Structure & Function of the Cells



All Materials © Cmassengale

I. All Organisms are Made of Cells


A. The cell is the basic unit of structure & function


B. The cell is the smallest unit that can still carry on all life processes

C. Both unicellular (one celled) and multicellular (many celled) organisms are composed of cells

D. Before the 17th century, no one knew cells existed

E. Most cells are too small to be seen with the unaided eye


F. In the early 17th century microscopes were invented & cells were seen for the 1st time

G. Anton Von Leeuwenhoek, a Dutchman, made the 1st hand-held microscope & viewed microscopic organisms in water & bacteria from his teeth


Leeuwenhoek’s microscope consisted simply of:

  • A) a screw for adjusting the height of the object being examined
  • B) a metal plate serving as the body
  • C) a skewer to impale the object and rotate it
  • D) the lens itself, which was spherical



H. In 1665, an English scientist named Robert Hooke made an improved microscope and viewed thin slices of cork viewing plant cell walls


I. Hooke named what he saw “cells”

J. In the 1830’s, Matthias Schleiden (botanist studying plants) & Theodore Schwann (zoologist studying animals) stated that all living things were made of cells


K. In 1855, Rudolf Virchow stated that cells only arise from pre-existing cells


L. Virchow’s idea contradicted the idea of spontaneous generation (idea that nonliving things could give rise to organisms)

M. The combined work of Schleiden, Schwann, & Virchow is known as the Cell Theory





II. Principles of the Cell Theory


A. All living things are made of one or more cells

B. Cells are the basic unit of structure & function in organisms

C. Cells come only from the reproduction of existing cells


III. Cell Diversity


A. Not all cells are alike

B. Cells differ in size, shape, and function


C. The female egg cell is the largest cell in the body & can be seen without a microscope

relative sizes of cells and their components

D. Bacterial cells are some of the smallest cells & are only visible with a microscope

E.coli Bacterial Cells

E. Cells need surface area of their cell membrane large enough to adequately exchange materials with the environment (wastes, gases such as O2 & CO2, and nutrients)


F. Cells are limited in size by the ratio between their outer surface area & their volume


G. Small cells have more surface area for their volume of cytoplasm than large cells

H. As cells grow, the amount of surface area becomes too small to allow materials to enter & leave the cell quickly enough

I. Cell size is also limited by the amount of cytoplasmic activity that the cell’s nucleus can control

J. Cells come in a variety of shapes, & the shape helps determine the function of the cell (e.g. Nerve cells are long to transmit messages in the body, while red blood cells are disk shaped to move through blood vessels)


IV. Prokaryotes


A. Prokaryotic cells are less complex

B. Unicellular

C. Do not have a nucleus & no membrane-bound organelles


D. Most have a cell wall surrounding the cell membrane & a single, looped chromosome (genetic material) in the cytoplasm


E. Include bacteria & blue-green bacteria


F. Found in the kingdom Monera



V. Eukaryotes


A. More complex cells

B. Includes both unicellular & multicellular organisms


C. Do have a true nucleus & membrane-bound organelles


D. Organelles are internal structures in cell’s that perform specific functions


a. Nucleusb. Chloroplastc. Golgid. Mitochondria


E. Organelles are surrounded by a single or double membrane


F. Entire eukaryotic cell surrounded by a thin cell membrane that controls what enters & leaves the cell

G. Nucleus is located in the center of the cell

H. The nucleus contains the genetic material (DNA) & controls the cell’s activities

I. Eukaryotes include plant cells, animal cells, fungi, algae, & protists

J. Prokaryotes or bacteria lack a nucleus

K. Found in the kingdoms Protista, Fungi, Plantae, & Animalia



VI. Cell Membrane


A. Separates the cytoplasm of the cell from its environment

B. Protects the cell & controls what enters and leaves


C. Cell membranes are selectively permeable only allowing certain materials to enter or leave

D. Composed of a lipid bilayer made of phospholipid molecules


E. The hydrophilic head of a phospholipid is polar & composed of a glycerol & phosphate group and points to the aqueous cytoplasm and external environment.

