Download Unit #1 Full Notes on Cells

Biology 11 - Ms. Bowie
Cellular Structure & Function
This Unit Includes:
Cell Theory
Cellular Structures & Functions
Plasma Membrane
Osmosis
Photosynthesis
Cellular Respiration
Cellular Organisation
This booklet belongs to:
_______________________________________
Winter 2017
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Biology 11 - Ms. Bowie
Cellular Structure & Function
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Table of Contents
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Topic
Cell Theory Overview
Cell Theory Practice Quiz
Prokaryotic vs. Eukaryotic Cells
Cell Size Math Lab
The Plasma Cell Membrane
Cytoplasm
The Cytoskeleton
The Nucleus (& Nucleolus)
The Endoplasmic Reticulum
Ribosomes
The Golgi Complex
Exocytosis & Endocytosis Diagram
Lysosomes
Peroxisomes
Vacuoles
Mitochondria
Centrioles
Cilia & Flagella
Plant Cell - Chloroplasts
Plant Cell - Plastids
Plant Cell - Cell Wall
Comparing Plant & Animal Cells
The Plasma Cell Membrane Structures
Passage of Materials Through the Cell Membrane
Cellular Transport
 Simple diffusion
 Osmosis
 Facilitated Diffusion
 Active Transport
Osmosis (Hypertonic, hypotonic & isotonic solutions)
Cellular Metabolism
 Photosynthesis
 Cellular Respiration
Cellular Respiration (Detailed Steps)
 Glycolysis
 Krebs Cycle
 The Electron Transport Chain (oxidative phosphorylation)
 Recap
Aerobic Respiration vs. Anaerobic Respiration
Levels of Organisation in Multicellular Organisms
Questions and Practice
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3
4
5
6-7
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9
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14
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27-29
30-31
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33-35
Biology 11 - Ms. Bowie
Cellular Structure & Function
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The Cell Theory states:
1. All living organisms are composed of one or more cells.
2. The cell is the basic unit of structure and function of all forms of life.
3. Cells arise from pre-existing cells through cellular division (mitosis).
Timeline for the Cell Theory Story:
Date
334 BCE
Event
Aristotle contemplates life
 Proposes that all life is either a plant or an animal
 Proposes that life can materialize from inanimate objects (Spontaneous Generation)
1268
Roger Bacon
 Roger Bacon, an English friar makes reference to a pair of eye glasses.
 This means that glass is being developed and used in a way that makes it easier to see small things.
1590
Zacharias Janssen
 Dutch eyeglass maker,
 makes the 1st microscope (& telescope) by placing two lenses on top of one another to make extra-large images.
1665
Robert Hooke
 An English scientist, discovered a empty box structure in a cork slice using a primitive compound microscope. They look like the
rooms in a monastery which were known as cells.
 He only saw cell walls as this was dead tissue.
 He coined the term "cell" for these individual compartments he saw.
1670
Anton van Leeuwenhoek

A Dutch linen merchant, looks at lake water with a microscope he made himself.

He sees the first living microorganisms (protists) which he called "Animacules".

He also sees bacteria from dental scrapings, red blood cells and sperm.
1668
Francesco Redi

Conducts experiments to prove that maggots do not appear in meat if flies cannot land on it!
1809
Jane Haldiman

Jane Haldimand, a teacher, writes textbooks for young people to learn about science.

Terms such as “cell”, “cellular system” and “Cellular tissue” appear in the book.
1831
Robert Brown

An English botanist, discovered the nucleus in plant cells (orchids).

He also makes important findings in atomic theory and particle motion (Brownian Motion).
1838
Matthias Jakob Schleiden

A German botanist, proposes that all plant tissues are composed of cells, and that cells are the basic building blocks of all plants.

This statement was the first generalized statement about cells.
1839
Theodor Schwann

A German botanist reached the conclusion that animal tissue is composed of cells.

This ended debates that plants and animals were fundamentally different in structure.

He also pulled together and organized previous statement on cells into one theory, which states:
o 1 - Cells are organisms and all organisms consist of one or more cells
o 2 - The cell is the basic unit of structure for all organisms
1850
Robert Remak

A Jewish Polish/German embryologist, physiologist, and neurologist

Discovered that the origin of cells was by the division of pre-existing cells while studying the blood of chick embryos Due to his
Jewish faith, he was never given status as a professor and his ideas were plagarized by Rudolph Virchow (a friend and colleague).
1856
William Henry Perkin

18 year old lab assistant accidentally spills ink well on prepared slides

Develops a new purple dye for staining cell parts making it easier to see cell parts with a microscope.
1858
Rudolf Virchow

A German physiologist/physician/pathologist who adds the 3rd part to the cell theory.

The original is Greek, and states Omnis cellula e cellula. This translates as all cells develop only from existing cells.

