Introduction for Bio Chemistry. B. Sc (N) I - Year

2.  Bio-chemistry is the study of chemical substances
and vital processes occurring in living organisms . it
includes the study of chemistry behind biological
processes and the synthesis of biologically active
molecules.
 SIGNIFICANCE AND IMPORTANCE OF BIO-
CHEMISTRY IN NURSING
 A review of the application of biochemistry in
nursing needs to mention of many therapeutic
agents whose existence was first demonstrated on
lab experiments e.g hormone insulin , all the
vitamins and many other products of therapeutic
significant .

3.  If an infants is always vomiting after giving
milk ,she or he probably has galactose
intolerance.
 If an infant is born with jaundice, her or his
liver is not fully funtional .
 When colour of infants urine turns dark
,probably he/she suffers from an amino acid
metabolic disorder.
 Anemic children ,older,elder,or geriatric
persons can be explained biochemistry,e.g
intake of Fe, hemolytic disorder (G6PD
defiency or pyruate kinase deficiency) or a
chronic renal disease.
 Many such condition thus,can be explained on
the basis of bio-chemistry.

5.  Cell is the structural and funtional unit of all
living organism.bacteria are unicellular (consist
of single cell),human beings are multicellular
(may have upto 10 cells.
 Each cell take nutrients and converts energy.a
cell also carried out specialized funtions and
reproduces and stores its own set of instructions
for carrying out these activities.
 There are two types of cells called prokaryote
and eukaryote cells.procaryote cells are usually
independent while eukaryote cells are found in
multicellular organisms.

6.  The simplest form and the first type of cells to evolve are
prokaryote cells. Prokaryotes are unicellular organisms
that do not developed or differentiate into multicellular
forms .some bacteria grow in filaments or masses of cells
but each cell in the colony is identical and capable of
independent existence. they may adjacent to one another
because they do not separate after cell division though
there is no continuity or communication between them.
 Besides lack of nuclear membrane, a prokaryote cell also
lacks intracellular organelles. Prokaryotic cells have three
architectural region that includes appendages called
flagella and vili, cell envelope or cell wall consisting of a
capsule and a cytoplasmic region.

7.  Enclosing a cell, there is cell envelope ,which
generally consists of a cell wall, covering a plasma
membrane .some bacteria have a further covering
layer, called capsule.
 A cell wall consists of peptidoglycans in bacteria and
act as a barrier against the external forces .it prevent
the cell from expanding and bursting insides the cell
is cytoplasmic region that contains cell genome
(DNA), ribosomes and various other inclusion.
 Prokaryotes carry chromosomal DNA elements called
plasmids, it function such as antibiotics resistance.

9.  Eukaryote cells include fungi, animal cells, plant cells
as well as some unicellular organisms. it 10 times
larger than a prokaryotic cell and can be as much as
1000 times more in volume.
 Composition and functions
 Human body contains different organs such as the
heart, lung and kidneys each one of which performs
different funtions.EC also have aset of intracellular
components called sub cellular organelles some of it
surrounded by a protective membrane. Composition
and functions of organelles are described below:

10.  Plasma membrane
The outer lining of a eukaryotic cell is called plasma
membrane. this serves to separate and protect cell
from its surrounding environment. it is made up of a
double layer of proteins and lipids.
 Cytoskeleton
Cytoskeleton is a complex and dynamic component that
acts to organise and maintain cell shape, anchor
organells in their place, helps during endocytosis
(uptake of material by the cell) and moves
intracellular organelles of the cell during the
processes of growth and motility. There are a number
of proteins associated with cytoskeleton.

11.  Cytoplasm
Inside the cell there is a large fluid –filled space called
cytoplasm. It is like soup within which all the cell
organelles .cytoplasm is also a home for cytoskeleton.it
contains several salts and is an excellent conductor of
electricity ,creating environment for the mechanics of
the cell.
 Nucleus
Nucleus ,also called cells information centre, is the most
conspicuous organelle found in a eukaryotic cell.

12.  It houses cells chromosomes and is a place where
almost all the DNA replication and RNA synthesis
occur. Nucleus is spheroidal in shape and is separated
from cytoplasm by a membrane called nuclear
envelope.
 Eukaryotic genetic material is more complex and is
divided into discrete units called genes. human genetic
material is made up of two distinct components called
nuclrar genome and mitochondrial genome.

13.  Ribosome
Ribosome is a large complex composed of many
molecules, including RNA and proteins. these are
responsible for the processing of genetic instruction
carried by mRNA. the process of converting mRNA
codon into the sequence of amino acids that make up a
protein is called translation. some of the ribosome
float free in the cytoplasm, called free ribosome while
others are bound to endoplasmic reticulum.

14.  Mitochondria and chloroplasts
These are power generator and self-replicating
organelles. they occur in various numbers, shapes and
sizes in the cytoplasm of all eukaryotic cells. Both the
organelles are surrounded by a double membrane
with an intermembrane space. they have many
folding, filling their inner space. they have two
functionally distinct membrane systems, inward folds
are called cristae.
 Chloroplast are similar to mitochondria but are
found in plants where they convert light energy (from
the sun) into ATP through the process called
photosynthesis.