F. The two hydrophobic tails are nonpolar point toward each other in the center of the membrane & are composed of two fatty acids

G. When phospholipids are placed in water, they line up on the water’s surface with their heads sticking into the water & their tails pointing upward from the surface.

H. The inside of the cell or cytoplasm is an aqueous or watery environment & so is the outside of the cell. Phospholipid “heads” point toward the water.

I. Phospholipid “tails” are sandwiched inside the lipid bilayer.

J. The cell membrane is constantly breaking down & being reformed inside living cells.

K. Certain small molecules such as CO2, H2O, & O2 can easily pass through the phospholipids


VII. Membrane Proteins


A. A variety of protein molecules are embedded in the cell’s lipid bilayer.

B. Some proteins called peripheral proteins are attached to the external & internal surface of the cell membrane

C. Integral proteins or transmembrane proteins are embedded & extend across the entire cell membrane. These are exposed to both the inside of the cell & the exterior environment.

D. Other integral proteins extend only to the inside or only to the exterior surface.

E. Cell membrane proteins help move materials into & out of the cell.

F. Some integral proteins called channel proteins have holes or pores through them so certain substances can cross the cell membrane.

G. Channel proteins help move ions (charged particles) such as Na+, Ca+, & K+ across the cell membrane

H. Transmembrane proteins bind to a substance on one side of the membrane & carry it to the other side. e.g. glucose


I. Some embedded, integral proteins have carbohydrate chains attached to them to serve as chemical signals to help cells recognize each other or for hormones or viruses to attach



VIII. Fluid Mosaic Model


A. The phospholipids & proteins in a cell membrane can drift or move side to side making the membrane appear “fluid”.

B. The proteins embedded in the cell membrane form patterns or mosaics.

C. Because the membrane is fluid with a pattern or mosaic of proteins, the modern view of the cell membrane is called the fluid mosaic model.


IX. Internal Cell Structure & Organelles of Eukaryotes

A. Cytoplasm includes everything between the nucleus and cell membrane.


B. Cytoplasm is composed of organelles & cytosol (jellylike material consisting of mainly water along with proteins.


C. Eukaryotes have membrane-bound organelles; prokaryotes do not


D. Mitochondria are large organelles with double membranes where cellular respiration (breaking down glucose to get energy) occurs

1. Energy from glucose is used to make ATP or adenosine triphosphate


2. Cells use the ATP molecule for energy

3. More active cells like muscle cells have more mitochondria


4. Outer membrane is smooth, while inner membrane has long folds called cristae


5. Have their own DNA to make more mitochondria when needed

E. Ribosomes are not surrounded by a membrane & are where proteins are made in the cytoplasm (protein synthesis)


1. Most numerous organelle

2. May be free in the cytoplasm or attached to the rough ER (endoplasmic reticulum)

F. Endoplasmic reticulum are membranous tubules & sacs that transport molecules from one part of the cell to another

1. Rough ER has embedded ribosomes on its surfaces for making proteins

2. Smooth ER lacks ribosomes & helps break down poisons, wastes, & other toxic chemicals

3. Smooth ER also helps process carbohydrates & lipids (fats)

4. The ER network connects the nucleus with the cell membrane


G. Golgi Apparatus modifies, packages, & helps secrete cell products such as proteins and hormones

1. Consists of a stack of flattened sacs called cisternae


2. Receives products made by the ER


H. Lysosomes are small organelles containing hydrolytic enzymes to digest materials for the cell

1. Single membrane

2. Formed from the ends of Golgi that pinch off


3. Found in most cells except plant cells

I. Cytoskeleton consists of a network of long protein tubes & strands in the cytoplasm to give cells shape and helps move organelles


1. Composed of 2 protein structures — microtubules, intermediate filaments, & microfilaments


2. Microfilaments are ropelike structures made of 2 twisted strands of the protein actin capable of contracting to cause cellular movement (muscle cells have many microfilaments)

3. Microtubules are larger, hollow tubules of the protein called tubulin that maintain cell shape, serve as tracks for organelle movement, & help cells divide by forming spindle fibers that separate chromosome pairs


Cytoskeleton Element General Function
MicrotubulesMove materials within the cell
Move the cilia and flagella
Actin FilamentsMove the cell
Intermediate FilamentsProvides mechanical support



