▪Introduction
▪Cell theory
▪Whitaker’s kingdom classification
▪Cell organelles, and their functions
▪Homeostasis
▪Replication and cell Division
▪Tissue differentiation
▪Stem cells and their applications
▪Genetic algorithms
UNIT 1
2
Living Organism
• A living organism may be defined as a complex unit of
physicochemical materials that is capable of self-regulation,
metabolism, and reproduction.
• Furthermore, a living organism demonstrates the ability to interact with
its environment, grow, move, and adapt.
3
What Are the main characteristics of organisms?
 Made of cells
 Require energy (food)
 Reproduce (species)
 Maintain homeostasis
 Organized
 Respond to environment
 Grow and develop
 Exchange materials with
surroundings (water, wastes, gases)
Concept of evolution
• The process by which different kinds of living organism are believed
to have developed from earlier forms during the history of the earth.
• Evolution is the change in the heritable characteristics of biological
populations over successive generations.
• Jean Baptistae Lamarck (1801)-spontaneous generation of species
according to needs and functionalities of the mutation
• Charles darwin (1859)- Based on survival of the fittest mutations
4
5
Cell theory
Cell - Basic unit of life
a. Smallest living form
b. Inside the cell some structure transport
c. Metabolize
d. Respire
e. Reproduce (Meiosis)
f. Multiply (Mitosis)
g. Energy producing
h. Keep information
6
7
CELL THEORY
• Suggested by German scientists Theodor Schwann and Matthias Jakob
Schleiden in 1838
• Matthias Schleiden, a German botanist, and Theodor Schwann, a
British Zoologist formulated the cell theory.
• The cell theory consists of the following information,
• All living things are made of cells
• Cells are the basic unit of structure and function in an organism (basic
unit of life)
• Cells come from the reproduction of existing cells (cell division)
8
Prokaryotes
• Nucleoid region (center)
contains the DNA
• Surrounded by cell membrane
& cell wall (peptidoglycan)
• Contain ribosomes (no
membrane) in their cytoplasm
to make proteins
9
Eukaryotes
• Cells that have a nucleus and
membrane-bound organelles
• Includes protists, fungi,
plants, and animals
• More complex type of cells
10
Whittaker’s five kingdom of Classification
11
Five Kingdoms and their chief characteristics
• Unicellular organisms that lack a nucleus and many of the specialized
cell parts, called organelles. Such organisms are said to be prokaryotic
(pro =‘‘before’’; karyotic =‘‘kernel,’’ ‘‘nucleus’’) and consist of
bacteria.
• All of the other kingdoms consist of eukaryotic (eu = ‘‘true’’)
organisms, which have cells that contain a nucleus and a fuller
repertory of organelles.
Five Kingdom and their Classification
12
Five Kingdom and their Classification
13
14
Cell Structure and Function
15
Organelles
• Very small (Microscopic)
• Perform various functions for a cell
• Found in the cytoplasm
• May or may not be membrane-bound
Plant Cell
16
Cell or Plasma Membrane
Outside
of cell
Inside
of cell
(cytoplasm)
Cell
membrane
Proteins
Protein
channel Lipid bilayer
Carbohydrate
chains
• Composed of double layer of phospholipids and proteins
• Surrounds outside of all cells
• Controls what enters or leaves the cell
• Living layer
17
• Jelly-like substance enclosed by
cell membrane
• Provides a medium for chemical
reactions to take place
• Contains organelles to carry out
specific jobs
• Found in all cells
Cytoplasm of a Cell
cytoplasm
18
• Controls the normal
activities of the cell
• Contains the DNA in chromosomes
• Bounded by a
nuclear envelope (membrane)
with pores
• Usually the largest organelle
• Each cell has fixed
number of chromosomes that
carry genes
• Genes control cell characteristics
The Control Organelle - Nucleus
19
Nucleolus
• Inside nucleus
• Cell may have 1 to 3 nucleoli
• Disappears when cell divides
• Makes ribosomes that make
proteins
20
Cytoskeleton
• Helps cell maintain cell shape
• Also help move organelles around
• Made of proteins
• Microfilaments are threadlike & made of ACTIN
• Microtubules are tube-like and made of TUBULIN
Cytoskeleton
Microtubules
Microfilaments
21
Centrioles
• Found only in animal cells
• Paired structures near nucleus
• Made of bundle of microtubules
• Appear during cell division
forming mitotic spindle
• Help to pull chromosome pairs
apart to opposite ends of the cell
22
Mitochondrion
(plural = mitochondria)
• “Powerhouse” of the cell
• Generate cellular energy (ATP)
• More active cells like muscle cells have more
mitochondria
• Both plants & animal cells have mitochondria
• Site of cellular respiration (burning glucose)
23
Mitochondria
• Surrounded by a double membrane
• Has its own DNA
– Mitochondria come from cytoplasm in the
egg cell during fertilization
– Therefore, you inherit your mitochondria
from your mother!
