Unit 2: Cell Structure and Function
Reading
Homework
Various handouts are posted near the bottom. Don't do them unless they're assigned in Canvas.
Labs
We will do what we have time to do:
- BJU Biology: Ch. 3 "Introduction to Cells"
- AP: OpenStax "Biology": Ch. 4 "Cell Structure" & Ch. 5 "Structure and Function of Plasma Membranes"
- OpenStax (orange) "Concepts of Biology": Ch. 3 - "Cell Structure & Function"
Homework
Various handouts are posted near the bottom. Don't do them unless they're assigned in Canvas.
Labs
We will do what we have time to do:
- Sheep's Heart Dissection: We have successfully used this lab for years as a launching pad for cells, tissues, components of blood, and the circulatory system. Plus it's a fun dissection!
- Diagnosing Diabetes lab. This is an excellent platform for learning cell structure and function.
- Enzyme Activity lab (fulfills AP lab #13). Looks at the enzyme 'Catalase' and the effects of concentration and pH.
| 3._cells_lecture_notes_2021.docx |
| cellstructfunct slides - (best?) |
| Cell Structure & Function slides.pptx |
Below: "Cell City" - it's helpful to think of the cell's components as parts of a city or factory
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Pancreas diagram by a former student: We will studying diabetes and the pancreas in our Diagnosing Diabetes lab, which is a really good platform to learn about cell transport systems.
Lecture Outline - part 1 (cell structure and function)
Every living thing is made of cells. This is quite amazing when you begin to learn what goes on in a cell! The Englishman Robert Hooke coined the term "cell" in 1665 as he was viewing cork cells under an early microscope with only 30X magnification (cork cells are big cells). A Dutch shopkeeper named Van Leeuwenhoek read Hooke's report, and by making himself some improved lenses in his eyeglass shop(!) was able to see microbes in pond water. By the 1800's, it was realized that the cell was the basic unit of life (Schleiden & Schwann).
Every living thing is made of cells. This is quite amazing when you begin to learn what goes on in a cell! The Englishman Robert Hooke coined the term "cell" in 1665 as he was viewing cork cells under an early microscope with only 30X magnification (cork cells are big cells). A Dutch shopkeeper named Van Leeuwenhoek read Hooke's report, and by making himself some improved lenses in his eyeglass shop(!) was able to see microbes in pond water. By the 1800's, it was realized that the cell was the basic unit of life (Schleiden & Schwann).
Living things are built from cells; this applies equally to humans, whales, finches, and corn plants
- The "Cell Theory" states
- The cell is the basic unit of all living things
- Cells perform all the functions of living things
- New cells are manufactured by existing cells
- Each of your trillions of cells can be viewed as a 'factory' or a 'city' (see student diagram above). This will become clear in the next two lessons!
- Cells are enclosed within a semipermeable membrane (plasma membrane) which allows only certain substances in-and-out of the cell.
- The plasma membrane is called a phospholipid bilayer, it is flexible (fluid), and it is crowded with numerous, large protein molecules which function as pumps, tunnels, docking stations, receptor sites, identification markers, and various machines/mechanisms which communicate with the cell's environment.
- Plant cells also have a rigid 'cell wall' comprised of cellulose, in addition to their plasma membrane. The cellulose cell-wall on the outside is what gives plants "rigidity".
- There are two basic types of cells, Prokaryotic and Eukaryotic:
- "Prokaryotic" cells are the Domains 'bacteria' and 'archaea', and don't have membrane-bound organelles. They are 'simple' cells.
- "Eukaryotic" cells are the animal and plant kingdoms, and have a nucleus and numerous membrane-bound organelles. Thus, Eukaryotic cells are more complex than Prokaryotic cells.
- Common "organelles" inside Eukaryotic cells include the nucleus, endoplasmic reticulum (ER), Golgi Apparatus, mitochondria, vesicles, vacuoles.
- Other important components of the cell include the cytoskeleton (microtubules and microfilaments), chromosomes (DNA), ribosomes, RNA, motor proteins, centrosome, nucleolus, flagella and cilia, etc.
- The contents of a cell are called the "cytoplasm". If you don't count the organelles, the watery contents are called the "cytosol".
