Biology Midterm Review
Introduction and Characteristics
of Living Things
What is S C I E N C E ???
• Science is a body of knowledge based on the study of nature.
• The nature or essential characteristics, of science is scientific
inquiry.
• Scientific inquiry is both a creative process and a process rooted
in unbiased observations and experimentation.
???
• Biology comes from the Greek bio, meaning “life”, and from logos, meaning
“study”
• Whenever you see –ology, it means “the study of”
• In Biology we study:
• The origins and history of life, both past and present
• The structures of living things
• How living things interactive with one another
• How living things function
What is S C I E N C E ???
• A theory is an explanation of a natural phenomenon supported
by many observations and experiments over time.
• A scientific law describes relationships under certain conditions
in nature, but does not explain why the relationship is the way it
is.
• Theories do not become laws and laws do not become theories.
Characteristics of Life
Organisms had or have all of the characteristics of life (8
Total):
• 1. Made of one or more cells
• Cells are the basic unit of all living things – the building blocks
• One cell = unicellular; more than one cell = multicellular
• 2. Displays organization
• They arrange in an orderly way
• Unicellular contain organized functional structures and often work together; multicellular have
specialized cells organized into tissues, tissues organized into organ, organs organized into
organ systems that work together to support life
• 3. Grows and develops
• Most everything starts as a single cell
• Mass is then added (usually by added new cells) through cell growth, and have natural
changes over organism’s lifetime that is called development
• 4. Reproduces
• Make offspring!
• Species are organisms that can breed to produce fertile offspring
Characteristics of Life, cont.
• 5. Responds to stimuli
• Stimuli = anything that causes a reaction (response) by the organism
• 6. Requires energy
• Food provides energy
• Most plants use light energy from the Sum to make their own (photosynthesis);
organisms that don’t make their own get it by consuming others (that leads back to
something that does)
• 7. Maintains homeostasis
• A balance and regulation of internal conditions
• 8. Adaptations evolve over time
• = inherited characteristic that allows species to survive more efficiently
• Usually caused by a change in environment
The Scientific Process
A Systematic Approach
• An observation is the act of gathering information.
• Qualitative data is obtained through observations that describe color, smell, shape, or some
other physical characteristic that is related to the 5 senses.
• Quantitative data is obtained from numerical observations that describe how much, how little,
how big, or how fast.
• A hypothesis is a tentative explanation for what has been observed.
• An experiment is a set of controlled observations that test the hypothesis.
A Systematic Approach
• A variable is a quantity or condition that can have more than one value.
• An independent variable is the variable you plan to change.
• The dependent variable is the variable that changes in value in response to a change in the
independent variable
• EXAMPLE: If you were trying to determine if temperature affects bacterial
growth, you would expose different petri dishes of the same bacteria to
different temperatures
• Temperature is your independent variable
• Bacteria growth is your dependent variable
Variables Song (Creepy guy)
Science literacy
• Scientific inquiry begins with observation.
• Scientific inquiry involves asking questions and processing
information from a variety of reliable sources.
• The process of combining what you know with what you have
learned to draw logical conclusions is called inferring; the
conclusions themselves are called inferences.
• The methods scientists use to gather data and answer
questions are referred to as scientific methods.
Scientific Method
• Scientific Method is a step-bystep organized plan for
gathering, organizing, and
communicating information.
STEPS
1. Make Observation
2. Ask Question
3. Develop Hypothesis
4. Experiment (include variables)
5. Analyze Data and Draw
Conclusions
- State if hypothesis is
supported or not supported
6. Develop Theory
Accuracy vs Precision
• Accuracy refers to how close
a measured value is to an
accepted value.
• Precision refers to how close
a series of measurements are
to one another.
SI Units of Measure
• All measurements need a number and a unit.
• Example: 5 ft 3 in
or
25ºF
• The metric system uses units with divisions that are powers of
ten (used in most of the world besides us – use the imperial
system
• Scientists usually do not use these units. They use a unit of
measure called SI or International System of Units.
• Base Units – more examples on following slide
• Length- straight line distance between 2 points is the meter (m)
• Mass- quantity of matter in an object or sample is the kilogram (kg)
The International System of
Units
•
Biochemistry
The atom
• There are three parts of a an atom
Subatomic
particle
Charge
Location
Proton
Positive
Nucleus
Neutron
Neutral
Nucleus
Electron
Negative
Surrounding
nucleus
Elements
• An element is one particular type of atom, and it cannot be broken
down into a simpler substance by ordinary chemical means
• Gold
• Aluminum
• Helium
Key Elements
• In biology, there are SIX very important elements
•
•
•
•
•
•
Carbon
Hydrogen
Oxygen
Phosphorus
Sulfur
Nitrogen
Ions
• Ions are atoms that have gained or lost one or more electrons.
• Results in a change in electrical charge
• Gain e• Lose e-
becomes negative
becomes positive
Ionic Bond
• Ionic bonds are formed through the electrical force between
oppositely charged ions
• Opposites attract!
• Ex: Salt aka sodium chloride (NaCl)
• Positive sodium (Na+)
• Negative chloride (Cl-)
Covalent Bond
• Not all atoms easily gain or lose their electrons!
• Some atoms share their electrons instead!
• Covalent Bond: forms when atoms share a pair of electrons
• Usually a very strong bond
• Atoms may have several covalent bonds to share several electrons
Evidence of a chemical reaction
Temperature change
Formation of a solid (precipitate)
Color change (sometimes)
Odor (sometimes)
Formation of gas
 Reactants
are the substance changed during a
chemical reactions

