Transcript CellsBesidesanimals

Besides animals:
Plant & bacteria cells
Prokaryotes
• Prokaryotes: Bacteria
– Pro: “Before” + Karyon:
“Kernel” i.e. a nucleus
• Has DNA, but not
wrapped up in a
membrane
– Often 1 double stranded
DNA looped in a coil
• Short generation time
means lots of chances to
change DNA
E. Coli for
example
• 4 million B.P. & 3000 genes
– 100xs more than a virus,
0.001x’s that of a
eukaryote
– Stretched out that’s about
a mm in length, 500 times
longer than the cell.
– Imagine eating a strand of
spaghetti 3000 feet long
– Also lots of plasmids
floating around
• About 1 or 2 genes on
those
• Double grains of rice
on each square on a
chess board
• You have more
ancestors than
the population
of the world
• We’re all a little
inbred
• Cheetahs and limited
genetic variation
• All genetically similar
• Seldom reject donor
organs
• ~12,500 left in the
wild
• Leaves little room for
chance
• If one is vulnerable to
a disease, unlikely to
be a resistant mutant
E. Coli: Binary fission
causes them to double
every 20 minutes
Go from 1  108 over
night
What does this have to
do with me? We lose
2 x 1010 E. Coli every
day, but they grow fast.
It keeps the sanitary authority
busy.
Harry Readshaw  chairman
of ALCOSAN
Rapid
generations
• Binary fission: Asexual,
– Offspring are genetically
identical to parents
• But combine small chance of
mutation with large large
numbers of offspring and you
get a couple mutants every
day
• Compare to slow-reproducing
organisms who don’t get
mutants that often.
Plant Cells
• Like animals
– Plasma membrane,Nucleus,
Ribosomes,ER,Golgi,Mitochondria,Peroxisomes,
microtubules
• Unlike animals
– Plastids
– Chloroplast  photosynthesis
– Vacuole  stores chemicals
– Cell Wall  maintain shape, protection
Cell Wall component: Lignin
• Derived from a.a. phenylalanine
• One of the most abundant biomolecules
on Earth after
– Cellulose & Chitin
– ~1/4 the mass of dry wood
• Effective barrier against invaders
• Hydrophobic, plants use it to channel
water
• Have to remove it before we get paper
• Burn it to get smoked flavor
Elodea cells
Elodea
• Genus of plants: “the
water weeds”
• Native to N. America
• Invasive to everywhere
else
• Can grow unrooted
• Good aquarium plant
• Good habitat
• Ducks & beaver eat it
• Iroquois used as a drug
• Say that box is 1 mm
across
• If 6 elodea cells fit
across the box how long
is 1 elodea cell?
• If ~14 elodea cells fit up
and down the box about
how wide is an elodea
cell?
You got math in my science!
• Assume the cell is as high as it is wide.
• Now you have the length, width, & height
of an elodea cell.
• Figure out the volume: L x W x H