Semester 1 Science Exam

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