Cells
The cell theory:
1. All living things are made up of cells.
2. Cells are the basic units of structure and function in living things.
3. Living cells come only from other living cells.
Cells that do the same job combine together to form body tissue, such as muscle, skin, or bone tissue. Groups of different
types of cells make up the organs in your body, such as your heart, liver, or lungs. Each organ has its own job to do, but
all organs work together to maintain your body. A group of different organs working together to do a job makes up a
system. All the systems in your body are like members of a team whose job it is to keep you alive and healthy.
Some facts:
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Some are membrane bound (organelles) while others do not
Genes are instructions for cells to create specific proteins
Information transfer carries no errors/mutations.
Cells arise from the division of other cells
Mitosis - the genetic complement of each daughter cell is identical to the other and to the mother cell. This is
asexual reproduction
Meiosis - the genetic complement of each daughter cell is reduced by half and each daughter cell is genetically
unique. This is used in sexual reproduction
Asexual - organelles from mother cell
Sexual - organelles predominately from one parent
Plant cells undergo photosynthesis and utilize energy
Most cells respire
Cells can perform a variety of chemical reactions
Cells control DNA synthesis and cell division
Types
The major differences between Prokaryotic and Eukarotic cells is that prokaryotes don't have a nucleus and rarely have
membrane bound organelles. They both do have DNA for genetic material, have an exterior membrane, have ribosomes,
accomplish similar functions, and are very diverse. For instance, there are over 200 types of cells in the human body that
vary greatly in size, shape, and function.
PROKARIOTIC:
The simplest types of cells were most likely the first type of cells that formed on Earth. These are called prokaryotic cells.
All prokaryotic cells have a cell membrane surrounding the cell, cytoplasm where all of the metabolic processes happen,
ribosomes that make proteins, and a circular DNA molecule called a nucleoid. Prokaryotic cells also have a rigid cell wall
that is used for protection. All prokaryotic organisms are unicellular. They are asexual, meaning they do not need a
partner to reproduce. Most reproduce through a process called binary fission where, basically, the cell just splits in half
after copying its DNA. This means that without mutations within the DNA, offspring are identical to their parent.
EUKARIOTIC:
Eukaryotic cells have cell membranes, cytoplasm, ribosomes, and DNA. However, there are many more organelles within
eukaryotic cells. These include a nucleus to house the DNA, a nucleolus where ribosomes are made, rough endoplasmic
reticulum for protein assembly, smooth endoplasmic reticulum for making lipids, Golgi apparatus for sorting and
exporting proteins, mitochondria for creating energy, a cytoskeleton for structure and transporting information, and
vesicles to move proteins around the cell. Some eukaryotic cells also have lysosomes or peroxisomes to digest waste,
vacuoles for storing water or other things, chloroplasts for photosynthesis, and centrioles for splitting the cell during
mitosis. Cell walls can also be found surrounding some types of eukarotyic cells. Eukaryotes may use either asexual or
sexual reproduction depending on the organism's complexity. Sexual reproduction allows more diversity in offspring by
mixing the genes of the parents to form a new combination and hopefully a more favorable adaptation for the
environment. Most eukaryotic organisms are multicellular. This allows the eukaryotic cells within the organism to
become specialized. There are a few unicellular eukaryotes as well. These sometimes have tiny hair-like projections
called cilia to brush away debris and may also have a long thread-like tail called a flagellum for locomotion.
Functions and structures
Animal cells
The red blood cells carry oxygen. They have a large surface area, for oxygen to pass through, and they contain
haemoglobin, which joins with oxygen.
The nerve cells carry nerve impulses to different parts of the body. They are long, and connected at each end. They can
also carry electrical signals.
The female reproductive cell (egg cell) joins with the male cell, and then provides food for the new cell that's been
formed. They are large and contain lots of cytoplasm.
The male reproductive cell (sperm cell) reaches the female cell, and joins with it. They have long tail for swimming and a
head for getting into the female cell.
Plant cells
The root hair cell absorbs water and minerals, and has a large surface area.
The leaf cell absorbs sunlight for photosynthesis, and has a large surface area and lots of chloroplasts.
Examples of different types of animal and plant cells
The cell wall is located in plant, fungi and bacteria cells, but not animal cells. It’s an outer layer, rigid and strong, that is
made of glucose. Its functions are to support and protect the cell, and allow H2O, O2 and CO2 to diffuse in and out of it.
The cell membrane is located in all cells. In plant cells, it’s found inside de cell wall, and in animal cells, it’s found in the
outer layer (cholesterol). It’s a double layer of phospholipids with proteins, selectively permeable. Its functions are to
support and protect the cell, and to control the movement of materials in and out of the cell. It could be seen as a
barrier between the cell and its environment. It also maintains homeostasis.
