chapter six part one Flashcards
components of microscopy
visible light, magnification, resolution, wavelength, contrast
light
light passed through specimen then through glass lenses
magnification
ratio of object’s image size to real size
resolution
measure of clarity of image, ability to see 2 distinct things
wavelength
light/electrons
contrast
difference in brightness between light/dark areas
stain
cell components stand out, can be distinguished
condenser
below stage, focuses light on specimen
when was microscopy first invented?
1590
Robert Hooke and cells
- 1665
- dead cells of oak bark
2 types of electron microscopes
transmission and scanning
electron microscope
focuses beam of electrons through specimen and on surface
TEM
internal structure (organelles), specimen stained
organelles
membrane-enclosed structures within eukaryotic cell
SEM
- detailed study of topography
- gold on surface, electrons excited, translated to pattern on screen
cell fractionation
takes cells apart, separates major organelles and structures
- centrifuges
centrifuges
holds mixtures of disrupted cells at different speeds, components settle in bottom of tube
2 types of cells
prokaryota and eukaryota
prokaryotic cells
- domain bacteria and archaea
- DNA in nucleoid (no membrane)
- no membrane-bound organelles
- smaller
eukaryotic cells
- domain eukarya
- DNA in nucleus
- membrane-bound organelles
- larger
similarities between prokaryotic and eukaryotic
plasma membrane, cytosol, chromosomes, ribosomes
cytoplasm
- eukaryotic - region between nucleus and plasma membrane, suspends organelles
- prokaryotic - regions surrounded by proteins
why are cells so small
surface vs. volume
surface vs. volume
as the cell increases in size, surface area grows less than volume
- not enough membrane to sustain transport
diffusion
movement of substances down concentration gradient (high to low)
membrane structure
hydrophilic heads, hydrophobic tails, proteins embedded, carbohydrate side chains, cholesterol
animal cells
plasma membrane, flagellum, microvilli
plant cells
cell wall, plasmodesmata, choloroplast
nucleus
contains most of genes
- some in mitochondria and chloroplasts
nuclear envelope
encloses nucleus and separates contents from cytoplasm
- double membrane (lipid bilayer), pore structures
what is nuclear side of nuclear envelope lined by?
nuclear lamina - netlike array of protein filaments that maintain shape of nucleus
nuclear pores
in envelope, lined by pore complex (protein that regulates entry/exit of proteins, RNAs, molecules)
nuclear matrix
framework of protein fibers extending throughout nuclear interior
chromatin
complex of DNA and proteins making up chromosomes
chromosomes
structures that carry genetic information
- human: 46 in nucleus, sex 23
- form loops when preparing to divide
nucleolus
small dense structure in nucleus
- ribosomal RNA synthesized from genes in DNA
- proteins from cytoplasm assembled w rRNA
ribosome function
carry out protein synthesis
what are ribosomes made out of
ribosomal RNA and proteins
why are ribosome not organelles
they are non membrane-bound
free ribosomes
suspended in cytosol
bound ribosomes
attached to outside of endoplasmic reticulum
endoplasmic reticulum
extensive network of membranous tubules and sacs (cisternae)
cisternal space
internal compartment (ER lumen)
endomembrane system
membranes related through direct physical continuity and vesicle transfer
rough ER
studded w ribosomes
- secrete proteins produced by ribosomes
- glycoproteins
- secrete transport vesicles
glycoproteins
proteins w/ carbohydrates
smooth ER
lacks ribosomes
- synthesis of lipids
- metabolism of carbohydrates
- detoxification of drugs/poisons
- storage of calcium ions
Golgi apparatus
receives, sorts, and ships transport vesicles
- proteins modified/stored then sent to other destinations
faces of Golgi apparatus
2 sides of stacks: cis and trans
- cis - toward ER, ER to golgi
- trans - opposite side, shipping
lysosomes
membranous sac of hydrolytic enzymes used to digest and hydrolyzed molecules
- phagocytosis
phagocytosis
amoebas/protists engulf/eat smaller organisms and particles
vacuoles
large vesicles derived from ER and Golgi
- transports solutes