What are some of the specialized cells found in animals and plants? Watch this video to discover more about specialized cells and tissues.
Lesson B7: Specialized Cells and Tissues
Figure B.2.7.1 β HeLa cells have been used for many kinds of medical research.
Figure B.2.7.2 β Scientists grow HeLa cells in research laboratories.
Figure B.2.7.3 β HeLa cells just after division.
Reading and Materials for This Lesson
Science in Action 8
Reading: Pages 120β124
Materials:
No additional materials are needed for this lesson.
Immortal HeLa Cells
Figure B.2.7.4 β A rare photo of Henrietta Lacks.
To carry out fair and repeatable medical research experiments, scientists require human cells that can stay alive and keep reproducing. Most human cells outside the body die in just a few days.
In the early 1950βs, a medical researcher observed some cancer tumor cells that kept living and reproducing outside of a human body. The tumor cells originally came from a woman named Henrietta Lacks, who died from her cancer. The reproducing tumor
cells were named HeLa after her.
Her contribution to science was not without controversy. Her cells were used without her permission, and neither Henrietta nor her family ever received any compensation for the use of her cells. Even though the cells were named after her, nobody knew
that βHeLaβ was short for βHenrietta Lacksβ until many years after her death.
HeLa cells that reproduced from that tumor are still alive today. HeLa cells are used to research and treat diseases. They were used to find a treatment for paralyzing polio disease, and are currently being used to research diseases like cancer.
Watch More
Henrietta Lacks and her Immortal Cells
Watch this video to learn more about HeLa cells and how they are used in scientific research.
Figure B.2.7.5 β Human life starts as stem cells.
Figure B.2.7.6 β One cell splits to form two new cells for growth or to repair damaged cells.
Figure B.2.7.7 β Stem cells can reproduce to form different specialized cells.
1 β 2 β 4 β 8 β 16 β 32 β
Humans start out as a single cell. How does a single cell reproduce to create all the different kinds of specialized cells found in people?
The first cells that eventually form a new human are called embryonic stem cells. Embryonic stem cells contain instructions to reproduce into specialized cells. Embryonic stem cells start changing into specialized cells several days after the first
cell forms.
Stem cells are also found in adult organ systems, but they are harder to isolate. Adult stem cells change into specialized cells to fix and regenerate dead or damaged cells. While embryonic stem cells can reproduce into any type of specialized cell
under the right conditions, adult stem cells belong to a specific organ system. For example, bone marrow contains lots of stem cells. Bone marrow stem cells reproduce into different types of specialized blood cells, like red and white blood cells.
Lesson Activity
Stem Cell Research
Both embryonic and adult stem cells are used in scientific research. However, the use of stem cells for research is controversial. Some people think it is morally wrong to use embryonic stem cells for scientific research.
In this activity, you will watch videos and record information about stem cell research.
Instructions:
ο»ΏYou need to choose a method of recording the information you collect about stem cell research. You can make
a mind map, a table, a list, or another method of your choice.
As you work through the activity, you need to find out information about the following aspects of stem cell research:
What are embryonic stem cells and how are they useful for research?
What are adult stem cells and how are they useful for research?
What are some benefits of stem cell research?
Why are some people opposed to stem cell research?
What are some recent research breakthroughs in stem cell research?
Watch the following videos. As you watch the videos, listen for examples and details about the aspects of stem cell research listed in step two (above). Pause the video when you hear relevant information and record it.
ο»ΏThis video explains embryonic stem cells.
This video explains induced pluripotent stem cells.
These videos provide an overview of stem cells and their applications in medical treatments and research.
Adult stem cells can be used to repair diseased organs. Watch these videos to learn more.
These videos explain the controversy around embryonic stem cell research.
Stem cells can be collected from umbilical cord blood when babies are born. Watch this news report to learn more.
Watch this video to learn how some new stem cell research might reduce the controversy around it.
After you have finished watching the videos and collecting information, answer and record this question:
What do you personally think about stem cell research, and why? Explain your answer in detail.
