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.