Studied by 4 peopleThree main points of cell theory
all organisms are made of cells
cells are the basic units of life
cells arise from pre-exisitng cells
what does cell structure and activity allow
it allows the human body to function and have structure
what are the main cell components
membrane, cytoplasm, organelles, cytosol, cytoskeleton and inclusions
cytoplasm structure
semi fluid matrix, jelly like substance which includes organelles and cytosol
how much of cytosol is water
75 - 90%
what is cytosol
liquid in cell which has dissolved substances, is a place for metabolic reactions and assists is osmotic pressure and flow of chemical around the cell
what are organelles
membranous structures (usually) with specialised functions
nucleus structure
largest organelle, surrounded by double membrane with pores and filled with nuceloplasm
what is inside the nucleus
DNA and nucleolus
what does DNA do
codes for protein synthesis which gives cells their functions and structure
what does the nucleolus do
helps make proteins by assembling ribosomes
ribosomes structure
non membranous, small spheres
what do ribosomes do
construct amino acid chains
where are ribosomes found
in cytosol or on rough ER
endoplasmic reticulum structure
parallel membrane network spanning from cell membrane to nuclear membrane
endoplasmic reticulum function
stores, synthesises and transports aswell as being a surface for chemical reactions
rough ER function
holds ribosomes, protein transport and membrane lipid forming
smooth ER function
steroid synthesis and lipid metabolism
golgi body structure
flat stacked membranes near nucleus with vesicles forming at the edges
golgi body function
modify and package proteins for secretion
lysosomes strucutre
small membrnaous spheres (made by golgi) containing digestive enzymes
lysosome fucntion
break down big molecules, particles, dead organelles and the cell when it dies
mitochondria structure
double membranes spherical sausages. smooth outer membrane surround mitochondria and highly convoluted inner membrane (cristae)
mitochondria function
release energy from large molecules and store it as ATP, conducts aerboic stage of cellular respiration
why does the cristae have a large surface area
so that more reactions can take place on it
cilia and flagella structure
cytoplasmic projections on cell surface, cilia are short and exist in numbers, flagella are long and exist usually alone
cilia and flagella function
beat rythmically to move whole cell or move substances across cell surface
centrioles structure
rings of microtubules at 90* to eachother
centrioles fucntion
form spindles during cell division
cytoskeleton structure
protein fibre framework made of microtubules (hollow rods) and microfilaments (solid rods)
cytoskeleton function
give cell shape, help cell move, support organelles and intracellular transport
inclusions
chemical substances which aren’t part of the cell structure
inclusions example
melanin and haemoglobin
Note 
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