cell biology Flashcards
what do eukaryotic (plant and animal cells) have?
cell membrane, cytoplasm and genetic material enclosed in nucleus
what do prokaryotic cells have (bacterial cells)
cytoplasm, cell membrane surrounded by cell wall, genetic material not in nucleus, single DNA loop, plasmids
whats bigger prokaryotic or eukaryotic cells?
eukaryotic
what does the nucleus hold?
genetic information
what does the cytoplasm do
holds chemical reactions
whats the cell membrane for?
regulates transport of materials entering and exiting the cells
whats the mitochrondria?
provides energy from respiration
what are the ribosomes?
place for protein synthesis
chloroplast?
produce energy through photosynthesis sustaining plant growth
permanent vacuole?
store and transport substances.
what is the cell wall made of? what does it do?
cellulose, strengthen the cells.
how are sperm cells specalised?
tail that moves by energy generated by many mitochondria. head releases enzymes so sperm cell can penetrate the coating of the egg.
how are nerve cells specalised?
they are thin, can be more than 1m long in your spinal cord, can carry messages over large distances quickly, branched connections at each end.
how are muscle cells specalised?
layers of protein, layers can slice over eachother causing muscle contraction, lots of mitochondria.
how are root hair cells specalised?
large surface area to increase rate of absorption, lots of mitochondria.
how is xylem specalised?
series of connected dead xylem cells, lignin strengths cell walls.
how are phloem cells specalised?
columns of living cells, end walls contain small holes to allow food to move up and down.
what stage do animal cells differentiate at? for what?
early stage, in mature animals = repair and replacement
when do plants differentiate?
they retain the ability to differentiate throughout life.
difference between electron and light microscopes?
electron= higher magnification and resolution, study finer detail.
light= cheaper, can view living organisms.
magnification calculation?
size of imagine divided by size of real object
how do you prepare uncontaminated culture?
petri dishes and culture media must be sterlisied.
inoculating loops must be sterilised in flame.
lid of petri dish must be secured with tape, store upsidedown and at 25.
what happens during mitosis?
set of chromosomes is pulled to each end and nucleus divides, cytoplasm + cell membrane divide, divides into 2 identical daughter cells.
what happens during meosis?
genetic material is doubled, divides into 2 daughter cells then divides again into 4 daughter cells.
what is a stem cell?
undifferentiated cell capable of turning into many more cells.
embronic stem cells?
most different types of human cells
bone marrow stem cells?
many cells even blood cells
meristem tissue?
any type of plant cell
what can stem cells help?
diabetes and paralysis
risk of stem cells?
infection, unethical, religious views
benefits of meristems?
rare species helped from extinction
create lots of disease resistant plants
whats diffusion?
higher concentration to low concentration, waste products of gas exchange and urea from cells excreted by diffusion.
what effects diffusion?
concentration gradient, temperature, surface area of membrane
effectiveness of an exchange surface is increased by?
large surface area, membrane that is thin, efficient blood supply, being ventilated
whats osmosis?
diffusion of water from dilute to concentrated solution through partially permeable membrane
active transport?
dilute solution to concentrated solution against a concentration gradient, requires energy from respiration.
what does active transport allow?
mineral ions to be abosrbed into root hairs from dilute soutions in soil.
