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What is an inference?
a logical interpretation of an observation
The statement "the worm is 2 cm long is________________
quantitative observation
To be useful in science, a hypothesis must be _________________
testable
What is a scientific Theory?
a well tested explanation that unifies a broad range of observations
What must happen for a hypothesis to become a theory?
it must be supported by extensive observation and experimentation
What is the control?
includes those factors that remain constant (not changing)
What is the independent variable?
the factor that is being tested and is changed or manipulated
What is the dependent variable?
The factor that is measured in an experiment. It is the result of the independent variable.
What is the difference between an observation and an inference?
An OBSERVATION uses the senses to gather information
An INFERENCE is an interpretation based on prior knowledge and experience
Why is it advantageous for scientists to test only one variable at a time?
so that only one observable factor affects the outcome of the experiment
Where is the independent variable recorded on a graph?
on the x-axis (horizontal)
Where is the dependent variable recorded on a graph
on the y-axis (vertical)
A chick hatching from an egg represents what characteristic of life?
reproduction
A seed developing into a tree represents what characteristic of life?
growth and development
A webbed foot on a duck represents what characteristic of life?
adaption
The information gathered from experiments is called
data
A clam closes its shell when it is removed from its watery environment. Why does the clam behave in this way?
maintains stable internal environment (homeostasis)
If members of a species fail to reproduce successfully, the species
will become extinct
All living things are composed of __________________
cells
Living things adjust to a stimulus by a reaction called a(n)
response
what is a quantitative observation?
types of measurements: how big, how much, how many, how many times
the parts of an organism (cell, tissues, organs, etc.) represent what characteristic of life
organization
Which action or event causes a response
stimulus
You begin to perspire in a hot classroom. What are you doing?
homeostasis
Tissues are made of cells that are made of molecules. This is an example of
organization
A tadpole becoming a frog is what?
growth and development
When it is cold outside and you begin to shiver. What are you doing?
homeostasis
What happens when something startles a turtle and it withdraws into its shell?
stimulus and response
Two plants, same size, same amount of water and fertilizer. One is placed int eh dark and one is placed in the window. What is the independent variable?
amount of light
A pet owner recorded the mass of her puppy once a month. At three months old, she started feeding it a special puppy food. What is the dependent variable?
Change in mass
How is the image formed for a compound light microscope?
light passes through one or more lenses
How is an image formed for electron microscopes?
a beam of electrons is uses
What adjustment knob is used for focusing while using the high power objective?
fine adjustment knob
What adjustment knob is used for focusing while using the low power objective
coarse adjustment knob
What is the purpose of the diaphragm on the compound light microscope?
adjustment of the amount of light through the microscope
which kind of microscope must view the specimen in a vacuum?
electron microscope
Which specimens may be magnified over 200,000 times?
electron microscope
What is the maximum magnification that is known for the compound light microscope?
2,000 times
What is meant by resolution for microscopes?
measurement of the clarity of the microscope image
Explain how to calculate total magnification for a compound light microscope?
multiply the power of the eyepiece lens and the objective lens
What is the purpose of the revolving nosepiece on the compound light microscope?
changes the power of the magnification
Which microscope can produce images that are three-dimensional?
electron
What is the purpose of the stage on the microscope
for the placement of the microscope slide
What is the definition of microscope magnification?
the ability to make an image appear larger than its actual size
Why can only dead cells be observed under a microscope?
the cells must be viewed in a vacuum
What is the contribution to Matthias Schleiden to the cell theory?
concluded that all plants are made of cells
What is the contribution of Theodor Schwann to the cell theory
concluded that all animals are made of cells
What is the contribution of Rudolf Virchow to the cell theory?
concluded that all cells come from preexisting cells
Name the three parts of the cell theory
-cell is the basic unit of structure of living organisms
-cells come from preexisting cells
-all living organisms are made of cells
a tissue is a group of
similar cells with a singular function (ex. muscle tissue for movement)
What is the contribution of Robert Hooke to the cell theory
observed dead cells in cork and named the "cell"
the cell is the basic unit of __________________ of living things
structure
Cells come from ____________________ cells
preexisting
All living organisms are made of ______________________
cells
How are cells like a whole organism?
cells can carry out similar life processes as a whole organism
Why are small cells more efficient than large cells?
substances do not have to travel as far in a smaller cell than a larger cell thus taking less time to provide nutrients or to get rid of wastes
What common boundary do all cells have?
cell membrane
All cells have _________________ on which proteins are made
ribosomes
What is the purpose of the system of microfibers in the cell?
to provide support for the shape of the cell
All cells have _______________ which provides instructions for making proteins
DNA
What organisms are prokaryotes?
bacteria
What is the main characteristic or prokaryotes?
do not have a nucleus or cell organelles
If a cell of an organism contains a nucleus, the organism is
a eukaryote
when did prokaryotes appear on earth?
3.5 billion years ago before eukaryotes
Animal and plant cells are eukaryotes or prokaryotes?
eukaryotes
It is believed that mitochondria and chloroplasts are the descendants of
prokaryotes
Which were the first cells with internal membrane compartments? (eukaryotes or prokaryotes)
eukaryotes
When did the eukaryotes first appear on the earth?
1.5 billion years ago
Which are the smallest and simplest cells? (eukaryotes or prokaryotes)
prokaryotes
How is the genetic material displayed in a prokaryotic cell?
as a single, circular molecule of DNA in the cytoplasm
Where is the DNA found in a eukaryotic cell?
in the nucleus
What do bacteria have in place of an internal supporting skeleton?
strong cell wall
What is the purpose of the capsule on some bacteria?
enables the bacteria to cling to almost anything
What is the purpose of the flagella for bacteria?
enable movement
What unit of measurement is used in determining the size of cells?
um (micrometer)
In many cells, the structure that controls the cell's activities is the
nucleus
What is a vesicle?
small membrane-bound sac
Distinct threadlike structures containing genetic information are
chromosomes
The organelle that makes energy available for the cell is
the mitochondrion
What is the function of the nuclear envelope?
a double membrane with pores that allow materials to move in and out of the cell
What happens in the rough endoplasmic ER
-ribosomes are found on the rough ER
-newly made proteins move form the ribosomes to the ER where they are chemically modified
What is the main function of the cell wall?
support and protection
What is the function of ribosomes?
produce proteins following the genetic code from the nucleus
describe the role of the golgi apparatus
proteins are packaged and sorted (by attaching carbohydrates and lipids to proteins) to be sent out of the cell
What is chromatin
granular material in the nucleus consists of DNA bound to proteins
What is the function of the nucleolus?
small dense region in the nucleus where the assembly of ribosomes begins
What are the two types of structures that make up the cytoplasm?
microfilaments and microtubules are dispersed throughout the cytosol to help maintain cell structure and help with movement of organelles
what is the purpose of the vacuole?
store water and dissolved substances in plants. Smaller vacuoles in animal cells may also store food
What is the difference between a rough and a smooth ER?
smooth ER does not have ribosomes as the rough ER does. SER is responsible for membrane manufacture
what is the function of a lysosome?
these small organelles contain digestive enzymes
what outer boundary to plants cells have that animal cells do not?
cell wall
the cell wall in plants contains what polysaccharide?
cellulose
what takes up the main part of the plant cell?
central vacuole
the organelle in plants that carries out photosynthesis is the
chloroplast
what organelle do animal cells have that plant cells do not have?
centrioles
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