magnification = size of image ÷ size of real object
Total Magnification = magnification of eyepiece x objective lens
resolution is the ability to distinguish two objects that are close together, or two objects that are far apart
electron microscope can magify up to 2 million times and can see sub-cellular structures
plant cell, cellulose wall is the outer layer, rigid, keeps the wall in shape
plant cell, large permanent vacuole, stores water, sugar and minerals, plant support
plant cell, chloroplasts, contain green chemical chlorophyll, which absorbs light energy for photosynthesis
Mitochondrion, found in cells cytoplasm that are the site of respiration, they release energy
Nucleus, controls cell, contains chromosomes that carry genes that control characteristics
Nuclear membrane, surrounds nucleus, contains pores to allow substances to move between nucleus and cytoplasm
cell membrane, controls what enters and leaves the cell
cytoplasm, jelly-like substance where most chemical reactions occur, keeps cell alive
Bacteria Cells, capsule, for defence against invading viruses
bacteria cells, non-cellulose cell wall, made from protein and carbohydrates
bacteria cell, plasmid, additional loop of DNA
bacteria cell, mesosome, for chemical reactions e.g. respiration
specialised cells and differentiated to do different jobs
Leaf palisade cell makes sugar, lots of them + cylindrical shape to pack tightly, on upper surface of leaves
Root hair cell, absorbs water + minerals from soil, long to increase surface area to absorb easier, at tip of plant root
sperm cell, male sex cell that fertilises egg, swims using flagellum, has many mitochondria to release energy for movement, half normal chromosomes, produced in testes
red blood cells, carry oxygen and haemoglobin around the body, biconcave disc to increase surface area for gas diffusion, no nucleus to hold more oxygen
nerve cell, carries nerve impulses, long nerve fibre to reach other cells, covered in myelin to speed up transmission of impulses, found in all parts of the body
ciliated epithelial cell, cells that line the bronchioles, use cilia to move mucus upwards towards the trachea
digestive system is the process of breaking down food into smaller molecules for absorption, mouth, stomach, intestines
respiratory system is the exchange of gases between the body and the environment, oxygen exchanges with CO2, trachea, bronchi, lungs
circulatory system is the transportation of materials around the body by the blood, heat and protection, heart, blood vessels
skeletal system is for support, protection and movement, ribs, backbone
excretory system is getting rid of toxic waste, liver, kidneys, bladder
reproductive system is the production of gametes and fertilisation, testes, ovaries
sensory system is touch, taste, smell, hearing, and vision, skin tongue nose ears eyes
nervous system is the response to stimuli and coordination, brain, spinal cord, nerves
tissue is a similar group of cells
organs are different tissues working together to do a particular job
organ systems are a collection of organs working together
an organism is a collection of organ systems that can carry out all characteristics of life
unicellular organisms exchange through the cell-surface membrane
multicellular organisms have cells that are not in direct contact with the surrounding enviornment
multicellular organisms have specialised exchange surfaces, have more complex transport system links
rate of exchange depends on organisms surface area that is in contact with the surroundings
As an organism increases in size the surface area to volume ratio decreases