Unfortunately, he publishes Remak's work without giving him any of the credit.
1860s
Louis Pasteur
 conducts a series of experiments that once and for all put to rest the idea of spontaneous generation and concluding that living
organisms do not arise from non-living matter.
 Using his swan-necked flask he shows how, even open to the air, the broth in the flask does not grow microorganisms unless dust
and other particles fall into the flask.
Biology 11 - Ms. Bowie
Cellular Structure & Function
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Biology 11 - Ms. Bowie
Cellular Structure & Function
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The Two Basic Types of Cells
Prokaryotic vs. Eukaryotic
Two types of cells that make up all living things on earth: prokaryotic and eukaryotic.
Prokaryotic cells, like bacteria, have no membranebound nucleus. Instead, the genetic material is
clustered toward the center in a region known as a
nucleoid.
Structure of a typical bacterium (prokaryote)
Eukaryotic cells, like those of the human body, have a true, membrane-bound nucleus. Eukaryotic cells also have
membrane bound organelles.
Both types of cells have a cell membrane (sometimes called a Plasma Membrane). They both also have
cytoplasm and ribosomes.
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Cellular Structure & Function
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Why must cells be so small?
CELL SIZE COMPARISON
Cells are limited in how large they can be. Let's explore why through some simple calculations.
Cell Size Calculations:
Cell Size Comparison Data Table
Surface Area (cm2)
Volume (cm3)
Ratio (Surface area : volume)
Surface area = (length x width) x 6 sides
Volume = length X width X height
Surface area/volume
2x2x2
24
8
3
3
3x3x3
54
27
2
4
4x4x4
96
64
1.5
5
5x5x5
150
125
1.2
6
6x6x6
216
216
1
7
7x7x7
294
343
0.86
8
8x8x8
384
512
0.75
Cell
Dimensions (cm)
1
1x1x1
2
These ratios show how many times larger the surface area is as compared with the volume. Notice that it becomes less
than one very quickly.
Biology 11 - Ms. Bowie
Cellular Structure & Function
Name: _______________________________________________
Section ____
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Date: _______________________
QUESTIONS:
1.
Which model has the largest surface area?
2.
Which model has the largest volume?
3.
Which model has the largest surface area to volume ratio?
4.
What happens to the surface area and volume ratio as the size increases.
The larger the cell becomes, the less surface area it has compared with its volume.
4.
To maintain life, and carry out cellular functions, materials must be able to move into and out of the cell. Also, material
needs to be able to move within the cell. What might be the advantage of having a large surface area?
It is therefore less efficient for a large cell to pass materials in and out through th e membrane, and to move materials
throughout the cell.
5.
What might be the disadvantage of having a large volume?
Conclusion (In your own words, explain why the cell must be so small.)
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Cellular Structure & Function
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The Structures & Functions of the Cell
Plasma cell membrane - encloses every human cell
There are 2 primary building blocks that make up the
plasma cell membrane:
 Proteins (about 60% of the membrane)
 Lipids (a type of fat, makes up 40% of the
membrane)
The primary lipid is called phospholipid, and
molecules of phospholipid form a 'phospholipid
bilayer' (two layers of phospholipid molecules).
This bilayer forms because the two 'ends' of phospholipid
molecules have very different characteristics:
 one end is polar (or hydrophilic), the heads and
 one is non-polar (or hydrophobic), the tails
Functions of the Plasma Cell Membrane




supporting and retaining the cytoplasm
being a selective barrier
o The cell is separated from its environment and needs to get nutrients in and waste products out. Some
molecules can cross the membrane without assistance, most cannot. Non-polar molecules can cross.
Non-polar molecules penetrate by actually dissolving into the lipid bilayer.
o Most polar compounds such as amino acids, organic acids and inorganic salts are not allowed entry,
but instead must be specifically transported across the membrane by proteins.
o For this reason, we say the plasma membrane is selectively permeable.
Transport
o Many of the proteins in the membrane function to help carry out selective transport.
o These proteins typically span the whole membrane, making contact with the outside environment and
the cytoplasm. They often require energy to help compounds move across the membrane.
Recognition
o The immune system works by
identifying and attacking foreign
invaders in the body. To do this they
must be able to recognize "self" from
"foreign".
o
Proteins on the outside of the
membrane act as tags to identify it as
"self".
More on the Plasma Cell Membrane later...
Biology 11 - Ms. Bowie
Cellular Structure & Function
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The Cytoplasm


