1.3 Cell Structures
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Transcript of 1.3 Cell Structures
1.3 Cell StructuresEssential tasks of the cellAll living cells must:• Obtain food + energy
• Convert energy from an external source to a usable form
• Build + maintain mculs that make up cell structures
• Carry out chemical reactions
• Eliminate wastes
• Reproduce
• Keep records of how to build structures
Two Basic Cell Types
• Prokaryotic Cells Eukaryotic Cells• No nucleus; nucleoid Nucleus• Smaller Larger• Simple internal structure More complex
internal structure• No membrane-bound Membrane boundOrganelles organellesEx. Bacteria Ex. Plants, animal, fungi
Cell Structures
• All cells have: – Cell membrane– Cytoplasm– Cytoskeleton
Eukaryotic cells have nucleus and other organelles!
The Cell Membrane : • Is composed of lipids (molecules that store energy) and proteins.
• Is the outermost covering of animal cells, which gives the cells their definite shape.• Is a semi-permeable barrier which allows only certain molecules to pass through.• Contains proteins that act as pumps, enzymes, etc.• Has the ability to connect one cell to an adjacent cell.
The Cell Membranehttp://www.cellsalive.com/cells/membrane.htm http://en.wikipedia.org/wiki/Cell_membrane McGraw-Hill Ryerson Biology 11
The “Gatekeeper”’s Function:
The cell membrane surrounds the protoplasm of a cell and separates the content of the cell from the outside environment. It provides the shape of the cell and attaches certain cells together to form tissues.
The cell membrane determines what enters and exits the cell based on what the cell needs to survive.
The membrane surrounds the entire cell which allows nothing to get into the cell without passing through the membrane first.
The cell membrane was discovered by Karl Wilhelm von Nageli in 1855
The Cell Membrane pt. 2
Description: -an organized structure of DNA and protein that is found in cells.
-The DNA molecule may be circular or linear, and can be composed of 10,000 to 1,000,000,000[1] nucleotides in a long chain
Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.
Function: Chromosomes function is to control all the activities of a living cell. Chromosomes are
essential for the process of cell division and are responsible for the replication, division and creation of daughter cells, that contain correct sequences of DNA and proteins.
Structure: A molecule of DNA is a very long, coiled structure that contains many identifiable subunits
known as genes. In prokaryotes, or cells without a nucleus, the chromosome is merely a circle of DNA. In
eukaryotes, or cells with a distinct nucleus, chromosomes are much more complex in structure.Facts:
Chromosomes were discovered in 1842 by Karl Wilhelm von Ngeil.
Chromosomes
http://en.wikipedia.org/wiki/Chromosome
Description is the combination of DNA and other proteins that make up chromosomes. chromatin is organized in seven progressive levels of organizational complexity,
which coils the DNA into more and more compact forms through combination of proteins.
It is found inside the nuclear envelope of eukaryotic cells. Function The functions of chromatin are to package DNA into a smaller volume to fit in the
cell, to strengthen the DNA to allow mitosis and meiosis, and to control gene expression and DNA replication.
Structure The structure of chromatin is determined and stabilized through the interaction of
the DNA with DNA-binding proteins. Facts Chromatin was discovered by Walter Flemming in 1879.
Chromatin
http://en.wikipedia.org/wiki/Chromatin
Membrane Bound Organelles Mitachondrion Endoplasmic reticulum Peroxisome Lysosome Golgi apparatus Vacuole Vesicle
Non-membrane bound organelles:ribosomeciliaflagella
General Information
The mitochondrion of a cell works like a power plant. It produces adenosine triphosphate (ATP) which the cell uses for energy. It works a bit like our brain's pituitary gland, as it controls cell growth, and cell death. Depending on the organism and type of cell, there can be various amounts of mitochondria. Mitochondria also contain DNA.(deoxyribonucleic acid)
Cutaway Diagram of a Mitochondrion
The outer membrane acts as the “skin” of the organelle, with the inner membrane acting as a second layer of “skin.” The matrix is the space inside the inner membrane. Cristae is the space formed by the infoldings of the inner membrane. There is intermembrane space between the outer and inner membranes.
