The document discusses cell theory and provides a brief history and overview of key concepts. It states that all living things are made of cells, which are the smallest units of life. Unicellular organisms consist of single cells, while multicellular organisms have specialized cell types. Cells come only from existing cells through division.
This is a presentation designed to help explain the section of the Edexcel IGCSE Biology course about classification in the variety of living organisms section. For more help with IGCSE Biology please visit mrexham.com
This is a presentation designed to help explain the section of the Edexcel IGCSE Biology course about classification in the variety of living organisms section. For more help with IGCSE Biology please visit mrexham.com
Edexcell Biology;
Most year 10 & 11 syllabus points by ppt.
Used in lessons to scaffold class teaching and as a revision resource for students
These resources are from many sources
A Level Biology - Classification and Biodiversitymrexham
This is a PowerPoint presentation for Topic 3 in the Edexcel Biology B A Level course that starts in 2015.
This is a free sample, the full PowerPoint presentation is available to purchase here: https://sellfy.com/MrExham
Atomic Structure and the Periodic TablePaul Schumann
Sharon Williams, Water Valley High School
Presented at CAST 2008, ACT2 Strand, 11/6/09
Objectives
Identify important developments in the history of atomic theory.
Summarize Dalton’s atomic theory.
Describe the size of an atom.
Distinguish among protons, electrons, and neutrons in terms of relative mass and change.
Describe the structure of an atom, including the location of the protons, electrons, and neutrons with respect to the nucleus.
Explain how the atomic number identifies an element.
Use the atomic number and mass number of an element to find the number of protons, electrons, and neutrons.
Explain how isotopes differ and why the atomic masses of elements are not whole numbers.
Calculate the average atomic mass of an element from isotope data.
Mr Exham IGCSE - Cell Differentiation and Organisationmrexham
This is a presentation designed to help explain the section of the Edexcel IGCSE Biology course about cell differentiation and organisation. For more help with IGCSE Biology please visit mrexham.com
This is the first PowerPoint in the mrexham IGCSE Biology series. It is also available on iBooks.
It covers the Cells section from life processes of the Edexcel IGCSE Biology course
Slideshow for students studying IB Biology, contains links to animations and videos and practice questions for calculating actual size from a scale bar.
Edexcell Biology;
Most year 10 & 11 syllabus points by ppt.
Used in lessons to scaffold class teaching and as a revision resource for students
These resources are from many sources
A Level Biology - Classification and Biodiversitymrexham
This is a PowerPoint presentation for Topic 3 in the Edexcel Biology B A Level course that starts in 2015.
This is a free sample, the full PowerPoint presentation is available to purchase here: https://sellfy.com/MrExham
Atomic Structure and the Periodic TablePaul Schumann
Sharon Williams, Water Valley High School
Presented at CAST 2008, ACT2 Strand, 11/6/09
Objectives
Identify important developments in the history of atomic theory.
Summarize Dalton’s atomic theory.
Describe the size of an atom.
Distinguish among protons, electrons, and neutrons in terms of relative mass and change.
Describe the structure of an atom, including the location of the protons, electrons, and neutrons with respect to the nucleus.
Explain how the atomic number identifies an element.
Use the atomic number and mass number of an element to find the number of protons, electrons, and neutrons.
Explain how isotopes differ and why the atomic masses of elements are not whole numbers.
Calculate the average atomic mass of an element from isotope data.
Mr Exham IGCSE - Cell Differentiation and Organisationmrexham
This is a presentation designed to help explain the section of the Edexcel IGCSE Biology course about cell differentiation and organisation. For more help with IGCSE Biology please visit mrexham.com
This is the first PowerPoint in the mrexham IGCSE Biology series. It is also available on iBooks.
It covers the Cells section from life processes of the Edexcel IGCSE Biology course
Slideshow for students studying IB Biology, contains links to animations and videos and practice questions for calculating actual size from a scale bar.