Cytoplasm consists of a gelatinous solution and contains
microtubules (which serve as a cell's cytoskeleton) and organelles
(literally 'little organs'). It occupies everything inside the cell
membrane and outside the nucleus.
Absorbed nutrients and processed here and the wastes that result
are held here until they can be removed from the cell.
The Cytoskeleton
The cyotoskeleton represents the cell's skeleton. Like the bony skeletons that give us stability, the cytoskeleton
gives our cells shape, strength, and the ability to move, but it does much more than that. The cytoskeleton is
made up of three types of fibers that constantly shrink and grow to meet the needs of the cell: microtubules,
intermediate filaments, and actin filaments. Each type of fiber looks, feels, and functions differently.
The cytoskeleton is dynamic; assembly occurs when monomers join a fiber and disassembly occurs when
monomers leave a fiber. Assembly and disassembly occur at rates that are measured in seconds and minutes.
The entire cytoskeletal network can even disappear and reappear at various times in the life of a cell.
 Microtubules consist of a strong protein called tubulin and they are the 'heavy lifters' of the cytoskeleton.
They do the tough physical labor of separating duplicate chromosomes when cells copy themselves and
serve as sturdy railway tracks on which countless molecules and materials shuttle to and fro. They also
hold the ER and Golgi neatly in stacks and form the main component of flagella and cilia. Prokaryotic cells
do not contain microtubules. In many cells, microtubule assembly is under the control of a microtubule
organizing center, MTCO, called the centrosome. The centrosome lies near the nucleus. Before a cell
divides, the microtubules assemble into a structure called a spindle that distributes chromosomes in an
orderly manner. At the end of cell division, the spindle disassembles, and the microtubules reassemble once
again into their former array.
 Intermediate filaments are unusual because they vary greatly according to their location and function in
the body. For example, some microfilaments form tough coverings, such as in nails, hair, and the outer
layer of skin (not to mention animal claws and scales). Others are found in nerve cells, muscle cells, the
heart, and internal organs. Intermediate filaments function as tension-bearing elements to help maintain cell
shape and rigidity.
 Actin filament (previously called microfilaments) are made up of two chains of the protein actin twisted
together. Although actin filaments are the most brittle of the cytoskeletal fibers, they are also the most
versatile in terms of the shapes they can take.
They can gather together into bundles, weblike
networks, or even three-dimensional gels. They
shorten or lengthen to allow cells to move and
change shape. Together with a protein partner
called myosin, actin filaments make possible
the muscle contractions necessary for
everything from your action on a sports field to
the automatic beating of your heart.
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Cellular Structure & Function
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The Nucleus
Cells also contain a nucleus within which is found DNA
(deoxyribonucleic acid) in the form of chromatin (or
chromosomes during cell division) plus nucleoli (within
which ribosomes are formed).
The nucleus is a highly specialized organelle that serves as
the information processing and administrative center of the
cell.
This organelle has two major functions:
 it stores the cell's hereditary material, or DNA, and
 it coordinates the cell's activities, which include
growth, intermediary metabolism, protein synthesis,
and reproduction (cell division).
The spherical nucleus typically occupies about 10 percent of a eukaryotic cell's volume, making it one of the cell's
most prominent features. A double-layered membrane, the nuclear envelope, separates the contents of the nucleus
from the cellular cytoplasm. The envelope is riddled with holes called nuclear pores that allow specific types and
sizes of molecules to pass back and forth between the nucleus and the cytoplasm. It is also attached to a network of
tubules and sacs, called the endoplasmic reticulum, where protein synthesis occurs, and is usually studded with
ribosomes.
The semifluid substance found inside the nucleus is called nucleoplasm. Within the nucleoplasm, most of the
nuclear material consists of chromatin, the less condensed form of the cell's DNA that organizes to form
chromosomes during mitosis or cell division.
The nucleus also contains one or more nucleoli, organelles that make the protein-producing molecules called
ribosomes.
Chromatin and Chromosomes - Packed inside the nucleus of every human cell is nearly 6 feet of DNA, which is
divided into 46 individual molecules, one for each chromosome and each about 1.5 inches long. Packing all this
material into a microscopic cell nucleus is an extraordinary feat of packaging. For DNA to function, it can't be
crammed into the nucleus like a ball of string. Instead, it is combined with proteins and organized into a precise,
compact structure, a dense string-like fiber called chromatin.
The Nucleolus - The nucleolus is a membrane-less organelle within the nucleus that manufactures ribosomes, the
cell's protein-producing structures.
The Nuclear Envelope - The nuclear envelope is a double-layered membrane that encloses the contents of the
nucleus during most of the cell's lifecycle. The envelope is perforated with tiny holes called nuclear pores. These
pores regulate the passage of molecules between the nucleus and cytoplasm, permitting some to pass through the
membrane, but not others.
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Cellular Structure & Function
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The Endoplasmic Reticulum


There are 2 forms: smooth and rough;
 the surface of rough ER is coated with ribosomes;
 the surface of smooth ER is not coated with ribosomes
Functions include:
 transport
 synthesis of proteins by rough ER,
 synthesis of lipids and carbohydrates (smooth ER)
 mechanical support
The endoplasmic reticulum (ER) is found only in eukaryotic cells.
The endoplasmic reticulum (ER), a complicated system of membranous channels and saccules (flattened vesicles),
is physically continuous with the outer membrane of the nuclear envelope. Rough ER is studded with ribosomes on
the side of the membrane that faces the cytoplasm (Fig. 3.5). Here, proteins are synthesized and enter the ER
interior, where processing and modification begin. Most proteins are modified by the addition of a sugar chain,
which makes them a glycoprotein. Proteins that require special conditions or are destined to become part of the cell
membrane are processed in the ER and then handed off to another organelle called the Golgi apparatus. Scientists
are studying many aspects of the ER and Golgi apparatus, including a built-in quality control mechanism cells use
to ensure that proteins are properly made before leaving the ER
Smooth ER, which is continuous with rough ER, does not have attached ribosomes. Smooth ER synthesizes the
phospholipids that occur in membranes and has various other functions depending on the particular cell. In the
testes, it produces testosterone, and in the liver, it helps detoxify drugs. Regardless of any specialized function,
smooth ER also forms vesicles in which proteins are transported to the Golgi apparatus.
Ribosomes
All living cells contain ribosomes, tiny organelles composed of approximately 60 percent RNA and 40 percent
protein. In eukaryotes, ribosomes are made of four strands of RNA. In prokaryotes, they consist of three strands
of RNA. Each cell contains many, many ribosomes.




