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GCSE - biology (start to finish re-do) (p5 and p6 (mitosis (cell division…
GCSE - biology (start to finish re-do)
page 1 and 2
animal cell
nucleuas - controls activites of the cell contains genetic material
cytoplasm most chemical reactions take place in cytoplasm
cell memebrane controls passage of substances inside and outside of the cell
mitochondria auerobic respiration takes place
ribosomes - where protein are synthesised
plant cells
a cell wall gives strcuture to the plant cell / strengthens it made of cellouse which gives it extra protection
permanenet vacoule - filled with cell sap to suport the plant and store water
chloroplasts - absorb light to make food (glucose) by photosynthesis
prokaryotic and eukaryotic cells
bacterial cells are prokayotic (do not have a nucleus)
smaller in size
genetic material outside nucleaus
genetic material is a single dna strand
one or more plasmids(dna rings)
no mitochondria or plasmids
contain flagells tail like strcuture roates the cell around to move the bacteria move
chromosonal DNA not found in bacteria long looped chromosone usally
eukaryotic - plant animal fungal cells
genetic material in nucelaus
p3 and p4
light microscope - cheaper than electron less focus availble however uses light through lens to see cells
sub cellur features can be looked into using an electron microscope
magnifciation = size of image divided by size of real object
required practicals
magnification
1.have tissue sample on microscope slide - 2.add few drops suitable strain 3.lower a coverslip onto the tissue -4.place microscope on stage-5.change to high power and refocus.6.draw any types of cells that can be seen-7.add scale line to the diagram
Osmosis required practical
potato dried and weighed before hand to check know water on
put in different concentrated solutions within test tubes
if high concentration soloution water moves out potato
else water moves in
to see which has been affected you take out the potato in each test tube dry them (remov e weight on outside) and then weigh them to see how much water has gone in
the one with most would be in lowest concentration gradient
some will not change weight because concentration insdie and outside is the same
p5 and p6
nucleus of a cell contains chromosomes made of DNA
each carrying lots of genes
different genes containc ode for different proteins
control development different charecteristic
chromosomes generally found in pairs
one chromosone from each parent
different species different number humans have 23 pairs however dogs have 39 pairs
mitosis
cell division process
cell chromosomes multiply so if you had 2 orignally you would have 4 and then the 2 remaining ones are broken up to form 2 pairs of 2
used for repair generally and to create sub culler structures e.g ribosome's
stem cells - undiffrentiated have no become specailised yet
can divide to create new cell types for example bone marrow and neurones and blood and heart muscle it can also be used to help with diabetes as it creates pancreatic islet cells
stem cells found in human embryos and umbilical cords
adult stem cells can be used to some extend as well for example bone marrow contains some stem cells however they do not work as well
therapeutic cloning is where you clone embroys
this allows for the large harvest of stem cells
also not rejected by paitents immune system
in plants stem cells found in meristems
allow plants to create new cells for growth rare species can be cloned to save speecies from extinction can be used for special features for gm crops
p7 and p8
diffiusion
diffiusion is the movement of substances across cell membranes
is the net movement of particles from an area of high concentration to an area of low concentration
this happens due to the particles move randomly and spread out
diffiusion is used in
gas exchange with aveloi
ura diffuses into the blood plasma for excreation from kidney
digested food molecules from small intestine diffuse into the blood
difference in concentrations is known as the concentration gradient which affects diffisuion
single celled organism has a large surface area to volume ratio
allows for substances to move in and out of cell
smaller surface area to volume ratios occur in smaller organisms however they have spcial features for exchanging materials
gills in fish lungs in mammals and roots and leaves in plant specially created for exchanging materials
this is due to: large surface area surface is thin so molecules only diffuse short distance surfaces kept moise so substances dissolve and diffuse across membrane quicker in animals rich blood supply maintains concentration gradient in animals ventilaition occurs to speed up gasoues exchange
Osmosis
osmosis is the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
