Cell biology

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Cell biology
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Protein structure
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Complex carbohydrates
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Complex carbohydrates
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Complex carbohydrates
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Announcements
There will be a quiz next laboratory session
and like always it will cover materials from
previous lab. and from up-coming one. Next
week lab. is Energy conversion (fermentation).
Home work for this lab. will is posted on my
web page. Another assignment a prospectus,
also due next week and is posted on my web
page. Read through page XIV and XV to be
prepared for next week assignment.
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Today

• cells and types of cells
• Domains of life
• Prokaryotes and eukaryotes
• Cell division
• Diffusion
• Osmosis

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The Cell
It is the the smallest unit of any living
organism. It is basically a protoplasmic mass
that is a cell membrane and cytoplasm. The
cytoplasm is composed of a fluid part (cytosol)
and solid structures (organelles) Some other
structures may exist depending on the type of
the cell (cell wall in plant cells, cell wall in
bacteria). Based on the type of cell,
living organisms are group into three
categories.
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Domains of life
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Cell type
Generally, cells are either prokaryote or
eukaryote Prokaryotes -genetic material
(chromosomal DNA) is free in the cytosol. -
there is no membrane-bound organelles -no
cytoskeleton Eukaryotes -genetic material
(chromosomal DNA) is surrounded by a membrane
(the nuclear membrane) -there are
membrane-bound organelles (endoplasmic
reticulum, Golgi apparatus, mitochondria,
chloroplast, etc.) -there is cytoskeleton
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Prokaryotes
These are bacteria (eubacteria)
unicellular They have different shapes, size
and environment. Some are pathogenic and others
are beneficial. Microscopic organisms.
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Archaea
These are middle stage between prokaryotes and
eukaryotes. They have ribosomal subunits
that is different from bacteria and
eukaryotes. They live in extreme environmental
conditions. They share bacteria in -no
membrane-bound organelles -no cytoskeleton
-method of cell division - unicellularity They
resemble eukaryotes in - transcription apparatus
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Eukaryotes
These includes cells of animals, plants,
protozoa, and fungi. Eukaryotic organisms
either uni- or multi-cellular Humans are multi-
cellular eukaryotes.
animal cell
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Eukaryotes
Plant cell
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Cell division
Porkaryotes and Archaea - Cell division occur
by process termed simple binary fission -
Basically, the cell double its contents and
divide - It a processes of reproduction
(multiplication). Eukaryotes -mitosis somatic
or asexual cell division -meiosis sexual cell
division - in multi-cellular organism e.g human,
mitosis is mainly growth related cell
division.
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Diffusion
It is the process by which particles are
transported across the cell membrane.
Particles moves from a region of higher
concentration toward a region of lower
concentration. Cell membrane exert a degree of
selectivity on the particle that diffuse
through it (selective permeability) O2,
Co2, nutrients, etc. diffuse through the cell
mem.
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Osmosis
It is a process of water molecules movement
from hypotonic solution (low solute
concentration) to hypertonic solution (high
solutes concentration) through a
semi-permeable membrane (cell membrane).
Cytoplasm is a hypertonic solution compared to
tap water. What will happen to animal cell
thrown into a beaker filled with tap water..
plant cell Bacterial Saline . 0.9 NaCl,
is isotonic solution.
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Fun time
15 minutes to read the materials and methods for
this laboratory. P 3-4 to 3-9 Check each
station and start work.