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B1- Cell structure and Transport - Coggle Diagram
B1- Cell structure and Transport
Transport
Diffusion
The net movement of particles from an area of high to low concentration
affected by...
An increase in temperature means particles will have more KE, so they will move around quicker
the bigger the difference in concentration, the faster the rate of diffusion, as more particles will move randomly
By increasing the surface area of the cell membrane, more substances can move in within a given time
Decreasing diffusion distance means particles will move quicker
to diffuse oxygen into blood into cell, and carbon dioxide into blood into lungs
Osmosis
The net movement of water molecules from an area of high water potential to an area of low water potential through a partially permeable membrane
Plant
turgid
net movement into the cell, causing vacuole to swell which presses the cytoplasm against cell wall
GOOD- keeps plants firm and upright
hypotonic
lower outside
flaccid
water moves into and out of the cell which becomes soft
BAD- plant wilts
isotonic
plasmolyzed
net movement of water out of the cell, causing the vacuole and cytoplasm to shrink and pull away from the cell
Doesn't happen naturally
hypertonic
higher outside
animal
In a low water potential - cell water and shrivel
In a high water potential - cell gain water, swell up and burst
Active transport
The movement of particles against a concentration gradient, from low to high, across a membrane, using energy from respiration
Transports ions and big molecules
The ion is bound to the protein. Energy changes the shape of the protein, so the opening is on the inside of the cell, before releasing the ion into
If a cell does lots of active transport, it needs lots of mitochondria to release energy
Cell structure
Eukaryotic & prokaryotic cells
Eukaryotes
Animal, plants, fungi and protista
have cell membrane, cytoplasm and genetic material enclosed in a nucleus
genetic material is a chemical called DNA, and forms chromosomes
Prokaryotes
Bacteria
0.2-2.0um in length
1-2 orders of magnitude smaller that eukaryotes
might have...
plasmids - extra rings of DNA
protective slime capsule
Flagellum[a] - long protein strand that lashes about
has cytoplasm and cell membrane and cell wall
no nucleus - genetic material is a single DNA loop found free in cytoplasm
Specialisation
Nerve cell
lots of dendrites to make connections to other nerve cells
axon carries nerve impulse from one place to another, and are designed to be very long
synapses pass impulses to other cells using special transmitter chemicals, and have lots of mitochondria for it
Sperm cell
long tail whips from side to side to help move sperm
middle section is full of mitochondria to transfer energy to tail
acrosome stores digestive enzymes for breaking down the outer layers of the egg
large nucleus contains the genetic information to be passed
Muscle cell
contain special proteins that slide over each other making fibres contract
contain lots of mitochondria to transfer energy needed
store glycogen (can be broken down to be used in respiration)
Root hair cell
greatly increase surface area available for water to move into the cell
lots of mitochondria to transfer energy needed for active transport of mineral ions
large permanent vacuole that speeds up osmosis from soil to cell
Phloem cell
cell walls between cells break down to form sieve plates that allow water carrying dissolved water to move
lose lots of internal structures, but supported by companion cells (e.g. transfer energy from mitochondria)
Xylem cell
cells are killed by lignin spirals, creating long hollow tubes that allow water and ions to go through
spirals and rings of lignin make them strong and help withstand pressure of moving water
Photosynthetic cell
have chloroplasts
large permanent vacuole that keeps cell rigid, because of osmosis, and keeps leaf spread out to capture as much sunlight as possible
positioned in continuous layers in leaves and outer cells of stem
Animal & plant cells
nucleus - controls all the activities of the cell and contains the genes of the cell
cytoplasm - a liquid gel in which the organelles are suspended and where most of the chemical reactions take place
cell membrane - controls the passage and movement of substances into and out of the cell
mitochondria - where aerobic respiration takes place to release energy
ribosomes - where proteins are made
plant cells have...
10-100um in length
cell wall - made of cellulose that strengthens and supports the cell
chloroplasts - contain chlorophyll (green) which absorbs light for photosynthesis
permanent vacuole - contains cell sap to keep cell rigid for support
animal cells are 10-30um long
Magnitudes
Magnification
Image size = magnification x size of real object
Resolution
the ability to distinguish between 2 separate points (clarity)
affects how much detail it can show
Microscopes
Light
uses a beam of light
magnifies around x2000
cheap
used almost anywhere
can magnify live specimens
resolution of 200nm
Transmission electron
Magnifies x2 million
large, expensive, kept in special rooms controlling temperature, pressure and humidity
resolution of 10nm
Scanning electron
3D images
resolution of 0.2nm
Orders of Magnitude
An order of magnitude bigger = 10^1
2 orders of magnitude bigger = 10^2
If the bigger number divided by the smaller number is less than 10 then they are the same order of magnitude
If the bigger number divided by the smaller number is around 10, then it's 10^1 bigger
If the bigger number divided bu the smaller number is around 100 then it's 10^2 bigger