active transport
active transport moves against concentration gradient
area low concentration to an area of high concentration requires energy from respiration (active)
allows mineral ions t be absorbed into plant root hairs from very dilute soloutions in the soil
active transport allows sugar molecules to be absorbed from lower concentration in the gut into blood which has a higher concentration
allows molecules to move - diff osmos activ
which factrs affect what
allows molecules to mvoe diff and osmos and active
movement is down a gconcentration gradient diffusion and osmosis
always involves the movement of water osmosis
needs energ from respiration active transport
p9 and p10
tissues and organs
specailised cells
neurone cell contians dentrites at the left cell body just le
of the axon - big tail middle - and sheath - at the end of tail thing
tail - propels sperm to fertilise the egg
sperm
mitochondria
used to give sperm energy
nucleaus
contains the genetic material
acrosome : contains enzymes allow to enter the egg
muscle cells
mitochondria for enegy nucleaus for dna protein fibres that contract
specailised plant cells
xylem
xylem end walls broken down to form hollow tubes for water to pass up
cell strengthend by lignin
pholem
end walls of cells allow sugars though but spport the tubes
pholem cells are arranged end to end into tubes
companion cells are used to collect more sugar
root hair cell
lots of mitochondria for active transport of materials active transport needs energy
long projection to increase the surface area to absorb water and minerals
most organisms cells are arranged into tissues
tissues are used to create organs like the heart and the stomach
organ systems are a list of organs with a partiular job
e.g the digestive system
mouth recutm stomach intestine
types tissue ephilical tissue is used to cover up parts of an organ muscle tissue is used to give stengh to an organ and glnadular tissue i used to produce digestive tissues
some organisms only have tissues not organs
single cell organisms have no tissues or orgns becuase they only have 1 cell so they can not create more
p10 and p11
blood is a tissue
made of a liquid beng plasma
red blood cells
white blood cells
plateless
plasma transports various chemical substances around the body
red blood cells
contains haemoglobin which binds to oxygen to transport it from lungs to the tissues and cells need it for respiration
not contains nuctain a nucelais so there is more room for hameoglobin
very small fit through tiny capillaries
very smalls can fit through tiny capillaries
shaped like bioconcave disks giving them a large surface area that oxygyn can quickly diffuse across
white blood cells
helps protects the body against infection
can change shape so they can squeeze out of the blood vessels into the tissues or surround and engulf microrganisms
plateless are fragments of cells which collect at wounds and trigger blood clotting
blood vessels 3 types
arteries take blood from your heart to your organs thick walls made from muscle and elastic fibres
veins take blood from your organs to your heart thinner walls and valves to prevent backflow
capillaries
allow substances needed by the cells to pass out of the blod
allows substances produced by the cells to pass in to the blood narrow thin walled blood vessels
narrow thin walled blood vessles
the heart pumps blood around the body in a double circulatory system b
blood passes through the heart twice on each circuit
left and right atria which recieve blood from veins
left right ventricles pump blood out into arteriesh
atria recieve blood from veins
deoxygenated blood gets pumped at the lungs then goes to the heart and then goest to rest body like muscle in arms and legs
pace maker controls the pumping of blood
artificial pacemakers can be made if someones natural one fails
heart sends blood to lungs via pulmonary artery
air obtained by breathing reaches the lungs through the trachea which has rings of cartiledge preventing it from collapsing
trachea divides into two tubes the bronchi
bronchelies divide intill they turn into aveoli
aveoli divide untill they end in tiny air sacs called alvelo
millions of alveoli are adapted to be very efficiant at exachanging oxygen and carbon dioxide
large moist surface area
very rich blood supply
very close to the blood capillaries so the distance for the gases to diffuse is small
blood taken back to the heart through the pulmonary vein
p12 p13
communicable and non communicable diseases
communicable diseases are ones that cna spread
non communicable disease ones that can not spread
caused by health problems in terms of perhaps eating disorder
e.g type 2 diabetes is non communicable does not spread
can be trasnmitted by bacteria or vector e.g malaria
risk factors
risk factors are things which could create diseases