cell biology Flashcards
eukaryotic cell vs prokaryotic
- examples
- dna
- cell wall
- eukaryotic- animal, plant
- prokaryotic- bacteria
- eukaryotic- DNA sored in nucleus
- prokaryotic- single loop of DNA in cytoplasm
- eukaryotic- cellulose
- prokaryotic- peptidogylcan
do bacteria contain mitochondria? ribosomes?
NO mitochondria!!!!!!!!!!!!!!!!!
but they have ribosomes #omgikr
function of nerve cells
transmits electrical impulses
adaptations of nerve cells
- long axon to carry impulses at long distances
- dendrites to communcate with other never cells, muscles, glands
- axon covered in myelin sheath- insulates to speed up nerve impulse
function of muscle cells
to contract for movement
adaptation of muscle cells
-LOT of mitochondria to release energy
- protein filaments that slide over each other to allow contraction
function of sperm cells
transfer DNA to egg cell for fertilisation
function of root hair cells
absorbtion of water and mineral ions from soil
adaptation of sperm cells
- mitochondria to release energy to move
- acrosome contains digestive enzymes- break egg membrane
- tail to swim
- stream-lined head to move with HALF nucleus
adaptations of a root hair cell
- root hairs increase surface area:volum ratio- rate increased
- thinner walls- shorter distance
- mitochondria- energy for active transort
function of xylem cells
transports water and dissolved ions
adaptations of xylem cell
- lignin kills cells- they become hollow- form continous tube w no organelles
- liginin strengthens cells
function of phloem cells
transport dissolved sugars and amino acids
adaptations of phloem cells
- cells walls called sieve plates with holes to allow flow of movement
- few subcellular structures- allow flow of mateials- mitohondria
what is cell differentiation?
cells becoming specialised and adapting their features for specific function
electron vs light microscope
- electron ^ mag ^ res
- electron deep inside sub-cellualr structures
bacteria in right conditions multiply as much as…
every 20 minutes by 2
2 ways bacteria can be grown
- nutrient broth solution
- colonies in agar gel plate
4 precautions to prepare for uncontaminated culture using aseptic techniques
- petri dish and culture media- sterilised before use- kill microorganisms!!
- inoculating loop passed through flame- kill microorganisms!! (can also keep flame on throughout- convection)
- petri dish stored upside down- prevent condensation
- petri dish taped abit!- allow oxygen otherwise anaerobic- harmful bacteria
- store at 25^c- prevent harmful bacteria
how to calculate bacteria in a population
- calculate no. divisions= time dividing/mean divison time
- 2^no.divisions
how many cells in gamete- egg, sperm
23 chromosomes haploid
describe each stage of the cell cycle
1st- cell grows and sub-cellular structures double, chromosomes double
2nd- MITOSIS!! chromosomes line up in centre before being pulled apart by spindle fibres to eitehr side
3rd- cell memebrane and cytoplasm divide- 2 identical daughter cells form
role of mitosis
important for growth and development
stems cells in animals vs plants
animals- bone marrow- blood- & embryo- all
plants- meristem- all