composed of rRNA (ribosomal RNA) & protein
may be dispersed randomly throughout the cytoplasm or attached to surface of rough endoplasmic
reticulum
primary function is to produce proteins
cells need a steady supply of proteins to carry out all their life functions.
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Cellular Structure & Function
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Golgi Complex (AKA Golgi Body, Golgi Apparatus)


consists of a series of flattened sacs (or cisternae)
functions include:
 synthesis (of substances likes phospholipids),
 packaging of materials for transport (in vesicles), and
 production of lysosomes
The Golgi apparatus consists of a stack of three to twenty slightly curved saccules whose appearance can be
compared to a stack of pancakes. In animal cells, one side of the stack (the inner face) is directed toward the
ER, and the other side of the stack (the outer face) is directed toward the plasma membrane.
Vesicles can frequently be seen at the edges of the saccules. The Golgi apparatus receives protein and also
lipid-filled vesicles that bud from the smooth ER. These molecules then move through the Golgi from the
inner face to the outer face.
During their passage through the Golgi apparatus, glycoproteins have their sugar chains modified before
they are repackaged in secretory vesicles. Secretory vesicles proceed to the plasma membrane, where they
merge with the plasma membrane and discharge their contents. This process is known as exocytosis.
Because this is secretion, the Golgi apparatus is said to be involved in processing, packaging, and secretion.
The Golgi apparatus is also involved in the formation of lysosomes, vesicles that contain proteins and
enzymes. These remain within the cell.
This diagram shows both exocytosis and endocytosis
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Cellular Structure & Function
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Lysosomes



Only found in animal cells
membrane-enclosed spheres that contain powerful digestive enzymes
functions include:
 destruction of damaged cells (which is why they are sometimes called
'suicide bags'),
 digestion of phagocytosed materials (such as bacteria)
Lysosomes are membrane-bounded vesicles produced by the Golgi apparatus. Lysosomes contain hydrolytic
digestive enzymes. Sometimes macromolecules are brought into a cell by vesicle formation at the plasma membrane
(endocytosis). When a lysosome fuses with such a vesicle, its contents are digested by lysosomal enzymes into
simpler subunits that then enter the cytoplasm. Some white blood cells defend the body by engulfing pathogens by
vesicle formation. When lysosomes fuse with these vesicles, the bacteria are digested.
Even parts of a cell are digested by its own lysosomes (called autodigestion). Normal cell rejuvenation takes place
in this manner. Lysosomes contain many enzymes for digesting all sorts of molecules. Lysosomes break down
cellular waste products and debris from outside the cell into simple compounds, which are transferred to the
cytoplasm as new cell-building materials.
Peroxisomes
Peroxisomes, similar to lysosomes, are membrane-bounded vesicles that enclose
enzymes. However, the enzymes in peroxisomes are synthesized by cytoplasmic
ribosomes and transported into a peroxisome by carrier proteins. Typically,
peroxisomes contain enzymes whose action results in hydrogen peroxide (H2O2).
Hydrogen peroxide, a toxic molecule, is immediately broken down to water and oxygen by another peroxisomal
enzyme called catalase. The enzymes in a peroxisome depend on the function of the cell. Peroxisomes are especially
prevalent in cells that are synthesizing and breaking down fats. In the liver, some peroxisomes break down fats and
others produce bile salts from cholesterol.
Plant cells also have peroxisomes. In germinating seeds, they oxidize fatty acids into molecules that can be
converted to sugars needed by the growing plant. In leaves, peroxisomes can carry out a reaction that is opposite to
photosynthesis (cellular respiration) — the reaction uses up oxygen and releases carbon dioxide.
Vacuoles
A vacuole is a large membranous sac. A vesicle is smaller than a vacuole. Animal cells
have vacuoles, but they are much more prominent in plant cells. Typically, plant cells have
a large central vacuole so filled with a watery fluid that it gives added support to the cell.
Vacuoles store substances.
Plant vacuoles contain not only water, sugars, and salts but also pigments and toxic
molecules. The pigments are responsible for many of the red, blue, or purple colors of
flowers and some leaves. The toxic substances help protect a plant
from herbivorous animals.
The vacuoles present in unicellular protozoans are quite specialized,
and they include contractile vacuoles for ridding the cell of excess
water and digestive vacuoles for breaking down nutrients.
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Cellular Structure & Function
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Mitochondria
Mitochondria are found exclusively in eukaryotic cells
(including plants and algae). These organelles are often called
the "power plants" of the cell because their main job is to
provide energy (ATP). They convert nutrients and oxygen into
usable energy (ATP) in a chemical reaction known as cellular
respiration. The energy comes from the breaking of the bonds
of glucose molecules which is then stored in ATP molecules.
The more active a cell is, the more mitochondria it has.
 They have a double membrane structure: the smooth outer membrane and a inner membrane with many
folds called cristae;
 primary function is production of adenosine triphosphate (ATP)
Mitochondria are highly unusual--they contain their own genetic material and protein-making machinery within a
double membrane.
In mitochondria, the inner fluid-filled space is called the matrix. The matrix contains DNA, ribosomes, and enzymes
that break down carbohydrate products used for ATP production. The inner membrane of a mitochondrion folds
back and forth to form cristae. Cristae provide a much greater surface area to accommodate the protein complexes
and other participants that produce ATP. We will look at this much more closely later during cellular respiration.
Centrioles






paired cylindrical structures located near the nucleus
play an important role in cell division
Centrioles are self-replicating organelles made up of nine bundles of
microtubules
Found only in animal cells.
They appear to help in organizing cell division, but aren't essential to
the process.
Cilia and Flagella - For single-celled eukaryotes, cilia and flagella are essential for the locomotion of individual
organisms. In multicellular organisms, cilia function to move fluid or materials past an immobile cell as well as moving
a cell or group of cells.
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Cellular Structure & Function
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Plant-specific Organelles
Plant cells are different from animal cells because they can make and store their own food in special organelles
known as plastids. Most of the inner structure of the plant cell is taken up with a large water-filled vacuole. This
large central vacuole, as it fills with water, presses against the fibrous structure of the cell wall creating turgor
pressure. The cell wall is another structure not found in animal cells, but present in plant cells.
Chloroplasts (a type of plastid)










