Download Standard 3 review notes The parts of the cell I want you to know are

Standard 3 review notes
The parts of the cell I want you to know are shown below. The example below is a plant cell because it has a cell wall
and chloroplasts which animal cells do not have.
Cells are the basic unit of structure and function of all living things. All cells come from other cells. All cells are similar
because they perform the BASIC functions of life (smallest unit of LIFE). They are different because they may also
perform some specialized functions as well (like a blood cell carries oxygen to different parts of the body, but a cell in
the lining of your stomach produces a slippery substance called mucus to protect your stomach from the stomach acid,
all while also performing the basic functions of living things). The best way to see individual cells is by using a
microscope.
DNA is found in the nucleus of organisms with a nucleus (Eukaryotes). DNA is the genetic information (the blueprint) of
living things. In organisms with no nucleus (Prokaryotes) the DNA is found floating in the cytoplasm. The DNA is
responsible for guiding all the processes that happen inside a cell. This means in Eukaryotes the cell nucleus is the
operations center (it guides all the functions of the cell).
Only plants can produce food from sunlight because as a general rule they are the only organisms with chloroplasts.
And only plant cells have cell walls. The cell wall provides the structure for PLANTS to grow without bones (animal cells
don’t have cell walls).
One of the most important functions of the cell membrane is controlling what substances get in and out of the cell. The
one thing that the cell membrane doesn’t control very well is the flow of water. Water passes in and out of the cell
easily. This process is a type of diffusion called osmosis. (Osmosis and diffusion are both the movement of particles of a
fluid from an area of high concentration of the fluid to an area of low concentration. The only difference is that osmosis
happens over some sort of membrane).
Osmosis is the movement of water from an area of high concentration of water (lots of water compared to other stuff)
to an area of low concentration of water (low amounts of water compared to other stuff). This is a natural process and
requires no energy from the living thing. If a cell is placed in pure water the concentration of water compared to other
stuff outside the cell is very high because there is no “other stuff” in the pure water. This will cause water to flood into
the cell. The cell will swell with water and perhaps even pop because of it.
Now the opposite is true when a cell is placed in salt water. When a cell is placed in salt water the concentration of
water OUTSIDE the cell compared to the salt is very low, so water rushes out of the cell to balance it out and the cell
shrinks and gets dehydrated. This is why drinking salt water when lost at sea kills people. They get dehydrated faster
than if they drank no water at all. Particles of a solid like salt and sugar do NOT move over the cell membrane easily.
This requires something called active transport where the cell membrane actively moves those things across the
membrane. This requires energy that is made by the mitochondria from sugar that already got moved across the cell
membrane. The mitochondria break down the sugar into smaller parts and that releases energy. The wastes produced
by this process are moved OUT of the cell through the cell membrane. On rare occasion these wastes can be broken
down into other helpful substances but MOSTLY the wastes are moved outside the cell (over the cell membrane)
because often these wastes are toxic.
All living things are made of cells. If something is considered alive it must be made of cells, eat, grow, reproduce, breath
and for some organisms it may have the ability to move (this doesn’t apply to almost all plants or fungi). This is tricky
when you think about fire, it eats (burns wood), it breaths air in order to burn and it can definitely grow, but what’s
missing is that it isn’t made of cells. Cells are the basic (smallest) unit and structure of all life.
Tissues like the lining of your stomach are made of cells. Each type of tissue has a specific function (that means it has a
special job that it does and it usually does nothing else). All organs are made of groups of different kinds of tissues that
perform a specific job like a kidney that filters bad things out of your blood and directs them to your bladder (a different
organ) to be removed from your body. The bladder, kidneys and the tubes that connect them are all part of the urinary
tract system (this system is the system responsible for filtering stuff out of your body and turning it into urine so your
body can get rid of it easily). When several organs come together to perform a special function, that is called an organ
system. When several organ systems work together, they form and organism. All tissues are made of cells, all organs
are made of tissues, and all organ systems are made of organs. There are several single celled organisms, like all the
types of bacteria. These single celled organisms don’t have tissues, organs or organ systems. In organisms with multiple
cells the tissues and organs help get the cells what they need to perform the functions of life, like creating energy or
removing waste products.
A way to draw this out would be
The human body is made of several organ systems. The circulatory system, the urinary system, the digestive system, the
respiratory system, the nervous system, the skeletal system, the lymphatic system and more.
