1. INTRODUCTION TO BIOLOGY

2. INTRODUCTION TO BIOLOGY
A. What is Biology?
Biology means the study of life.
Biology is the science that seeks to understand the living world.
Bio = Life ology =Study of

3. Characteristics of Life-
1. Living things are made of Cells.
A cell is the smallest working unit of life.
Living organisms are grouped by the number of cells:
* Unicellular – single-celled organisms; ex. Bacteria, amoebas
* Multicellular – organisms made up of more than one cell; ex. Humans, frogs, fish, insects, plants

4. Characteristics of Life
Cells 
Tissue 
Organ 
Organ system 
Organism
Characteristics of Life
2. Living things Displays Organization
A cell is a collection of organized structures that carries on life functions
All living structures are composed of atoms and molecules.
In multicellular organisms
Specialized cells are organized into groups that work together called tissues.
Tissues are organized into organs,
Organ systems work together to support an organism

5. Characteristics of Life
3. Living things Grow & Develop
Growth- all living things grow at least part of their lives, single-celled organism simple increase in size
Development- describes physical changes that take place during the lifetime of an organism

6. Characteristics of Life
4. Living things Reproduce
Not essential for individual organisms, but essential for the species
Species- group of organisms that can breed with one another and produce fertile offspring
Two ways:
Asexual- new organism has a single parent; example- single-celled organism splits in half NO EXCHANGE OF GENETIC MATERIAL
Sexual- two cells ( egg & sperm) from different parents unit to form an embryo There IS AN EXCHANGE OF GENETIC MATERIAL

7. Characteristics of Life
5. Living things Respond to Stimuli
External stimulus- includes all things that are OUTSIDE the organism. Ex: temperature, light
Internal stimulus- all things that are INSIDE the organism. Ex: hunger, thirst

8. Characteristics of Life
6. Living things Require Energy
two main ways to obtain energy
Photosynthesis- energy from the sun. Plants, some bacteria & protist use this process
Consumer- energy from the food they eat. Us, other animals & fungi
All organisms use energy for metabolism- chemical reactions which builds up or breaks down materials as it carries out its life processes.

9. Characteristics of Life
7. Living things Maintain Homeostasis
process by which organisms maintain a relatively stable internal environment

10. Characteristics of Life
8. Adaptations Evolve over time
Adaptations are inherited changes that occur over time that help the species survive and pass their genes to their offspring.

11. REMEMBER:
Cells
Homeostasis
Adaptation/evolution
Reproduction
Metabolism
I-stimuli
N-Organization
Growth & Development

12. Which of these best describes an organism’s ability to maintain the constant internal conditions necessary for life?
Homeostasis
Stability
Reproduction
Adaptation

13. Which two characteristics of life are important to the species but NOT to the individual
Evolution & Growth and development
Evolution & Reproduction
Reproduction & Respond to the environment
Respond to the environment & Growth and development

14. chemical reactions which builds up or breaks down materials
Metabolism
Homeostasis
Reproduction
Response to stimuli

15. When a ball is thrown at you and you move, this is an example of which characteristic?
Homeostasis
Reproduction
Adaptation
Response to stimuli

16. For years people have been using pesticides to kill lice
For years people have been using pesticides to kill lice. Well some lice are able to survive the pesticides and are able to reproduce. Their offspring are also immune to the pesticide. This is an example of?
Growth and development
Adapt/Evolve
Reproduction
Homeostasis

17. A caterpillar changes into a butterfly
Reproduction
Adaptation
Growth and development
Organization

18. Biochemistry

19. Hierarchy of Life
Atom - Smallest unit of matter that retains its elemental properties
Molecule - Groups of atoms bonded together
Cell - Smallest working unit of life
Organism - Individual living thing; depending on the complexity, an organism may be composed of
Tissue - groups of cells working together
Organ – groups of tissues working together
Organ system - groups of organs working together
Population - Group of organisms of one species in one area
Community - Different populations that live together in a specific area
Ecosystem - A community and its non-living components
Biosphere – Earth

20. What is the smallest working unit of Life?
Atom
Cell
Tissue
Organ

21. THE CHEMISTRY OF LIFE
Organisms are composed of matter, which is anything that takes up space and has mass. All matter is composed of elements, pure substances that consists entirely of one type of atom.
Atoms- made up of the following
Nucleus
Center of an atom
Protons have a positive charge
neutrons are neutral
Electron cloud/orbital
space surrounding nucleus
electrons in constant motion in this space
electrons have a negative charge; therefore attracted to the + charged nucleus
Charge of Atoms- Have equal # of protons & electron so they are neutral

22. Compounds elements combined in fixed ratios of atoms form compounds
held together by chemical bonds
Chemical formula
shorthand to show elements in a compound
Chemical Equation
recipe for making a compound
Reactants- what goes into the reaction
Products- substance that is formed

23. H2SO4 How many H? How many S? How many O?
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24. 2H2 + O2  2H2O Reactants? Products?
Reactant= 2H2 + O2 Products= 2H2O
Reactant= 2H2O Products= 2H2 + O2
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25. Chemical Bonds 3. Covalent Bonds
involves the valence electrons, what would be the outermost electrons
Ionic Bonds
one or more electrons are transferred from one atom to another
results in 2 oppositely charged particles called IONS
an atom that gains electrons has a positive charge
an atom that losses electrons has a negative charge
attraction between oppositely charged ions forms ionic bonds
3. Covalent Bonds
electrons are being shared
results in very stable compounds called MOLECULES

27. Water & Solutions
Water is the most essential and abundant substance on Earth. Cells are made up of mostly water and most cells are surrounded by water. The importance of water is largely due to its unique characteristics, which all directly relate to one very important property of water Water is polar.

28. What is the Equation for Water?
H2O2 OH
HO2
H2O
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29. What does H2O Mean? There are 2 oxygens & 1 Hydrogen
There are 2 Hydrogens & 1 Oxygen
There is 1 Hydrogen & 1 Oxygen
There are 2 Hydrogens & 2 Oxygens
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30. Polarity
Unequal sharing of electrons in molecules formed with covalent bonds

31. Polarity
How it works:
oxygen has 8 protons in nucleus & hydrogen has 1 proton in their nucleus
10 shared electrons will be more attracted to the more positively charged oxygen nucleus; thus orbiting around the oxygen end of the molecule just about all the time
The oxygen end will have a slightly negative charge
The hydrogen ends will have a slightly positive charge
Not true charges because the electrons are not transferred; just shared unequally

32. Hydrogen “Bonds” not a true bond- does not form a new compound
attraction between two polar molecules; like water
attraction between slightly positively charged hydrogen end of one polar molecule and the slightly negatively charged end of another polar molecule
in water : forms between positively charged H end of one water molecule and the negative end of another water molecule

33. What type of bond holds the 2 H’s and the 1 Oxygen together?
Ionic
Covalent
Hydrogen
Carbon
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34. What type of bond holds one water molecule to another water molecule?
Ionic
Covalent
Hydrogen
Carbon
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35. What is Polarity? Unequal sharing of electrons
When one atom has a slight positive charge and one has a slight negative charge
Will form a hydrogen bond
All of the above
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