What will you know ? • collect information about the microscopic structure of organisms • identify the similarities and differences between plant and animal cells • explain the cell theory and link its development to that of microscopes • draw diagrams of cells and tissues seen under the microscope • explain cell specialisation and give some examples found in plants and animals • make connections between organisation at the cellular, tissue, organand system levels • relate structure and function at different organisational levels. M Nortje 4
Cell theory There is no typical cell shape. Cells come in shapes such as cubes (cells lining sweat ducts), spheres (white blood cells in the immune system), columns (cells lining the stomach), rods (some bacteria) and pancakes (cells on the surface of the skin). • All living things are made up of cells. • Cells are the basic units of structure and function in living things. • All cells arise from pre-existing cells. M Nortje 5
CELL THEORY M Nortje 6 FIRST TWO PRINCIPLES Matthias Schleiden and Theodor Schwann All living things are made up of cells Cells are the basic units of structure and function in living things. .
Third principle Further work by Rudolf Virchow led to 3. All cells arise from pre-existing cells. M Nortje 7
History: important dates in the study of cells Year Event 1590 Hans and Zacharias Janssen invented the first microscope. 1665 Robert Hooke saw cells in cork. He first used the name ‘cells’. 1675 Anton van Leeuwenhoek saw bacteria in tooth plaque. 1838 Matthias Schleiden stated that ‘all plants are made of cells’. 1839 Theodor Schwann and Matthias Schleiden proposed the cell theory. 1858 Rudolf Virchow found that cells are able to reproduce. 1860 Ernst Abbe invented the first modern microscope. 1865 Louis Pasteur found that bacteria cause disease. 1931 Max Knoll and Ernst Ruska made the first electron microscope. 1942 Viruses were fi t seen under an electron microscope. 1973 The first successful genetic engineering experiment was performed. 1978 The first baby was born through in-vitro fertilisation (IVF). 1980 to present Further advances were made in genetic engineering and IVF. M Nortje 8
Robert hooke1665 microscope M Nortje 9 Used Light from a candle directed by a lens onto the specimen
THE MICROSCOPE Van Leeuwenhoek’s microscope One lens mounted in a tiny hole brass plate. Adjusted the position and the focus by turning two screws. First person to observe organisms in water M Nortje 10
Anton van Leeuwenhoek A Dutch drapper Used lenses to examine pieces of cloth he want to buy Began to use lenses to look at other things Made about 500 microscopes – few still survive today Called microscope – but only Powerful magnifying glasses Could magnify 270 times Could see smaller thing than Hooke could 1675 Observe living things in stagnant water 1683 Observed bacteria under his bacteria – A FIRST M Nortje 12
cell membrane cells cell theory cell wall chlorophyll chloroplast M Nortje 18 Vocabulary chromosomes cilia cytoplasm endoplasmic reticulum Golgi apparatus
mitochondrion lysosome nuclear membrane nucleic acid nucleus organ organelles M Nortje 19 Vocabulary organism photosynthesis ribosomes stomata system tissue vacuole
M Nortje 20 http://puzzlemaker.school.discovery.com Makes crosswords, word search
M Nortje 21 Table 4 .1 PARTS OF A CELL AND THEIR FUNCTION
CELL MEMBRANE A thin boundary around the cell that keeps things inside the cell, lets some needed things into the cell, and lets wastes out.
NUCLEAR MEMBRANE A very thin boundary around the nucleus of the cell.
VACUOLE A storage area of the cell that is full of fluid.
RIBOSOME Little round organelle that makes proteins, which are needed for survival and growth.
CHROMOSOMEStrand of nucleic acids in the nucleus of the cell; carries all the genetic information passed from parents to offspring.
