cell structure and transport Flashcards
when was the light microscope made
late 1700s
how does a light mkcroscope work
uses a beam of light to form an image
properties of light microscope
magnifies up to x2000
cheap
resolving power of 200nm
when were electron microscopes made
1930s
how does a electron mkcroscope work
uses a beam of an electron to form an image
traits of electron microscope
mag up to x2000000
very large and need to be kept in a sepecial habittat
difference between scanning and transmition microscopes
scanning have lower magnifications but are in 3d whilst trans are not
magnification equation
I (image sie) = A (actual size) X M (magnification)
what is reslution
how much detail it can show between two dif points
what does an animal cell have
neucleas
mitrocondria
ribosomes
cytoplasm
cell membrane
what does the neucleas do
controls all cell activities
carries the genes on the chromasones that instruct it how to make proteins to create new cells
cytoplasm functions
liquid gel throughout where reactions take place and organelles are suspended
cell membrane functions
controls passage into cell
mitochondria functions
where aerobic respiration takes place releasing energy
ribosome funtions
protien synthesis happens creating all protiens
what makes plant cells different
make their own food by photosynthesis
often larger
all have a cell wall
most have chloroplasts and a permenant vacuole
functions of chloroplasts
contain green chlorophyll
absorbs light so it can mmake food
permenant vacuole functions
space in the cytoplasm filled with sap that maintains the shape
all parts of an optical microscope
center is the stage which s aslab with clips to attach the slide. under there is light that shines up the slab and sometumes mirrors to relect light. ontop there are usually threelenses w dif mags and ontop of that theres the eyepiece which has a mag of 10x. there are two dialls on the side one corse is for moving the lense and one is for making it more resolute
explain practical microscope
you put the thing on the slab and you view it with the lowest mag lense and blah. repeat w dif lenses and to find the mag you do eyepice mag (10x) times the objective lense.
eukaryotic cells
contain dna in their neucleas
have cell membrane and cytoplasm
membrane bound organelles
prokaryotic cells
cell wall cytoplasm and cell membrane
no neucleas
dna is in a single loop- sometimes theres plasmids
often a flagellum and a slime capsule
bacteria
smaller than euk
what is differentiation
when a cell becomes specialised to cater to its specific purpose
adaptations of a sperm cell
long tail to swim
loads of mitochondria for energy
streamlines
digestive enzymes to break down outer layer of the egg
half the genetic info of a normal cell
nerve cell adaptations
dendrites increase SA to make connections w other nerve cells
synapses pass the impulse w lots of mitocondria for energy and insulating border
mylin sheath insulates the long axons
long axons carry electrical impulses
muscle cell adaptations
protiens help them contract by shrinking and sliding during contractions
mitochondria loads for energy
glycogen is stored which is converted into glucose for respiration
root hair cell adaptations
need to take in water and mineral ions
hair increases SA so its easier to absorb water
large vacuole that speeds water by osmosis
lots of mitochondria that give them energy for active transport mineral ions
photosynthesis cell adaptions
chloroplasts and chlorophyll trap light
positioned in outer layers to absorb
large permenant vacole keeps the shape, supports the stem and keeps leaf spread out for light capture
xylem cell adaptions
carries water and minerals from root to leaves
the chem lignin builds up and thickens stem and then kills the cell making long hollow tubes
no internal structure so more water and ions can move through
spiral shape that strengthens it and witholds the water
phloem cell adaptions
carries photosynthesis food aroudn
tube shape but not dead
cell walls break down to make sieve plates which can be easily moved through
little internal strcture but are supported by other cells which give them mitocondria energy
what is diffusion
spreading out of particles from a higher to lower concentration
things affecting rate of diffusion
temperature (more KE)
concentration of particles
larger SA
how do dif gases use diffusion
oxygen comes from the air in the lungs into blood cells to the cells where its used for respiration
co2 is caused by respiration and si difused out in the oposite direction to the oxygen
urea goes from liver cells to the kidney
what and how to find net movement
net movement is the oveall movement and its particles mooving in - moving out
what is osmosis
diffusion of water from a dilute to more concentrated solution (of another substance) through a partially permiable membrane