Summary
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The mitochondria of a cell keep it going. Without mitochondria, cells would not live. Mitochondria are complicated, essential organelles.
Endoplasmic Reticulum (ER)
There are two types: Rough and Smooth. They are named so because one type has ribosomes attached to it (Rough) and the other does not (Smooth). Both made of a series of membranes,
the Rough ER looks like many flattened cavities surrounding the nucleus of a cell, and the Smooth ER appears to be many small tubes. The Smooth is outside of the Rough. The interior
of the ER is called the lumen. The Rough ER has a variety of jobs, often depending on what type of cell it is in. It creates
membranes and secretory proteins. It is what aids in the creation of insulin in the pancreatic cells, and antibodies in leukocytes.
The Smooth ER creates lipids and metabolizes carbohydrates. It receives proteins from the ER and moves them to other places. In liver cells,
it makes enzymes that helps remove toxins. In the brain it synthesizes hormones. The shape and placement of the ER allows transportation of membranes and such to be easier because it is in the middle of the cell and has a large surface area. The Endoplasmic Reticulum is essentially a shipping department, because it ‘packages’ and transports important proteins.
http://biology.about.com/library/weekly/aa041300a.htm
PeroxisomesCharacteristics:-Spherical shape, surrounded by lipids and proteins, lipid plasma bilayer membrane, and crystalline core.
Functions:-Peroxisomes help get rid of toxins within the cell. –- In plants they also assist in the process of Photosynthesis.-Peroxisomes also are a big part of the cell metabolism process. -They also help with breaking down fats and fatty acids. -The Peroxisomes also help with the breakdown of alcohols in the cell, much like a small version of the liver but for a cell.
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Sources:-http://en.academic.ru/pictures/enwiki/80/Peroxisome.jpg-http://www.wisegeek.com.what-is-a-peroxisome.htm -http://micro.magnet.fsu.edu/cells/peroxisomes/images/peroxisomesfigure1.jpg
Peroxisomes - The structure also helps with the metabolism process in the way that it can easily take in lipids and proteins and start the breakdown into energy that the sell uses
• Extra Info:• -Peroxisomes have the ability to
break into another peroxisome if the cell needs another, much like DNA
Structure Functions:- The structure of the Peroxisomes give them the ability to breakdown toxins and convert them into by products like hydrogen peroxide or just oxygen and water.
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The vacuole is a storage bubble found in cells. It is a space within a cell that is empty of cytoplasm, lined with a membrane,
and filled with fluid.Plant vacuoles serve as a “cellular trashbag” for all sorts of compounds and ions (such as salt, mineral nutrients, heavy
metals and organic compounds) that would be toxic if they were in the cytoplasm. Plant vacuoles accumulate enough dissolved
compounds to give the plant and cell a low enough osmotic potential to absorb water through osmosis. In conjunction with the cell wall, the vacuole functions to provide turgor for plant
cells. The vacuole can also store protein or carbohydrates.
The vacuole stores food or any variety of nutrients a cell might need to survive, and stores waste products so the rest of the cell is protected from contamination. It is responsible for maintaining the shape and structure of the cell. The vacuole also
performs functions such as storage, ingestion, digestion, excretion, and expulsion of excess water.
The vacuole is formed by the fusion of multiple membrane vesicles and are effectively formed larger forms of these. This organelle has no basic shape or size. Its structure
varies according to the needs of the cell. The vacuoles nickname is “the control center”. It was found between the late
1600’s/early 1700’s, by Anton van Leeuwenhoek.
Ribosome
Ribosome's are made from complexes of RNAs and proteins. It is divided into two subunits. One subunit is larger than the other.
Description
FunctionThe ribosome makes proteins from all amino acids. The ribosome reads the information in the RNA and uses it to create proteins. This process is known as translation. The smaller subunit binds to the mRNA while the larger subunit binds to the tRNA and the amino acids. The ribosome finishes reading a mRNA and then the two subunits split apart.
FactsThe ribosomes nickname is Protein Factories.
