SBBS 1201

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SBBS 1201 ASAS BIOLOGI 1
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• BUKU RUJUKAN
• Cambell, N.A. Biology 6th Edition,
  Benjamin/Cummings Pub.
• 2. Raven Johnson, Biology.

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Biology (from Greek ß???, bio, "life" and
?????, logos, "knowledge") is the study of life.
botany - plants Zoology - animals microbiology -
microorganisms. Biochemistry - the fundamental
chemistry of life cellular biology - the basic
building block of all life, the cell Physiology -
the mechanical and physical functions of an
organism
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General subfields within biology
Anatomy - structure of living things.
Astrobiology - is the study of life in space,
combining aspects of
astronomy, biology and geology Bioinformatics
Cell biology Ecology Developmental biology
Evolutionary biology Genetics Marine
biology Human biology Molecular
biology Paleontology Parasitology Pathology Physio
logy Taxonomy
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Biological technology is technology based on
biology, especially when used in agriculture,
food science, and medicine. The United Nations
Convention on Biological Diversity has come up
with one of many definitions of
biotechnology "Biotechnology means any
technological application that uses biological
systems, living organisms, or derivatives
thereof, to make or modify products or processes
for specific use."
"The application of indigenous and/or scientific
knowledge to the management of (parts of)
microorganisms, or of cells and tissues of higher
organisms, so that these supply goods and
services of use to human beings.
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• Cell biology - also called cellular biology or
  formerly known as cytology.
• - from the Greek kytos, "container")
• studies on cell structure, organels, movement
  across Cell
• membranes,cell dvision.

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A cell is a single unit or compartment,
enclosed by a border, wall or membrane.
The cell is the smallest unit of matter that can
carry on all the processes of life.
The cell is the structural and functional unit of
all living organisms, and is sometimes called the
"building block of life. Some organisms, such
as bacteria, are unicellular (consist of a single
cell). Other organisms, such as humans, are
multicellular. (Humans have an estimated 100
trillion or 1014 cells a typical cell size is
10 µm a typical cell mass is 1 nanogram.) The
largest known cell is an ostrich egg.
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The Cell Theory Proposed by Schleiden and
Schwann in 1838. The cell theory states that
1. All life forms are made from one or more
cells. All living thing are composed of one
or more cells 2. Cells only arise from
pre-existing cells. Cells come only from the
replication of existing cells. 3. The cell is
the smallest form of life. Cell are the
basic units of structure and function in an
organism.
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Prokaryotic Cells 
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A Prokaryotic cell (bacterium)
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Cytoplasm. Contains all the enzymes needed for
all metabolic reactions, since there are no
organelles Ribosomes. The smaller (70 S) type.
Nucleoid (or Nuclear Zone). The region of the
cytoplasm that contains DNA. It is not surrounded
by a nuclear membrane. DNA. Always circular, and
not associated with any proteins to form
chromatin. Plasmid. Small circles of DNA, used
to exchange DNA between bacterial cells, and very
useful for genetic engineering. Cell membrane.
made of phospholipids and proteins, like
eukaryotic membranes. Mesosome. A tightly-folded
region of the cell membrane containing all the
membrane-bound proteins required for respiration
and photosynthesis. Can also be associated with
the nucleoid Cell Wall. Made of murein (not
cellulose), which is a glycoprotein (i.e. a
protein/carbohydrate complex, also called
peptidoglycan). There are two kinds of cell wall,
which can be distinguished by a Gram stain Gram
positive bacteria have a thick cell wall and
stain purple, while Gram negative bacteria have a
thin cell wall with an outer lipid layer and
stain pink.
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• Capsule (or Slime Layer). A thick polysaccharide
  layer outside of the cell wall. Used for sticking
  cells together, as a food reserve, as protection
  against desiccation and chemicals, and as
  protection against phagocytosis.
• Flagellum. A rigid rotating helical-shaped tail
  used for propulsion. The motor is embedded in the
  cell membrane and is driven by a H gradient
  across the membrane. Clockwise rotation drives
  the cell forwards, while anticlockwise rotation
  causes a chaotic spin. This is the only known
  example of a rotating motor in nature.

