Cell division is essential but must be controlled. There are two phases of cell division - interphase and mitosis. Interphase is the non-dividing phase where the cell grows and carries out normal functions. Mitosis is the dividing phase where the nucleus divides into two identical daughter nuclei through the stages of prophase, metaphase, anaphase and telophase. Cytokinesis then divides the cytoplasm. Chromosomes condense through supercoiling during mitosis. Cyclins control progression through the cell cycle. Mutations from mutagens can lead to cancer development if they occur in oncogenes and are not repaired. Smoking strongly correlates with increased lung cancer rates, with a lag time between smoking and cancer development
Multicellular organisms develop from a single cell known as zygote by the process of mitosis. Asexual reproduction in some organisms like amoeba and vegetative reproduction in plants takes place by mitosis. This type of cell division involves many steps and it does not alter the genetic material.
This presentation include the process of cell division. It hope it will helpful for all the medical students. Cell division is the series of events of equally dividing of one single mother cell into two identical daughter cell. Cell cycle and cell division terms are alternately used. Cell division is an important part of the all living processes.
At the time of cell division, RNA replication is a natural process.
The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells.
These events include the duplication of its DNA (DNA replication) and some of its organelles, and subsequently the partitioning of its cytoplasm and other components into two daughter cells in a process called cell division.
There are two types of cell division
A) Mitosis and Binary fission – (Asexual reproduction) and B) Meiosis – (Sexual reproduction)
In prokaryotic cell, the cell division occurs via a process termed as Binary fission.
• In eukaryotic cell, the cell cycle can be divided in two periods i.e Interphase and Mitosis.
• During Interphase, the cell grows and DNA is replicated.
During Mitotic phase, the replicated DNA and cytoplasmic contents are separated, and cell divides.
The duration of cycle varies from hours to years. A typical human cell cycle has duration of 24 hours.
Some cells, such as skin cells, are constantly going through cell cycle, while other cells may divide rarely.
Some cells don’t grow and divide once they mature for ex. Neuron
Eukaryotic cell have a more complex cell cycle than prokaryotic cell.
Homecell divisionCell division
Cell division
Miller November 05, 2022
Every living organism depends on the growth and multiplication of its cells for growth and development because a multicellular organism begins as a single cell and undergoes repeated division. The characteristic trait of all living things is an increase in cell size brought on by growth. The cell starts to divide once its growth has reached its maximum. An organism grows vegetatively when its number of cells increases through cell divisions that follow a geometric progression. The three stages of cell division, which is a continuous and dynamic process, are as follows:
Replicating the genome or DNA
Karyokinesis, or nuclear division
Cytokinesis, also known as cell division
Based on the number of genomes present in the daughter cells in comparison to the dividing parent cell, there are two types of cell division: mitosis and meiosis.
1. Mitosis- W. Flemming first used the word mitosis in 1882. Mitosis, also known as somatic division, is the process by which a body cell divides into two daughter cells, each of equal size and with the same number of chromosomes as the parent cell.
2. Meiosis- J. Meiosis was the first to use the term. B. Farmer and J. Smith in 1905 Moore, E. Only the gonads (germ mother cells) undergo meiosis during the development of gametes like sperm and ovum. Meiosis is the process by which chromosomes go from having two copies, or 2N or diploid, to having only one copy, or N or haploid. Additionally known as the reduction process. Every cell that is able to divide undergoes a regular cycle of alterations known as the cell cycle. A cell is diploid when it begins its cycle.
Phases of cell cycle
The cell cycle has two phases: the long interphase, also known as Iphase, and the short mitotic, also known as M-phase, phases. 1. Interphase-
The interphase is the period of time between telophase's conclusion and the start of the following Mphase. The stage is long and complicated, lasting between 10 and 30 hours. The cell develops during this phase by producing biological molecules like lipids, proteins, carbohydrates, and nucleic acids.
First gap, also known as the G1 phase, second gap, also known as the G2 phase, and synthetic phase make up the interphase.
(i) G1 phase- The G1 phase represents the duration between the previous mitosis and the start of DNA synthesis. During this phase, a newly formed cell begins to grow. During this stage, a wide range of biological molecules—including RNAs, proteins, lipids, and some non-histones—are created.
In order to prepare for the DNA replication that will occur next to it, normal metabolism is carried out. This phase does not involve DNA synthesis. (ii) S Phase- Each chromosome is duplicated during this phase by replicating new DNA molecules using the existing DNA as a template. Only in S-phase do histone protein and their mRNA, some non-histone protein, and new nucleosome formation take place. Most eukary
Cell cycle and cell division are fundamental processes governing the growth, development, and reproduction of all living organisms. Understanding these processes is crucial in the field of biology as they play a pivotal role in shaping life at both the cellular and organismal levels.