Oxygen (O2) & Glucose (C6H12O6)
 Products
are the substances made by a chemical
reaction

Carbon Dioxide (CO2) & Water (H2O)
6O2 + C6H12O6
6CO2 + 6H2O
 Generous chemical RXNs
that release more energy
than they absorb



= Exothermic reaction
Excess energy is the difference in bond energy
between the reactants and products
Excess energy is often released as heat or light

Cellular respiration releases usable energy for your cells &
heat!
 Greedy chemical RXNs
that absorb more energy
than they release

= Endothermic reaction

In photosynthesis, plants absorb energy from sunlight and use
that to make sugars and carbohydrates
But how does a rxn start?
• Some energy must first be absorbed by the reactants in ANY chemical
reaction
• The amount of energy needed will vary
• Activation energy is the amount of energy that needs to be absorbed
for a chemical reaction to start
• Push a rock up a hill
Catalysts & Enzymes
• A catalyst is a substance that lowers the activation energy needed to
start a chemical reaction.
• Special proteins called enzymes are the biological catalysts that speed
up the rate of chemical reactions in biological processes.
______________________
1. HIGH
SPECIFIC HEAT
______________________
2. COHESION
______________________
3. ADHESION
Cohesion: the attraction among
__________________
of the same
MOLECULES
substance.
Cohesion from hydrogen bonds makes
water molecules _____________________.
STICK TOGETHER
Cohesion produces __________________,
SURFACE TENSION
( “skin on water” )
Adhesion: the attraction among
__________________
MOLECULES of ______________
DIFFERENT
substances.
For example, water molecules stick to other
things.
Water in a test tube, (water is attracted
to the ____________)
GLASS
Mixtures
Heterogeneous
Homogeneous
• A mixture with easily separated
parts with their distinct
properties
• A mixture that it the SAME
throughout and hard to tell
individual characteristics
ACIDS
BASES
Some compounds form ______________
or _____________
BREAK UP
IONS
because they _______________
into _______________
WATER
when they dissolve in ___________.
BASE:
ACID:
Compounds
that release
a proton
- a hydrogen ion(H+) –
when it dissolves
in water
Compounds that
remove H+ ions
from
a solution
PROTEIN
____________________
LIPIDS
____________________
CARBOHYDRATES
____________________
ATP
____________________
NUCLEIC ACID
____________________
•USED BY CELLS FOR __________
ENERGY ___________
SOURCE
AND
__________
ENERGY____________.
STORAGE
SIMPLE CARBS = _______________________________
ONE OR TWO SUGAR MOLECULES
COMPLEX CARBS =LONG
_____________________________
CHAINS OF SUGAR
MOLECULES
_____________________________
Ex) Starches such as potato,
________________________________
pasta, bread
________________________________
CELLS
•MAKE UP _________________.
LIFE PROCESSES
•INVOLVED IN ALL _______ ____________.
ACIDS
•BUILDING BLOCKS = _________AMINO
__________.
ENZYME
•_________________=
TYPE OF PROTEIN THAT STARTS AND
SPEEDS UP CHEMICAL REACTIONS IN CELLS.
WATER
•DON’T MIX WITH ______________.
CELL MEMBRANE
•PHOSPHOLIPIDS – MAKE UP ________
______________.
STORE___________.
ENERGY
•FATS AND OILS THAT _________
•ORGANISMS USE FATS AND OILS WHEN THEY HAVE
CARBOHYDRATES
USED UP ___________________.
FATS
•_________SOLID AT ROOM TEMPERATURE.
OILS
•_________LIQUID AT ROOM TEMPERATURE.
ENERGY CARRYING
•MAJOR ___________
___________ MOLECULE IN CELL.
CARBOHYDRATES AND __________
LIPIDS
•ENERGY IN __________________
AND
PROTEINS
_____________________
MUST BE TRANSFERRED TO
ATP IN CELL TO BE USED.
PROTEIN
•HAVE ALL INFO NEEDED TO MAKE __________.
BLUE PRINT
•“_______________”
OF LIFE.
•BUILDING BLOCKS OF NUCLEOTIDES
_____________.
DNA
RNA
•TWO TYPES: ________
AND _______.
COMPOUND
BUILDING BLOCK
(POLYMER)
(MONOMER)
PROTEIN
AMINO ACID
LIPID (FAT)
FATTY ACID
CARBOHYDRATE
SUGARS
NUCLEIC ACIDS
NUCLEOTIDE
Cells
Microscope Technology
Compound light microscopes
•
Use a series of glass lenses and visible light to magnify images
•
Magnify images up to ~1000× actual size
Electron microscopes
•
Create an image by illuminating a sample with a beam of electrons and
collecting the electrons that are reflected back from the sample
•
Magnify images up to 500,000× actual size
Cell Discovery and Theory
ALL ORGANISMS ARE MADE OF CELLS
1. ___________________________________________________________
THE CELL IS THE MOST BASIC UNIT OF LIFE.
2. ___________________________________________________________
ALL EXISTING CELLS ARE PRODUCED BY OTHER LIVING CELLS
3. ___________________________________________________________
HOOKE
_____________
CORK
The first to
IDENTIFYcells.
____________
Responsible for
NAMING them
____________
LEEUWENHOEK
_____________
ANIMALCULES