• Folded inner membrane called cristae
(increases surface area for more chemical
reactions)
• Interior called matrix
24
Endoplasmic Reticulum - ER
• Network of hollow membrane tubules
• Connects to nuclear envelope & cell membrane
• Functions in synthesis of cell products & transport
Two kinds of ER ---Rough & Smooth
25
Rough Endoplasmic Reticulum (Rough ER)
• Has ribosomes on its surface
• Makes membrane proteins and proteins for
export out of cell
• Proteins are made by ribosomes on ER surface
• They are then threaded into the interior of the
Rough ER to be modified and transported
26
Smooth Endoplasmic Reticulum
• Smooth ER lacks ribosomes on its surface
• Is attached to the ends of rough ER
• Makes cell products that are used inside
the cell
• Makes membrane lipids (steroids)
• Regulates calcium (muscle cells)
• Destroys toxic substances (Liver)
Includes nuclear membrane
connected to ER connected
to cell membrane (transport)
27
Ribosomes
• Made of proteins and rRNA
• “Protein factories” for cell
• Join amino acids to make proteins
• Process called protein synthesis
• Can be attached to Rough ER OR Be free (unattached) in
the cytoplasm
28
Golgi Bodies
• Stacks of flattened sacs
• Have a shipping side (trans face) and
receiving side (cis face)
• Receive proteins made by ER
• Transport vesicles with modified
proteins pinch off the ends
Transport
vesicle
CIS
TRANS
29
Golgi Bodies
Look like a stack of pancakes
Modify, sort, & package molecules from ER for storage or transport
out of the cell.
30
Lysosomes
• Contain digestive enzymes
• Break down food, bacteria, and worn-out cell parts for cells
• Programmed for cell death (Autolysis)
• Lyse (break open) & release enzymes to break down & recycle cell
parts)
31
Lysosome Digestion
• Cells take in food by phagocytosis
• Lysosomes digest the food & get
rid of wastes
32
Vacuoles
• Fluid filled sacks for storage
• Small or absent in animal cells
• Plant cells have a large Central
Vacuole
• No vacuoles in bacterial cells
• In plants, they store Cell Sap
• Includes storage of sugars, proteins,
minerals, lipids, wastes, salts, water,
and enzymes
33
Chloroplasts
• Found only in producers (organisms containing chlorophyll)
• Use energy from sunlight to make own food (glucose)
• Energy from sun stored in the Chemical Bonds of Sugars
34
Surrounded by double membrane
Outer membrane smooth
Inner membrane modified into sacs called thylakoids
Thylakoids in stacks called Grana & interconnected
Stroma – gel like material surrounding thylakoids
35
Chloroplasts
• Contains its own DNA
• Contains enzymes & pigments for Photosynthesis
• Never in animal or bacterial cells
• Photosynthesis – food making process
36
Cell growth, reproduction, and differentiation
37
The Cell Cycle
• Mitosis and meiosis are single steps in cell cycle
• G1, S, G2, and M phases
– Cells not in process of dividing are in G0 phase
– Chromosomes are duplicated in preparation for the next round of
division during Interphase
38
39
Control of the Cell Cycle
• The stimuli for entering the cell cycle is in the form of growth factors
and cytokines that are capable of inducing mitotic divisions
• The cell cycle is highly regulated
– Proteins whose concentrations rise & fall in a controlled manner
• Cyclin and cyclin-dependent kinases (cdk)
• p53 and pRb
• Inhibitors of cdk
• Internal checkpoints & guardians monitor cell health
• Errors in this process can lead to uncontrollable growth and cancer
40
• Cell cycle control is
focused at 3 places:
• G1 checkpoint
• G2 checkpoint
• M checkpoint
– Before S phase (DNA
synthesis)
– At transition between
G2 and M phase
Control of the Cell Cycle
41
DNA replication-Binary fission
Daughter cells are identical copies
(1) (2) (3)
(4) (5) (6)
Chromosome Plasma membrane
Neither mitosis nor meiosis occurs in prokaryotes
Bacteria
Reproduction
• Asexual, through binary fission
• No true sexual reproduction, since neither mitosis nor
meiosis exist in prokaryotes
• Horizontal transfer of genetic material
DNA
cell wall
43
 Transformation - Uptake of genetic material from the environment
 Transduction - Transfer of genetic material between prokaryotes by viruses
 Conjugation - Direct transfer of genetic material from one prokaryote to another
44
Mitosis
Four phases –
a. Prophase: chromosomes condense, spindle apparatus forms,
nuclear envelope breaks down
b. Metaphase: chromosomes line up at equator of cell
c. Anaphase: sister chromatids separate
d. Telophase: new nuclear envelopes form, chromosomes
unwind
45
46
nuclear
envelope
pair of
homologous,
duplicated
chromosomes
sister
chromatids of
one duplicated
homologue
47
(d) Anaphase: Sister
chromatids
have separated, and one set
has moved toward each pole.
(a) Interphase in a seed cell: The
chromosomes (blue) are in the
thin, extended state and appear
as a mass in the center of the
cell. The spindle microtubules
(red) extend outward from the
nucleus to all parts of the cell.