15.  Endoplasmic recticulam and golgi apparatus
ER is the transport network for molecules. It is present
in two forms called rough endoplasmic reticulum
(RER) and smooth endoplasmic reticulum (SER) .
Proteins that are to be exported out of the cell are passes
to the Golgi apparatus, also called golgi bodies or
Golgi complex .
 Lysosomes and peroxisomes
They are also referred as garbage disposal system of the
cell.both are spherical ,bound by a single membrane
and are rich in digestive enzymes for degrading
proteins, nucleic acids and polysaccharides that work
as low pH. an important function of lysosome is to
digest foreign bacteria that invade the cell.

16.  They also help in recycling of receptor proteins and
other membrane components , help in repair of the
damage to plasma membrane.
 Peroxisomes function to get the body of toxic
substances such as hydrogen peroxide or other
metabolites, and contain enzyme for enzyme
utilization. higher number of peroxisomes can be
found in liver where toxic by-products are known to
accumulate. it resemble lysosomes.peroxisomes are
self-replicating whereas lysosomes are formed in
Golgi complex.

17.  Centrosome
 Centrosome called cytoskeleton organizer,
produce microtubules of a cell, which is the key
component of cytoskeleton .cetrosomes are
composed of two centrioles. a single centrosome
is present in animal cells. it found in some fungi
and algae.
 Vacuoles
 Vacuoles store food and waste products. some
vacuoles also store water and are described as
liquid –filled spaces. they are surrounded by a
membrane.

20.  Cells because of their small size cannot been seen by a
naked eye, but can be observed with the aid of
instrument called “Microscope”.
 It provides a magnified image of a tiny objects.
 Microscope gives a wide range of magnification, they
are of 2 types.
1. Simple Microscope
2. Compound Microscope

21.  Cell membrane
 It refers to the outer covering of the cell and is
found in all living cells. it is a highly viscous
structure.
 Fluid-mosaic model of cell membrane
 Biological membranes have such a structure
where some proteins span a lipid bilayer while
others are partially immersed. this is called
Fluid-mosaic model as a membrane consists of
mosaic of proteins and lipids.

22.  A simple microscope works like a biconvex lens.
 Compound microscope employs two separate
lens system for greater magnification.
 There are two types of compound microscope
referred as optical or light microscope and
electron microscope.
 Optical Microscope uses optical lens and light
wave for magnification. It magnifies about 1000
to 1500 times.

23.  Electron Microscope – In electron microscope a
magnification of 10000 to 50000 can be obtained
and objects as smallest 1 – 2 microns can be
photographed.

25.  1.cell membrane may be associated with several
enzymes e.g. Phospholipase are used as markers of cell
membrane.
 2. Membranes also contain specific receptors for
external stimuli such as hormones. after a hormone
binds to its receptor, it generates signals and regulates
intracellular activities.
 3.carbohydrates components of glycoproteins in a
membrane act as recognition sites for several
substance such as antibodies.
 4. A membrane also acts as a barrier thereby loss of
useful substances while permitting entry of nutrients,
thus it is important in transport of substances.

26.  Tight junctions are specialized sites of contact that
block solutes from diffusing between the cells in an
epithelium.
 A simple epithelium like the lining of the intestine or
the lungs is composed of a layer of cells that adhere
tightly to one another to form a thin cellular sheet.
 Solutes cannot diffuse freely through this layer
because of the specialized contacts referred to as
called tight junctions.
 Tight junction strands are composed of proteins called
occludin and claudins.

27.  Tight junction serves as a barrier to the free diffusion
of water and solutes from the extra-cellular
compartment to the other side.
 some tight junctions are permeable to specific ions or
solutes, to which other tight junctions are impermeale.
 TJ are also present between the endothelial cells that
line walls of the capillaries. it form blood brain
barrier, which prevent substance from passing from
the bloodstream into the brain. small ions and water
may not penetrate BBB.

28.  Cytoskeleton is a system of protein fibbers that
pervades cytoplasm. It is composed of three distinct
types of fibrous structures called microtubules,
intermediate filaments and microfilaments.
 Functions:
 1.it provides structural support that determines
shape of the cell .
 2.it functions as an internal frame work which is
responsible for the positioning of various organelles
within the cell.
 3.it functions as a force –generating apparatus that
moves cells from one place to another e.g
.locomotion of sperm, white blood cells.

29.  MICROTUBULES :
 Microtubules are stiff ,hollow and tubular structures
that are assembled from protein tubulin .these are
arranged in longitudinal rows and are called proto-
filaments.
 They help in determining shape of the cell and
maintaining the position of the membranous
organelles such as Endoplasmic Reticulum and Golgi
Complex.

30. Intermediate Filaments
They are strong rope like fibbers, Depending on the cell
type they are composed of a variety of different
globular proteins sub units. Examples: Keratin
filaments, Neuro filaments.
Microfilaments
They are composed of a double helical polymer of the
protein actin, which is one of the major proteins of
the muscle cells.
They play a key role in all type of contractility and
motility with in cells.