Only found in plants and algae.
the organelles that allow them to produce
their own organic food through
photosynthesis.
Chloroplasts belong to a group of organelles
known as plastids.
A chloroplast is green, of course, because it
contains the green pigment chlorophyll.
A chloroplast is bounded by two
membranes that enclose a fluid-filled space
called the stroma.
A membrane system within the stroma is
organized into interconnected flattened sacs called thylakoids.
In certain regions, the thylakoids are stacked up in structures called grana (sing., granum). There can be
hundreds of grana within a single chloroplast.
Chlorophyll, which is located within the thylakoid membranes of grana, captures the solar energy needed
to enable chloroplasts to produce carbohydrates.
The stroma also contains DNA, ribosomes, and enzymes that synthesize carbohydrates from carbon dioxide
and water.
Plant cells contain both chloroplasts and mitochondria.
Other Plastids

Among the plastids are also:
o the amyloplasts, common in
roots, which store starch, and
o the chromoplasts, common in
leaves, which contain red and
orange pigments.
Biology 11 - Ms. Bowie
Cellular Structure & Function
Plant Cell Wall
Most plant cells are surrounded by cell walls that are made
of cellulose. Its main function is to protect and support the
cells. Some cells have a single wall (a primary wall). Other
cells have a 2nd cell wall (secondary wall) which provides
the cell with extra strength and support. Flower petals and
the flesh of fruit would be composed of a delicate primary
wall. The stronger, more fibrous parts of a tree would have
a stronger, secondary wall.
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Cellular Structure & Function
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Cellular Structure & Function
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The Plasma Cell Membrane
Most of the cell membrane is composed of phospholipids. Each phospholipid molecule is made up of a hydrophilic
(water-loving) head and a hydrophobic (water-fearing) tail.
The hydrophilic heads always align themselves
so that they face an aqueous environment (i.e.
water).
The hydrophobic tails move so that they are as far away from water as
possible. This results in a phospholipid bilayer.
There are also proteins embedded in the phospholipid
bilayer. Each of the proteins has a specific task within the
membrane. There are 2 major types of proteins:
1. Rod-shaped fibrous proteins
2. Compact globular proteins (integral proteins and
peripheral proteins)
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Cellular Structure & Function
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Three examples of globular proteins are:
Passage through the Cell Membrane
The cell membrane, composed mostly of non-polar lipid molecules are only soluble to other non-polar substances
(i.e. like dissolves like). Therefore, only oxygen, carbon dioxide and steroids can pass through the membrane
directly.
Water-soluble and polar substances such as water, glucose, amino acids and ions (charged particles) require the
assistance of integral proteins to pass through the membrane.
Protein Helpers
Fibrous proteins span the cell membrane as serve as receptor proteins.
They work somewhat like a key in a lock.
Pore proteins also span the membrane. They allow water to
pass through the membrane.
Channel proteins span the membrane and transport
ions that are needed by the cell.
Glycoproteins are not transport proteins. Instead,
their role is to identify the cell as belonging to "self".
When our immune system encounters a cell that is
not displaying the correct glycoprotein, it will attack and
kill it. Glycoproteins do not span the membrane. They
are peripheral proteins, as they only need to be displayed
on the outside, like a uniform or a sign.
Cholesterol is a steroid found only in
animal cell membranes. It is a sticky
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Cellular Structure & Function
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molecule that serves to stabilize the phospholipid matrix. The phospholipids are not attached to each other. Instead
they flow freely. This is why the plasma cell membrane is sometimes called the Fluid Mosaic Model. The addition
of cholesterol reduces the movement of the phospholipids, thus making the membrane more stable. Plant cell
membranes do not contain cholesterol as they don't need it due to the cell wall.
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Cellular Structure & Function
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Cellular Transport
Movement Across Membranes
1 - Passive processes - require no expenditure of energy by a cell:



