b1- cell structure and transport Flashcards
how much can light microscopes magnify?
up to x2000
what is light microscopes resolving power?
200 nm
how much can electron microscopes magnify?
x 2 000 000
what are electron microscopes resolving power?
0.2 nm
magnification=
size of image / size of real object
what features do animal cells contain?
a nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
what are features that plant cells contain but animal cells do not?
a cellulose cell wall
chloroplasts
vacuole
what is an example of eukaryotic cells?
animal and plant cells
what is an example of prokaryotic cells?
bacteria
do prokaryotic cells have a nucleus?
no
what do eukaryotic cells contain?
cell membrane
cytoplasm
genetic material in a nucleus
what do prokaryotic cells contain?
cytoplasm
cell membrane
cell wall
dna loop
may contain plasmids
what are plasmids?
extra, small rings of dna
what are examples of specialised animal cells?
nerve cells
muscle cells
sperm cells
what are examples of specialise plant cells?
root hair cells
photosynthetic cells
xylem cells
phloem cells
what is diffusion?
the spreading out of particles of any substance in solution or a gas. moving from high concentration to low concentration
what effects rate of diffusion?
concentration
temperature
surface area
what is osmosis?
a special case of diffusion, the movement of water from a dilute to a concentrated solution through a partially permeable membrane that allows
water to pass through
how can animal cells be damaged in osmosis?
if concentration outside the shell changes dramatically
what does osmosis in plant cells help maintain?
turgor
what is active transport?
it moves substances from a dilute solution to a concentrated solution
how does active transport get the energy needed for the movement?
it uses energy released from food in respiration
why do single celled organisms have a relatively large surface area to volume ratio?
so all necessary exchanges with the environment take place over this surface
what do exchange surfaces have?
large surface area and thin walls
how are the cells in the small intestine adapted for active transport?
many mitochondria to release energy for active transport
what is the function of mitochondria?
the site of respiration where energy is released
what is the function of a permanent vacuole?
contains sap and enzymes also stores excess water
