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Basic Cell Structure
Cells
Basic building blocks of
life
Understanding of cell
helps the study of
biotechnology
Cell
Smallest living unit of an
organism
Grow, reproduce, use
energy, adapt, respond to
their environment
Cell
Many cannot be seen with
the naked eye
A cell may be an entire
organism or it may be one of
billions of cells that make up
the organism
Cells
Divided and classified in
many ways
One common classification
method is the presence or
absence of a cell nucleus
Nucleus
Relatively large structure
with a cell
Directs cell activities
Some simple single celled
organisms lack a nucleus
Nucleus
Prokaryotes – have no
nucleus
Eukaryotes – have a
nucleus
Prokaryotes
Single celled organism
Kingdom Monera
Lacks a cell nucleus
Internal structure is less
organized than other cells
Prokaryotes
Genetic info needed is
within the cell
Two most common – blue
green bacteria and true
bacteria
Blue green bacteria
Have ability to produce
their own food like plants
Most bacteria get their
food from other sources
Prokaryotes
Less complex than
eukaryotes
Still have many of the
basic internal
characteristics
Common prokaryote
structures
Cytoplasm
Chromosomal material
Cell membrane and wall
Ribosomes
Some have flagellum for
mobility
Eukaryotes
Organism made up of cells
that have a nucleus
May be single celled –
Kingdom Protista
May have billions of cells like
plant and animal kingdoms
Eukaryotes
Single celled eukaryotes
include paramecia,
euglena, and diatoms
Eukaryotes
Typically are highly
organized
Infinite number of shapes
and purposes
Eukaryotes
Human body has at least
85 different cell types
All eukaryotes have a
number of structures in
common
Common structures
Organelles – smaller parts
of the cell with specific
funtions
Cell membrane – acts as
a gatekeeper
Cell membrane
Controls what enters and
leaves the cell
Plants, algae and bacteria
typically have a tough outer
structure known as a cell
wall
Cell wall
Provides additional structure
and protects the cell from
pressure caused by
movement of water
Animal cells do not have
walls
Cytoplasm
Organelles are surrounded
by a jelly like substance
Mostly water
Nucleus
Largest and most identifiable
part of the cell
Other organelles
Ribosomes
Mitochondria
Golgi bodies
Endoplasmic reticulum
Other organelles
Lysosomes
Vacuoles
Chloroplasts in plants
Nucleus
Brain of the cell
Site of much of the
manipulation done in
biotechnology
Nucleus
Controls activity of the cell
Round or oval structure
Typically found in the middle
of the cell
Appears darker than
surrounding material
Nucleus
Surrounded by a membrane
that controls passage of
materials in and out of the
area
Nucleus
Contains DNA
DNA is located on
chromosomes
Most organisms are diploid –
have tow chromosomes for
each trait
Diploid
Humans – 23 pair
Goldfish – 90 chrms, 45 pair
Cytoplasmic
Organelles
Organelles are required for
proper cell function
Ribosome – make proteins for
cellular use and communication
May be attached to
endoplasmic reticulum
Endoplasmic
reticulum
Layered membraneous
Make and transport proteins
Vacuole
Large organelle, without
specific shape
Store waste or raw materials
used in synthesis of proteins
Golgi Bodies
Golgi apparatus
Similar to endo. Ret.
Look like a thick elastic band
that has been folded several
times
Golgi Bodies
Adds modifications to
unfinished proteins
Makes lysosomes
Lysosome
Small round
Store enzymes that break
down food into chemical
compounds
Destroy cell organelles and
the cell itself
Mitochondria
Energy factories
Rod shaped
Change food into molecules
that can be used for energy
Mitochondria
Contain DNA
Can replicate themselves
Chlorplast
Found in plants and some
other organisms
Contain chlorophyll
Cellular processes
Respiration
Osmosis
Diffusion
Photosynthesis
Respiration
Cells break down
carbohydrates and other
molecules to produce energy
Oxidation of glucose is one
of most common forms
Respiration
Breaking down of sugar into
water, carbon dioxide, and
energy
Energy is used to do the
work of the cell
Osmosis & Diffusion
Transport of raw materials,
wastes, and synthesized
materials out of the cell
Diffusion
Movement of molecules,
especially gases and liquids
from areas of high
concentration to areas of low
concentration
Osmosis
Specific type of diffusion
Movement of water through
a membrane from areas of
high concentration to areas
of low concentration
Equilibrium
Diffusion and osmosis
happen to enable a cell to
reach equilibrium
Cellular reproduction
Three ways
Fission
Mitosis
Meiosis
Fission
Prokaryotes
Cell grows larger and makes a
second copy of its DNA
At some point the cell
membrane divides the cell by
the growth of a transverse
septum
Fission
Two new cells are formed as
the division grows inward from
either side of the cell
Two cells now called “daughter
cells”
Sometimes known as “binary
fission”
Mitosis
Eukaryotes
Requires 6 stages
Interphase, prophase,
metaphase, anaphase,
telophase, cytokinesis
Mitosis
Creates cells that are
identical to the original cell.
Have the entire compliment
of chromosomes existing in
pairs - diploid
Meiosis
Division of sex cells
Stages of Meiosis I:
Interphase I, prophase I,
metaphase I, anaphase I,
telophase I, cytokinesis I
Meiosis
Meiosis II
Interphase II, prophase II,
metaphase II, anaphase II,
telophase II, cytokinesis II
Meiosis
Each cell receives one
chromosome from each pair
randomly
Resulting cells have half the
normal number of
Chromosomes - haploid