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Eukaryotic Cells 
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A Eukaryotic cell (plant)
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Diagram of a typical eukaryotic cell, showing
subcellular components. Organelles (1)
nucleolus (2) nucleus (3) ribosome (4) vesicle
(5) rough endoplasmic reticulum (ER) (6) Golgi
apparatus (7) Cytoskeleton (8) smooth ER (9)
mitochondria (10) vacuole (11) cytoplasm (12)
lysosome (13) centrioles
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virus (from the Latin noun virus, meaning toxin
or poison) is a microscopic particle (ranging
in size from 20 - 300 nm) that can infect the
cells of a biological organism. Viruses can
replicate themselves only by infecting a host
cell. They therefore cannot reproduce on their
own. At the most basic level, viruses consist
of genetic material contained within a protective
protein coat called a capsid. They infect a
wide variety of organisms both eukaryotes
(animals, plants, protists, and fungi) and
prokaryotes (bacteria and archaea). A virus that
infects bacteria is known as a bacteriophage,
often shortened to phage. It has been argued
extensively whether viruses are living organisms.
Most virologists consider them non-living, as
they do not meet all the criteria of the
generally accepted definition of life.
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AIDS - Acquired immune deficiency syndrome -
human immunodeficiency virus (HIV). Chickenpox
Common cold Dengue fever Hepatitis Influenza
(Flu) Measles Mumps Poliomyelitis
Rabies Rubella SARS Smallpox (Variola) Yellow
fever
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Cytoplasm - entire contents of the cell,
exclusive of the nucleus and bounded
by the plasma membrane. Cytosol
semifluid portion of the cytoplasm.
- It contains enzymes for glycolysis, sugars,
salts, amino acids, nucleotides
and everything else needed for the cell to
function. Cytosol organelles
cytoplasm. In Eukaryotic cells, most organelles
are surrounded by a membrane, but in Prokaryotic
cells there are no membrane-bound organelles.
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• Nucleus.
• - This is the largest organelle.
• - Surrounded by a nuclear envelope - a
  double membrane with nuclear
• pores
• - The interior is called the nucleoplasm -
  chromatin.
• - During cell division the chromatin becomes
  condensed into discrete
• observable chromosomes.
• - The nucleolus is a dark region of
  chromatin, involved in making
• ribosomes.

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• Mitochondrion (pl. Mitochondria).
• - This is a sausage-shaped organelle (8µm long)
• - aerobic respiration
• - surrounded by a double membrane - the outer
• membrane is simple and quite permeable
• - inner membrane is highly folded into cristae
• - The space enclosed by the inner membrane is
  called
• the mitochondrial matrix and contains small
  circular
• strands of DNA.

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• Chloroplast
• Bigger and fatter than mitochondria
• photosynthesis - only found in photosynthetic
  organisms (plants
• and algae)
• enclosed by a double membrane
• thylakoid membrane is folded into thylakoid
  disks, which are then
• stacked into piles called grana.
• The space between the inner membrane and the
  thylakoid is called
• the stroma.
• The thylakoid membrane contains chlorophyll and
  other
• photosynthetic pigments.
• - also contain starch grains, ribosomes and
  circular DNA.

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• Ribosomes
• - These are the smallest and most numerous of the
  cell organelles
• sites of protein synthesis
• they are composed of protein and RNA
• manufactured in the nucleolus of the nucleus
• Ribosomes are either found free in the
  cytoplasm, where they make
• proteins for the cell's own use, or they are
  found attached to the rough
• endoplasmic reticulum, where they make proteins
  for export from the cell. - All eukaryotic
  ribosomes are of the larger, "80S", type.

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Rough Endoplasmic Reticulum (RER) - continuous
with the outer membrane of the nuclear
envelope. - studded with numerous ribosomes,
which give it its rough appearance. - the
ribosomes synthesis proteins, which are processed
in the RER, modify it before being
exported from the cell via the Golgi Body.
Smooth Endoplasmic Reticulum (SER) Series of
membrane channels involved in synthesizing and
transporting materials, mainly lipids, needed
by the cell.
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• Golgi Body (or Golgi Apparatus)
• series of flattened membrane vesicles, formed
  from the
• endoplasmic reticulum
• Its job is to transport proteins from the RER to
  the cell membrane
• for export.
• parts of the RER containing proteins fuse with
  one side of the Golgi
• body membranes, while at the other side small
  vesicles bud off and
• move towards the cell membrane, where they
  fuse, releasing their
• contents by exocytosis.