Week 2 DiscussionThe Cell,Lokiarcharum, and the Chemicalsnicolleszkyj
Week 2 Discussion
"The Cell,
Lokiarcharum, and the Chemicals of Life"
This week is all about the some of the smallest parts of life: atoms, molecules, and cells. For your primary post, please respond to
one
of the following two topics and address all questions. Also, reply to at least one fellow student on any topic.
Topic 1 [video]: Introduction to the Cell.
Watch the Khan Academy video “Introduction to the cell” (1)* and then address the following issues.
(a) In the video, the narrator says that we might think that since cells are so small, that they must be simple, but “nothing could be further from the truth.” What did he mean by that?
(b) Describe features that are only found in eukaryotic (but not prokaryotic) cells.
(c) Did anything in this video surprise you, or was it mainly a recap of material you already knew?
Topic 2 [article]:
Lokiarchaeum.
Read about Lokiarcheum in the article by Yong (2)* and/or the article by Zimmer (3)*. Both articles describe recently discovered evidence about a previously unknown organism. Then, address the following questions:
(a) Lokiarchaeum may be a “transitional form” between archaea and eukarya. What evidence suggests this?
(b) Describe one way that this relates to this week's lesson.
Topic 3 [video]: Chemicals of Life Video
. (added on 1/8/2018) Watch Dr. Cox's video on the "Chemicals of Life" (4)* in the "Instructor Insights" area of Week 2. Then, describe three things you learned from this video.
Note: To get credit for this topic, your post
must be based on the video
. Answers based on other materials will receive a grade of zero.
References (in Strayer Writing Standards format).
Khan Academy, November 29, 2017. Introduction to the cell,
https://www.youtube.com/watch?v=5KfHxF6Vhps
Ed Yong, May 6, 2015. New Loki microbe is closest relative to all complex life,
http://phenomena.nationalgeographic.com/2015/05/06/new-loki-microbe-is-closest-relative-to-all-complex-life/
Carl Zimmer, May 6, 2015, Under the sea, a missing link in the evolution of complex cells,
http://www.nytimes.com/2015/05/07/science/under-the-sea-a-missing-link-in-the-evolution-of-complex-cells.html?_r=0
James Cox, July 12, 2016, The Chemicals of Life (revised). Kaltura video found in Week 2 - Instructor Insights section.
Week 5 Discussion
"Apoptosis, Crossover, and Tumor-suppressor genes"
This week’s discussion is focused mechanisms that cells use to keep cell division under control, to prevent cancer, and to function well. For your primary post, respond to
one
of the following three topics. Also, please reply to at least one fellow student on any topic.
Topic 1 [video]: Apoptosis
. Watch the Khan Academy video about apoptosis (1)*, then answer the following questions in your own words:
(a) What is the difference between apoptosis and necrosis?
(b) What is the role of apoptosis in the normal, healthy development of animals?
Topic 2 [article]: Crossover
.
Read the article from the University ...
How International Is Our School? MA DissertationStephen Taylor
Title: A pilot-test of a visualization and set of evaluation rubrics for factors affecting the promotion of international-mindedness and global engagement (IMaGE) of a school.
Defining Inquiry for the PreK-12 continuum. Inquiry as a 'theory of everything' of good education, built on a solid foundation of well-taught knowledge, skills and concepts.
This is an assignment for my University of Bath MA in International Education, based on the tensions in transition from MYP to DP. It revolved around the different schools of through about learning and, most importantly, inquiry. It focuses on the different approaches to inquiry characterised by Dewey and Vygotsky, before moving onto a modern look at evidence-based practices.
MA International Education University of Bath assignment (Education in and International Context).
In this assignment I have tried to propose an original idea for helping schools define and measure the degree to which they demonstrate the values of international education.
I use this lab sequence over a couple of lessons to get to grips with some basics of different types of reactions, balancing, writing formulas and problem-solving.
In this formative in-class Criterion C task, we connect the content from the last unit with some basics on Forces, using the Red Bull Stratos jump as a basis.
