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Lesson 2.2 – The Simple Bare
Necessities of Life
ALL ORGANISMS HAVE THE SAME
BASIC NEEDS
1. FOOD
2. WATER
3. AIR
4. LIVING SPACE
1. FOOD
All Living Things Need Food
Food provides organisms with the energy
and raw materials needed to carry out life
processes and to build and repair cells
and body parts.
Not all organisms get food in the same
way
FOOD
PRODUCERS: organisms that can
produce their own food.
CONSUMERS: organisms that must eat
(consume) other organisms to get food.
DECOMPOSERS: organisms that get
their food by breading down the nutrients
in dead organisms or animal wastes.
2. WATER
Your body is made mostly of water.
Your cells and the cells of almost all living
organisms are approximately 70% water.
Most of the Chemical Reactions involved
in metabolism require water.
A person could survive for only about 3
days without water.
You obtain water from the fluids you drink
and the food you eat.
3. AIR
 Air is a mixture of several different gases
Including: Oxygen and Carbon Dioxide
4. A PLACE TO LIVE
 All organisms must have somewhere to live that
contains all of the things they need to survive.
 Amount of space on Earth is limited
Organisms often compete with each other for
food, water and other necessities.
PROTEINS
Almost All
Life process of a cell involve proteins
Proteins are large molecules that are
made up of smaller molecules called
Amino Acids
Organisms break down proteins in food to
supply their cells with amino acids.
The amino acids then link up to form new
proteins
CARBOHYDRATES
Molecules made up of sugars are called
carbohydrates.
Cells use carbs as a source of energy
Simple carbs – made of one or a few
sugar molecules
Complex carbs – made of hundreds of
sugar molecules linked together
Plants store extra sugar as starch
LIPIDS
Lipids – compounds that can not mix with
water.
Phospholipids - type of lipid that makes
up most of the cell membrane
Fats & Oils – types of lipids that store
energy.
When an organism has used up most of its
carbs, it can get energy from these lipids
Fats – solid at room temperature
Oils – liquid at room temterature