Download Tour of the Cell

Tour of the Cell
Part 2
AP Biology
2007-2008
From food to making Energy
 Cells must convert incoming energy to
forms that they can use for work
mitochondria:
ATP
from glucose to ATP
 chloroplasts:
from sunlight to ATP & carbohydrates

 ATP = immediate energy
 carbohydrates = stored energy
ATP
AP Biology
+
Mitochondria & Chloroplasts
 Important to see the similarities

transform energy
 generate ATP
double membranes = 2 membranes
 semi-autonomous organelles

 move, change shape, divide

AP Biology
internal ribosomes, DNA & enzymes
Lynn Margulis
U of M, Amherst
Membrane-bound Enzymes
glucose + oxygen  carbon + water + energy
dioxide
AP Biology
C6H12O6 +
6O2  6CO2 + 6H2O + ATP
Membrane-bound Enzymes
carbon + water + energy  glucose + oxygen
dioxide
light  C H O + 6O
6CO
+
6H
O
+
6 12 6
2
2
2
AP Biology
energy
Mitochondria are everywhere!!
animal cells
plant cells
AP Biology
Cells gotta live!
 What jobs do cells have to do?

building proteins
 proteins control
every cell function

make energy
 for daily life
 for growth

build more cells
 growth
 reproduction
 repair
AP Biology
Cytoskeleton
 Function

structural support
 maintains shape of cell
 provides anchorage for organelles
 protein fibers


microfilaments, intermediate filaments, microtubules
motility
 cell locomotion
 cilia, flagella, etc.

regulation
 organizes structures
& activities of cell
AP Biology
Cytoskeleton
 actin
 microtubule
 nuclei
AP Biology
Centrioles
 Cell division
in animal cells, pair of centrioles
organize microtubules
 guide chromosomes in mitosis

AP Biology
Cell Size
AP Biology
2007-2008
Limits to cell size
 Lower limit

smallest bacteria
 mycoplasmas
 0.1 to 1.0 micron (µm = micrometer)

most bacteria
 1-10 microns
 Upper limit

eukaryotic cells
 10-100 microns
 micron = micrometer = 1/1,000,000 meter
Biology
APdiameter
of human hair = ~20 microns
What limits cell size?
 Surface to volume ratio

as cell gets bigger its volume increases
faster than its surface area
 smaller objects have greater
ratio of surface area to volume
Why is a huge
single-celled
creature not
possible?
AP Biology
s:v
6:1
~1:1
6:1
Limits to cell size
 Metabolic requirements set upper limit
in large cell, cannot move material in &
out of cell fast enough to support life
aa
aa
What process is this?
CH
NH3
aa

CHO
O2
CH
aa
CO2
CO2
CHO
CH
AP Biology
aa
aa
O2
CO2
CHO
O2
NH3
CHO
O2
NH3
O2
NH3
CO2
CH
aa
What’s the solution?
How to get bigger?
 Become multicellular (cell divides)
But what challenges do you have to solve now?
CO2
CO2
aa
aa
CO2
CHO
NH3
CH
AP Biology
CO2
O2
NH3
aa
aa
CO2
NH3
CO2
CO2
NH3
NH3
CO2
CH
NH3
NH3
CO2
CHO
O2
NH3
CO2
O2
CH
aa
O2
NH3
CHO
CO2
aa
Cell membrane
 Exchange structure

plasma membrane functions as
selective barrier
 allows passage of O2 & nutrients IN
 allows passage of products & wastes OUT
Phospholipid
AP Biology
Membrane
proteins
Cholesterol
Any Questions??
AP Biology
2007-2008