This presentation is for my class to work through as teachers are on a series of PD days. It is based on a very bad One Direction joke cracked in a class about vectors.
I split the presentation for the unit into two, as I added so many slides to help with student questions and misconceptions. This one focuses on mathematical aspects of the unit.
In the first week of High School, my Grade 9 Chemistry class were asked to put on a short show for the BBP and KA students (3-5 year-olds) about water. We used it as a chance to get to know each other and to formatively assess Criterion B: Communication and F: Attitudes in Science.
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
JMeter webinar - integration with InfluxDB and GrafanaRTTS
Watch this recorded webinar about real-time monitoring of application performance. See how to integrate Apache JMeter, the open-source leader in performance testing, with InfluxDB, the open-source time-series database, and Grafana, the open-source analytics and visualization application.
In this webinar, we will review the benefits of leveraging InfluxDB and Grafana when executing load tests and demonstrate how these tools are used to visualize performance metrics.
Length: 30 minutes
Session Overview
-------------------------------------------
During this webinar, we will cover the following topics while demonstrating the integrations of JMeter, InfluxDB and Grafana:
- What out-of-the-box solutions are available for real-time monitoring JMeter tests?
- What are the benefits of integrating InfluxDB and Grafana into the load testing stack?
- Which features are provided by Grafana?
- Demonstration of InfluxDB and Grafana using a practice web application
To view the webinar recording, go to:
https://www.rttsweb.com/jmeter-integration-webinar
Generating a custom Ruby SDK for your web service or Rails API using Smithyg2nightmarescribd
Have you ever wanted a Ruby client API to communicate with your web service? Smithy is a protocol-agnostic language for defining services and SDKs. Smithy Ruby is an implementation of Smithy that generates a Ruby SDK using a Smithy model. In this talk, we will explore Smithy and Smithy Ruby to learn how to generate custom feature-rich SDKs that can communicate with any web service, such as a Rails JSON API.
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
Are you looking to streamline your workflows and boost your projects’ efficiency? Do you find yourself searching for ways to add flexibility and control over your FME workflows? If so, you’re in the right place.
Join us for an insightful dive into the world of FME parameters, a critical element in optimizing workflow efficiency. This webinar marks the beginning of our three-part “Essentials of Automation” series. This first webinar is designed to equip you with the knowledge and skills to utilize parameters effectively: enhancing the flexibility, maintainability, and user control of your FME projects.
Here’s what you’ll gain:
- Essentials of FME Parameters: Understand the pivotal role of parameters, including Reader/Writer, Transformer, User, and FME Flow categories. Discover how they are the key to unlocking automation and optimization within your workflows.
- Practical Applications in FME Form: Delve into key user parameter types including choice, connections, and file URLs. Allow users to control how a workflow runs, making your workflows more reusable. Learn to import values and deliver the best user experience for your workflows while enhancing accuracy.
- Optimization Strategies in FME Flow: Explore the creation and strategic deployment of parameters in FME Flow, including the use of deployment and geometry parameters, to maximize workflow efficiency.
- Pro Tips for Success: Gain insights on parameterizing connections and leveraging new features like Conditional Visibility for clarity and simplicity.
We’ll wrap up with a glimpse into future webinars, followed by a Q&A session to address your specific questions surrounding this topic.
Don’t miss this opportunity to elevate your FME expertise and drive your projects to new heights of efficiency.
2. All living things are made of
C
E
L
L
S
Longitudinal section of a root tip of Maize (Zea mays)
by Science and Plants for Schools on Flickr (CC) http://flic.kr/p/bNNM6M
3. All living things are made of
Unicellular organisms are singlecelled and can carry out all of the
functions of life independently.
Multicellular organisms have
specialized cells to carry out specific
functions.
C
E
L
L
S
Longitudinal section of a root tip of Maize (Zea mays)
by Science and Plants for Schools on Flickr (CC) http://flic.kr/p/bNNM6M
5. C
E
L
L
S
are the smallest
units of
life.
Specialized
structures within
cells (organelles) carry
out different functions.
