Introduction to the Medical biology

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Transcript Introduction to the Medical biology

Introduction to the Medical
biology. Structural and functional
organization of a cell.
Autor Iryna
Pryvrotska
Questions to answer
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General and medical Biology as the sciences.
Characteristics of living things.
Levels of living organization.
The cell theory in its modern form.
Cellular level of life organization:
-prokaryotic and eukaryotic cells
-the differences between plant and animal
cells.
The main components of eukaryotic cell.
Characteristics of living
things.
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use energy – have a metabolism- the building up and breaking down of
chemicals
grow and develop become larger and more complex
respond to their surrounding
reproduce- produce offspring that are similar to the parents
have the chemicals of life, carbohydrates, proteins, lipids and nucleic
acids (genetic material)
have cells
The fundamental characteristics of living things:
reproduction (self-reproduction), which is the process that gives rise to
offspring;
genes (self-renewal) are the units of inheritance, passed prom parent to
offspring, that control many daily functions.
Finally, populations of living organisms adjust to environment variations
through evolution, a change in the traits of a species over time (selfregulation).
CELLS- are the basic units of structure and
function in living things.  ROBERT HOOKE- first to
look at cells
looked at a thin section of
cork
 ANTON VAN
LEEUWENHOEK – made his
own lenses made first
compound microscope drew
pictures that we can still
identify today
 Schleiden –concluded all
plants are made of cells
 Schwann – concluded all
living things are made up of
cells
Three main levels of living
organization:
 Microsystem - molecular, subcellalar,
cellular levels;
 Mesosystem – tissular, organellic,
organismic;
 Macrosystem of population and species,
biocenotical, biosheric.
Cell theory
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All organisms are composed of one or more
cells, within which the life processes of
metabolism and hereditary occur.
Cells are the smallest living things, the basic
unit of organization of all organisms.
Cells arise only by division of a previously
existing cell.
What are the cells?
 Basic unit of life
 Properties
- biomembrane enclosed
- four biomolecules: proteins, polysacharides,
nucleic acids, lipids
- metabolism and energy transformation
Two major types:
- Prokaryotic: lack defined nucleus
- Eukaryotic: contain membrane bound nucleus
What are the differences between
prokaryotic and eukaryotic cells?
 Kindoms
1. Monera (Fubacteria)
2. Archaea (Archaebacteria)
Characteristics
1. Lack a nuclear membrane
Kindoms
1. Protista
2. Fungi
3. Plantae
4. Animalia
Characteristics
1. Have a nuclear membrane
2. Have no membrane bound organels 2. Have membrane bound organels
Current evidence indicates that eukaryotic evolved from prokaryotic between
1 and 1,5 billion years ago
What are the differences between
plant and animal cells?
 1. Chloroplast
 2. Central vacuole
 3. Cell wall
1. Centriole
2. Lysosome
Survey of organelle
structure and function
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Cytoplasm and cytosol
Plasma membrane
Nucleus
Mitochondria and plastids
Endoplasmic reticulum
Golgy apparatus( complex)
Lysosomes
Vacuoles
Ribosomes
Centrioles
Nonmembane
Cytosceleton.
organelles
Membranbound
organelles
Cytoplasm
 Viscous contents of cell between the
nuclear membrane and the plasma
membrane. This include cell organelles
 Cytosol- aqueous part. The semi-fluid
medium found in the cytoplasm. This
does not include the organelles
 Cytoskeleton nightly organized network
fibrous proteins that support the cell.
Mitochondria
 A double membrane
cellular organelle with its
own circular DNA
(prokaryote like
genomes) and
ribosomes.
 It is the site of cellular
respiration, a catabolic,
exergonic, oxygen
requiring process that
uses energy extracted
from organic
macromolecules (like
glucose) to produce ATP.
Endoplasmic reticulum
 Extensive membranous
networks of tubules and sacs
called cisternae
 A .Rough Endoplasmic
reticulum (RER)
-Studded with ribosome's.
-Site of protein synthesis.
B. Smooth Endoplasmic
reticulum (SER)
-Synthesizes lipids,
phospholipids and steroids.
-Detoxifies drugs, alcohol
and poisons
-Carbohydrate Addition and
modification
Ribosomes
 Nuclear and cytoplasmic organells. Composed
of 60 % protein and 40% ribosomal RNA
 Site of protein synthesis
 Can be found or as Polyribosomes
Golgy apparatus
(complex)
 Stacked, flattened
membranous organelle
with sacs called cisternae
 Modifies, stores, and
routes products from the
ER to the Plasma
membrane
Lysosomes
 Membrane-enclosed
bag of hydrolytic
enzymes (digestive
enzymes)
Degradation of old cell
components or
ingested materials
Vacuoles
 Large membraneclosed sac for
cellular storage
 Three types
 Food vacuole
(lysosomes attach)
 Contractile vacuole
(Protozoons)
 Central vacuole
(mature plant cell)
Plasma membrane
 The boundary of every cell approximately 8nm
thick
Functions
 Separates the living cell from its nonliving
surroundings.
 Acts as selective barrier
 Regulate movement of material into and out of
the cell
 Cellular recognition
Plasma membrane
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envelops the cell and aids in
maintaining its structural and
functional integrity.