(b) Late prophase: The
chromosomes (blue) have
condensed and attached to
the spindle microtubules (red).
(e) Telophase: The
chromosomes have gathered
into two clusters, one at the
site of each future nucleus.
(c) Metaphase: The chromosomes
have moved to the equator of the
cell.
(f) Resumption of interphase: The
chromosomes are relaxing again
into their extended state. The spindle
microtubules are disappearing,
and the microtubules of the two
daughter cells are rearranging into
the interphase pattern.
48
Parent Cell
Chromosomes have
been replicated
Daughter Cells
Each cell has the same genetic
makeup as the parent cell
Mitosis
Each new nucleus is genetically identical to the parent nucleus
49
Mitosis or Somatic Cell Division
• A cell divides producing two genetically identical
daughter cells.
• New cells are produced for growth or repair of
aging or damaged tissues.
• For asexual reproduction
50
Interphase
• The stage between two successive cell divisions.
• Prior to mitosis, thin strands of DNA in a cell thicken into chromosomes,
which then duplicate
51
Early Prophase
• The centrioles divide and with the asters, move apart
• The nuclear membrane begins to disintegrate
Late Prophase
• The centrioles and asters are pushed to the opposite poles of the cell.
• Spindle fibers extend between the poles
• The nuclear membrane and nucleolus have almost disappeared
52
Metaphase
• Nuclear membrane disappears completely
• The double chromosomes, their centromeres attached to the spindle
fibers, align at the metaphase plate, midline of the cell.
53
Early Anaphase
• The centromeres split half moving to one pole and half to the other pole
Late Anaphase
• The chromosomes have almost reached to their respective poles.
• The cell membrane begins to contract at the midline.
Telophase
• The cell membrane completes contraction, closing over to split the cell
in two.
• Nuclear membrane form around the chromatin masses within each new
daughter cell.
Mitosis completed
There are now two cells, with structures and chromosomes identical to
each other and the original cell
Once Telophase completes,
the cell divides at a stage
called CYTOKINESIS where
two daughter cells form
completely.
55
Meiosis
Characteristics of meiosis -
 Occurs in sex cells (germ cells) and produces
gametes.
 A reduction division resulting in haploid cells.
 Involves two sequential divisions resulting in four
cells.
 Produces cells that are genetically different because
of genetic recombination (crossing-over).
56
Meiosis produces gametes for sexual reproduction
• Multiplies number of cells but also reduces chromosome
number in each daughter cell to exactly half the number
present before meiosis
• Daughter cells get 1 member of each homologous pair, i.e. 1
allele for each gene
• Mitosis produces 2 daughter cells
• Meiosis produces 4 daughter cells
• All body cells in humans are diploid, except gametes
• Cells with 1 member of each homologous pair are haploid
57
Parent Cell
(2n)
1st
division 2nd
division
Daughter Cells (1n)
each chromosome has 2
chromatids
Gamete Cells (1n)
Meiosis
58
59
60
61
Cell Differentiation
• The process of altering the pattern of gene expression and thus becoming a cell of
a particular type is called cell differentiation.
• Presence of chemicals (or other influences) starts altering the decisions as to
which genes will be turned on or off.
• The zygote is a totipotent cell - its daughter cells can become any cell type. As the
development proceeds, some of the cells become pluripotent - they can become
many, but not all cell types.
• Later on, the specificity narrows down further and a particular stem cell can turn
into only a very limited number of cell types, e.g., a few types of blood cells, but
not bone or brain cells or anything else. That is why embryonic stem cell research
is much more promising than the adult stem cell research.
62
Stem cells and their applications
63
Differentiation of different tissues and organs
64
Differentiation of different tissues and organs
65
66
67
68
69
70
71
72
73
74
75
Homeostasis
76
Homeostasis
Definition : Maintenance of the relative stability of the physical and chemical aspects of the
internal environment within a range compatible with cellular function.
Maintaining a constant internal environment with all that the cells need to survive (O2, glucose,
minerals, ions, and waste removal) is necessary for individual cells. The processes by which
the body regulates its internal environment are referred to as homeostasis.
Components : 1) sensor
2) afferent pathway
3) integration center or comparator
4) efferent pathway
5) effector organ(s)
• Physiological control systems are the nervous system, endocrine system, and immune system
through feedback mechanisms.
77
78
79
Classification of Nervous System
80
Endocrine System
81
• Stimulus (Change in environment)
↓
• Receptor (detects the change)
↓
• Afferent Signal (body to brain)
↓
• Control Center (Brain / Hypothalamus)
↓
• Efferent Signal (brain to body)
↓
• Effector Organs(muscles / glands / organs)
↓
• Response (restores normal condition)
Homeostatic Pathway
Nervous System
• The nervous system maintains homeostasis by controlling and
regulating the other parts of the body.
– A deviation from a normal set point acts as a stimulus to a
receptor, which sends nerve impulses to a regulating center in the
brain. The brain directs an effector to act in such a way that an
adaptive response takes place.
• The nervous system has two major portions: the central nervous
system and the peripheral nervous system.