The circulatory system includes the heart, veins and arteries. This controls the flow of blood through the body,
delivering oxygen to the cells of the body. The chambers of the heart and the valves between them affect the
circulatory system by controlling the flow of blood to the parts of the body.
The urinary system includes the kidneys, bladder and the tubes that connect them. The urinary system is responsible for
removing toxins from the blood and getting them out of the body. This means the bladder and kidneys are responsible
for collecting and excreting cell wastes.
The digestive system includes the esophagus, the stomach, the intestines, the pancreas and the colon. The digestive
system is responsible for getting the usable nutrients out of the food we eat, absorbing water and getting rid of what
our bodies can’t use. The majority of the stomach is made of muscle so that it can churn the food to help break it down.
The stomach, intestine and pancreas break down food to be used by cells.
The respiratory system includes the trachea in your throat, the bronchial tubes and the lungs and it transfers gasses into
and out of the blood. These things work together to get the oxygen from the air we breathe and get it into the blood.
The lungs are also responsible from removing CO2 (carbon dioxide) from the blood and breathing it out. The lungs are
made of tiny sacs that create a large surface area inside the lungs, allowing the air to contact the large surface. This
allows the air from outside to come in close contact with the blood in our bodies. This allows for easy exchange of gases
between the blood in our bodies and the air in our lungs.
The nervous system includes the brain, the eyes, the hearing parts of our ears and all the nerves (usually single cells)
running to all parts of the body. It is responsible for communication between the parts of the body to the brain so we
know how to respond to things to keep us safe and help us make good decisions about how to react to what is
happening around us.
Standard 3, Objective 1
a1. Which instrument is best for viewing cells and cell parts?
A. glasses B. microscope
C. telescope
D. magnifying glass
a2. What is the best description of a cell? They are
A. the smallest thing that scientists know about.
B. free-swimming animals that have cilia.
C. box shaped units that cork is made from.
D. the small units that all living things are made of.
a3. How are all cells similar?
A. They perform the functions of life.
C. They have the same parts as one another.
B. They make food from sunshine, air and water.
D. They can swim in water and find their own food.
Using the following diagram of a cell to answer the next two questions:
b4. Organelle X controls cell functions.
What have scientists named this organelle?
A. nucleus
B. cytoplasm
C. cell membrane D. cell wall
b5. What substance is found at Y?
A. DNA
B. cytoplasm
C. membrane
D. cell wall
b6. Which part of the cell contains genetic materials?
A. cell membrane
B. nucleus
C. cytoplasm
D. cell wall
b7. What are the food-making structures in plant cells?
A. cell membrane
B. nucleus
C. cytoplasm
D. chloroplasts
b8. Which cell organelle do all cells have that controls the movement of materials into and out of the
cell?
A. Cell wall
B. Nuclear membrane
C. Nucleus
D. Cell membrane
c9. Which organelles would you expect a plant cell to have but not an animal cell?
A. cell wall, chloroplast
B. nucleus, cell membrane
.
C. cytoplasm, diffusion
D. osmosis, cell membrane
Use these diagrams to answer the next three questions:
c10. Which diagram best represents a plant cell?
A. A
B. B
C. both
D. neither
c11. What is the function of the green circles in “B”?
A. get rid of cell waste products
B. control the entry of food into the cell
C. use sunlight to make sugar
D. control the activities of the cell
c12. What is the difference between the outer covering of “A” and “B”?
A. A has a shell like an egg, B is a soft membrane.
B. A has only a cell membrane, B has a cell wall and cell membrane
C. A and B both have cell walls that support the organism
D. A is covering a plant cell, B is covering an animal cell
d13. What is the process by which water moves across a cell membrane called?
A. osmosis
B. active transport
C. diffusion
D. resolution
d14. A cell is placed in pure water. What will happen to the cell size?
A. it will shrink
B. it will expand in size
C. it will not change
D. it is impossible to predict
Use this diagram to answer the next two questions. The cells are separated by a membrane
that allows water to pass through.
The dots represent sugar atoms. The rest
of each cell is filled with water and the
lines are the cell membrane.
A
B
d15. How will water move in this example?
A. more will move from A to B
B. more will move from B to A
C. it will move equally back and forth D. it will not move
d16. Why does the sugar stay in the cell?