Simple diffusion = net movement of a substance from an area of high concentration to an area
of low concentration . The rate of diffusion is influenced by:
o concentration gradient
o cross-sectional area through which diffusion occurs
o temperature
o molecular weight of a substance
o distance through which diffusion occurs
Osmosis = diffusion of water across a semipermeable membrane (like a cell membrane) from an
area of low solute concentration to an area of high solute concentration
Facilitated diffusion = movement of a substance across a cell membrane from an area of high
concentration to an area of low concentration. This process requires the use of membrane
proteins. When a large molecule (e.g., acetylcholine) binds to the membrane protein, it causes a
conformational change or, in other words, an 'opening' in the protein through which a substance
(e.g. sodium ions) can pass.
2 - Active processes - require the expenditure of energy by cells:
o
Active transport = movement of a substance across a cell
membrane from an area of low concentration to an area of
high concentration using a carrier molecule
Endocytosis & exocytosis - moving material into (endo-) or out of (exo-) cell in bulk form.
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Cellular Structure & Function
Page 22 of 36
Osmosis
Hypertonic, Hypotonic & Isotonic Solutions
Hyper = “More than”
 To classify any solution you must compare it to something else (a solution
or a cell's interior).
Hypo = “Less than”
 If a solution outside the cell has more solute than inside the cell, we say
that the solution is HYPERTONIC (relative to the inside of the cell).
Iso = “Same as”
 Water always flows toward the higher concentration of solute.
You already learned that in osmosis, water will move from an area that has the least solute (the most water) to an area that
has the most solute (the least water). Cells will change size and shape if they are placed in difference types of solutions. As
the above prefixes show, there are three main types of solutions: hypertonic, hypotonic & isotonic.
Hypertonic solutions have MORE SOLUTE than the object (cell) placed in it. Therefore, if there is more solute outside the cell,
the water will move _____________________________________________.
Hypotonic solutions have LESS SOLUTE than the object (cell) placed in it. Therefore, if there is less solute outside the cell, the
water will move _________________________________________________.
Isotonic solutions have the SAME AMOUNT of solute as the object placed in it. Therefore, you would expect
________________________________________________________________________________.
Let’s take a microscopic look:
Legend:
= Water
= Solute
Classify each of the following solutions in the beakers. Show the direction of flow of the water (osmosis) with arrows.
Solution Type: __________________
Solution Type: _________________
Solution Type: _________________
Result: ________________________
Result: _______________________
Result: _______________________
Biology 11 - Ms. Bowie
Cellular Structure & Function
Page 23 of 36
CELLULAR METABOLISM:
Energy-Related Organelles
Life is possible only because of a constant input of energy
used for maintenance and growth. Chloroplasts and
mitochondria are the two eukaryotic membranous
organelles that specialize in converting energy to a form
that can be used by the cell.
Chloroplasts use solar energy to synthesize carbohydrates,
and carbohydrate-derived products are broken down in
mitochondria (singular - mitochondrion) to produce ATP
molecules, as shown in the following diagram:
Photosynthesis
Only plants, algae, and cyanobacteria are capable of carrying out photosynthesis in this manner:
Plants and algae have chloroplasts while cyanobacteria carry on photosynthesis within independent thylakoids.
Solar energy is the ultimate source of energy for cells because nearly all organisms, either directly or indirectly, use
the carbohydrates produced by photosynthesizers as an energy source.
Cellular Respiration
All organisms carry on cellular respiration, the process by which the chemical energy of carbohydrates is converted
to that of ATP (adenosine triphosphate). ATP is the common carrier of chemical energy in cells. All organisms,
except bacteria, complete the process of cellular respiration inside mitochondria. Cellular respiration can be
represented by this equation:
C6H12O6 + O2  CO2 + H2O + ENERGY
Here energy is in the form of ATP molecules. When a cell needs energy, ATP supplies it. The
energy of ATP is used for synthetic reactions, active transport, and all energy-requiring
processes in cells.
Cells require energy for active transport, synthesis, impulse conduction (nerve cells),
contraction (muscle cells), and so on. Cells must be able to 'capture' and store energy & release that energy in
appropriate amounts when needed. An important source of energy for cells is glucose (C6H12O6).
Biology 11 - Ms. Bowie
Cellular Structure & Function
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Cell Respiration
Introduction
Cellular respiration is the process by which the chemical energy of "food" molecules is released
and partially captured in the form of ATP. Carbohydrates, fats, and proteins can all be used as fuels
in cellular respiration, but glucose is most commonly used as an example to examine the reactions
and pathways involved.
We can divide cellular respiration into three metabolic processes: glycolysis, the Krebs cycle,
and oxidative phosphorylation. Each of these occurs in a specific region of the cell.
1. Glycolysis occurs in the cytosol (cytoplasm of the cell).
2. The Krebs cycle takes place in the matrix of the
mitochondria.
3. Oxidative phosphorylation via the electon transport chain is
carried out on the inner mitochondrial membrane.
In the absence of oxygen, respiration consists of two metabolic pathways: glycolysis and
fermentation. Both of these occur in the cytosol. We will talk about this anaerobic respiration later
in this booklet.
Biology 11 - Ms. Bowie
Cellular Structure & Function
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Overview of the processes
C6H12O6 + 6O2 -------------------> 6CO2 + 6H2O + ~38 ATP
Glucose + oxygen → carbon dioxide + water + ATP (energy)
Glycolysis
Glycolysis literally means "splitting sugars." In glycolysis, the 6-carbon sugar, glucose, is broken
down into 2 molecules of a 3-carbon molecule called pyruvate. In the process, two molecules of
ATP, two molecules of pyruvic acid and two "high energy" electron carrying molecules of NADH
are produced.
Glycolysis can occur with or
oxygen. In the presence of