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CYTOPLASMLiving jelly-like material inside a cell, which is continually moving. NUCLEUSControls the activities of the cell. MITOCHONDRIONThe powerhouse of the cell; supplies energy to the cell. M Nortje 23
DIFFERENCES BETWEEN PLANT AND ANIMAL CELLS M Nortje 28 ANIMAL CELLS Cell membrane Nucleus Cytoplasm PLANT CELLS Cell wall + cell membrane -> cellulose Large cavity -> Vacuole -> watery fluid ->cell sap Cytoplasm May contain starch grains ->nuclues Chloroplasts located in cytoplasma -> green pigment/parts ->exposed to light(leaves) roots - none Chlorophyll used for photosynthesis Cells vary tremendously in their SHAPE
The diagram below will help you interpret the photo. ANIMAL CELLS:These cells are from the inside lining of a human cheek. PLANT CELLS:These cells are from the leaf of a plant. M Nortje 29
Drawing cells How to draw what you see under the MICROSCOPE • Use a sharp lead pencil (unless you are using a computer drawing package). • Draw only the lines that you see; don’t use shading or colouring. • Each diagram should take up a third to a half of an A4 page. • Record the magnificationnext to the diagram. • State the name of the specimen and the date of the observation. • A written description below the diagram is also often helpful. • When you are viewing many cells of the same type, it is often useful to draw only three or four as a representation of the tissue being observed. M Nortje 32
Worksheet 4.3Cells crossword Groups of cells of the same type. A group of organs that work together. Jelly-like substance inside cells. General name for any living thing. The organelle containing the pigment that gives plants their green colour. The organelle that makes proteins. The type of reticulum found in cells. Discovered by Robert Hooke. The ‘power house’ of the cell. The control centre of the cell. Pores in the leaf through which gases enter and leave a plant. Organelle that destroys unwanted cells. A magnifier that enable us to see cells and other very small things. Made up mainly of DNA M Nortje 39
Cell specialisation (1) M Nortje 40 Most plants and animals are made up of many different types of cells. The cells have different shapes and sizes because they have different jobs to do. Cells are complex things, and they can perform a wide range of tasks including: • taking in nutrients and carrying out chemical reactions • producing waste products
Cell specialisation(2) M Nortje 41 • making useful substances such as bone
reproducing by dividing in two
• moving, for example some special cells such as muscle cells can contract, while sperm cells can ‘swim’ • exchanging gases with their surroundings • capturing light energy from the Sun, which is used to convert carbon dioxide and water to sugar.
Does this list sound familiar? It should! Anything an organismcan do is a result of its cells M Nortje 42 .
Different types of animal cells DIFFERENT TYPES OF ANIMAL CELLS Cells that make up an organism often differ in shape and size.
This is because of the functions or particular jobs that they carry
out within the organism.
The human body is made up of many different types of cells, with each one specialised so that it can perform its own individual job.
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M Nortje 44 GOBLET CELL Goblet cells are shaped like wine glasses, as the name suggest. They make mucus to lubricate and help and protect our intestines, stomach and windpipe
If a cell has to absorb special things that the body needs, for example digested food from the gut, then the cell membrane is foldedto increase its surface area. Cells that are protective, for example skin cells, are flat and fit together to form a complete layer. Cells that line areas where things need to move, for example the fallopian tubes in the female reproductive system or cells lining the respiratory tract, have cilia. Ciliaare hair-like structures that can move. Hair cells from the inner ear carry special stereo cilia that move in response to sound vibrations and send electrical signalsto the brain. Red blood cells have a shape and structure so that they can carry the maximum amount of oxygen. M Nortje 45 Read Only
faculty.college-prep.orgWhite Blood Cells M Nortje 47 sciencequiz.net RED BLOOD CELLS Lots of Nucleus-> packed with oxygen carrying protein haemoglobin. Shaped like biconcave discs – for large surface area for diffusion
PLANT CELLS HAVE: Nucleus, cytoplasm and a cell membrane, but unlike animal cells, that possess a cell wall and often have large vacuoles. Some contain chloroplasts, which enables them to make their own food M Nortje 49 cimateuagro.org
Special cells on the roots of plants extend into hair-like structures that burrow between soil particles. These cells increase the surface area of the roots. This means that the plant is very efficient at taking up water and nutrients from the soil. Cells in the transport system of plants are modified so that they can provide continuous tubular pathways through roots, stems and leaves. This enables fluids to flow easily to all parts of a plant. M Nortje 51
Sci File – Did you know? In the stems of plants are long thin tubes made up of hollow cells, called the xylem and phloem. These tubes are commonly called the veins of the plant. They continue into the leaves and carry water and food to all parts of the plant. M Nortje 52
FROM CELL TO ORGANISM M Nortje 53 In any plant or animal there may be millions of different cells. Each cell will carry out its own job. Different types of cells have different structures to enable them to carry out these specific jobs. All the cells working together will make an organism.