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• Vacuoles
• a sac bounded by single membrane called
  tonoplast.
• most cells can have small vacuoles that are
  formed as required
• plant cells usually have one very large
  permanent vacuole that fills
• most of the cell
• plant cell vacuoles are filled with cell sap, a
  concentrated solution of
• various substances, such as mineral salts,
  sugars, pigments, organic
• acids and enzymes.
• cell sap also important in keeping the cell
  rigid, or turgid.
• - storage of various substances including waste
  products.

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• Lysosomes
• These are small single membrane-bound vesicles
  formed from the RER
• containing a cocktail of digestive enzymes.
• They are used to break down unwanted chemicals,
  toxins, organelles or
• even whole cells, so that the materials may be
  recycled.
• - They can also fuse with a feeding vacuole to
  digest its contents.

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• Centriole
• - This is a pair of short microtubules involved
  in cell division.
• Before each division the centriole replicates
  itself and the two centrioles
• move to opposite ends of the cell, where they
  initiate the spindle that
• organises and separates the chromosomes.

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• Cytoskeleton
• This is a network of protein fibres extending
  throughout all eukaryotic
• cells, used for support, transport and
  motility.
• The cytoskeleton is attached to the cell
  membrane and gives the cell its
• shape, as well as holding all the organelles in
  position.

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• Microvilli
• These are small finger-like extensions of the
  cell membrane found in
• certain cells such as in the epithelial cells
  of the intestine and kidney,
• where they increase the surface area for
  absorption of materials.

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Cell Wall This is a thick layer outside the cell
membrane used to give a cell strength and
rigidity. Cell walls consist of a network of
fibres, which give strength but are freely
permeable to solutes Plant cell walls are made
mainly of cellulose, but can also contain
hemicellulose, pectin, lignin and other
polysaccharides. They are built up in three
layers called the primary cell wall, the
secondary cell wall and the middle
lamella. There are often channels through plant
cell walls called plasmodesmata, which link the
cytoplasms of adjacent cells. Animal cells do
not have a cell wall.  
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Cell Membrane (or Plasma Membrane) This is a
thin, flexible layer round the outside of all
cells made of phospholipids and
proteins. It separates the contents of the cell
from the outside environment, and controls the
entry and exit of materials.
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Cell Differentiation   Cellular Level The
smallest unit of life capable of carrying out all
the functions of living things. Tissue Level A
group of cells that performs a specific function
in an organism, eg. epithelium (lining tissue),
connective, skeletal, nerve, muscle Organ Level
Several different types of tissue that function
together for a specific purpose, eg.
Stomach Organ System Level Several organs
working together to perform a function, eg. the
circulatory, digestive, nervous, respiratory,
reproductive, urinary and muscular-skeletal
systems.
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Movement across Cell Membranes  Cell membranes
are a barrier to most substances, and this
property allows materials to be concentrated
inside cells, excluded from cells, or simply
separated from the outside environment. There
are five main methods by which substances can
move across a cell membrane 1. Lipid Diffusion
2. Osmosis 3. Passive Transport 4. Active
Transport 5. Vesicles
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1. Lipid Diffusion (or Simple Diffusion) 
A few substances can diffuse directly through the
lipid bilayer part of the membrane. The only
substances that can do this are lipid-soluble
molecules such as steroids, or very small
molecules, such as H2O, O2 and C2O. A passive
diffusion process, no energy is involved and
substances can only move down their concentration
gradient.
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2. Osmosis  Osmosis is the diffusion of water
across a membrane. Water molecules can diffuse
freely across a membrane, but always down their
concentration gradient, so water therefore
diffuses from a dilute to a concentrated solution.
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Water Potential. Osmosis can be quantified using
water potential, so we can calculate which way
water will move, and how fast. Water potential
(Y, the Greek letter psi, pronounced "sy") is
simply the effective concentration of water. It
is measured in units of pressure (Pa, or usually
kPa), and the rule is that water always "falls"
from a high to a low water potential). 100
pure water has Y  0, which is the highest
possible water potential, so all solutions have
Y lt 0, and you cannot get Y gt 0.
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Osmotic Pressure (OP). This is an older term used
to describe osmosis. The more concentrated a
solution, the higher the osmotic pressure. It
therefore means the opposite to water potential,
and so water move from a low to a high OP. Always
use Y rather than OP.
Cells and Osmosis. The concentration (or OP) of
the solution that surrounds a cell will affect
the state of the cell, due to osmosis. There are
three possible concentrations of solution to
consider Isotonic solution - a solution of
equal OP (or concentration) to a cell
Hypertonic solution - a solution of higher OP
(or concentration) than a cell Hypotonic
solution - a solution of lower OP (or
concentration) than a cell
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The effects of these solutions on cells are shown
in this diagram
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3. Passive Transport (or Facilitated
Diffusion).
Passive transport is the transport of substances
across a membrane by a trans-membrane protein
molecule. The transport proteins tend to be
specific for one molecule, so substances can only
cross a membrane if it contains the appropriate
protein. As the name suggests, this is a
passive diffusion process, so no energy is
involved and substances can only move down their
concentration gradient. There are two kinds of
transport protein
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1. Channel Proteins form a water-filled pore or
channel in the membrane. This allows
charged substances (usually ions) to diffuse
across membranes. Most channels can be gated
(opened or closed), allowing the cell to control
the entry and exit of ions.
2. Carrier Proteins have a binding site for a
specific solute and constantly flip between
two states so that the site is alternately open
to opposite sides of the membrane. The
substance will bind on the side where it at
a high concentration and be released where it is
at a low concentration.
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4. Active Transport (or Pumping). 