82
Extrinsic homeostatic systems
83
• Regulating centers are located in the central nervous system,
consisting of the brain and spinal cord.
– The hypothalamus is a portion of the brain particularly
concerned with homeostasis; it influences the action of the
medulla oblongata, a lower part of the brain, the autonomic
nervous system, and the pituitary gland.
• The peripheral nervous system consists of the spinal nerves. The
autonomic nervous system is a part of peripheral nervous system
and contains motor neurons that control internal organs. It has two
divisions, the sympathetic and parasympathetic systems.
• The endocrine system consists of glands which secrete special
compounds called hormones into the bloodstream.
• Each hormone has an effect on one or more target tissues. In this way
the endocrine system regulates the metabolism and development of most
body cells and body systems.
• For e.g. the endocrine system has sex hormones that can activate
sebaceous glands, development of mammary glands, alter dermal blood
flow, and release lipids from adipocytes etc. besides governing
reproduction.
84
Endocrine System
85
• In the muscular system, hormones adjust muscle metabolism, energy
production, and growth.
• In the nervous system, hormones affect neural metabolism, regulate
fluid/electrolyte balance and help with reproductive hormones that
influence CNS (central nervous system), development and behaviors.
• In the cardiovascular system, hormones regulate heart rate and blood
pressure.
• Hormones also have anti-inflammatory effects and control the
lymphatic system.
86
• Negative feedback : a control system that causes the value of a
physiological measurement to change in the direction opposite to
the initial deviation from set point.
87
• Positive feedback : a control system that causes the value of a
physiological measurement to change in the same direction as the
initial deviation from set point.
88
Genetic Algorithm
Genetic Algorithms
89
Genetic algorithms (GA) in programming, simulate the process of
natural selection which means those species who can adapt to changes
in their environment are able to survive and reproduce and go to next
generation. In simple words, they simulate “survival of the fittest” among
individual of consecutive generation for solving a problem. Genetic
algorithms are based on an analogy with genetic structure and behavior
of chromosomes of the population.
Following is the foundation of GAs based on this analogy –
1. Individual in population compete for resources and mate
2. Those individuals who are successful (fittest) then mate to create
more offspring than others
3. Genes from “fittest” parent propagate throughout the generation, that
is sometimes parents create offspring which is better than either
parent.
4. Thus each successive generation is more suited for their environment.
90
91
92
• Gene represents a single solution to a problem
• chromosome (individual) is composed of several genes or multiple
similar solutions.
• population of individuals are maintained within search space - all
solutions to the problem
The whole algorithm can be summarized as –
‾ Randomly initialize n populations
‾ Determine fitness of population
‾ Until convergence repeat:
a) Select parents from population
b) Crossover and generate new population
c) Perform mutation on new population
d) Calculate fitness for new population
Components of a search space in Genetic algorithm
The Fitness score
• The GAs maintains the population of n individuals (chromosome/solutions)
along with their fitness scores.
• The individuals having better fitness scores are given more chance to reproduce
than others.
• The individuals with better fitness scores are selected who mate and
produce better offspring by combining chromosomes of parents.
• Always the new generation of solutions will have better fitness than the parent
population.
93
Operators for GA
• The Algorithm uses certain
biological concepts as operators
to find better solutions
• Cross Over
• Mutation
• Selection ( best fitness score in
previous generation)
94
Crossover
Mutation
Uses of GA
• Genetic Algorithms are primarily used in optimization problems of
various kinds, but they are frequently used in other application areas.
• Optimization − Genetic Algorithms are most commonly used in
optimization problems wherein we have to maximize or minimize a
given objective function value under a given set of constraints.
• DNAAnalysis − GAs have been used to determine the structure of DNA
using spectrometric data about the sample.
95
96
• Neural Networks − GAs are also used to train neural networks,
particularly recurrent neural networks.
• Parallelization − GAs also have very good parallel capabilities,
and prove to be very effective means in solving certain problems,
and also provide a good area for research.
Advantages of GA
• Does not require any derivative information (which may not be
available for many real-world problems).
• Is faster and more efficient as compared to the traditional methods.
• Provides a list of “good” solutions and not just a single solution.
97
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Disadvantages of GA
• GAs are not suited for all problems, especially problems which are
simple and for which derivative information is available.
• Fitness value is calculated repeatedly which might be
computationally expensive.
• Being stochastic, there are no guarantees on the optimality or the
quality of the solution.
Thank you
99

CB_UNIT 1.pptx555555DJKDJBCJNNJNDJNXJCNJ

  • 1.
    ▪Introduction ▪Cell theory ▪Whitaker’s kingdomclassification ▪Cell organelles, and their functions ▪Homeostasis ▪Replication and cell Division ▪Tissue differentiation ▪Stem cells and their applications ▪Genetic algorithms UNIT 1
  • 2.
    2 Living Organism • Aliving organism may be defined as a complex unit of physicochemical materials that is capable of self-regulation, metabolism, and reproduction. • Furthermore, a living organism demonstrates the ability to interact with its environment, grow, move, and adapt.