TISSUES M Nortje 55 In multi - cellular organisms, similar cells work together in groups called tissues. Tissues are made up of cells that all have a similar appearance and function. An example of an animal tissue is muscle. An animal muscle cell can shorten. One muscle cell by itself is not strong enough to move a bone but many muscle cells together can move the bones of the skeleton. Many muscle cells together are called muscle tissue.
TISSUES M Nortje 56 Although there are many types of cells in the human body they are all arranged to form one of the four basic tissue types. THESE ARE: • epithelial tissue (covering tissue), e.g. upper layers of our skin • connective tissue, e.g. bone, blood • muscle tissue • nerve tissue.
M Nortje 57 Cells in the bodies of animals vary in size and shape according to their function
A system is made up of a group of organs all working together to perform a particular function.
For example, humans possess a circulatory system.
The function of the circulatory system is to move materials through the body. It consists of the heart, blood vessels and the blood.
systems M Nortje 62
Diagram of the skin – many different types of tissue M Nortje 63
organisms M Nortje 64 An organism such as a human is made up of many different systems. The systems all work together to help the organism to survive. For example, the muscles cannot work unless they receive oxygen from the blood in the circulatory system
Diagram – relationship between cells, tissue, organs and systems M Nortje 65
organisms The blood transports oxygen that it collects from the respiratory system. It also supplies nutrients that are used to make energy, and these have been obtained from the digestive system. Some organisms are less complex and have bodies with only a few simple tissues. Other organisms are only one cell, and this cell has to carry out all the functions of our complex tissues, organs and systems. M Nortje 66
Word puzzle - cells M Nortje 67 WORD BANK cell membrane cells cell theory cell wall chlorophyll chloroplast chromosomes cilia cytoplasm endoplasmic reticulum Golgi apparatus lysosome mitochondrion
M Nortje 68 Find the word in the puzzle and make connections.
Some ideas or rules about cells.
• A very thin boundary around the nucleus of the cell. • A storage area of the cell that is full of fluid. • The basic building blocks of all living things. • Many cells working together to do the same job. • Many tissues working together to do the same job. • Many organs working together to do the same job. • All the systems together. • A tool that helps us to see small things, such as cells, that we cannot see with our eyes. • How many times bigger the object looks than it really is. Strong microscopes magnify objects many times. • A living, jelly-like material that makes up the inside of cells. It has lots of chemicals and cell parts in it.
M Nortje 69 • The control center of the cell. It is a bit like the brain of the cell. • Small parts of the cell that make the energy for the cell to work. • A thin boundary around the cell that keeps things in cells and lets some things that are needed into the cells. • Little round parts of cells that make chemicals called proteins. Proteins are needed so that we can survive and grow. • Chemicals in the nucleus of the cell that carry all the information we get from our parents. • A boundary around the cell that gives the plant cells a definite shape. These help to give plants shape because plants do not have bones or skeletons like many animals. • Green parts of plant cells that carry out the chemical reaction called photosynthesis. Photosynthesis turns light energy from the Sun into chemical energy (carbohydrates) that animals can use for energy to survive when plants are eaten.
Do: Chapter 4 on disc CELLS OF LIFE e TEST M Nortje 70
bibliography Coffey,R.Spence, R& Spenceley, M. 2009 Heinemann Queensland Science Project – Science 8 A Contextual Approach. Harcourt Education. Port Melbourne Victoria M Nortje 71