Lesson #1: Cells and Organelles Flashcards
(16 cards)
The Cell Theory
All living things are composed of cells and cell products
New cells are formed only by the division of pre-existing cells
The cell contains inherited information that are used as
instructions for growth, functioning, and development
The cell is the functioning unit of life; the chemical reactions of
life take place within cells
Homeostasis
Homeostasis is the result of conditions in every cell remaining nearly
constant.
In unicellular organisms the cell maintains homeostasis in the whole
organism
In multicellular organism, cells specialize to perform different tasks to
maintain homeostasis in the organism.
There are two types of cells:
Prokaryotic
Eukaryotic
Prokaryotic Cells
Evolved 3.5 billion years
ago
Most cells are 1-10 µm in
size
No nucleus
No membrane-bound
organelles
Small ribosomes
Eukaryotic Cells
Evolved 1.5 billion years
ago
Cells can be between 2 –
1000 µm in size
Have a nucleus
Many organelles
Larger ribosomes
Common Components and
Cellular Organization
Plasma Membrane – boundary
surrounding the cell
Genetic Material (DNA) –
controls cell
Cytoplasm – semi-fluid matrix
containing enzymes and
organelles
Cytoskeleton – network of
filaments and tubules in
cytoplasm that maintains cell
shape and allows for movement.
Features of
Prokaryotic Cells
Plasma Membrane –
regulates the flow of
materials into and out of
the cell.
Nucleoid – cytoplasmic
region containing genetic
material.
Cytoplasm – fluid
containing ribosomes and
enzymes
Cell Wall – supports the
cell and maintains shape
Capsule – protects from
drying and immune cells
Flagellum – movement
Plasmid – small circular
DNA
Eukaryotic Organelles
Organelles are membrane bound
structures that perform special
functions within the cell.
Each organelle performs a
specific task that contributes to
the homeostasis of the cell.
Nucleus
contains the genetic
information of the cell
(DNA)
contains the Nucleolus,
which is a dark region
inside the nucleus that
produces ribosome parts
surrounded by a double
layered porous
membrane called the
nuclear membrane
Plasma Membrane
Encloses the cell contents
and separates them from
the outside
Layer between the inside
and outside of the cell
Selectively permeable
Cytoplasm
Fluid substance that
contains enzymes and
organelles
Endoplasmic Reticulum (ER)
continuous with the
nuclear membrane
two types:
Rough – involved in
the synthesis,
folding,
modification and
transport of
proteins
Smooth – involved
in synthesis of
cholesterol and
phospholipids for
the construction of
cell membranes.
Ribosomes
found in both prokaryotic
and eukaryotic cells.
Prokaryotic ribosomes
are known as 70S and
eukaryotic ribosomes
are known as 80S (the
s refers to
sedimentation rate in
Svedberg units)
synthesize proteins
made up of a small and a
large subunit
found attached to the
endoplasmic reticulum
and free in the cytoplasm
Mitochondria
Produces cellular energy
through the process of
cellular respiration
Golgi Apparatus
also known as Golgi Complex or Golgi
Body.
modifies proteins and packages them
into membrane-bound vesicles destined
for targets outside the cell.
Vacuoles
enclosed storage
compartments that vary
in size and shape
depending on the type
and needs of the cell.
may be used to:
Isolate materials
that might be
harmful or a threat
to the cell
Contain waste
products
Contain water in
plant cells
Maintain
internal pressure
within the cell
Lysosomes
Found only in animal cells
Vesicles that contain catabolic enzymes that
can break down virtually all types of
biological molecules.
Chloroplast
found only in plants
performs
photosynthesis to
produce
carbohydrates for
the cell.
Cell Wall
found only in plant cells
rigid outer membrane that gives structure
and support