J. Cilia are short, more numerous hair like structures made of bundles of microtubules to help cells move


1. Line respiratory tract to remove dust & move paramecia

Cross section of Cilia & Flagella

K. Flagella are long whip like tails of microtubules bundles used for movement (usually 1-3 in number)

1. Help sperm cells swim to egg

L. Nucleus (nuclei) in the middle of the cell contains DNA (hereditary material of the cell) & acts as the control center


1. Most cells have 1 nucleolus, but some have several

2. Has a protein skeleton to keep its shape

3. Surrounded by a double layer called the nuclear envelope containing pores

4. Chromatin is the long strand of DNA in the nucleus, which coils during cell division to make chromosomes


5. Nucleolus (nucleoli) inside the nucleus makes ribosomes & disappears during cell division


M. Cell walls are nonliving, protective layers around the cell membrane in plants, bacteria, & fungi

1. Fungal cell walls are made of chitin, while plant cell walls are made of cellulose


2. Consist of a primary cell wall made first and a woody secondary cell wall in some plants


N. Vacuoles are the largest organelle in plants taking up most of the space

1. Serves as a storage area for proteins, ions, wastes, and cell products such as glucose


2. May contain poisons to keep animals from eating them

3. Animal vacuoles are smaller & used for digestion

O. Plastids in plants make or store food & contain pigments to trap sunlight

1. Chloroplast is a plastid that captures sunlight to make O2 and glucose during photosynthesis; contains chlorophyll

a. Double membrane organelle with an inner system of membranous sacs called thylakoids


b. Thylakoids made of stacks of grana containing chlorophyll

2. Other plastids contain red, orange, and yellow pigments

3. Found in plants, algae, & seaweed

X. Multicellular Organization


A. Cells are specialized to perform one or a few functions in multicellular organisms

B. Cells in multicellular organisms depend on each other


C. The levels of organization include:
Cells –> Tissues –> Organs –> Systems –> Organism

D. Tissues are groups of cells that performs a particular function (e.g. Muscle)


E. Organs are groups of tissues working together to do a job (e.g. heart, lungs, kidneys, brain)

F. Systems are made of several organs working together to carry out a life process (e.g. Respiratory system for breathing)

G. Plants have specialized tissues & organs different from animals

1. Dermal tissue forms the outer covering of plants

2. Ground tissue makes up roots & stems

3. Vascular tissue transports food & water

4. The four plant organs are the root, stem, leaf, & flower


H. Colonial organisms are made of cells living closely together in a connected group but without tissues & organs (e.g. Volvox)

Build a Cell

Use of our material:
This activity was created by Kelly Riedell for students in Biology class at Brookings High School. We have worked very hard on activities, Powerpoints/games/worksheets, etc to make this a resource for our students. If you are using our materials, please give us credit for our efforts by listing us as a source with links to our site.
Any questions, comments, or corrections can be directed to us at

Students review by answering questions AND
by practicing what parts look like and their
location as they build their cell.

1. Make a copy of the question cards. and cut them apart
You will need a set of question cards for each group of 4
I make the sets different colors so the cards don’t get mixed up.

2. Print out the Build a cell game parts sheets.
Copy the blank cell page onto colored paper (1 for each student)
Copy off the cell parts pieces onto clear transparency sheets, cut out,  and place in
paper lunch bags. (1 lunch bag per game group with enough parts in it to make 4 cells.)
Using clear transparencies allows some cell parts to build on top of each other.
(Ex: nucleolus goes inside nucleus, ribosomes sit on top of Rough ER)

Students play in groups of 3-4. Each group has a lunch bag with cell parts pieces and a deck of question cards. Each student has his/her own blank cell score sheet. Students play by taking turns answering questions.  If they answer correctly, they get to pick a cell part from the lunch bag and place it on their cell scorecard in the correct place. If they get  it wrong they don’t get a part and the next student gets a turn.

First student to get all 9 cell parts into their cell is the winner.