• Active transport is the pumping of substances
  across a membrane by a trans-
• membrane protein pump molecule.
• The protein binds a molecule of the substance to
  be transported on one side
• of the membrane, changes shape, and releases it
  on the other side.
• The proteins are highly specific, so there is a
  different protein pump for each
• molecule to be transported.
• The protein pumps are also ATPase enzymes, since
  they catalyse the
• splitting of ATP ADP phosphate (Pi), and
  use the energy released to
• change shape and pump the molecule.
• Pumping is therefore an active process, and is
  the only transport mechanism
• that can transport substances up their
  concentration gradient.

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The NaK Pump. This transport protein is present
in the cell membranes of all animal cells and is
the most abundant and important of all membrane
pumps.
The NaK pump is a complex pump, simultaneously
pumping three sodium ions out of the cell and two
potassium ions into the cell for each molecule of
ATP split. This means that, apart from moving
ions around, it also generates a potential
difference across the cell membrane. This is
called the membrane potential, and all animal
cells have it. It varies from 20 to 200 mV, but
and is always negative inside the cell. In most
cells the NaK pump runs continuously and uses
30 of all the cell's energy (70 in nerve cells).
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5. Vesicles 
The processes described so far only apply to
small molecules. Large molecules (such as
proteins, polysaccharides and nucleotides) and
even whole cells are moved in and out of cells by
using membrane vesicles.
Endocytosis is the transport of materials into a
cell. Materials are enclosed by a fold of the
cell membrane, which then pinches shut to form a
closed vesicle. Strictly speaking the material
has not yet crossed the membrane, so it is
usually digested and the small product molecules
are absorbed by the methods above. When the
materials and the vesicles are small (such as a
protein molecule) the process is known as
pinocytosis (cell drinking), and if the materials
are large (such as a white blood cell ingesting a
bacterial cell) the process is known as
phagocytosis (cell eating).
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Exocytosis is the transport of materials out of a
cell. It is the exact reverse of endocytosis.
Materials to be exported must first be enclosed
in a membrane vesicle, usually from the RER and
Golgi Body. Hormones and digestive enzymes are
secreted by exocytosis from the secretory cells
of the intestine and endocrine glands.
Sometimes materials can pass straight through
cells without ever making contact with the
cytoplasm by being taken in by endocytosis at one
end of a cell and passing out by exocytosis at
the other end.
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Summary of the Differences Between Prokaryotic
and Eukaryotic Cells