UNIT 4 CHARACTERISTICS OF LIFE

STUDY GUIDE FOR TEST

2-14-18 STARS-COCOCCIA/LAKE/PHILLIPS

2-15-18TRIPES - LEAMY/PHILLIPS

System issomething with two or more parts that interact.

A.A change in one part of the system will cause a change in the system overall.

B.Systems have boundaries (you can define what is part of the system and what is not)

Characteristics of Life are Organisms, which are things that show all of the characteristics of life such as:

1. OrganizationareLiving things are organized into specialized structures that carry out specific functions that help the organism function as a whole.

Ex: Muscles are organized into the muscular system which helps organisms move

Ex: Organelles like a cell wall protects plant cell, provides structure

A. Unicellular organisms = one cell (organelles are the structures that carry out each life function)

B. Multicellular organism = two or more cells working together

Generally, multicellular organisms have different TYPES of cells that do different jobs. They can be organized into more complex systems (tissues, organs, organ systems)

  1. Growth and Development

Growth:Both unicellular and multicellular organisms grow.

Ex:Unicellular - increase in size, Multicellular – increase the number of cells

Developmentoccurs as each living thing goes through its life cycle and matures

  1. Reproduction means that livings things must be able to create more living things.

A.This can happen in different ways:

  1. Sexual reproduction – requires a mate

2. Asexual reproduction – one parent (divides, etc.

  1. Response to Stimuli - Adjust and respond to changes in the environment

A.Internal Stimuli – changes within the organisms internal environment

Ex: Getting a fever when you are sick, feeling thirsty or hungry

B.External Stimuli – changes in the environment around an organism

Ex: Sweating when it’s hot, shivering when it’s cold, eyes dilating when its bright out

Ex: Plants grow towards sunlight, animals fluffing their fur when it’s cold

  1. Homeostasis- Maintaining stable internal conditions. Each organism has a certain set of requirements that have to remain relatively constant in order for them to be able to function

Ex: maintaining a certain body temperature, blood pressure, fluid levels, nutrient levels, oxygen levels, etc.

  1. Energy-Living things need to obtain (get) and use energy to carry out all of the other life needs. Living things obtain energy in different ways: producers, consumers, decomposers, etc.

Cell - is the smallest unit of life. It is made of small parts called organelles(little organs) which work together so the cell will function correctly

NOTE: Plant, animal, and bacteria cells are structured differently

Cell Membrane-controls what enters/leaves the cell and helps protect it from the outside environment

NOTE: All cells have a cell membrane

Cell Wall - surrounds plant cells, as well as some fungal and bacterial cells

It surrounds the cell membrane and serves as extra protection

In some plant and fungal cells, it also provides structure/support

Nucleus-The “brain” of the cell

Gives the other organelles instructions so that they can carry out their functions

Contains DNA (deoxyribonucleic acid), genetic material that determines how an organism looks and contains the “instructions for life”

Mitochondrion(plural = mitochondria)

Produces energy for the cell through the process of cellular respiration so the cell can carry out its functions

Cellular respiration is a chemical reaction where food is converted into energy

Chloroplast isfound in plant cells and some single celled organisms. It contains a green pigment called chlorophyll. It carries out photosynthesis, a chemical reaction where the cell uses sunlight to convert carbon dioxide and water into food called glucose (sugar)

Other Organelles:

Ribosome- manufacture proteins (each protein has a unique function)EndoplasmicReticulum - makes ribosomes and lipids (used in membranes and energy storage) and helps transport those materials around the cell

Golgi Apparatus – packages substances in the cell

Lysosome-break down and recycle cell components

Vacuole – store food, water, and waste; plant cells contain a giant one that stores water to give the cell support