what is isotonic
when the concentration of solutes are the same as the internal
what is hypertonic
when the solution outsde has a higher concentration of other substances so the water inside the cell all rush out to be in a less dilute (with water) area
what is hypotonic
when the inside has a higher concentration of other substances so all the water from the outisde rushes in
how can animal cells be dangered by osmosis
if its too conc inside they can all rush in and burst, if its not enough the cell can shrivel as theres not enough water to maintain stability
explain required practical osmosis
i think it can be done in mnay diferent ways but idk thats abit stupid. sp ypu get a potato and you cork box it into three very equal cylinders and you measure the mass and lenght. then you put them into three test tubes, one with 0.25 sugar solution one with 0.5 and one with distilled water. leave oveer night and then dry with a towel. in water it will gain weight because its more concentrated but it wont in conc sugar
whats tugor
when the plant cell is concentrated so so much water enters, swelling the vacolole and pushing the cytoplasm to the wall the pressure is as much as it will stand so it becomes rigid which is good as it supports the plant
whats plasmosis
when the outside more concentrated (w other substances) and water diffuses out by osmosis, plant cells lose all their strength and the cell membrane disconnects from the wall
whats active transport
moving substances against the conc gradient
active transport in root hair
absorbs minerals from the dilute soil to the plant
sugar active transport
taken from the gut or the small intestine into the bllood where the conc is higher for respiration
the larger the volume..
smaller the surface area
what makes a good exchange surface
large SA
thin for a short diffusion path
ventilation
good supply of blood
permiable- able to pass across
what are chromasones and how many do we have
we have 23 pairs in each neuc and they carry our genetic material
explain mitosis
- dna forms 2 copies of each chromasone, the cell expands and all internal structures are copied
- mitosis occurs so one set of chromasones is pulled so each side and the neucleas splits in two
- finally the cytoplasm and cell membrane split in two forming two new cells
dif between plant and animal differenciation
plants can change while animal cannot
why does mitosis take place
to grow, repair and developement in asexual reproduction
what do adult stem cells do
replace any damaged cells and birth many of their type
can only differencaite into blood cells
what are stem cells
unadapted cells that can grow to be any type and can divide by mitosis
what is meristem
a tissue which helps plant cells grow and differenciate
oposition to embryotic stem cells
it comes from an embryo who cannot give permission
slow and expensive
its against the religious belief of interfering with the process of reproduction- sacred
it can become infected w a virus in the lab
they divide rapidly and can become malignment and cause cancer
hard to make the cells differentiate into the desired versions
normal stem cells are often rejected but embryos shouldnt be
whats theraputic cloning
using adult cells to create an embryo of themslves which would work because they have the same genes so cant be rejected
what does a cell wall do
maxe of cellulose it strengthens the cell
whats a zygote
a single cell
whats an embryo
a divided many times zygote that becomes a hollow ball of cells
what are embryotic stem cells
the inner cells of the ball of zygote/embryo that can divide and specialise to become all bodily cells
what are some things stem cells are treating
diabetes
eyesight
damaged bones
how are scientists overcoming the ethical issues with embryotic cloning
theyve found some embryotic stem cells on unbilical chords and even in new babies
they hope theraputic cloning- making an embryo of someones adult cells- will work
theyre trying to grow adult stem cells and find them in areas of the body
what is Cytokinesis
when the cell cytoplasm and membrane splits to become two daughter cells
three types of cells in order of size
plant- 10-100 um
animal- 10-30 um
bact- 0.2-2um
purpose of a slime capsule in prok cells
most outside layer, protects the cell and stops it from drying out
adaptions that help exchange sites
- large sa
- think membrane/ thin
- consnat blood supply or ventilation moves substances away from surface to maintain the conc gradienet
process of stem cell treatment
Extract embryonic stem cells from early embryos.
Grow them in a laboratory.
Stimulate them to differentiate into whichever type of specialised cell that we want.
Give them to the patient to replace their faulty cells.
