The Necessities of Life

Book A-Chapter 1-Section 2

Discussion

What needs to humans have?

Do we have the same needs as animals?

Water The body is mostly made up of water Cells are 70% water Most chemical reactions having to do with metabolism require water Different organisms require different amounts of water

Example of different water intake:humans vs. camels

Humans can only survive for about 3 days without water Camels don’t drink water during the whole winter! During the

hottest part of the summer, they can go for a week without water!

Air Air is a mixture of gases Most organisms require oxygen and get it from

either air or water Green plants, algae, and some bacteria need

carbon dioxide gas in addition to oxygen These organisms produce food and oxygen by

using photosynthesis-or converting energy in sunlight to energy stored in food

A place to live

All living things need a place to live Some move around, and some stay in the same

place throughout the duration of their life Example: the Warbler

Food All living things need food

Food provides organisms with energy

Organisms use nutrients from food to replace cells and build body parts

Not all animals get food in the same way

Producers Some organisms, such as plants, are called producers PRODUCERS: make own food by using energy from its

surroundings Plants use energy from the sun to make food from water

and carbon dioxide

Consumers

CONSUMERS: organisms that eat other organisms or organic matter

Decomposers Some consumers are decomposers DECOMPOSERS are organisms that get their food by breaking down the

remains of dead organisms or animal wastes and consuming or absorbing the nutrients

Earthworms, fungi, termites, bacteria

Brainpop video

http://www.brainpop.com/science/populationsresourcesandenvironment/foodchains/zoom.weml

Nutrients All organisms eat to get nutrients Nutrients are made up of molecules A molecule is a substance when two or more atoms

combine Molecules of different kinds of atoms are compounds Molecules found in living things are usually made of

different combinations of six elements: carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.

These elements combine to form proteins, carbohydrates, lipids, ATP, and nucleic acid

Proteins

PROTEIN: a molecule that is made up of amino acids and that is needed to build and repair body structures and to regulate processes in the body

Animals break down proteins with amino acids

Proteins in Action

Some proteins have visible functions:

Proteins in Action (2) Other proteins are small and help cells do their

jobs Inside blood, the red protein, hemoglobin, bind to

oxygen to deliver and release oxygen throughout the body

Some proteins protect cells Other proteins, called enzymes start or speed up

chemical reactions

Carbohydrates

CARBOHYDRATES: a class of energy-giving nutrients that includes sugars, starches, and fiber; contains carbon, hydrogen, and oxygen

There are two kinds of carbohydrates: simple and complex

Simple Carbohydrates

Made up of one sugar molecule or a few sugar molecules linked together

Table sugar and sugar in fruits are examples

Complex Carbohydrates

When an organism has more sugar than it needs, its extra sugar may be stored as complex carbohydrates

Complex carbohydrates are made of hundreds of sugar molecules linked together

Brainpop video

http://www.brainpop.com/health/personalhealth/carbohydrates/

Lipids

LIPIDS: a type of biochemical that does not dissolve in water; fats and steroids are lipids

Some lipids store energy

Other lipids form cell membranes

Phospholipids

All cells are surrounded by a membrane Membrane helps protect the cell from the outside

environment PHOSPOLIPIDS:a lipid that contains phosphorus

and that is a structural component in cell membranes

Fats and Oils Fats and Oils are lipids that store energy When an organism has burned through its

carbohydrates, it can get energy from these lipids The structure of fats and oils are almost the same,

but at room temperature, most fats are solid, and most oils are liquid

Most of the lipids stored in plants are oils Most of the lipids stored in animals are fats

ATP ATP=adenosine triphosphate ATP-the major energy carrying molecule in the cell The energy in carbs and lipids must be transferred to ATP

which provides fuel for cellular activity

Nucleic Acids Sometimes called the “blueprints” of life because they

have all the information needed for a cell to make proteins NUCLEIC ACID-a molecule made up of subunits called

nucleotides DNA is a nucleic acid that provides information on how to

make a DNA The order of nucleotides tells the cell the order of the

amino acids that are linked together to make that protein