Organelles cannot
survive alone.
Paramecium multimicronucleatum
by Proyecto Agua on Flickr (CC) http://flic.kr/p/7W7J3y
6. C come
only
E from
L existing
cells.
L
S
4-cell stage of a sea biscuit by Bruno Vellutini on Flickr (CC) http://flic.kr/p/daWnnS
7. C come
only
E from
L existing
cells.
L
S
Cells multiply through
division.
All life evolved from
simpler ancestors.
Mitosis results in
genetically identical diploid
daughter cells.
Meiosis generates haploid
gametes (sex cells).
Pasteur disproved the
theory of spontaneous
generation with his
experiments.
4-cell stage of a sea biscuit by Bruno Vellutini on Flickr (CC) http://flic.kr/p/daWnnS
8.
9. 1665
Hooke names “cells” in his book
“Micrographia” after observing
cork under a lense.
All living things
are made of cells.
Hooke’s Micrographia in full!
http://lhldigital.lindahall.org/cdm/ref/collection/nat_hist/id/0
10. All living things are
made of cells.
1676
van Leeuwenhoek, a master microscope maker identifies
“animalcules” and becomes the father of microbiology.
http://en.wikipedia.org/wiki/Antonie_van_Leeuwenhoek
11. 1833
Robert Brown names the cell nucleus.
Cells are the smallest units of life.
He also discovered Brownian motion:
Robert Brown: http://en.wikipedia.org/wiki/Robert_Brown_(botanist)
http://en.wikipedia.org/wiki/Brownian_motion
12. 1855
Robert Remak discovers cell division and confirms the existence
of the plasma membrane. Cells come only from pre-existing cells.
Robert Remak: http://en.wikipedia.org/wiki/Robert_Remak
13. 1864
Pasteur disproves the prevailing theory of “spontaneous
generation” with his swan-neck flask experiments.
Populations need to be seeded by existing populations: cells come
only from pre-existing cells.
Image from Amoeba Mike’s Blog (go read the original post): http://amoebamike.wordpress.com/2009/10/06/spontaneousgeneration-a-brief-history-of-disproving-it
14. Labeling the parts of the microscope activity:
http://www.biology.ualberta.ca/facilities/multimedia/uploads/intro-biology/microscope.html
15. Magnification
The image we see through
the light microscope has
been magnified.
Objective lens
x eyepiece lens
Image from wikimedia commons: http://commons.wikimedia.org/wiki/File:Microscope-blank.svg
17. Modern Microscopy
As we develop more and
more sophisticated and
precise imaging tools, we can
see more detail of the cells
and molecules that make us.
Scanning electron
microscopes deliver highresolution, 3D surface
images of structures,
whereas transmission
electron microscopes give us
a view inside cells and
organelles.
Image: d2540-6 by USDA on Flickr (CC): http://flic.kr/p/dPqvvY
19. Transmission electron micrograph of HIV particles.
120nm
HIV-1. Transmission electron micrograph, via wikimedia commons: http://commons.wikimedia.org/wiki/File%3AHIV1_Transmission_electron_micrograph_AIDS02bbb_lores.jpg
20. Scanning electron micrograph of HIV particles
budding on a human lymphocyte.
1μm
False-coloured scanning electron micrograph of HIV (green) budding on a lymphicoyte (blue)
http://en.wikipedia.org/wiki/File:HIV-budding-Color.jpg OR http://phil.cdc.gov/phil/details.asp?pid=10000
21.
22. Unicellular Organisms
carry out all the functions of life
M ovement
R espiration
S ensitivity
G rowth
R eproduction
E xcretion
N utrition
Paramecium bursaria
by Proyecto Agua on Flickr (CC) http://flic.kr/p/7WXdFz
23. Given the right conditions, cells can
survive outside their normal habitat.
Art from Petri dishes_1 by Image in Science and Art on Flickr (CC) http://flic.kr/p/838xjC
24. VIRUSES
Are they living or non-living?
Hmm…..