  • 3.
    3 What Are themain characteristics of organisms?  Made of cells  Require energy (food)  Reproduce (species)  Maintain homeostasis  Organized  Respond to environment  Grow and develop  Exchange materials with surroundings (water, wastes, gases)
  • 4.
    Concept of evolution •The process by which different kinds of living organism are believed to have developed from earlier forms during the history of the earth. • Evolution is the change in the heritable characteristics of biological populations over successive generations. • Jean Baptistae Lamarck (1801)-spontaneous generation of species according to needs and functionalities of the mutation • Charles darwin (1859)- Based on survival of the fittest mutations 4
  • 5.
  • 6.
    Cell - Basicunit of life a. Smallest living form b. Inside the cell some structure transport c. Metabolize d. Respire e. Reproduce (Meiosis) f. Multiply (Mitosis) g. Energy producing h. Keep information 6
  • 7.
    7 CELL THEORY • Suggestedby German scientists Theodor Schwann and Matthias Jakob Schleiden in 1838 • Matthias Schleiden, a German botanist, and Theodor Schwann, a British Zoologist formulated the cell theory. • The cell theory consists of the following information, • All living things are made of cells • Cells are the basic unit of structure and function in an organism (basic unit of life) • Cells come from the reproduction of existing cells (cell division)
  • 8.
    8 Prokaryotes • Nucleoid region(center) contains the DNA • Surrounded by cell membrane & cell wall (peptidoglycan) • Contain ribosomes (no membrane) in their cytoplasm to make proteins
  • 9.
    9 Eukaryotes • Cells thathave a nucleus and membrane-bound organelles • Includes protists, fungi, plants, and animals • More complex type of cells
  • 10.
  • 11.
    11 Five Kingdoms andtheir chief characteristics • Unicellular organisms that lack a nucleus and many of the specialized cell parts, called organelles. Such organisms are said to be prokaryotic (pro =‘‘before’’; karyotic =‘‘kernel,’’ ‘‘nucleus’’) and consist of bacteria. • All of the other kingdoms consist of eukaryotic (eu = ‘‘true’’) organisms, which have cells that contain a nucleus and a fuller repertory of organelles. Five Kingdom and their Classification
  • 12.
    12 Five Kingdom andtheir Classification
  • 13.
  • 14.
  • 15.
    15 Organelles • Very small(Microscopic) • Perform various functions for a cell • Found in the cytoplasm • May or may not be membrane-bound Plant Cell
  • 16.
    16 Cell or PlasmaMembrane Outside of cell Inside of cell (cytoplasm) Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains • Composed of double layer of phospholipids and proteins • Surrounds outside of all cells • Controls what enters or leaves the cell • Living layer
  • 17.
    17 • Jelly-like substanceenclosed by cell membrane • Provides a medium for chemical reactions to take place • Contains organelles to carry out specific jobs • Found in all cells Cytoplasm of a Cell cytoplasm
  • 18.
    18 • Controls thenormal activities of the cell • Contains the DNA in chromosomes • Bounded by a nuclear envelope (membrane) with pores • Usually the largest organelle • Each cell has fixed number of chromosomes that carry genes • Genes control cell characteristics The Control Organelle - Nucleus
  • 19.
    19 Nucleolus • Inside nucleus •Cell may have 1 to 3 nucleoli • Disappears when cell divides • Makes ribosomes that make proteins
  • 20.
    20 Cytoskeleton • Helps cellmaintain cell shape • Also help move organelles around • Made of proteins • Microfilaments are threadlike & made of ACTIN • Microtubules are tube-like and made of TUBULIN Cytoskeleton Microtubules Microfilaments
  • 21.
    21 Centrioles • Found onlyin animal cells • Paired structures near nucleus • Made of bundle of microtubules • Appear during cell division forming mitotic spindle • Help to pull chromosome pairs apart to opposite ends of the cell
  • 22.
    22 Mitochondrion (plural = mitochondria) •“Powerhouse” of the cell • Generate cellular energy (ATP) • More active cells like muscle cells have more mitochondria • Both plants & animal cells have mitochondria • Site of cellular respiration (burning glucose)
  • 23.
    23 Mitochondria • Surrounded bya double membrane • Has its own DNA – Mitochondria come from cytoplasm in the egg cell during fertilization – Therefore, you inherit your mitochondria from your mother! • Folded inner membrane called cristae (increases surface area for more chemical reactions) • Interior called matrix
  • 24.
    24 Endoplasmic Reticulum -ER • Network of hollow membrane tubules • Connects to nuclear envelope & cell membrane • Functions in synthesis of cell products & transport Two kinds of ER ---Rough & Smooth
  • 25.
    25 Rough Endoplasmic Reticulum(Rough ER) • Has ribosomes on its surface • Makes membrane proteins and proteins for export out of cell • Proteins are made by ribosomes on ER surface • They are then threaded into the interior of the Rough ER to be modified and transported
  • 26.
