Review: Plant and Animal Cells
Learning Goal:
 Understand the various parts of the cell
 Understand differences between Prokaryotes and Eukaryotic cells
The cell theory states that
1. All living things are made up of one or more cells and their products.
2. The cell is the simplest unit that can carry out all life processes.
3. All cells come from other cells; they do not come from non-living matter.
**Spontaneous generation: a theory that living things can form from non-living things. => is not true
Cells can be grouped into two categories:
1) Prokaryotic
2) Eukaryotic
Prokaryotic
 Simple cell
 small
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Eukaryotic cells
Complex cells
Larger than prokaryotic cells: 10 -1000x larger
than prokaryotic cells

Do not have a proper nucleus. Genetic material
is stored in a region of the cell called the
nucleoid, so DNA within cytosol.

Has a proper nucleus

Have no membrane around organelles: no
membrane bound organelles

Has membrane around organelle ex. Ribosomes,
chloroplasts, mitochondria, lysosomes, golgi
apparatus

Makes up single-celled organisms

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Prokaryotic cells include cells of archaebacteria
and bacteria

Eukaryotic cells make up single-celled organisms
like yeast or multicellular organisms like humans
Eukaryotic cells include cells of protista, fungi,
animals, and plants. Protista are eukaryotic cells
that have traits of fungi, animals, and/or plants
and cannot fit into those categories, therefore,
they have a mix of traits of fungi, animals, and
plants AND therefore are put into protista as
they do not fit in one of the those categories ex.
Amoeba, euglena (move like animals and have
chloroplasts like plants, therefore, they are put
into protista)
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Cell Structure
 Body is made up of organs that carry out processes needed to live.
 Cell has specialized parts called organelles that carry out specific functions necessary for that cell to
function.
 Structures Common to Plants and Animal Cells
o All cells have to perform the same basic activities to stay alive:
 use energy
 store materials
 take materials from the environment
 get rid of wastes
 move substances to where they are needed
 reproduce.
o Each organelle (little organ) has a specific function within the cell. The various organelles of a cell
work together to meet the needs of the cell
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Organelles:
Cytoplasm
 All the organelles inside the cell are held in the cytoplasm. Organelles can move around
 Cytoplasm is mostly water and other substances that cell stores until needed.
 Place of many chemical reactions and processes such as protein synthesis
Cell membrane
 flexible double-layered cell membrane bilayer has 2 layers
 Function:
o support the cell
o semi-permeable: allow some substances to enter while keeping others out.
 Water and oxygen molecules can easily pass through the cell membrane
 larger molecules: proteins cannot pass through the cell membrane
 A membrane similar to the cell membrane surrounds most organelles in a eukaryotic cell.
Nucleus
 Nucleus: roughly spherical structure in the cell
 nucleus contains genetic information that controls all cell activities. Genetic information is DNA
(deoxyribonucleic acid), the substance that carries the coded instructions for all cell activity. DNA is stored in
chromosomes/chromatin.
 When a cell divides, the DNA is copied so that each new daughter cell has a complete set of the parent DNA.
Nuclear envelope is the membrane around the nucleus
Chromatin is thread-like pieces of DNA. Chromosome = condensed DNA.
Nucleolus is core of the nucleus and makes ribosome
Nuclear pore: controls movement of material into and out of nucleus=> is the holes in the nuclear envelope
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Mitochondria
 Cells contain many mitochondria (singular: mitochondrion) (Figure 5).
 Mitochondria are sometimes called “power plants” of the cell because they make energy available to the cell.
 How do Mitochondria make energy available to the cell?
 The mitochondria contain enzymes that help to convert the stored energy (in glucose) into an easily usable
form called ATP. This process is called cellular respiration and requires oxygen. The waste products of this
reaction are carbon dioxide and water.
Cellular Respiration occurs in the mitochondria: glucose + oxygen → carbon dioxide + water + usable
energy (ATP)
 Note: This is the carbon dioxide that we breathe out.