For more information, visit-www.vavaclasses.com
cell division & physiology of cell division, types, binary fission, meiosis, mitosis, regulation of cell cycle, cell cycle checkpoints, what is cyclin-dependent kinases and its importance
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
Phenomics assisted breeding in crop improvementIshaGoswami9
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Toxic effects of heavy metals : Lead and Arsenicsanjana502982
Heavy metals are naturally occuring metallic chemical elements that have relatively high density, and are toxic at even low concentrations. All toxic metals are termed as heavy metals irrespective of their atomic mass and density, eg. arsenic, lead, mercury, cadmium, thallium, chromium, etc.
2. Understandings
Statement Guidance
1.6 U.1 Mitosis is division of the nucleus into
two genetically identical daughter
nuclei.
The sequence of events in the four phases of mitosis
should be known. To avoid confusion in terminology,
teachers are encouraged to refer to the two parts of a
chromosome as sister chromatids, while they are
attached to each other by a centromere in the early
stages of mitosis. From anaphase onwards, when sister
chromatids have separated to form individual
structures, they should be referred to as chromosomes.
1.6 U.2 Chromosomes condense by
supercoiling during mitosis.
1.6 U.3 Cytokinesis occurs after mitosis and is
different in plant and animal cells.
1.6 U.4 Interphase is a very active phase of the
cell cycle with many processes
occurring in the nucleus and
cytoplasm.
1.6 U.5 Cyclins are involved in the control of
the cell cycle.
1.6 U.6 Mutagens, oncogenes and metastasis
are involved in the development of
primary and secondary tumours.
3. Applications and Skills
Statement Guidance
1.6 A.1 The correlation between smoking and incidence
of cancers.
1.6 S.1 Identification of phases of mitosis in cells viewed
with a microscope or in a micrograph.
Preparation of temporary mounts of root
squashes is recommended but phases in
mitosis can also be viewed using permanent
slides.
1.6 S.2 Determination of a mitotic index from a
micrograph.
4. Why do cells divide:
• Growth: Multicellular organisms
increase their size by increasing
their number of cells through
mitosis
• Asexual reproduction: Certain
eukaryotic organisms may
reproduce asexually by mitosis
(e.g. vegetative reproduction)
• Tissue Repair: Damaged tissue
can recover by replacing dead or
damaged cells
• Embryonic development: A
fertilized egg (zygote) will
undergo mitosis and
differentiation in order to
develop into an embryo
5. • Cellular division in
eukaryotic cells.
• Chromatin is arranged
into chromosomes.
• Chromosomes double.
• Cell grows in size.
• Cells divide.
• Is cellular cloning.
Cell division
6. 2 phases:
1. Interphase
2. M phase
(mitotic phase)
a. Prophase
b. Metaphase
c. Anaphase
d. Telophase &
cytokinesis
Figure 12.4 The cell cycle
Phases of the Cell Cycle (life cycle of a cell)
7. Interphase
• The non-dividing phase in a cell
• Lasts about ~ 90% of the cell cycle.
• The cell grows and replicates DNA
preparing for Mitosis.
• There are three periods:
3 periods of Interphase
1. Go – a cell functioning as normal
2. G1 phase – first growth phase
3. S phase- synthesis of DNA
4. G2 phase- 2nd growth phase
Mitosis is a reliable process. Only one error
occurs per 100,000 cell divisions.
1.6 U.4 Interphase is a very active phase of the cell cycle with many
processes occurring in the nucleus and cytoplasm.
8. 1.6 U.5 Cyclins are involved in the control of the cell cycle.
Cyclinsare a family of proteins that control the progression of
cells through the cell cycle
Cells cannot progress to the next
stage of the cell cycle unless the
specific cyclin reaches it threshold.
http://upload.wikimedia.org/wikipedia/commons/thumb/9/99/Protein_CCNE1_PDB_1w98.png/800px-Protein_CCNE1_PDB_1w98.png
Cyclins bind to enzymes called
cyclin-dependent kinases
These kinases then become active and
attach phosphate groups to other proteins
in the cell.
The attachment of phosphate triggers the other proteins to become active
and carry out tasks (specific to one of the phases of the cell cycle).
4
3
2
1
10. 1.6 U.4 Interphase is a very active phase of the cell cycle with many
processes occurring in the nucleus and cytoplasm.