Image: Swine Flu H1N1 virus influenza 9.0 by hitthatswitch on Flickr (CC) http://flic.kr/p/74e4SP
25. Some units that I use & know
Unit abbr.
Metric equivalent
kilometer
km
1,000m
1 x 103m
meter
m
1m
1m
centimeter
cm
0.01m
1 x 10-2m
mm
0.001m
1 x 10-3m
millimeter
micrometer
nanometer
μm
nm
write this correctly
0.000 001m
0.000 000 001m
1x
10-6m
1x
10-9m
μm = micrometers
We usually use this in discussion of cells.
There are 1,000μm in one mm.
X 1,000
÷1,000
÷1,000
÷1,000
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38. 50μm
Human egg cell, from Gray’s Anatomy (1858). http://commons.wikimedia.org/wiki/Gray%27s_Anatomy_plates
39. 5μm
Human sperm cell, from Gray’s Anatomy (1858). http://commons.wikimedia.org/wiki/Gray%27s_Anatomy_plates
40. Scanning electron micrograph of
human sperm and egg cells.
5μm
Image from wikimedia commons http://en.wikipedia.org/wiki/Spermatozoon
41. Which dissolves faster: sugar
cubes or sugar crystals? Why?
Sugar Cubes by Uwe Hermann on Flickr (CC) http://flic.kr/p/cFMMc
42. What will go cold faster: French
fries or a baked potato? Why?
French Fries by Ian Britton on Flickr (CC) http://flic.kr/p/6RLQ8j
43. Which makes green tea faster: tea leaves or powder?
Matcha Latte by Cupcake Murder Aftermatch on Flickr (CC) http://flic.kr/p/fCkpb5
44. What type of crisps
delivers more
flavour:
regular-cut
or
crinkle-cut?
Why?
Smiths Plain Chips by Penguin Cakes on Flickr (CC) http://flic.kr/p/5ygb8v
45. IN:
Oxygen
Nutrients
Water
The plasma membrane
of a cell is the surface of
exchange for materials
between the inside and
the outside of the cell.
OUT:
Carbon dioxide
Waste
Products (e.g. proteins)
http://commons.wikimedia.org/wiki/Sphere
46. As the cell gets larger, it requires
more resources to be imported and
produces more products (and waste)
to be exported.
Therefore, a larger volume requires
more exchange across the membrane.
http://commons.wikimedia.org/wiki/Sphere
47. As the cell gets larger…
http://commons.wikimedia.org/wiki/Sphere
48. As the cell gets larger…
…the surface area to
volume ratio
actually gets
smaller…
http://commons.wikimedia.org/wiki/Sphere
49. As the cell gets larger…
…the surface area to
volume ratio
actually gets
smaller…
…so the
exchange
processes
become less
efficient with
increasing size.
http://commons.wikimedia.org/wiki/Sphere
50. Diffusion Pathways
are shorter (and
more efficient)
in
with a larger
surface are to
volume ratio.
http://commons.wikimedia.org/wiki/Sphere
51.
52.
53. C
E
L
L
S
D
I
V
I
D
E
Surface are to volume ratio
is a factor that limits the
size of cells.
By dividing to make more,
smaller cells, the efficiency
of the exchange processes
across the membranes (into
and out of the cells) can be
kept high.
Shorter diffusion paths.
More surfaces for reactions.
Removal of heat and waste
4-cell stage of a sea biscuit by Bruno Vellutini on Flickr (CC) http://flic.kr/p/daWnnS
54. Structure/Function
Natural selection favours adaptations that give an advantage.
Folded structures are everywhere in nature, maximising the surface
area to volume ratio for exchange of materials.
Mammalian liver mitochondria: http://commons.wikimedia.org/wiki/File:Mitochondria,_mammalian_lung_-_TEM_(2).jpg
55. Big Cell Exceptions
Caulerpa species of algae are
one giant cell with many
nuclei distributed throughout.
http://en.wikipedia.org/wiki/Caulerpa
56. Big Cell Exceptions
Epulopiscium is a giant
species of bacteria. Read
more about it here:
NotExactlyRocketScience.