    26 Smooth Endoplasmic Reticulum •Smooth ER lacks ribosomes on its surface • Is attached to the ends of rough ER • Makes cell products that are used inside the cell • Makes membrane lipids (steroids) • Regulates calcium (muscle cells) • Destroys toxic substances (Liver) Includes nuclear membrane connected to ER connected to cell membrane (transport)
  • 27.
    27 Ribosomes • Made ofproteins and rRNA • “Protein factories” for cell • Join amino acids to make proteins • Process called protein synthesis • Can be attached to Rough ER OR Be free (unattached) in the cytoplasm
  • 28.
    28 Golgi Bodies • Stacksof flattened sacs • Have a shipping side (trans face) and receiving side (cis face) • Receive proteins made by ER • Transport vesicles with modified proteins pinch off the ends Transport vesicle CIS TRANS
  • 29.
    29 Golgi Bodies Look likea stack of pancakes Modify, sort, & package molecules from ER for storage or transport out of the cell.
  • 30.
    30 Lysosomes • Contain digestiveenzymes • Break down food, bacteria, and worn-out cell parts for cells • Programmed for cell death (Autolysis) • Lyse (break open) & release enzymes to break down & recycle cell parts)
  • 31.
    31 Lysosome Digestion • Cellstake in food by phagocytosis • Lysosomes digest the food & get rid of wastes
  • 32.
    32 Vacuoles • Fluid filledsacks for storage • Small or absent in animal cells • Plant cells have a large Central Vacuole • No vacuoles in bacterial cells • In plants, they store Cell Sap • Includes storage of sugars, proteins, minerals, lipids, wastes, salts, water, and enzymes
  • 33.
    33 Chloroplasts • Found onlyin producers (organisms containing chlorophyll) • Use energy from sunlight to make own food (glucose) • Energy from sun stored in the Chemical Bonds of Sugars
  • 34.
    34 Surrounded by doublemembrane Outer membrane smooth Inner membrane modified into sacs called thylakoids Thylakoids in stacks called Grana & interconnected Stroma – gel like material surrounding thylakoids
  • 35.
    35 Chloroplasts • Contains itsown DNA • Contains enzymes & pigments for Photosynthesis • Never in animal or bacterial cells • Photosynthesis – food making process
  • 36.
    36 Cell growth, reproduction,and differentiation
  • 37.
    37 The Cell Cycle •Mitosis and meiosis are single steps in cell cycle • G1, S, G2, and M phases – Cells not in process of dividing are in G0 phase – Chromosomes are duplicated in preparation for the next round of division during Interphase
  • 38.
  • 39.
    39 Control of theCell Cycle • The stimuli for entering the cell cycle is in the form of growth factors and cytokines that are capable of inducing mitotic divisions • The cell cycle is highly regulated – Proteins whose concentrations rise & fall in a controlled manner • Cyclin and cyclin-dependent kinases (cdk) • p53 and pRb • Inhibitors of cdk • Internal checkpoints & guardians monitor cell health • Errors in this process can lead to uncontrollable growth and cancer
  • 40.
    40 • Cell cyclecontrol is focused at 3 places: • G1 checkpoint • G2 checkpoint • M checkpoint – Before S phase (DNA synthesis) – At transition between G2 and M phase Control of the Cell Cycle
  • 41.
    41 DNA replication-Binary fission Daughtercells are identical copies (1) (2) (3) (4) (5) (6) Chromosome Plasma membrane Neither mitosis nor meiosis occurs in prokaryotes
  • 42.
    Bacteria Reproduction • Asexual, throughbinary fission • No true sexual reproduction, since neither mitosis nor meiosis exist in prokaryotes • Horizontal transfer of genetic material DNA cell wall
  • 43.
    43  Transformation -Uptake of genetic material from the environment  Transduction - Transfer of genetic material between prokaryotes by viruses  Conjugation - Direct transfer of genetic material from one prokaryote to another
  • 44.
    44 Mitosis Four phases – a.Prophase: chromosomes condense, spindle apparatus forms, nuclear envelope breaks down b. Metaphase: chromosomes line up at equator of cell c. Anaphase: sister chromatids separate d. Telophase: new nuclear envelopes form, chromosomes unwind
  • 45.
  • 46.
  • 47.
    47 (d) Anaphase: Sister chromatids haveseparated, and one set has moved toward each pole. (a) Interphase in a seed cell: The chromosomes (blue) are in the thin, extended state and appear as a mass in the center of the cell. The spindle microtubules (red) extend outward from the nucleus to all parts of the cell. (b) Late prophase: The chromosomes (blue) have condensed and attached to the spindle microtubules (red). (e) Telophase: The chromosomes have gathered into two clusters, one at the site of each future nucleus. (c) Metaphase: The chromosomes have moved to the equator of the cell. (f) Resumption of interphase: The chromosomes are relaxing again into their extended state. The spindle microtubules are disappearing, and the microtubules of the two daughter cells are rearranging into the interphase pattern.
  • 48.