The nucleus is located in all cells except prokaryotes, and has a large, oval shape, which contains 1 or more nucleoli, and
holds DNA. Its functions are to control cell activities and contain its hereditary material.
The nuclear membrane is located in all cells except prokaryotes. It’s a double membrane that surrounds the nucleus
(selectively permeable). It controls movement of materials in/out of nucleus.
The cytoplasm is located in all cells and is described as a clear, thick, jellylike material (cytosol) with organelles found
inside cell membrane. It contains the cytoskeleton fibers, and supports and protects cell organelles.
The endoplasmic reticulum (ER) is also found in all cells except prokaryotes, and is described as a network of tubes or
membranes with smooth ribosomes. It is also rough with embedded ribosomes and connects to nuclear envelope and
cell membrane. Its functions are to carry materials through the cell and aids in making proteins.
The ribosomes are found in all cells as small bodies free or attached to ER, and are made of RNA and proteins. Their
function is to synthesize proteins.
The mitochondrion is located in all cells except prokaryotes, and it is described as a peanut shape with a smooth outer
membrane and an inner membrane folded into cristae. It breaks down sugar (glucose) molecules to release energy, and
is the site of aerobic cellular respiration.
The vacuole is present in plant cells as a single, large vacuole, and in animal cells as a small vacuole. It’s a fluid-filled sac,
and is the largest organelle in plant cells. They store food, water, metabolic & toxic wastes, and a large amount of food
or sugars in plants.
The lysosome is located in plants as an uncommon organelle and in animals as a common one. It’s described small and
round with a single membrane. It breaks down larger food molecules into smaller molecules, and digests old cell parts.
The chloroplast is located in plants and algae. It is a green and oval organelle, that contains chlorophyll (a green
pigment). It has a double membrane with inner membrane modified into sacs called thylakoids, and contains a gel like
innermost substance called stoma. It uses energy from sun to make food (glucose) for the plant in a process called
photosynthesis, in which it releases oxygen.
The nucleolus is located in all cells except prokaryotes, and its function is to make ribosomes. It’s found inside the cell's
nucleus. The nucleus may have more than one, but this will disappear during cell division.
The golgi apparatus is located in all cells except prokaryotes, and is described as stacks of flattened sacs, which modify
proteins made by the cells. They also package and export proteins.
The cilia is located in animal cells and protozoans. They and are responsible for movement. They are short, but
numerous.
The flagellum is located in bacterial cells and protozoans, and is also responsible for movement. It is long, but they are
few in number.
The centrioles are found in animal cells. They are paired structures near the nucleus, made of a cylinder of microtubule
pairs. Their function is to separate chromosome pairs during mitosis.
The cytoskeleton is located in all cells, and is made of microtubules (7 microfilaments). They strengthen cell & maintains
the shape, and move organelles within the cell.
Animal Cell
Plant Cell
The Cell Theory Timeline
Year of Discovery Scientist
Contribution
1595
Hans and Zacharias Janssen
produced the first compound microscope by combining two convex lenses within a
tube
1665
Robert Hooke
discovered the cellular composition of cork and introduced the word cell to science
1674
Anton van Leeuwenhoek
improved magnification of microscopes by polishing lenses
1676
Anton van Leeuwenhoek
"animacules" were discovered
1683
Anton van Leeuwenhoek
discovered bacteria from a sample of saliva from his mouth
1838
Matthias Schleiden
discovered the plants were made up of cells
1839
Theodor Schwann
discovered that animals were made up of cells
1855
Rudolph Virchow
stated that all living things come from other living things
Videos
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https://www.youtube.com/watch?v=gFuEo2ccTPA
https://www.youtube.com/watch?v=rABKB5aS2Zg
Games
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http://schoolmediainteractive.com/view/object/video/473F353293B156A0472E0561416301A1?done=set_devic
e
Articles
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http://www.infectioncontroltoday.com/news/2015/03/energetic-immune-cells-are-vital-for-fightingdisease.aspx
http://news.harvard.edu/gazette/story/2015/03/a-new-stem-cell-advance/
Bibliography
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http://www.bbc.co.uk/bitesize/ks3/science/organisms_behaviour_health/cells_systems/revision/4/
http://www.biologyjunction.com/cell_functions.htm
http://www.ucmp.berkeley.edu/bacteria/bacteria.html
http://www.uic.edu/classes/bios/bios100/lecturesf04am/lect06.htm
http://202.114.65.51/fzjx/wsw/website/cellb/chapter1/cell_chapter1.html
http://evolution.about.com/od/Overview/a/Types-Of-Cells.htm
http://www.cpschools.com/schools/osm/theory.htm
Prezi:
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https://prezi.com/qeym8u-nxz8d/present/?auth_key=h9fe4gd&follow=1bbnmttv_dnn
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Lucila Picos
Sofía Feldstein
Bianca Ricci
Sol Rodríguez
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