Williams
Dr. Joshua Bhuvana
Biology 202
March 15, 2010
Little Mito Answers
1. The names Nuc, Flag, ER, Mito, Chlora, Golgi, Ves, and Lys are short for
nucleus, flagella, endoplasmic reticulum, mitochondria, chloroplast, golgi
apparatus, vesicles, and lysosome respectively. The nucleus of the cell is
surrounded by a double membrane and contains protons, neutrons, and genetic
material. The nucleus is a dense organelle. The flagella of a cell are threadlike
structures that move like whips to allow the cell to move. The endoplasmic
reticulum of a cell is a membranous network continuous with the outer nuclear
membrane that is active in distribution and storage, membrane synthesis, and
metabolic processes. It may or may not be covered with ribosomes. The
mitochondrion is the powerhouse of the cell. It carries out cellular respiration
and generates ATP. Chloroplasts carry out photosynthesis. They convert sunlight
energy to chemical energy stored in sugar molecules. The golgi apparatus is an
organelle that makes, sorts, modifies, and secretes cell products. Lysosomes are
membranous sacs of hydrolytic enzymes used to digest macromolecules. Animal
cells lack chloroplasts and plant cells lack lysosomes and flagella.
2. The autogenic hypothesis of the origin of the eukaryotic cell is that a prokaryotic
cell infolded its plasma membrane, pinched off little groups inside the cell that
began to specialize in certain functions as the intercellular organelles they that are
today.
3. The evidence that supports the autogenic hypothesis is the existence of the
membranes in the cell. Basically, all of the organelles of the endomembrane
system share the same type of membrane. They are all bilipid membranes, just
opposite in orientation to the membrane surrounding the cell itself.
4. The endosymbiotic hypothesis says that a bacterial predator ate individual bacteria
that were too strong for it, and thus continued to live inside the cell in a mutual
relationship where the consumed bacteria continued to produce energy and
perform their functions.
5. The evidence for the endosymbiotic hypothesis is that mitochondria and
chloroplasts have their own separate DNA and protein-synthesizing abilities that
are more like bacteria than eukaryotes. Mitochondria and chloroplasts can only
arise from other mitochondria and chloroplasts. And there are numerous other
similarities between prokaryotes and cell organelles.
Strengths
Autogenic
Endosymbiosis
Accounts for
Demonstrates why
relationship of the
mitochondria and
organelles.
chloroplasts are
Accounts for the
similar to bacteria
existence of the
membranes of the
organelles
6.
Weaknesses
Autogenic
Endosymbiosis
Doesnt specify how Doesnt explain
or why membranes
how prokaryotes
pinched off from the would have
cell membrane to
survived digestion
form organelles or
and thrived as
how they could
functioning,
begin to specify
specialized
their functions
organelles