2.1- cells and microscopes Flashcards
eukaryotic cells contain
membrane bound organelles
nucleolus
site of ribosome production
nucleus
- ALL eukaryotes except rbc
-contains CHROMATIN
-chromosomes are made of sections of linear DNA wound around proteins called histones
nuclear envelope
- double membrane surrounding nucleus
- contains nuclear pores which allow molecules (ribosomes, enzymes etc) to enter and leave the nucleus
prokaryotes contain (6)
- cell wall
- capsule
- plasmid
- flagellum
- pili
- ribosomes
preparation of solid slide for light microscope
- cut a thin (so light can pass through) section of tissue (scissors?)
- place on slide using forceps
- add a drop of stain
- add coverslip using MOUNTED NEEDLE at 45 degrees to avoid trapping air bubbles
equation for mag
image size = actual size * magnification
magnification
- factor by which the image is larger than the actual specimen
resolution(2)
- ability to distinguish between 2 objects close together
- level of detail
mag and res of TEM
mag : x500,000
res : 0.2 nm
mag and res of light
x1500
200nm
ribosomes
- in ALLLL CELLS
-foubd free in cytoplasm or in rough ER - made of PROTEINS and ribosomalRNA
- large subunit (which joins amino acids)
- small subunit (with mRNA binding site)
- translation here
80s ribosomes
- from 60 and 40 subunits
- eukaryotic cells
70s ribosomes
- prokaryotes, mitochondria, chloroplasts
- from 50 and 30 subunits
function of mitochondria
- site of aerobic respiration to produce ATP
-light microscope - has cristae-folds to increase SA
- matrix formed contains enzymes for aerobic respiration andDNA and ribosomes
cristae
folds of inner membrane in mitochondria; enable compartmentalisation
chloroplasts
- plant cells
- LARGER than mitochondria
-site of photosynthesis to convert solar energy to chemical energy
bacterial cell wall is made of?
peptidoglycan
fungal cell wall is made of?
chitin
cell wall
- structural support
- cellulose polysaccharide in plants
plasmodesmata
- threads of cytoplasm
- connect cytoplasm of neighbouring plant cells
flagellum
- hollow helical tube made of the protein FLAGELLIN
-made of microtubules - rotates to propel organism (usually unicellular)
cilia
- hair like projections made of microtubules
microvilli
- in specialised animal cells
- cell membrane projections
- increase SA of plasma membrane to increase rate of exchange if substances
role of cytoskeleton
- provide support for organelles and shape of cell
- intracellular movement; forms tracks where organelles can move
- enables cell movement via cilia and flagella
SIMILARITIES euk and prok
- plasma membrane
- cytoplasm
- ribosomes
ribosomes eukaryote
LARGER : 80S
ribosomes prokaryote
SMALLER: 70s
how do prokaryotes reproduce
binary fission - ALWAYS asecual
how do eukaryotes reproduce
mitosis and meiosis, sexual and or asexual
plasma membrane
- ALL CELLS
-regulates movement of substances into and out of the cell - has receptor molecules which allow it to respond to chemicals eg hormones
- formed from phospholipid bilayer