glycolysis is the first stage of
respiration.
without
oxygen,
cellular
Without oxygen, glycolysis
cells to make small amounts of
This process is called
fermentation.
allows
ATP.
Biology 11 - Ms. Bowie
Cellular Structure & Function
Page 26 of 36
Krebs Cycle
The Krebs cycle occurs in the mitochondrial matrix and generates a pool of chemical energy (ATP,
NADH, and FADH2) from the oxidation of pyruvate.
Pyruvate moves into the mitochondria. In an intermediate transition step, the 2 pyruvate molecules
each combine with Coenzyme A and lose carbon dioxide to become 2 molecules of Acetyl-CoA.
This is a 2-carbon molecule.
In the presence of Oxygen gas (O2), all the hydrogens (H2) are stripped off the Acetyl CoA, two by
two, to extract the electrons for making ATP, until there are no hydrogens left - and all that is left
of the sugar is CO2 - a waste product - and H2O (exhaled). The Krebs cycle results in the
production of only ~4 ATPs, but produces a lot of NADH, which will go on to the next step... Hans
Krebs won the Nobel Prize in 1953 for his discovery of the Citric Acid Cycle, which we now call
the Krebs Cycle.
When acetyl-CoA is oxidized to carbon dioxide in the Krebs cycle, chemical energy is released
and captured in the form of NADH, FADH2, and ATP.
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Cellular Structure & Function
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The Electron Transport Chain - Oxidative Phosphorylation
The electron transport chain allows the release of the large
amount of chemical energy stored in NADH and FADH2. The
energy released is captured in the form of ATP (3 ATP per
NADH and 2 ATP per FADH2).
NADH + H+ + 3 ADP + 3 Pi + ½ O2 → NAD+ + H2O + 3 ATP
FADH2 + 2 ADP + 2 Pi + ½ O2 → FAD+ + H2O + 2 ATP
The electron transport chain (ETC) consists of a series of molecules, mostly proteins, embedded in
the inner mitochondrial membrane; the mitochondrial cristae.
http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__electron_transport_system_and_atp_synthesis__quiz_1_.html
http://www.sumanasinc.com/webcontent/animations/content/cellularrespiration.html
Biology 11 - Ms. Bowie
Cellular Structure & Function
To Recap
Cellular Respiration is the reverse process of photosynthesis
Cellular Respiratin consists of 3 basic steps:
Glycolysis
takes place in the cytosol of the cell (outside the mitochondria)
It involves the splitting of a glucose molecue into 2 pyruvate colecules
In the process 2 NADs are charged to become 2 NADH and 4 ADPs gain another phosphorus
atom to become 4 ATPs (the high energy storage molecules) - only 2 in total since 2 ATPs were
needed to begin the process. Two water molecules are also released.
Don't stop now though since each pyruvate contains lots more energy! Bring on the Krebb Cycle...
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Biology 11 - Ms. Bowie
The Krebb Cycle
Cellular Structure & Function
The pyruvates 1st move from the cytosol into the mitochondrial matrix.
On the way the 2 pyruvates undergo a transformation to become 2 acetyl-CoA
molecules when they interact with 2 co-enzyme A molecules.
Note: 2 more NAD molecules are charged to become NADH.
Carbon dioxide is also released in this step.
Next, the acetyl-CoA molecules undergo a series of reactions the charge a lot more
NAD molecules into NADH. Another type of "energy carrier" called FAD+ becomes
charged into FADH2.
Although some ATP are produced in this cycle, it is actually the NADH and FADH2 that
are the important part of this phase of the story. These two highly charged particles
must move on to the electron transport chain to give up their electrons.
When these molecules release their electrons in the presence of oxygen, loads of ATP
are produces.
Let's move on and look at how this happens in the electron transport chain...
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Biology 11 - Ms. Bowie
Cellular Structure & Function
Page 30 of 36
The Electron Transport Chain
This step takes place in the mitochondrial cristae (the folds in
the inned membrane of the mitochondria).
In this step, the NADH and FADH2 will be used to
produce many, many ATP molecules.
The NADH and FADH2 molecules give their electrons in order to pump hydrogen atoms across the cristae membrane.
Oxygen atoms MUST be present to snatch the
electrons away at the bottom of the transport
chain process. When they do, they create 2
water molecules.
The hydrogen concentration builds up
inside the cristae. As they flow back to
their normal concentration, they
convert ADP into ATP!
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Cellular Structure & Function
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Aerobic Respiration vs. Anaerobic Respiration
The molecular process that breaks down glucose produces waste products and energy is called respiration. There are
two kinds of respiration: Aerobic and Anaerobic. Living organisms use energy released by respiration for their life
processes.
Aerobic respiration takes place in the presence of oxygen, produces a large amount of energy. Carbon dioxide
and water are produced as the waste products.
Anaerobic respiration takes place without the use of oxygen, produces small amounts of energy. Alcohol or
lactic acid or other compounds are produced as waste products depending on the kind of cells that are active.
The type of energy needed for a long-distance race versus a short-term wrestling match can also help explain the
difference between aerobic and anaerobic respiration. For a long-distance race, aerobic respiration takes place
producing a large amount of energy. For a short-term wrestling match, anaerobic respiration takes place and will
produce small bursts of energy.
The race is a cardio exercise, and the heart must maintain a steady rate of about 60 to 80% of its maximum, and
there must be enough oxygen to sustain muscle power. On the other hand, an intense, short workout like a wrestling
match requires the heart rate to increase to more than 80% of its maximum, and there must be enough oxygen for an
immediate source of power.
In brief, aerobic respiration allows for long-term energy needs, and anaerobic for short-term energy needs. Of
course, most sports and activities use a combination of aerobic and anaerobic respiration.
There are also other technical differences between aerobic and anaerobic respiration. For aerobic, the cells involved
include those in most organisms and body cells; however, anaerobic may occur in muscle cells and red blood cells,
and is some types of bacteria and yeast.
Lactic acid is produced during Anaerobic, and none is produced during aerobic. A high amount of energy is
