Cell Biology Flashcards
(21 cards)
adaptations of the phloem?
energy supplied by mitochondria in companion cells
sieve plates allow movement of substances between cells
what does the cell wall do?
provides strength to a cell
adaptations of muscle cells?
lots of mitochondria to provide energy
special muscles slide over one another, causing the muscle to contract
why do nerve cells have long axons?
allows impulses to travel longer areas
name 3 adaptations of a root hair cell.
large permanent vacuole
large surface area to volume ratio
mitochondria
adaptations of the xylem?
lignin causes cells to die
lignin is deposited in spirals which helps the cells withstand pressure from water movement
continuous tube of water (hollow and joined end to end)
what are the two types of electron microscope?
scanning electron microscope - 3D images with a slightly lower magnification
transmission electron microscope - 2D images with detailed organelle
why are petri dish stored upside down?
to prevent condensation from the lid landing on agar surface and disrupting growth
what are 3 factors that affect diffusion?
concentration gradient
surface area
temperature
what is a hypertonic solution?
a concentrated solution
what is a hypotonic solution?
a dilute solution
what is are isotonic solutions?
both solutions have equal concentration strength
what happens if outside a plant is more dilute?
pressure in plant builds up called turgor
what happens is outside a plant is more concentrated?
the cell gets plasmolysis and dies as the cell membrane moves away from the cell wall
what are the benefits of embryonic stem cells?
replace damaged things
unwanted embryos
research into differentiation
what are the disadvantages of embryonic stem cells?
don’t completely understand differentiation
destruction of embryo
religious/ethical objections
benefits of adult stem cells?`
no ethical issues
multipotent
downsides to adult stem cells?
not totipotent
operation required
what are the advantages of therapeutic cloning?
embryos are produced with the same genes as their parents which means they aren’t rejected and they can grow into cells patients need
stages of mitosis?
cell grows and organelles grow and increase in number and DNA is replicated
chromosomes line up at equator and cell fibres pull each chromosome to either side of the cell
2 identical daughter cells formed when cytoplasm and cell membrane divide
how do you calculate the number of bacteria in a population over a given time?
bacteria at the beginning x 2^number of divisions
