2.1 Flashcards
eukaryotic cells
state 2 types of stains and what they can be used for
methylene blue - nuclei of animal cells
iodine - starch containing materials (plant cells)
define resolution
how close together two objects can be before they are seen as one
3 advantages of light microscopes
light and portable
cheap and assessable
can view living cells
3 disadvantages of electron microscope
specimen must be dead as they are viewed in a vacuum
expensive
preparing specimen is complicated
2 differences between TEM and SEM
TEM: 2D image
highest magnification
SEM: 3D image
lower magnification
how can you add colour to specimen in an electron microscope
add a heavy metal and the image will show the different density’s which are then coloured
state the 11 organelles inside a cell
centriole
SER
mitochondria
nuclear membrane
nucleolus
chromosomes
lysosomes
RER
vesical
golgi body
ribosomes
why is cholesterol needed in the cell membrane
for the fluidity of the membrane
contrast 70s and 80s ribosomes
80s: 40s + 60s subunits
eukaryotic cells
bigger
70s: 30s + 50s subunits
prokaryotic cells
smaller
what is the endosymbiotic theory
mitochondria and chloroplasts evolved from bacteria which got caught inside eukaryotic cells
what is the general structure and function of endoplasmic reticulum
interconnected network of folded membranes
formation + transport of proteins and lipids
why is it important for organelles to have separate membranes
to make it possible to have the right conditions for a particular reaction in one part of a cell and different conditions to suit other reactions elsewhere in the same cell
state 3 uses of the cell membrane
controlling what passes into & out of the cell
allowing fluids either side to have different compositions
where chemical processes take place
why do cell membranes need to be flexible
allow cell to change shape
water context
engulfing
break & fuse easily to allow vesicles through
what are vesicles
membrane ‘bags’ that hold secretions made in cells
what is the cell membrane mostly made up of
lipids & proteins
what are polar lipids
lipids with one end attached to a polar group
hydrophobic tail, hydrophilic head
how does the number of unsaturated fatty acids effect the fluidity of the membrane
the more unsaturated fatty acids the more fluid the membrane is
what are gated channels
protein channels through the lipid bilayer that are opened and closed depending on the conditions of the cell
state some of the roles of proteins in the lipid bilayer
transport of molecules
specific receptors so cells can respond to hormones
enzymes to control reactions linked to the membrane
glycoproteins often found on the surface of cells are used as a way for cells to recognize each other
state the molecules found in the fluid mosaic model
phospholipid
integral protein
peripheral protein
glycoprotein -> carbohydrate chain
cholesterol
define eukaryotes
a group of organisms with cells that have genetic material contained in a membrane bound nucleus and membrane bound organelles
define prokaryotes
a groups of organisms that have few organelles and do not have genetic material contained in a membrane bound nucleus
what is the protoplasm
the cytoplasm and nucleus combined
what is the ultrastructure of a cell
the detailed organization of the cell, only visible using an electron microscope, to ensure the cell is best suited to its role
state 2 uses of of intracellular membranes
localize enzymes in reaction pathways (best suited conditions)
compartmentalize chemicals
describe the structure of a nucleus `
spherical shape
surrounded by double nuclear membrane containing pores
contains nucleic acids and proteins
when not dividing DNA bonds to the protein to form chromatin
contains nucleolus (extra dense area of DNA & protein)
describe the structure of mitochondria
outer membrane
inner membrane which is folded forming cristae which increases surface area
fluid matrix
mitochondrial dna
describe the role of centrioles and their structure
when cell divides they produce spindle fibres which pull chromosomes apart to the poles of the cell
bundle of 9 tubules
what is the cytoskeleton
dynamic 3D web like structure which fills the cytoplasm and is made up of microfilaments and microtubules found both singularly and in bundles
what is the structure of micro tubules
consist of globular protein tubulin
why is the cytoskeleton needed
gives cytoplasm structure
keeps organelles in place
cell movement
transport within cells
what are microfilaments
contractile proteins in muscles