Made better
LENSES
______________
and observed cells
in greater
DETAIL
______________.
First to observe
NUCLEUS
______________
SCHLEIDEN
_____________
SCHWANN
_____________
VIRCHOW
_____________
RESPONSIBLE FOR CELL THEORY
The first to note
that
_____________
PLANTS
were made up of
CELLS
___________
Concluded that all
LIVING
THINGS
___________
___________ were
made up of
CELLS
___________
Proposed that all
cells come from
OTHER
CELLS
____________
__________
Basic Cell Types
• Eukaryotic cells contain a nucleus and other organelles.
• Organelles are specialized structures that perform specific cell functions.
• The nucleus is the distinct central organelle that contains the cell’s
genetic material.
• Prokaryotic cells are cells without a nucleus or other membrane-bound
organelles.
• Smaller and simpler than eukaryotes
• Probably similar to first organisms that lived on earth
Cell Discovery and Theory
Function of the Plasma Membrane
•
The process of maintaining balance in an organism’s internal environment is
called homeostasis.
•
One of the structures responsible for homeostasis is the plasma membrane.
•
The plasma membrane forms a thin, flexible boundary between a cell and its
environment.
The Plasma Membrane
Function of the Plasma Membrane
• Plasma membranes have selective permeability, meaning they allow some
substances to pass through while keeping others out.
• Control of how, when, and how much of various substances enter and leave a
cell depends on the structure of the plasma membrane.
The Plasma Membrane
Fluid Mosaic Model
The
clear, jellylike material between the cell membrane and
_________________________________________________
the nucleus that makes up most of the cell
_______________________________________
(Most of all cell activity occurs here.)
____________________________________________
CYTOPLASM
_______________
The control center of the cell.
___________________________________________________
Parts of the Nucleus:
_________________________________________________
Nuclear Membrane:
The membrane that surrounds the nucleus.
__________________________________
Nuclear Pores: allow__________________________________
some particles to move in and out of the nucleus
Nucleolus
__________________________________
Chromosomes
__________________________________
NUCLEUS
_______________
MAKES PROTEINS FOR THE BODY.
_____________________________________
FOUND ON ENDOPLASMICE RETICULUM AND THROUGHOUT
__________________________________________________________
CYTOPLASM
___________________________________
RIBOSOMES
_______________
_________________________________________________________
Moves cell materials from cell membrane to nuclear membrane and
_______________________________
visa versa.
____________________________________________
(Can usually find ribosomes on this network.)
ENDOPLASMIC
_______________
RETICULUM
_______________
Packages materials for the cell.
_______________________________________
______________
GOLGI
______________
APPARATUS
Stores food and water for cell
_______________________________________
ANIMAL CELL
PLANT CELL
Contains
many small vacuoles
____________________________
________________________________
Contains one large “central vacuole
________________________________
that takes up most of the space
_______________________
inside of a plant cell
VACUOLE
________
Helps digest, (break down), waste materials of cell.
_________________________________________________
_______________________________________
LYSOSOMES
____________
Parts of an ANIMAL cell that help with cell REPRODUCTION
____________________________________________
Responsible for supplying ENERGY to the cell.
__________________________________________________________________________
MITOCHONDRIA
____________
_________________________________________________
The plant cell parts that contain the green pigment,
_________________________________________________
chlorophyll, which are responsible for producing food.
__________________________________
______________________
CHLOROPLASTS
The_________________________________________________________
outer most side of an plant cell, (surrounds the cell membrane), that
gives the cell structure, and a specific shape.
__________________________________________________________
(More rigid than cell membrane.)
__________________________________________________________
______
CELL
______
WALL
Centrioles
Large central vacuole
Diffusion and Osmosis
• There are three types of solutions.
•
isotonic – concentrations are equal
•
hypertonic – solution has more solutes than a cell, cell
shrivels and dies
• Hypotonic – solution has fewer solutes than a cell, cell
expands and may burst
hypertonic
hypotonic
Exocytosis