    48 Parent Cell Chromosomes have beenreplicated Daughter Cells Each cell has the same genetic makeup as the parent cell Mitosis Each new nucleus is genetically identical to the parent nucleus
  • 49.
    49 Mitosis or SomaticCell Division • A cell divides producing two genetically identical daughter cells. • New cells are produced for growth or repair of aging or damaged tissues. • For asexual reproduction
  • 50.
    50 Interphase • The stagebetween two successive cell divisions. • Prior to mitosis, thin strands of DNA in a cell thicken into chromosomes, which then duplicate
  • 51.
    51 Early Prophase • Thecentrioles divide and with the asters, move apart • The nuclear membrane begins to disintegrate Late Prophase • The centrioles and asters are pushed to the opposite poles of the cell. • Spindle fibers extend between the poles • The nuclear membrane and nucleolus have almost disappeared
  • 52.
    52 Metaphase • Nuclear membranedisappears completely • The double chromosomes, their centromeres attached to the spindle fibers, align at the metaphase plate, midline of the cell.
  • 53.
    53 Early Anaphase • Thecentromeres split half moving to one pole and half to the other pole Late Anaphase • The chromosomes have almost reached to their respective poles. • The cell membrane begins to contract at the midline.
  • 54.
    Telophase • The cellmembrane completes contraction, closing over to split the cell in two. • Nuclear membrane form around the chromatin masses within each new daughter cell. Mitosis completed There are now two cells, with structures and chromosomes identical to each other and the original cell Once Telophase completes, the cell divides at a stage called CYTOKINESIS where two daughter cells form completely.
  • 55.
    55 Meiosis Characteristics of meiosis-  Occurs in sex cells (germ cells) and produces gametes.  A reduction division resulting in haploid cells.  Involves two sequential divisions resulting in four cells.  Produces cells that are genetically different because of genetic recombination (crossing-over).
  • 56.
    56 Meiosis produces gametesfor sexual reproduction • Multiplies number of cells but also reduces chromosome number in each daughter cell to exactly half the number present before meiosis • Daughter cells get 1 member of each homologous pair, i.e. 1 allele for each gene • Mitosis produces 2 daughter cells • Meiosis produces 4 daughter cells • All body cells in humans are diploid, except gametes • Cells with 1 member of each homologous pair are haploid
  • 57.
    57 Parent Cell (2n) 1st division 2nd division DaughterCells (1n) each chromosome has 2 chromatids Gamete Cells (1n) Meiosis
  • 58.
  • 59.
  • 60.
  • 61.
    61 Cell Differentiation • Theprocess of altering the pattern of gene expression and thus becoming a cell of a particular type is called cell differentiation. • Presence of chemicals (or other influences) starts altering the decisions as to which genes will be turned on or off. • The zygote is a totipotent cell - its daughter cells can become any cell type. As the development proceeds, some of the cells become pluripotent - they can become many, but not all cell types. • Later on, the specificity narrows down further and a particular stem cell can turn into only a very limited number of cell types, e.g., a few types of blood cells, but not bone or brain cells or anything else. That is why embryonic stem cell research is much more promising than the adult stem cell research.
  • 62.
    62 Stem cells andtheir applications
  • 63.
  • 64.
    Differentiation of differenttissues and organs 64
  • 65.
    Differentiation of differenttissues and organs 65
  • 66.
  • 67.
  • 68.
  • 69.
  • 70.
  • 71.
  • 72.
  • 73.
  • 74.
  • 75.
  • 76.
    76 Homeostasis Definition : Maintenanceof the relative stability of the physical and chemical aspects of the internal environment within a range compatible with cellular function. Maintaining a constant internal environment with all that the cells need to survive (O2, glucose, minerals, ions, and waste removal) is necessary for individual cells. The processes by which the body regulates its internal environment are referred to as homeostasis. Components : 1) sensor 2) afferent pathway 3) integration center or comparator 4) efferent pathway 5) effector organ(s) • Physiological control systems are the nervous system, endocrine system, and immune system through feedback mechanisms.
  • 77.
  • 78.
  • 79.
  • 80.
  • 81.
    81 • Stimulus (Changein environment) ↓ • Receptor (detects the change) ↓ • Afferent Signal (body to brain) ↓ • Control Center (Brain / Hypothalamus) ↓ • Efferent Signal (brain to body) ↓ • Effector Organs(muscles / glands / organs) ↓ • Response (restores normal condition) Homeostatic Pathway
  • 82.
    Nervous System • Thenervous system maintains homeostasis by controlling and regulating the other parts of the body. – A deviation from a normal set point acts as a stimulus to a receptor, which sends nerve impulses to a regulating center in the brain. The brain directs an effector to act in such a way that an adaptive response takes place. • The nervous system has two major portions: the central nervous system and the peripheral nervous system. 82 Extrinsic homeostatic systems
  • 83.
    83 • Regulating centersare located in the central nervous system, consisting of the brain and spinal cord. – The hypothalamus is a portion of the brain particularly concerned with homeostasis; it influences the action of the medulla oblongata, a lower part of the brain, the autonomic nervous system, and the pituitary gland. • The peripheral nervous system consists of the spinal nerves. The autonomic nervous system is a part of peripheral nervous system and contains motor neurons that control internal organs. It has two divisions, the sympathetic and parasympathetic systems.
