Cell biology Flashcards
Electron v light miscroscope
magnifications + resolutions
Electron-2,000,000x 0.2nm
Light-2,000x 200nm
Functions:
Mitochondria
Ribosome
permanent vacuole
mitochondria-aerobic respiration, released energy
ribosome-protein synthesis
permanent vacuole-filled with cell sap, keeps cell rigid + supports
Eukaryotic cells:
which ones are they?
about
fungi, protista
genetic material inside nucleus
Prokaryotic cells:
which one is that?
about
bacterial cell
cell wall (not cellulose), may have plasmids, may have flagellum, no chlorophasts or mitochondria, genetic material in a single loop of DNA
Specialised cells: Animal
sperm
muscle
nerve
sperm-many mitochondria to release energy, digestive enzyme to penetrate egg, DNA to create offspring
muscle-lots of mitochondria, special proteins for contractions, stores glycogen which can be broken down into glucose for respiration
nerve- long axen to carry impulse, nerve endings release chemical messages
Specialised cells: plant
root hair cell
xylem
phloem
root hair cell-large SA for absorption
xylem-long hollow tube, spirals of lignin to support
phloem-sieve plates, dissolved food moves easily through
Diffusion- def + factors
spreading out of particles of any substance in solution/ gas resulting in a NET movement of particles from an area of high concentration to one of low concentration
higher temp-faster
greater concentration gradient-faster
larger surface area-faster
Osmosis- def
Hypotonic, Isotonic and Hypertonic
the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
Hypotonic-water moves into cell, may burst, happens when its more dilute than cell’s internal enviroment
Isotonic-nothing happens, when conc is same as cell’s internal enviroment
Hypertonic-water moves out of the cell, shrinks, happens when the concentration is hugher than the cell’s internal enviroment
active transport- def + what does it require
the movement of molecules from a low concentration to a high concentration (across conc gradient) through a partially permeable membrane
requires energy from respiration
Mitosis:
steps of it
what it is needed for
1) longest stage, cell grows, increases no, of subcellular structures, DNA replicates
2)one set of chromosomes is pulled to each side of the nucleus, nucleus splits in two
3) cytoplasm and membranes divide, forming 2 identical cells
needed for: development, growth, repair
Stem cells:
used for?
Animal- examples
Plant-example + what used for
issues
used for differentiation or giving rise to other stem cells
animal-embryonic, adult
plant-meristem tissue-used to clone plants, save rare species, used for research
issues- if virus is passed on through stem cells (adult), patient may need to take immuno-suppressant drugs, ethical issues, religious beliefs
Binary fission
what is it?
Steps to it
how bacteria multiply
1) loop of DNA replicates
2) two copies move to each end of cell
3) cystoplasm divides + new cell walls form
how to calculate population size after given time
divisions= time given/length of division
then do 2 to whatever number that is
e.g 3.5/0.5=7 so 2 to the power of 7= 128
Microbiology required practical
steps to it
1) agar jelly should be sterilised+ inoculating loop must be sterilised over flame
2) spread bacteria over petri dish, tape shut
3)store upside down so ocndensation doesn’t drip onto agar jelly
4) keep at 25 degrees celcius