A. it is dissolved in the water
C. it cannot pass through the membrane
B. it is connected to the nucleus
D. it is a solid made of crystals.
d17. Why does osmosis occur? It happens because
A. gravity pulls all matter toward the center of Earth.
B. water moves from high concentrations to low.
C. cells are alive and only living things have osmosis.
D. cells are the smallest parts of living things.
e18. How do cells get energy from food?
A. Cells break food into smaller parts, releasing energy.
B. Cells have electricity in the nucleus that travels to the rest of the cell.
C. Cells create energy because they are able to move.
D. The sun sends food through space that turns into energy.
e19. What do cells do with waste products?
A. They store wastes in the cell membrane.
B. Wastes are passed out through the cell membrane.
C. Wastes are broken down into helpful substances.
D. The cells store the wastes, which allow them to grow.
e20. Why are only plant cells able to produce food from sunlight? Plant cells
A. have cell walls that tell the cell how to produce food.
B. have cytoplasm which creates and stores food.
C. have chloroplasts which is where food is produced.
D. have a cell wall to give the plant support and strength.
e21. What guides all cell processes?
A. genetic material in the nucleus
C. movement through the cell membrane
B. energy from the mitochondria
D. osmosis in the vacuole
Essay
1. Compare and contrast the processes of diffusion and osmosis. Provide one similarity and one
difference.
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2. Compare and contrast plant and animal cells. Provide two similarities and two differences.
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Standard 3, Objective 2
a1. Which answer correctly identifies the 5 levels of cell organization from simplest to most complex?
A. tissue, organs, organ systems, cell, organism
B. organism, organ system, organ, tissue, cell
C. organ system, cell, tissue, organ, organism
D. cell, tissue, organ, organ system, organism
a2. Which answer correctly identifies the 5 levels of cell organization in a dog’s body from simple to
most complex?
A. bone cell, bone tissue, femur (thigh bone), skeleton, dog
B. dog, skeleton, femur, bone tissue, bone cell
C. skeleton, bone tissue, bone cell, dog, femur
D. bone tissue, bone cell, femur, skeleton, dog
Use this diagram to answer the next two questions.
a3. Overlapping circles can be used to show relationships. In this
diagram, levels of organization within living things are shown. If each
circle is made from the smaller circles inside it, what does
circle “W” stand for?
A. organs
B. cells
C. tissues
D. organ systems
a4. What would circle “Y” be?
A. organs
B. cells
C. tissues
D. organ systems
b5. The brain is an example of which level of organization in a body?
A. cell
B. tissue
C. organ
D. organ system E. organism
b6. A nerve is an example of which level of organization in a body?
A. cell
B. tissue
C. organ
D. organ system E. organism
b7. The lining of the stomach is an example of which level of organization in a body?
A. cell
B. tissue
C. organ
D. organ system E. organism
b8. A cow is an example of which level of organization in a body?
A. cell
B. tissue
C. organ
D. organ system E. organism
c9. How do the chambers of the heart and valves between them affect the circulatory system?
A. They control the flow of blood to different parts of the body.
B. They create new blood cells than travel to body tissues.
C. They allow blood to absorb oxygen and release carbon dioxide.
D. They store the blood for the times when it is needed.
c10. The lungs are composed of tiny sacs that fill with air during breathing. How does this tissue
help the lungs do their job?
A. it allows air to contact a large surface
B. it allows muscles to open and close them.
C. it allows the lung to pump the air.
D. it allows the lungs to produce more blood.
c11. Why does the stomach need to be made of muscle tissue?
A. So liquids do not pool in the intestine.
B. To give the body strength in the middle.
C. So it can churn the food and help break it down.
D. To help the heart pump blood containing food to the body.
d12. Which organ system transfers gasses into and out of the blood?
A. nervous system
B. respiratory system
C. skeletal system
D. lymphatic system
d13. Which organs collect and excrete cell wastes?
A. skin and heart
B. stomach and pancreas
C. bladder and kidneys
D. lungs and heart
d14. Which organs break down food to be used by the cells?
A. heart, arteries, blood
B. stomach, intestine, pancreas
C. nerve, brain, spinal cord
D. skin, pancreas, skeletal
Essay
1. What is the difference between tissue and organ?
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2. Describe how the needs of cells are met by tissues and organs. Give an example.