Interphase
This when the cell carries out it’s normal functions
Metabolic reactions (e.g. respiration to produce ATP) are
necessary for the life of the cell
Protein synthesis - proteins and enzymes are necessary to allow
cell grow
Organelles numbers are increased to first support the enlarged
cell
DNA is replicated to ensure a second copy is available to enable
mitosis
Cells spend the majority of their time in interphase. It is a
very active phase of the cycle.
Mr
P
O
D
http://botit.botany.wisc.edu/Resources/Botany/Mitosis/Allium/Various%20views/Interphase%20prophase.JPG
11. 1.6 U.1 Mitosis is division of the nucleus into two genetically identical
daughter nuclei.
http://commons.wikimedia.org/wiki/File:Chromosome.svg
centromere is the part
of a chromosome that
links sister chromatids
Sister chromatids are duplicated
chromosomes attached by a centromere
Get the terminology right centrioles
organise spindle
microtubules
Spindle
microtubules
(also referred to
as spindle
fibres)
In animal cells two centrioles are held by a
protein mass referred to as a centrosome
After anaphase when the sister chromatids
separate they should then be referred to as
chromosomes
It is easy to misuse the terms chromatid and
chromosome. It is even easier to confuse the terms
centromere, centriole and centrosome due to their
similar spelling. Keep the terms clear in your mind
to avoid losing marks.
http://commons.wikimedia.org/wiki/Mitosis#mediaviewer/File:Mitosis_cells_sequence.svg
13. 1.6 U.2 Chromosomes condense by supercoiling during mitosis.
Why supercoil chromosomes? Human cells are on average
10μm in diameter and the
nucelus within each is less
than 5 μm in diameter.
Human chromosomes are
15mm to 85mm (15,000μm
to 85,000 μm) in length.
Chromosomes need to be
stored compactly to fit
within the nuclei of cells.
This problem becomes more
acute during mitosis when
chromosomes need to be
short and compact enough
that they can be separated
and moved to each end of
the cell.
http://www.genome.gov/dmd/img.cfm?node=Photos/Graphics&id=85282
Chromatin fibres
14. 1.6 U.2 Chromosomes condense by supercoiling during mitosis.
How are chromosomes
supercoiled? Strain is placed on a DNA helix by over winding or under
winding of the helix
This causes the DNA molecule to coil back on itself
becoming shorter and wider
n.b. in eukaryotes proteins called histones aid the process
http://www.maths.uq.edu.au/~infinity/Infinity7/images/supercoiling.gifhttp://vanat.cvm.umn.edu/mMeiosis/images/chromosome-X.jpg
15. Prophase
• The nucleolus disappears.
• Chromatin condenses into
visible chromosomes.
• There are two sister
chromatids held together by a
centromere.
• The mitotic spindle forms in
the cytoplasm.
.
1.6 S.1 Identification of phases of mitosis in cells viewed with a
microscope or in a micrograph
16. Metaphase
• The nuclear envelope
disappears.
• Spindle fibers extend
from each pole to the
cell’s equator.
• Spindle fibers attach to
the centromeres.
18. Anaphase
• Characterized by
movement. It begins when
pairs of sister chromatids
pull apart.
• Sister chromatids move to
opposite poles of the cell.
• Chromosomes look like a
“V” as they are pulled.
• At the end of anaphase, the
two poles have identical
number and types of
chromosomes.
19. Telophase
• Microtubules elongate the cell.
• Daughter nuclei begin to form at the
two poles.
• Nuclear envelopes re-form.
• Nucleolus reappears.
• Chromatin uncoils.
• The cells cytoplasm begins to pinch.
• It is basically the opposite of
prophase.
20. 1.6 U.3 Cytokinesis occurs after mitosis and is different in plant and
animal cells.
mitosis is the division of the nucleus,
cytokinesis is the division of the cytoplasm
to create two cells
Though mitosis is similar for animal and plant cells
cytokinesis is very different.
http://wwwprod.biochem.wisc.edu/biochem/faculty/bednarek/images/figure_color.gif
http://glencoe.mheducation.com/sites/983
4092339/student_view0/chapter10/animati
on_-_cytokinesis.html
http://www.haroldsmithlab.com/images/pg_HeLa_cell_division.jpg
22. 1.6 S.1 Identification of phases of mitosis in cells viewed with a microscope or in a micrograph.
1.6 S.2 Determination of a mitotic index from a micrograph.
http://www.nuffieldfoundation.org/practical-biology/investigating-mitosis-allium-root-tip-squash
A very good, well explained lab outline for creating slides and calculating the
mitotic index.
http://www.biology.arizona.edu/cell_bio/activities/cell_cycle/cell_cycle.html
An excellent online
alternative if resources don’t
permit students to create
and view their own slides
23. 1.6 U.6 Mutagens, oncogenes and metastasis are involved in the
development of primary and secondary tumors.
