins; understand the meaning of the terms primary, secondary, tertiary and quaternary structure and their importance in the structure of enzymes; understand that condensation and hydrolysis reactions are involved in the synthesis of proteins; understand the nature and roles of fibrous and globular proteins as illustrated by collagen and (insulin?) hemoglobin.
 * **Carbohydrates**: understand that pentose and hexose’s are monosaccharide and have roles as monomers; understand that disaccharides and polysaccharides are composed of monomers joined by glycosidic bonds.; understand that condensation and hydrolysis reactions are involved in the synthesis and degradation of disaccharides and polysaccharides. Recall the structure and roles of basic carbohydrates.
 * **Vitamins and minerals**: understand their role and the effects of deficiency
 * **Enzymes**: understand the structure of enzymes as globular proteins, and the concept of active site and specifity; understand that enzymes are catalysts which reduce activation energy; understand how enzyme activity is affected by temperature, pH, substrate and enzyme concentrations; understand active site-directed and non-active site-directed inhibition of enzyme action; have an appreciation of the commercial uses of enzymes as illustrated by pectinases in food modification and proteases in biological detergents; discuss the advantages of immobalisation of commercial enzymes, as illustrated by lactase;