AP Unit 2 Cell Study Guide

Unit 2    Cells Study Guide

How do bacterial cells differ from animal cells?
Cells that make proteins would have a large number of ________?
What protein makes up the cytoskeleton & gives a cell its shape?
How do phospholipids in the cell membrane move?
If a body cell had 24 chromosomes, how many chromosomes would be in the gamete?
If chromosomes have the same genes in the same location & the same banding pattern, they are said to be ___?
What chemical in animal cell membranes maintains their fluid nature?
Facilitated diffusion & active transport both require what molecules in cell membranes?
Name the 3 stages of cell signaling.
How does a sexual life cycle increase genetic variation?
What organelle converts light energy into chemical energy?
What will happens to the chromosomes in a cell that passes the restriction checkpoint?
What type of scope is needed to study the internal structure of a cell?
Does the cytoskeleton limit cell size?
Describe the signal-transduction pathway in animals.
What type of cells do not reproduce more cells by mitosis & cytokinesis?
Is diffusion active or passive transport?
How can you determine if a cell is in an isotonic solution?
What organelle makes lipids?
What is the function of these cell structures — mitochondrion, chloroplast, ribosome, lysosome, cell wall, & chromosomes?
How does CO2 move into a cell?
Name the parts of the cytoskeleton.
What cell organelles have two membranes?
What is active transport?
How does potassium move into & out of a cell?
How does one rotting piece of fruit affect the ripening of others?
Name all structures in a cell responsible for movement.
In what organisms is cell signaling less important?
If a cell has 92 chromosomes at the start of mitosis, how many will be in the daughter cells?
Describe paracrine signaling.
When do tetrads from in a cell?
What is the function of tyrosine-kinase receptors?
At what point are chromatids attached to each other?
What is the function of glycolipids & glycoproteins in animal cell membranes?
How does telophase of mitosis differ in plant & animal cells?
When the signal molecule changes the protein receptor, what process begins?
What is membrane potential?
What effect would calcium deficiency have on a plant?
Besides the nucleus, where else can DNA be found in a cell?
Do plant cells have mitochondria? Why or why not?
Which proteins in the cell membrane function in active transport?
Why would bacterial cells not be capable of phagocytosis?
Why are eukaryotic cells larger than prokaryotic cells?
What is the purpose of cell fractionation?
Through what type of junctions do ions travel between cells?
How can you determine if a karyotype is from a male or female?
How do genetic differences in clones occur?
If the spindle can not form, at what stage will mitosis no longer proceed?
What will be true of cells that undergo mitosis but not cytokinesis?
What cellular structure helps form the cleavage furrow in animal cells?
How do receptor proteins in a membrane act like enzymes?
What occurs during prophase of mitosis?
By what process do large solids move into a cell?
Does the movement of oxygen & carbon dioxide across cell membranes require energy?
Describe the interior of chloroplasts & mitochondria.
How is synaptic signaling different than hormone signaling?
What is a karyotype?
How do daughter & parent cells compare with each other?