Tumors are abnormal growth of tissue that develop at any stage of life in any part of the body. A
cancer is a malignant tumour and is named after the part of the body where the cancer
(primary tumour) first develops. Use the links to find out:
• most common types of cancer
• what causes cancer and associated risk factors
• how cancer can be treated
http://www.cancer.gov/cancertopics/types/commoncancers
http://youtu.be/8BJ8_5Gyhg8
http://www.cancerresearchuk.org/cancer-
info/cancerandresearch/all-about-cancer/what-is-cancer/
What causes
cancer?
http://www.e-learningforkids.org/health/lesson/cancer/
24. 1.6 U.6 Mutagens, oncogenes and metastasis are involved in the
development of primary and secondary tumors.
Mutagens are agents that
cause gene mutations. Not all
mutations result in cancers,
but anything that causes a
mutation has the potential to
cause a cancer.
Mutagens can be:
• chemicals that cause
mutations are referred to as
carcinogens
• high energy radiation such
as X-rays
• short-wave ultraviolet light
• Some viruses
A mutation is a change in an organisms genetic code. A mutation/change in the
base sequence of a certain genes can result in cancer.
http://en.wikipedia.org/wiki/Oncogene#mediaviewer/File:Oncogenes_illustration.jpg
25. 1.6 U.6 Mutagens, oncogenes and metastasis are involved in the
development of primary and secondary tumors.
mutation in a oncogene
If a mutation occurs in an oncogenes it can become cancerous. In normal cells
oncogenes control of the cell cycle and cell division.
http://en.wikipedia.org/wiki/Oncogene#mediaviewer/File:Oncogenes_illustration.jpg
uncontrolled cell division
tumour formation
malfunction in the control
of the cell cycle
26. 1.6 U.6 Mutagens, oncogenes and metastasis are involved in the
development of primary and secondary tumours.
Factors (other than exposure to
mutagens) that increase the
probability of tumour
development include:
• The vast number of cells in a
human body – the greater
the number of cells the
greater the chance of a
mutation.
• The longer a life span the
greater the chance of a
mutation.
Several mutations must occur in the same cell for it to become a tumour
causing cell. The probability of this happening in a single cell is extremely small.
http://en.wikipedia.org/wiki/Oncogene#mediaviewer/File:Oncogenes_illustration.jpg
27. There are two major types of tumor:
1. Benign Tumors this is a
mass of cancerous cells that do not
invade other areas of the body.
These are not as dangerous to
health but may still require
removing to prevent effects on
neighboring tissue
1.6 U.6 Mutagens, oncogenes and metastasis are involved in the
development of primary and secondary tumors.
28. 2. Malignant Tumors is a mass
of cancer cells that may
invade surrounding tissues
or spread to distant areas
of the body. Cancer cells
replace normal functioning
cells in distant sites:
e.g. replacing blood forming
cells in the bone marrow,
replacing bones leading to
increased calcium levels in
the blood, or in the heart
muscles so that the heart
fails.
1. Image is a normal CT. Images 2, 3 & 4
Are PET scans, Light green/blue areas
show cancer cells
29. 1.6 A.1 The correlation between smoking and incidence of cancers.
http://en.wikipedia.org/wiki/File:Smoking_lung_cancer.png
There are many other similar
surveys in different countries,
with different demographics
that show similar results.
Along with lung cancer,
cancers of mouth and throat
are very common as these
areas are in direct contact with
the smoke too. It might
surprise you that the following
cancers are also more
common in smokers:
• Head and neck
• Bladder
• Kidneys
• Breast
• Pancreas
• Colon
30. a. Describe the relationship shown.
b. What type of correlation is shown
c. How strong is the correlation? Justify your answer by discussing the evidence.
d. The correlation shown here is lagged. A lag is a time gap between the factors. Estimate the
size of the lag between cigarette consumption and lung cancer death.
31. http://en.wikipedia.org/wiki/File:Smoking_lung_cancer.png
a. Describe the relationship shown.
b. What type of correlation is shown
c. How strong is the correlation? Justify your answer by discussing the evidence.
d. The correlation shown here is lagged. A lag is a time gap between the factors. Estimate
the size of the lag between cigarette consumption and lung cancer death.
There are many other similar surveys
in different countries, with different
demographics that show similar
results. Along with lung cancer,
cancers of mouth and throat are
very common as these areas are in
direct contact with the smoke too. It
might surprise you that the following
cancers are also more common in
smokers:
• Head and neck
• Bladder
• Kidneys
• Breast
• Pancreas
• Colon