Ribosomes were observed in the 1950’s by George Palade. The term "ribosome" was proposed in 1958 by Richard B. Roberts.
Cilia and Flagella
Hair like features used to push cell or particles located on the outside of cell
Many hair like structures beat to move the cell
Cilia means ‘eyelash’ in Latin
A tail like projection from the outside of a cell used for movement
Tail whips back and forth to push cell forward i.e. Sperm cells
Cilia Flagella
Cilia and Flagella
http://www.dnatube.com/video/363/Cilia-and-Flagella
Website Information - http://www.dnatube.com/video/363/Cilia-and-Flagella
Structures Unique to ….
Animal cells: Centrioles
Plant cells: Cell wall Plastids (chloroplast, amyloplast,
chromoplast) Crystals
Chloroplast is one of the groups of organelles in plant cells called plastids. This gives green plants their color and transfers the energy in sunlight into stored energy in carbohydrates
during photosynthesis.
Chloroplasts
Chloroplast was first suggested by Mereschkowsky in 1905 after an observation by Schimper in 1883 that chloroplasts
closely resemble cyanobacteria.
The chloroplast is surrounded by a double-layered composite
membrane with an intermembrane space; further, it has reticulations, or many infoldings,
filling the inner spaces. The chloroplast has its own DNA, which codes for redox proteins involved in electron
transport in photosynthesis; this is termed the plastome.
URL: http://en.m.wikipedia.org/wiki/Chromoplast?wasRedirected=true URL: http://en.m.wikipedia.org/wiki/Chloroplast?wasRedirected=true
Amyloplasts are non-pigmented organelles found in
some plant cells.
Amyloplast
Large numbers of amyloplasts can be found in fruit and in underground storage tissues of some plants, such as in potato
tubers.
They are responsible for the synthesis and storage of starch granules, through the polymerization of glucose. Amyloplasts also convert this starch back
into sugar when the plant needs energy.
URL: http://en.m.wikipedia.org/wiki/Amyloplast?wasRedirected=true
Chromophlast
Chromoplasts are plastids responsible for pigment synthesis and storage. They, like all
other plastids (including chloroplasts and leucoplasts), are
organelles found in specific photosynthetic
eukaryotic species.
Chromoplasts in the traditional sense are
found in coloured organs of plants such as fruit and
floral petals, to which they give their distinctive
colors. This is always associated with a massive
increase in the accumulation of
carotenoid pigments. The conversion of
chloroplasts to chromoplasts in ripening
is a classic example.
The term "chromoplast" is occasionally utilized to include any plastid that has pigment, mostly to emphasize the contrast with the various types of leucoplasts, which are those plastids that have no pigments. In this sense, chloroplasts are a specific type of chromoplast. Still, "chromoplast" is more
often used to denote those plastids with pigments other than chlorophyll.
URL: http://en.m.wikipedia.org/wiki/Chromoplast?wasRedirected=true
Cell Wall
Identifying Characteristics of the Cell Wall
- Tough, flexible but sometimes fairly rigid layer that surrounds some types of cells.
- Located outside the Cell Membrane.
- Provides structural support and protection.
- Acts as a filtering mechanism.
How the structure relates to the function
The structure of the Cell Wall relates to the function because the structure of the Cell Wall is rigid and tough to offer protection against any stress that may be present. The structure and the function also relate because the Cell Wall limits the entry of any toxic molecules.
The structure of the Cell Wall is the function, it serves as a wall.
Cell Wall’s Function Determining Cell Shape - the shape of a plant is
determined by the cell wall, the cell wall is like a skeleton acting as the main supporting structure of a cell.
Strength - provides strength to the cell,
since the cell wall is also flexible Controlling Turgor Pressure - an important function of a cell
is to maintain Turgor Pressure, Turgor Pressure is the pressure applied by the cell constituents on the cell wall.
Passage of Substances - the cell wall allows
the movement of small molecules like protein to go in and out. But limits the large more toxic molecules it will allow in.
Protection - the cell wall is the
first line of defense against attacks.