 Composed of lipid bilayer and
associated proteins.
 bilayer composed:
- Phospholipids (hydrophilic and
hydrоphobic),
-Glycolipids are present in outer leaflet
only. They have polar carbohydrate
residues that extend from the outer
leaflet into the extracellular space,
forming part of glycocalix.
-Cholesterol is located in both leaflets
and assists in maintaining the
structural integrity of the plasma
membrane.
 Membrane proteins :
-integral (are dissolved in the lipid
bilayer)
- peripheral proteins (don‘t extend into
the lipid bilayer).
Glycocalyx
 is a sugar coat
commonly associated
with the
extracytoplasmic
aspects of the outer
leaflet of plasma
membrane (in animal
cells).
 Functions
 aiding in cellular
attachment to
extracellular matrix
components
 binding of cellular and
enzymes to the cell
Plasma Membrane
Transport Processes.
 These processes include transport of a
single molecule (uniport) or cotransport
of two different molecules in the same
(symport) or opposite (antiport) direction.
Passive transport Active transport
 molecules move across the plasma
membrane down a concentration or
electrochemical gradient.
 1. Simple diffusion transports
small nonpolar molecules (02 and
N2) and small, uncharged, polar
molecules (H20, C02, and glycerol).
 2. Facilitated diffusion occurs via
ion channel and/or carrier proteins.
It is faster than simple diffusion.
 3. Osmosis is the diffusion of water
across a selectively permeable
membrane in response to its
concentration gradient.
 is an energy-requiring
process which transports a
molecule against an
electrochemical gradient via
carrier proteins.
Comparison active and
passive transport
Exocytosis
 is way that
substances can exit
cells.
Endocytosis
 is way that
substances can
enter cells.
Phagocytosis and
Pinocytosis
 Phagocytosis (cell eating)
is transport process by
which amoeboid-type cells
engulf large material,
forming an intracellular
vacuole.
 When macromolecules are
taken in by endocytosis,
the process is called
Pinocytosis (cell
drinking), and the result is
formation of vesicle.
CYTOSKELETON
 Network of fibers through out the cytoplasm.
 Aids in cellular support and movement.
 Composed of three components:
1. Microfilaments - globular protein (actin) - support and cellular
contraction
2.
Intermediate filaments - fibrous protein - support
3.
Microtubles - globular protein (tubulin) support and cell motility
CENTRIOLES
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found in animal cells
only
 Paired cylindrical
organelles near nucleus
 - Composed of nine
tubes, each with three
tubules
 - Involved in cellular
division
 - Lie at right angles to
each other
Nucleus
 The cell nucleus is a
conspicuous membranebound cellular organelle.
 It functions to:
 Store genes into
chromosomes to allow cell
division
 Produce messages
(messenger ribonucleic acid
or mRNA) that code for
proteins
 Transport regulatory factors
and gene products vie
nuclear pores
 Organise the incoiling of
DNA to replicate key genes
Heterochromatin -- tightly packed regions
Euchromatin --- Regions where DNA is more openly
packed, location of most functional genes
Chromosome banding (requires special stains)
 Types
of
chromo
somes
Karyotype is a diploid number of chromosomes
and it is a characteristics of the number and
morphology of chromosomes, that is peculiarities
of each species.
 Male karyotype
 46=22A+XY
 Female karyotype
 46=22A+XX
Nucleic acids
 The nucleic acids are
polymers of smaller units
called nucleotides.
 A nucleotide consist of:
 1) five-carbon sugar
(deoxyribose in DNA and
ribose in RNA);
 2) a phosphate group
(PO4);
 3) one of five types
nitrogen-containing
compounds called
nitrogenous bases.
 The nitrogenous bases
are:
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Purines, which are
larger – Adenine (A),
Guanine (G);
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Pyramidines, which
are smaller – Thymine
(T), Cytosine (C), Uracil
(U).
Nucleic acids
 there are 2 types of nucleic acids: DNA
(deoxyribonucleic acid) and RNA (ribonucleic
acid).
 DNA Provides Information for the Structure of
Proteins
Structure
DNA
RNA
Sugar
Deoxyribose
Ribose
Bases
Adenine, guanine,
thymine, cytosine
Adenine, guanine,
uracil, cytosine
Strands
Double-stranded with
base pairing
Single-stranded
Helix
Yes
No
DNA
1. Located in nucleus,
packaged into
cromosomes
• Organelles
(mitochondria,
chloroplasts)
2. DNA is double
stranded, present in
the form of a
double helix
3. Bases make up
complementary
base pairs
RNA
 Messenger RNA carries
the genetic code to the
cytoplasm to direct protein
synthesis.
 1. This single-stranded
molecule (hundreds to
thousands of nucleotides
contains codons ).
 Transfer RNA is folded into a
cloverleaf shape and contains
about 80 nucleotides..
 Ribosomal RNA associates
with many different proteins
(including enzymes) to form
ribosomes.
Realization of hereditary
information
 A gene is generally a
collection of DNA
nucleotides that contains
the instructions for an
individual protein.
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Each set of three nucleotides
codes for an amino acid = “The
Genetic Code”
 Characteristics of
Genetic Code
 Universality
 Triplet Nature.
 No Overlapping
 No Punctuation
 Degeneracy
 Colinearity
Thank you for attention!