  • 84.
    • The endocrinesystem consists of glands which secrete special compounds called hormones into the bloodstream. • Each hormone has an effect on one or more target tissues. In this way the endocrine system regulates the metabolism and development of most body cells and body systems. • For e.g. the endocrine system has sex hormones that can activate sebaceous glands, development of mammary glands, alter dermal blood flow, and release lipids from adipocytes etc. besides governing reproduction. 84 Endocrine System
  • 85.
    85 • In themuscular system, hormones adjust muscle metabolism, energy production, and growth. • In the nervous system, hormones affect neural metabolism, regulate fluid/electrolyte balance and help with reproductive hormones that influence CNS (central nervous system), development and behaviors. • In the cardiovascular system, hormones regulate heart rate and blood pressure. • Hormones also have anti-inflammatory effects and control the lymphatic system.
  • 86.
    86 • Negative feedback: a control system that causes the value of a physiological measurement to change in the direction opposite to the initial deviation from set point.
  • 87.
    87 • Positive feedback: a control system that causes the value of a physiological measurement to change in the same direction as the initial deviation from set point.
  • 88.
  • 89.
    Genetic Algorithms 89 Genetic algorithms(GA) in programming, simulate the process of natural selection which means those species who can adapt to changes in their environment are able to survive and reproduce and go to next generation. In simple words, they simulate “survival of the fittest” among individual of consecutive generation for solving a problem. Genetic algorithms are based on an analogy with genetic structure and behavior of chromosomes of the population.
  • 90.
    Following is thefoundation of GAs based on this analogy – 1. Individual in population compete for resources and mate 2. Those individuals who are successful (fittest) then mate to create more offspring than others 3. Genes from “fittest” parent propagate throughout the generation, that is sometimes parents create offspring which is better than either parent. 4. Thus each successive generation is more suited for their environment. 90
  • 91.
  • 92.
    92 • Gene representsa single solution to a problem • chromosome (individual) is composed of several genes or multiple similar solutions. • population of individuals are maintained within search space - all solutions to the problem The whole algorithm can be summarized as – ‾ Randomly initialize n populations ‾ Determine fitness of population ‾ Until convergence repeat: a) Select parents from population b) Crossover and generate new population c) Perform mutation on new population d) Calculate fitness for new population Components of a search space in Genetic algorithm
  • 93.
    The Fitness score •The GAs maintains the population of n individuals (chromosome/solutions) along with their fitness scores. • The individuals having better fitness scores are given more chance to reproduce than others. • The individuals with better fitness scores are selected who mate and produce better offspring by combining chromosomes of parents. • Always the new generation of solutions will have better fitness than the parent population. 93
  • 94.
    Operators for GA •The Algorithm uses certain biological concepts as operators to find better solutions • Cross Over • Mutation • Selection ( best fitness score in previous generation) 94 Crossover Mutation
  • 95.
    Uses of GA •Genetic Algorithms are primarily used in optimization problems of various kinds, but they are frequently used in other application areas. • Optimization − Genetic Algorithms are most commonly used in optimization problems wherein we have to maximize or minimize a given objective function value under a given set of constraints. • DNAAnalysis − GAs have been used to determine the structure of DNA using spectrometric data about the sample. 95
  • 96.
    96 • Neural Networks− GAs are also used to train neural networks, particularly recurrent neural networks. • Parallelization − GAs also have very good parallel capabilities, and prove to be very effective means in solving certain problems, and also provide a good area for research.
  • 97.
    Advantages of GA •Does not require any derivative information (which may not be available for many real-world problems). • Is faster and more efficient as compared to the traditional methods. • Provides a list of “good” solutions and not just a single solution. 97
  • 98.
    98 Disadvantages of GA •GAs are not suited for all problems, especially problems which are simple and for which derivative information is available. • Fitness value is calculated repeatedly which might be computationally expensive. • Being stochastic, there are no guarantees on the optimality or the quality of the solution.
  • 99.

Editor's Notes

  • #47 Figure: 10-07 Title: The cell cycle in a plant cell. Caption: Interphase and mitosis in the African blood lily. The chromosomes are stained bluish-purple, and the spindle microtubules are stained pink to red. Compare these micrographs with the drawings of mitosis in an animal cell shown in Figure 10-8. (Each micrograph is of a different single cell that has been fixed and stained at a particular stage of mitosis. Only chromosomes and microtubules have been stained.)
  • #48 Figure: 10-08a Title: The cell cycle in an animal cell: late interphase. Caption: The cell cycle in an animal cell.
  • #57 Figure: 10-11a Title: The details of meiotic cell division: prophase I. Caption: In these diagrams, two pairs of homologous chromosomes are shown, large and small. The yellow chromosomes are from one parent and the violet chromosomes are from the other parent. Note that each daughter cell contains one member of each pair of parental homologous chromosomes.