AP Study Guide Unit 3 Cell Energetics



Unit 3     Cellular Energetics


What form of energy is the most random?
What changes occur in H, S, and G when a protein forms from amino acids?
How does an enzyme catalyze a reaction?
Explain the 2nd law of thermodynamics.
Is a chemical reaction with a positive G endergonic or exergonic?
List the properties of enzymes.
Why is ATP an important metabolic molecule?
Describe the change in free energy at equilibrium.
Increasing substrate concentration has what effect on competitive inhibition?
What is the first law of thermodynamics?
When energy is transformed, what is the effect on entropy in the system?
If temperature is kept uniform in a system, free energy will be what?
If products have less free energy than reactants, is the reaction endergonic or exergonic?
What is catabolism?
How is energy obtained from ATP to energize cellular processes?
If the concentration of reactants is decreased, what effect will this have on the rate of the reaction/
What type of pathways are coupled with anabolic pathways to supply ATP to cells?
Explain enzyme cooperativity & allosteric sites.
Explain the induced fit explanation for enzymes & substrates.
What is free energy?
Describe CO2 fixation & the Calvin cycle in CAM plants.
Photorespiration decrease the efficiency of photosynthesis because it removes what from the Calvin cycle?
What is synthesize across thylakoid membranes?
Why can C4 plants better at photosynthesis without photorespiration?
What pigments can absorb light energy?
Proton gradient are responsible for producing what energy molecules?
Give 2 examples of products of the Calvin cycle that are used in the light reactions?
What 2 main energy molecules are products of the light reactions?
Is glucose required for the Calvin cycle? Explain.
In what reactions is glyceraldehyde phosphate produced?
If a pigment appears red to your eyes, what color of light is not being absorbed?
During what process is CO2 incorporated into PGA?
The chemiosomotic process in chloroplasts occurs when what type of gradient is established?
Name the most abundant protein (enzyme) in the world.
In what tissue does carbon fixation occur in C4 plants before being transferred to bundle-sheath cells?
Photosystem II uses which chlorophyll a molecule?
What gas is required and which gas is not required for photosynthesis to occur?
What is the primary energy source for plants? for animals?
What enzyme catalyzes phosphorylation?
Where in the chloroplast does the Calvin cycle occur?
What type of plants fix CO2 into organic acids during the day?
When does the Calvin cycle in most plants occur?
Which color of light is least effective in driving photosynthesis?
Cyclic electron flow in chloroplasts produces what energy molecule?
Where does the ETS in plants occur?
In terms of energy how are photosynthesis & cellular respiration related?
In what 2 membranes in plant cells is ATP synthetase found?
Is oxygen released in the light or dark reactions of photosynthesis?
Does photophosphorylation occur in Photosystem II?
In which photosystem is water split?
Which process does not give a net gain in ATP —glycolysis, aerobic respiration, or fermentation?
Which would release more energy from glucose — combustion or cellular respiration?
Is ATP a product of lactate fermentation?
If a metabolic poison interferes with glycolysis, what must its structure be most like?
Are water and CO2 end products of glycolysis?
Which has more energy —NAD or NADH?
Oxidative phosphorylation occurs across ___________in a cell.
which has more energy — glucose at the start of glycolysis or the 2 pyruvate molecules at the end of glycolysis?
Molecular oxygen supplies the oxygen atoms during oxidative phosphorylation to form what?
What is chemiosmosis?
Lactate is a byproduct of fermentation in what type of animal cells?
What type of enzyme in cellular respiration helps remove electrons from organic molecules?
The ETS helps a cell generate what energy molecule?
Will glycolysis occur if oxygen is present? Is oxygen needed for the process?
The difference in H+ concentration of either side of the mitochondrial membrane drives the synthesis of what molecule?
Where in a cell will the enzymes needed for glycolysis be found?
Citric acid has 6 carbons. In the Krebs cycle 2 CO2 molecules are given off before succinic acid is formed. How many carbons will succinic acid have?
During substrate-phosphorylation, how many ATP molecules are made each cycle?
Isocritic acid has 6 carbons while ketoglutaric acid in the Krebs cycle only has 5 carbons. What happened to the “missing” carbon?
What gas accepts electrons at the end of the ETS?
Substrate-level phosphorylation during fermentation generates what molecule?
Acetyl CoA is made in muscle cells only under what conditions?
The end products of glycolysis are ATP, NADH, and what carbon molecule?
What 2 electron acceptor molecules in the Krebs cycle convert their energy to ATP in the ETS?
In chemiosmotic phosphorylation what is the direct energy source that drives the conversion of ADP + free P into ATP?
The glycolysis of glucose by a yeast cell nets how many ATP’s?
What intermediary metabolite of pyruvate enters the Krebs cycle?
How is a proton gradient established in the mitochondria?
How many O2 molecules are produced from the complete oxidation of glucose?
What type of animal tissue has a high ATP requirement?



AP Lecture Guide 07 – The Cell


AP Biology: CHAPTER 7



1. The tool that lead to the understanding that cells are the basic unit of life was the…


2. The smallest structures visible with the light microscope are the ….


3. What is the advantage of the electron microscope?




4. How do biologists isolate cell components?




5. What are four things all cells have in common?

a. _________________________________________________________________________

b. _________________________________________________________________________

c. _________________________________________________________________________

d. _________________________________________________________________________


4. Golgi bodies and lysosomes





5. Nucleus and endoplasmic reticulum





6. Endoplasmic reticulum and Golgi bodies and vesicles





7. Endoplasmic reticulum and cell membrane