Sharing:
Congratulations on completing this stem cell research activity! Your teacher and other students would be interested in your thoughts and the notes you collected on stem cell research. They would especially be interested in hearing
your opinions. Consider sharing your notes and thoughts in the course Sharing Forum. You can also email your stem cell research notes and thoughts
to your teacher and ask for feedback.
Figure B.2.7.9 β Growing tissues in a lab may heal people affected by illness.
Figure B.2.7.10 β Some of the meat we eat could one day be produced in a laboratory.
Connections β Technology >> Growing Body Tissues
Body tissues grown in a lab have the potential to help heal people suffering from illnesses. For example, burn survivors usually require a skin graft to cover and heal severely burned skin. Skin grafts involve taking skin from an unaffected part of
the patientβs body. The process is painful and causes scarring. Researchers hope to eventually grow new skin tissue in the lab to cover burns.
An interesting application of growing body tissues is growing animal muscle tissue for edible meat. Using animals for meat is not sustainable as Earthβs population gets larger. Animals like cows, chickens, and pigs use far more land and water than
what is required for growing vegetables and grains. Animals also produce a lot of greenhouse gases that contribute to climate change. Growing meat in a lab might eventually solve these problems.
Watch More
Growing Body Tissues
Watch this video to learn more about medical research on growing new human tissues and organs.
Would you eat a hamburger grown in a lab? Watch these videos to learn more about lab-grown animal tissues for meat.
Make sure you have understood everything in this lesson. Use the Self-Check below, and the Self-Check & Lesson Review Tips to guide your learning.
Unit B Lesson 7 Self-Check
Instructions
Complete the following 6 steps.
Don't skip steps β if you do them in order, you will confirm your
understanding of this lesson and create a study bank for the future.
ANSWER all the questions on the downloaded quiz in the spaces provided. Think carefully before typing your answers. Review this lesson if you need to. Save your quiz when you are done.
COMPARE your answers with the suggested "Self-Check Quiz Answers" below. WAIT! You didn't skip step 2, did you? It's very important to carefully write out your own answers before checking the suggested answers.
REVISE your quiz answers if you need to. If you answered all the questions correctly, you can skip this step. Revise means to change, fix, and add extra notes if you need to. This quiz is NOT FOR MARKS, so it is perfectly OK to correct
any mistakes you made. This will make your self-check quiz an excellent study tool you can use later.
SAVE your quiz to a folder on your computer, or to your Private Files. That way you will know where it is for later studying.
CHECK with your teacher if you need to. If after completing all these steps you are still not sure about the questions or your answers, you should ask for more feedback from your teacher. To do this, post in the Course Questions Forum,
or send your teacher an email. In either case, attach your completed quiz and ask; "Can you look at this quiz and give me some feedback please?" They will be happy to help you!
Be a Self-Check
Superhero!
Self-Check Quiz Answers
Click each of the suggested answers below, and carefully compare your answers to the suggested answers.
If you have not done the quiz yet β STOP β and go back to step 1 above. Do not look at the answers without first trying the questions.
Individual cells in multicellular organisms are too small to perform complex functions on their own. Joining with other cells to form tissues and organs allows cells to work together to perform more complex functions.
Connective tissue holds tissues close together in organs. Epithelial tissue coats the surface of organs, providing protection. Nervous tissue sends signals between tissues and organs. Muscle tissue causes tissues and organs to move.
Embryonic stem cells can turn into any kind of specialized cell. This makes it possible to grow any type of human tissue from an embryonic stem cell, for research or regeneration of body organs.
Examples of cells in the circulatory system are red blood cells and white blood cells. Examples of tissues that have a specific function in the circulatory system are heart muscle tissue and blood. An example of an organ in the circulatory system
is the heart.
Photosynthetic tissue makes food for plants. Protective tissue supports and protects the plant. Transport tissue moves water and nutrients to different parts of the plant.
Reading and Materials for This Lesson