produced in aerobic respiration with 38 glucose molecules, and low energy with only 2 glucose molecules during
anaerobic.
In addition, the reactants for aerobic respiration is both oxygen and glucose, yet for anaerobic the reactant is just
glucose. The reaction site in the cell for aerobic is in the cytoplasm or mitochondria, and just in the cytoplasm for
anaerobic respiration.
Both aerobic and anaerobic respiration involves a first stage called glycolysis. The additional stage in anaerobic is
fermentation, but in aerobic there is the Krebs cycle and electron transfer chain. Finally, combustion is complete in
aerobic respiration, and incomplete during anaerobic respiration.
In summary, when thinking of aerobic respiration, relate it to aerobic exercises, which involves the need for a large
amount of energy over a long time period. Oxygen is present and carbon dioxide and water is produced as waste
products. For anaerobic, short burst and small amounts of energy produced, oxygen is not present, lactic acid and
other compounds are produced as waste products depending on the kind of active cells.
Biology 11 - Ms. Bowie
To Recap:
Cellular Structure & Function
Page 32 of 36
Biology 11 - Ms. Bowie
Cellular Structure & Function
Levels of Organisation in Multicellular Organisms
CELLULAR LEVEL
Cells are the basic structural and functional units of the human
body & there are many different types of cells (e.g., muscle,
nerve, blood, etc.)
TISSUE LEVEL
A tissue is a group of cells that perform a
specific function and the basic types of tissues in
the human body include epithelial, muscle,
nervous, and connective tissues.
ORGAN LEVEL
An organ consists of 2 or more tissues that
perform a particular function (e.g., heart, liver,
stomach, and so on)
ORGAN SYSTEM LEVEL
An association of organs that have
a common function; there are 11
major systems in the human body,
including digestive, nervous,
endocrine, circulatory, respiratory,
urinary, reproductive, muscular,
lymphatic, skeletal, and
integumentary.
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Biology 11 - Ms. Bowie
Cellular Structure & Function
Page 34 of 36
Test Review
Cell Structure and Function Interpreting Diagrams Use the terms listed in the box to label the diagram below.
Write your answers in the spaces provided. Then, answer the questions.
TERMS cell membrane cell wall chloroplast nucleus vacuole
1. ____________________________________________
2. ____________________________________________
3. ____________________________________________
4. ____________________________________________
5. ____________________________________________
6. What kind of cell is shown in Part A of the diagram? __________________________________________
7. What kind of cell is shown in Part B of the diagram? ___________________________________________
8. What are three jobs of the cell membrane? ____________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
9. What part of the cell is made up of cellulose? _________________________________________________
10. What part of the cell is needed to make food? _________________________________________________
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Cellular Structure & Function
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Multiple Choice
Write the letter of the term or phrase that best completes each statement in the spaces provided.
______ 1. A scientific tool that makes objects appear larger than they really are is a
a. scale.
b. thermometer.
c. balance.
d. microscope.
______ 2. A piece of curved glass that causes light rays to come together or spread apart as they pass through is a
a. lens.
b. meter stick.
c. balance.
d. microscope.
______ 3. The basic unit of structure and function in living things is the
a. nucleus.
b. membrane.
c. cell.
d. chloroplast.
______ 4. The thin structure that surrounds a cell is known as a.
a nucleus.
b. a cell membrane.
c. cytoplasm.
d. a vacuole.
_____ 5. The control center of a cell is the
a. cell wall.
b. organelles.
c. cytoplasm.
d. nucleus.
_____ 6. All the living material inside a cell, except the nucleus, makes up the
a. cytoplasm.
b. membranes.
c. vacuole.
d. mitochondria.
_____ 7. The movement of material from a more crowded area to a less crowded area is called
a. osmosis.
b. photosynthesis.
c. respiration.
d. diffusion.
_____ 8. Small, round structures in a cell that make proteins are known as
a. cellulose.
b. ribosomes.
c. vacuoles.
d. mitochondria.
_____ 9. The movement of water through a membrane is called
a. diffusion.
b. synthesis.
c. osmosis.
d. photosynthesis.
_____ 10. The process by which cells reproduce is
a. diffusion.
b. osmosis.
c. cell division.
d. respiration.
_____ 11. The cell structures that break down food to produce energy are the
a. ribosomes.
b. mitochondria.
c. vacuoles.
d. chloroplasts.
_____ 12. The cell structures that break down nutrient molecules and old cell parts are known as
a. ribosomes.
b. lysosomes.
c. vacuoles.
d. chloroplasts.
Biology 11 - Ms. Bowie
Cellular Structure & Function
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______ 13. The small network of tubes that makes proteins in the cell is known as the
a. lysosomes.
b. mitochondria.
c. vacuoles.
d. endoplasmic reticulum.
______ 14. Animal cells have all of the following except
a. ribosomes.
b. mitochondria.
c. vacuoles.
d. a cell wall.
______ 15. The specialized cells that carry information throughout the body are known as
a. white blood cells.
b. red blood cells.
c. nerve cells.
d. guard cells.
______ 16. The movement of materials through a membrane without the use of energy is known as
a. passive transport.
b. photosynthesis.
c. active transport.
d. fermentation.
______ 17. The nucleus of a cell divides by the process of
a. mitosis.
b. osmosis.
c. diffusion.
d. respiration.
______ 18. Oxygen is carried throughout the body by
a. white blood cells.
b. red blood cells.
c. guard cells.
d. bone cells.
______ 19. All of the following are types of organelles except
a. ribosomes.
b. cell walls.
c. mitochondria.
d. vacuoles.
______ 20. All of the following are found only in plant cells except
a. vacuoles.
b. cell walls.
c. chlorophyll.
d. chloroplasts.
Test Answers:
Cell Structure and Function Interpreting Diagrams
1. cell wall 2. cell membrane 3. vacuole 4. nucleus 5. chloroplast 6. animal cell 7. plant cell 8. protects the cell, supports the cell
and gives it shape, controls movement of materials into and out of the cell. 9. cell wall 10. chloroplasts
Multiple Choice 1. d 2. a 3. c 4. b 5. d 6. a 7. d 8. b 9. c 10. c 11. b 12. b 13. d 14. d 15. c 16. a 17. a 18. b 19. b 20. a