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Biology Revision (Yr 9 EOY) - Coggle Diagram
Biology Revision (Yr 9 EOY)
Respiration
Cellular respiration is an exothermic reaction (transfers energy to the environment) which is continuously occurring in living cells.
The energy transferred supplies all the energy needed for living processes.
Respiration in cells can take place aerobically (using oxygen) or anaerobically (without oxygen) to transfer energy.
Aerobic respiration takes place in the mitochondria
Aerobic respiration is represented by the equation: glucose + oxygen → carbon dioxide + water + energy release
Recognise the chemical symbols: C6H12O6, CO2, O2 and H2O
Anaerobic Respiration
Glucose → lactic acid.
Anaerobic respiration in muscles is represented by the equation:
Respiration in cells can take place anaerobically (without oxygen).
Organisms need energy for:
• chemical reactions to build larger molecules
• movement
• keeping warm
Digestion
Transport In Cells
Cell Organisation And Microscopy
Cells are the basic building blocks of all living organisms.
Tissue: A group of cells with the same structure and function.
Organ: Aggregations of tissues performing specific functions.
Organs are organised into organ systems, which work together to form organisms.
Plant and animal cells are eukaryotic - they have a cell membrane, cytoplasm and genetic material (DNA) enclosed in a nucleus.
Most animal cells have the following parts:
A nucleus, which controls the activities of the cell.
Cytoplasm, in which most of the chemical reactions take place.
A cell membrane, which controls the passage of substances into and out of the cell. It also contains receptor molecules.
Mitochondria, which is where aerobic respiration takes place.
Ribosomes, which are where protein synthesis occurs.
In addition to the parts found in animal cells, plant cells often have:
Chloroplasts, which absorb light (using chlorophyll) to make food by photosynthesis.
A permanent vacuole filled with cell sap, which supports the cell.
Plant and algal cells also have a cell wall made of cellulose, which strengthens the cell.
Bacterial cells:
The genetic material is not enclosed by a nucleus. It is a single DNA loop and there may be one or more small rings of DNA plasmids
They have cytoplasm and a cell membrane surrounded by a cell wall.
Bacterial cells are prokaryotic and are much smaller in comparison.
Cells may be specialised to carry out a particular function:
Sperm cells, nerve cells and muscle cells in animals.
Root hair cells, xylem and phloem cells in plants.
Magnification = Size of image / Size of real object.
1cm = 10mm = 10,000µm = 10,000,000nm
History of the microscope.
Microscopy was first used by Ancient Egyptians and Romans.
Not until 1590 that a device was designed to specifically produced magnified images.
This consisted of a sliding tube with different sized lenses on either end. By sliding the tube, you could focus on an object.
In 1609, Galileo Galilei created one of the first compound microscopes with a convex and concave lense. This magnified x20-30.
By the late 17th century, it was discovered objects could be magnified further by using different shaped ground lenses.
In 1729, Chester Moor Hall made further developments in microscope technology when he created the achromatic lens, which is made by combining two different types of lenses with different focal powers.
In 1931, the first electron microscope was develop[ed by Max Knoll and Ernst Ruska. This used electrons instead of light to view objects.
A scanning electron microscope (SEM) scans the surface of an object using a beam of electrons.
Magnification: x30,000
Resolution: 1-50nm.
A transmission electron microscope (TEM) uses beams of electrons thin slices or sections of cells and tissues.
Magnification: x1,000,000
Resolution: Less than 1nm