Structure:
o Have a kidney-bean shape
o The mitochondrion has two membranes:
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outer membrane and inner membrane (cristae)
 inner membrane also called cristae and is where cellular respiration processes occurs (you
will learn more about this in Grade 12U Biology)
intermembrane space = space between the outer and inner membranes
matrix is the interior aqueous environment of the organelle. Internal fluid part of the organelle
(cytoplasm of the mitochondria)
Cells which require lots of energy such as muscle cells (movement) and liver cells (must detoxify body) require
many mitochondria
Cells that are fairly inactive, meaning they do not require much energy, tend to have very few mitochondria.
Example: Fat cells (adipose cells) may have only one or two mitochondria.
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Class question: This picture is from a transmission electron microscope, are cells kept alive or made dead to
be viewed under the transmission electron microscope? What about the light microscope?live
Ribosomes:
 Small structures that exist on the endoplasmic reticulum or on their own in the cytosol
 They create proteins. How?
 Read mRNA (messanger RNA) and convert or translate into proteins [Learn about this more in the Genetics Unit
and in Grade 12 Biology U]
 Ribosomes consists of two parts the Large subunit and the Small subunit.
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Endoplasmic Reticulum (ER)
 The endoplasmic reticulum is a three-dimensional network of branching tubes and pockets (Figure 6).
 Extends through cytoplasm from nuclear membrane to the cell membrane.
 ER are Fluid-filled tubes that transport materials, such as proteins, through the cell and during transport, they
mature these molecules to be released or used by the cell.
 [Think of ER as the subway system that transports proteins all through the cell, just like the subway system
transports people all through the city
 There are 2 types of endoplasmic reticulum:
o Rough Endoplasmic Reticulum: ribosomes are on the endoplasmic reticulum, ribosome will create the
protein and send it down into the endoplasmic reticulum for processing and maturation. With the
ribosomes on the surface of the endoplasmic reticulum, the endoplasmic reticulum have a rough
structure and therefore are called the Rough Endoplasmic Reticulum.
o When ribosomes are not present on the endoplasmic reticulum surface, the endoplasmic reticulum has a
smooth surface and therefore is called the Smooth Endoplasmic Reticulum (SER)
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SUMMARY OF ER Function and Structure: Endoplasmic Reticulum runs from nuclear envelope to cell membrane. it
contains fluid. Molecules like proteins are put inside of it and they get modified as they move through the
endoplasmic reticulum
Golgi Bodies:
 Takes in molecules from the endoplasmic reticulum and modifies them into their final form so they are ready to
be released out of the cell.
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The Golgi apparatus is a series of flattened sacs. When a molecule has been modified into its final form by the
Golgi Body, it is released from the golgi body in a vesicle and moves towards the cell membrane. The vesicle
fuses with the cell membrane and releases its contents to the outside of the cell.
Which molecules does the Golgi body process? Hormones, proteins, fats
Cells that secrete a lot of substances have many Golgi bodies [just like cells that do a lot of activity, need lots of
ATP, and therefore have lots of mitochondria]
o examples
 Intestinal cells secrete mucus
 Stomach cells that secrete acid
 You will learn about the digestive processes in The Digestive Unit of this course.
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Vacuoles
 A vacuole is a single layer of membrane which encloses fluid in a sac.
 Vacuole functions include:
o Storage of nutrients
o removing unwanted substances from the cell
o maintaining internal fluid pressure (turgor) within the cell.
o Ingestion of substances: ingested substances are held inside a vacuole.
 NOTE:
o Animal cells may have many small vacuoles that are often not visible.
o Mature plant cells usually have one central vacuole that is visible under a microscope.
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Lysosomes
o A lysosome is a membrane-bound cell organelle that contains digestive enzymes. These enzymes break
down excess or worn-out cell parts and destroy microbes such as invading viruses and bacteria.
o A vesicle containing a cell part or microbe fuses with the lysosome, allowing the hydrolytic enzymes in the
lysosome to access the cell part or microbe in the vesicle. The lysosome destroys the cell part/microbe.
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Organelles in Plants Cells only
 Cell Wall
o The cell wall is found just outside the cell membrane of a plant cell.
o Rigid with pores
o Made up of cellulose (rigid macromolecule – you will learn more about this in Grade 12 Biology
o This cell wall provides support for the cell and protection from physical injury.
o Paper contains cellulose from cell walls of trees
.
 Large Vacuole
o Plant cells have one large vacuole, which takes up most of the space inside the cell.
o When vacuole are full of water, turgor pressure (water pressure from inside the cell) is high AND
keeps the plant cells plump, which keeps the plant’s stems and leaves firm. This is why fruits and
vegetables are sprayed in the grocery store to keep their turgor pressure high, so that the vegetables
remain firm and fresh
o Turgor pressure = pressure from inside the cell (from the vacuole) that puts pressure on the
cell wall and keep the cell plump
o If the water level drops, vacuoles lose turgor pressure and the cells become soft. The plant stems and
leaves become limp and droopy until the water is replaced. This is what happens when you keep
celery in the fridge for a long time, the stalks become limb and wobbly because the turgor pressure
has dropped as water has been evaporated
Chloroplasts (learn more about chloroplasts in Grade 12 U Biology)
o Plant cells contain chloroplasts.
o Chloroplasts contain the pigment chlorophyll, which gives the plant its green colour
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o Chloroplasts absorb light from the Sun to do photosynthesis.
o Photosynthesis is the process of converting carbon dioxide and water into glucose and oxygen.
 carbon dioxide + water + energy (sunlight) → glucose + oxygen
o Photosynthesis allows plants to obtain their energy from the Sun so that they can make their own
food.
o Plant cells rely on mitochondria to break down glucose into ATP (cellular respiration) just as animal
cells do.
o Chloroplasts consists of a stacks of discs. The discs called thylakoids and the stack of discs is called a
grana. The grana are connected to one another by lamella. Here is where part of the
photosynthesis reactions occur.
Review animation: https://www.cellsalive.com/cells/cell_model_js.htm
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Interactive Questions
For the following cell parts, describe their structure and function
Cell part
Structure
Cell membrane
Mitochondria
Ribosomes
Golgi Body
Endoplasmic Reticulum
Cytoplasm
Chloroplasts
Vacuole
Cell Wall
Function
Watch on your own: https://www.youtube.com/watch?v=URUJD5NEXC8
Lesson 1 Interactive Questions:
https://docs.google.com/document/d/1cFunvUG3jyOAI11Hdn_Y1X49n7bApa0UA2kFk5bNKdQ/edit?usp=sharing
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