BE-2102
INTRODUCTION
The Cell
Cell Theory:
All organisms are composed of cells
A cell is the smallest unit of living matter
Cells come only from preexisting cells
All living organisms are composed of cells that have a
fundamentally similar chemistry and operate according to the
same basic principles
Cells A cell is a membrane-bounded unit that contains DNA and cytoplasm. All organisms are cells or aggregates of cells, descendants of the first cells.
Cells Are Small The relative surface area of small cells enables more rapid communication between the cell interior and the environment.
Eukaryotic cells are far more complex than bacterial cells
Bacteria Are Simple Cells, small, and lack membrane-bounded organelles.
Eukaryotic Cells Have Complex Interiors,i.e. compartmentalized by membranes.
(A) A nerve cell from the cerebellum (a part of the brain that
controls movement). This cell has a huge
branching tree of processes, through which
it receives signals from as many as
100,000 other nerve cells.
(B) Paramecium. This protozoana single giant cellswims by means of the beating cilia that cover its surface.
(C) A section of a young plant stem in which
pectin is stained orange and cellulose red.
The outermost layer of cells is at the top of
thephoto.
(D) A tiny bacterium, Bdellovibrio
bacteriovorus, that uses a single terminal
flagellum to propel itself. This bacterium
attacks, kills, and feeds on other, larger
bacteria.
(E) A human white blood cell (a neutrophil)
approaching and engulfing a red blood cell.
Cells come in a variety of shapes and sizes
This diagram shows the size of human skin cells, organelles, and molecules.
In general, the diameter of a human skin cell is 20 m or 2 10-2 mm,
a mitochondrion is 2 m or 2 10-3 mm,
a ribosome is 20 nm or 2 10-5 mm,
a protein molecule is 2 nm or 2 10-6 mm
an atom is 0.2 nm or 2 10-7 mm.
The size of cells and their contents
BASIC PROPERTIES OF CELLS
CELLS ARE HIGHLY COMPLEX AND ORGANIZED
CELLS POSSES A GENETIC PROGRAM AND THE MEANS TO
USE IT
CELLS ARE CAPABLE OF PRODUCING MORE OF
THEMSELVES
CELLS ACQUIRE AND UTILIZE ENERGY
CELLS CARRY OUT A VARIETY OF CHEMICAL REACTIONS
CELLS ENGAGE IN NUMEROUS MECHANICAL ACTIVITIES
CELLS ARE ABLE TO RESPOND TO STIMULI
CELLS ARE CAPABLE OF SELF-REGULATION
Ciri-ciri Hidup vs
Properties of Cells
CIRI-CIRI HIDUP:
Memiliki struktur dan hidup alive
Membutuhkan Nutrisi
Melakukan aktivitas metabolisme
Membutuhkan, mengkonversi & memanfaatkan energi
Melakukan pergerakan
Mengalami pertumbuhan & perkembangan
Memperbanyak diri/bereproduksi
Merespon stimulus
Memiliki sistem pengaturan diri/self regulation
PROPERTIES OF CELLS
Cells are highly complex and organized
Cells posses a genetic program and the means to use it
Cells are capable of producing more of themselves
Cells acquire and utilize energy
Cells carry out a variety of chemical reactions
Cells engage in numerous mechanical activities
Cells are able to respond to stimuli
Cells are capable of self-regulation
Basic structures of a cell:
Basic components of
a cell:
Cell membrane
Genetic material
Ribosomes
Cytosol
Mycoplasma
A prokaryotic cell is enclosed by a plasma membrane and is usually encased in a
rigid cell wall
The cell wall may be
covered by a
sticky capsule Ribosomes
Figure 4.4
Capsule
Cell wall
Plasma
membrane
Prokaryotic
flagella
Nucleoid region
(DNA) Pili
Inside the cell are its DNA
and other parts
The Prokaryotic Cells
bacteria contain essentially no organellesnot even a nucleus to contain their DNA. They often
have a tough protective coat, called a cell wall,
surrounding the plasma membrane, which
encloses a single compartment containing the
cytoplasm and the DNA.
Origin of
Mitochondria
& Chloroplast
Prokaryotic & Eukaryotic cells
An eukaryotic cell compared to prokaryotic cells
An animal cell
Plasma membrane
Figure 4.5A
Golgi
apparatus
Ribosomes
Nucleus Smooth
endoplasmic
reticulum Rough
endoplasmic
reticulum
Mitochondrion
Not in most
plant cells
Cytoskeleton
Flagellum
Lysosome
Centriole
Peroxisome
Microtubule
Intermediate
filament
Microfilament
Figure 4.5B
Nucleus
Golgi
apparatus
Not in
animal
cells
Central
vacuole
Chloroplast
Cell wall
Mitochondrion
Peroxisome
Plasma membrane
Rough
endoplasmic
reticulum
Ribosomes
Smooth
endoplasmic
reticulum
Cytoskeleton
Microtubule
Intermediate
filament
Microfilament
The most complex eukaryotic cell
Viruses
Cell parts
Macromolecules of Cells
Proteins in
the cell
Proteins in the cell membranes
Biochemical
reactions
Essential Concepts
Cells are the fundamental units of life. All present-day cells are
believed to have evolved from the same ancestral cell that existed
more than 3 billion years ago.
All cells, and hence all living things, grow, convert energy from one form to another, sense and respond to their environment, and
reproduce themselves.
All cells are enclosed by a plasma membrane that separates the inside of the cell from the environment.
All cells contain DNA as a store of genetic information and use it to guide the synthesis of proteins.
Essential Concepts
Cells in a multicellular organism, though they all contain the same DNA,
can be very different. They use their genetic information to direct their
biochemical activities according to cues they receive from their
environment.
Cells of animal and plant tissues are typically 520 mm in diameter and can be seen with a light microscope, which also reveals some of their
internal components, or organelles. The electron microscope permits the
smaller organelles and even individual molecules to be seen
Bacteria, the simplest of present-day living cells, are procaryotes: although they contain DNA, they lack a nucleus and other organelles
Essential Concepts
The nucleus is the most prominent organelle in most plant and animal cells. It contains the genetic information of the organism, stored in the
structure of DNA molecules. The rest of the cells contents, apart from the nucleus, constitute the cytoplasm.
Within the cytoplasm, plant and animal cells contain a variety of internal membrane-enclosed organelles with specialized chemical
functions.
Mitochondria carry out the oxidation of food molecules. In plant cells, chloroplasts perform photosynthesis.
The endoplasmic reticulum, the Golgi apparatus, and lysosomes permit cells to synthesize complex molecules for export from the cell and for
insertion in cell membranes, and to import and digest large molecules.
Essential Concepts
The remaining intracellular component, excluding the membrane enclosed organelles, is the cytosol. This contains a concentrated
mixture of large and small molecules that carry out many essential
biochemical processes.
A system of protein filaments called the cytoskeleton extends throughout the cytosol. This governs cell shape and movement and
enables organelles and molecules to be transported from one
location to another in the cytoplasm.
Free-living single-celled eucaryotic microorganisms include some of the most complex eucaryotic cells known, and they are able to swim,
mate, hunt, and devour food. Other types of eucaryotic cells, derived
from a fertilized egg, cooperate to form large, complex multicellular
organisms such as ourselves, composed of thousands of billions of
cells.
Essential Concepts .
Although the minimum number of genes needed for a viable cell is
probably about 300450, most cells contain significantly more.
Despite their size, eucaryotic genomes are remarkably economical in terms of numbers of genes. The Drosophila genome programs the
development of a complex organism with about 14,000 genesthree times the number in E. coli.