E. coli
100μm
Epulpoiscium, by AJ Cann on Flickr (CC) http://flic.kr/p/4Nzq9t
57. Is maximising surface area to volume
ratio always an advantage?
Free images from: Presentations ETC, University of Florida. http://etc.usf.edu/presentations/
58. Two Minute Essay
Explain the importance of surface area to
volume ratio as a factor limiting cell size.
Free images from: Presentations ETC, University of Florida. http://etc.usf.edu/presentations/
59. Exploration: which cools faster?
Add 30ml hot water to a small cup and to a petri dish.
Predict: Will one cool faster? Why?
Record: Take the temperature of each one every minute.
Describe or plot the results.
30ml
30ml
61. Emergent Properties
the whole is
more than the sum
of its parts
Photo by Stephen Taylor: http://www.flickr.com/photos/gurustip/9668701965/in/photostream
62.
63.
64.
65. Stem Cells
A cluster of nascent retinae generated from 3D embryonic stem cell cultures, by UCL News on Flickr (CC): http://flic.kr/p/ffPBPT
66. A Stem Cell Story
http://www.youtube.com/watch?v=2-3J6JGN-_Y
67. Stem Cells retain the capacity to divide and can
differentiate along divergent pathways.
Totipotent
Can differentiate into any type
of cell.
Pluripotent
Can differentiate into many
types of cell.
Multipotent
Can differentiate into a few
closely-related types of cell.
Unipotent
Can regenerate but can only
differentiate into their
associated cell type
(e.g. liver stem cells can only
make liver cells).
Image from: http://en.wikipedia.org/wiki/Stem_cell
68. Stem Cells retain the capacity to divide and can
differentiate along divergent pathways.
By Fwfu at en.wikibooks [Public domain], from Wikimedia Commons
http://commons.wikimedia.org/wiki/File%3AStemcelldifferentiaion.jpg
69. Stem Cells retain the capacity to divide and can
differentiate along divergent pathways.
Screenshot from this excellent tutorial: http://www.ns.umich.edu/stemcells/022706_Intro.html
70. Differentiation (specialization) of cells:
All diploid (body) cells have the same chromosomes.
So they carry all the same genes and alleles.
BUT
Not all genes are expressed (activated) in all cells.
The cell receives a signal.
This signal activates or deactivates genes.
Genes are expressed accordingly and the cell is committed.
Eventually the cell has become specialized to a function.
Key Concept: Structure vs Function
How do the structures of specialized cells reflect their
functions? How does differentiation lead to this?
Screenshot from this excellent tutorial: http://www.ns.umich.edu/stemcells/022706_Intro.html
71. Therapeutic Uses of Stem Cells
Treatment for Leukemia
Problem
Treatment
Chemotherapy and radiotherapy can be used
to destroy the white blood cells, but these
need to be replaced with healthy cells. Bone
marrow transplants are often used for this.
Role of
Stem Cells
From:
Cancer of the blood or bone marrow,
resulting in abnormally high levels of poorlyfunctioning white blood cells.
Hematopoetic Stem Cells (HSCs) can be
harvested from bone marrow, peripheral
blood or umbilical cord blood. As these can
differentiate to form any type of white blood
cell, they can be used to repopulate the bone
marrow and produce new, healthy blood cells.
The use of a patient’s own HSCs means there
is far less risk of immune rejection than with a
traditional bone marrow transplant.
http://en.wikipedia.org/wiki/Pluripotential_hemopoietic_stem_cell
Animation of this process:
Animated tutorials from: http://outreach.mcb.harvard.edu/animations/thera7c.swf
72. Two Minute Essay
What is a stem cell?
How do stem cells differentiate into specialized cells?
Outline one therapeutic use of stem cells.
Free images from: Presentations ETC, University of Florida. http://etc.usf.edu/presentations/
73.
74.
75. For more resources & links
including many on Stem Cells.
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