B1 Flashcards
how much can a light microscope magnify by
2000x
how much can an electron microscope magnify by
20,000,000
name some differences between the light microspoe and the electron microscope
light microscopes are cheap and can be used anywhere but electron microscopes are very expensive and have to be used in special environments.
what is the formula to work out the magnification size
magnification=image size/size of real object
what is a eukaryotic cell
animal and plant cells
what is a prokaryotic cell
bacteria, they dont have a nucleus and the genetic info is free in the cytoplasm.
what is the smallest type of unit
nano metre
name 3 adaptions of the nerve cell
lot of dendrites to make connections to other nerve cells.
they have very long axons that carry nerve impulses from one part of your body to another( longest runs from base of spine to big toe)
nerve endings contain a lot of mitochondriato pass the impules to another cell or a musle.
name the 3 adaptions of a muscle cell
they contain special proteins that contract when they slide over each other.They contain lots of mitochondria to transfer the energy needed to contract amd relax
what is the flagella in a prokaryotic cell
a long protein strand that helps them move
where is the DNA in a prokaryotic cell
floating around in the cytoplasm
name 3 adaptions of a sperm cell
long tail to help the sperm swim towards the egg, full of mitochondria for it to transfer the energy needed to help the tail move, large nucleus for genetic info to be passed on.
name 3 adaptations in root hair cells
greatly increased surface area for water to enter it, large vacuole to speed up osmosis, many mitochondria to transfer the energy needed for active transport
name 3 adaptions of photosynthetic cells
they contain chloroplasts which trap the sunlight, placed in outer stem and leaves of plant so it can absorb as much sunlight as possible, it has a large permanent vacuole to keep the cell rigid during osmosis
what does a xylem cell do
it cit carries water and mineral ions from roots to leaves and top of plant
name 2 adaptions in xylem cells
they start off alive, but they then die and become hollow so water and ions can go through them, the spirals and rings of lignin keep it strong so it can stand the pressure of the water
what does a phloem cell do
allows food to move up and down a plant
name 2 adaptions of a phloem cell
cell walls between cells make sieve plates so water carrying dissolved food can move freely up and down the tubes, lose a lot of internal structures but have companion cells that keep them alive. The companion cells have a lot of mitochondria to transfer the energy needed to move dissolved food up and down the plant
what is a solute
the thing that gets dissolved
what is the solvent
the thing that does the dissolving
what is diffusion
the spreading out of particals in a solution
what is the net movement in diffusion
high to low concentration
does diffusion occur up or down the concentration gradient
down
what is gas exchange
where 2 gases move in opposite directions by diffusion
how does the concentration gradient work
if there is a big difference in concentration between the 2 areas, the particles move quicker, meaning there is a steeper concentration gradient if there is only a small difference in concentration between the 2 areas then the gradient is shallower. Overall, the bigger the difference in concentration between the 2 areas, the quicker the particles move and the steeper the concentration gradient
what is osmosis
the movement of water molecules from a dilute to a more concentrated solution through a partially permeable membrane that allows water to pass through
what causes the water to move during osmosis
a difference in concentrations of solutions inside and outside of the cell
does osmosis go up or down the concentration gradient
down
if the concentration of solutes outside the cell is the same as inside the cell it is
isotonic
if the concentration of solutes is higher outside the cell than inside it it is
hypertonic
if the concentration of solutes is higher inside the cell than outside it it is
hypotonic
why is osmosis important in plant cells
so it stays turgid
does active transport go down or against a concentration gradient
against
where does active transport move from and to
from a more dilute solution to a more concentrated solution
where does active transport get the energy from to work
energy from food released in respiration
what does active transport allow root hair cells to obtain
mineral ions that it needs from the ground against a concentration gradient
where does active transport allow suger molecules to go
the gut. it goes from a low concentration of sugar molecules to a high one