Lecture outline - part 2 (the membrane and cell transport systems)
You are made of trillions of cells. Each of your cells is a complex factory: for example, your muscle cells must contract-and-release using a biochemical-ratcheting mechanism, your nerve cells must pass electrical signals to each other, your pancreas cells must manufacture a protein called 'insulin', your red blood cells must manufacture a molecule called 'hemoglobin' so they can carry oxygen, and so on.
Cells must 'communicate' with other cells and with their environment. For example, the cell membrane (plasma membrane) must be able to allow-in certain molecules - while preventing others from entering, and it must pump-out certain molecules - while preventing others from leaving. As a simple example, all animal cells need to let-in glucose and oxygen for fuel purposes, and then let-out carbon dioxide (CO2) and water as waste products. In addition, cells in an organism are always surrounded by water and minerals. The minerals are things like sodium, calcium, potassium, chloride, and so on. A cell must be able to pump certain minerals in-and-out of its plasma membrane in order to maintain the proper concentration inside the cell. Think: every nerve cell in your body is constantly pumping sodium and potassium in-and-out to generate the electrical impulses needed to blink your eyes and keep your heart pumping. Other cells are simply trying to maintain the proper concentration of minerals in order to function.
You are made of trillions of cells. Each of your cells is a complex factory: for example, your muscle cells must contract-and-release using a biochemical-ratcheting mechanism, your nerve cells must pass electrical signals to each other, your pancreas cells must manufacture a protein called 'insulin', your red blood cells must manufacture a molecule called 'hemoglobin' so they can carry oxygen, and so on.
Cells must 'communicate' with other cells and with their environment. For example, the cell membrane (plasma membrane) must be able to allow-in certain molecules - while preventing others from entering, and it must pump-out certain molecules - while preventing others from leaving. As a simple example, all animal cells need to let-in glucose and oxygen for fuel purposes, and then let-out carbon dioxide (CO2) and water as waste products. In addition, cells in an organism are always surrounded by water and minerals. The minerals are things like sodium, calcium, potassium, chloride, and so on. A cell must be able to pump certain minerals in-and-out of its plasma membrane in order to maintain the proper concentration inside the cell. Think: every nerve cell in your body is constantly pumping sodium and potassium in-and-out to generate the electrical impulses needed to blink your eyes and keep your heart pumping. Other cells are simply trying to maintain the proper concentration of minerals in order to function.
- Homeostasis means "steady-state". All cells - and organisms - have feedback mechanisms to maintain the proper chemical balance within their environment. A simple example is tonicity - a cell will strive to maintain the proper balance of minerals, by passing or pumping minerals through its cell membrane.
- Cells are bathed in a solution of water and minerals. Water will diffuse in and out of the cell, depending on the surrounding concentration of minerals. The movement of water across a membrane due to concentration differences is known as osmosis.
- If a cell is placed in too-salty water, the situation is called hypertonic. (hyper = excessive). Water will then diffuse out of the cell, leaving a shriveled-up cell.
- If a cell is placed in too-pure water, the situation is called hypotonic. (hypo = less than normal). Water will then diffuse into the cell, resulting in a burst cell.
- When the salt concentration is the same inside and outside the cell, the situation is called isotonic. (iso = equal). Since there is no concentration gradient, there will be no net change in water in or out of the cell.
- In addition - food, waste products, and gases must continually pass through - or be pumped through - the cell membrane.
- Passive transport requires no energy expenditure and is driven simply by the concentration gradient inside and outside. Important gases (O2, CO2, N2) will simply diffuse across the cell membrane in this way.
- Facilitated diffusion requires the help of transport proteins embedded in the cell membrane. Larger molecules like water, amino acids, and sugars require this method to get across the cell membrane. Ionic salts also cross over using transport proteins - also called "channel proteins". These transport proteins actually carry the molecules across the cell membrane by binding to them, changing shape, and releasing them on the other side of the membrane. It's a type of pumping mechanism, and the energy input comes from the concentration gradient itself.
- Active transport can go against the concentration gradient, and is carried out by transport proteins which function as pumps mounted in the cell membrane. Since these proteins actively pump molecules against their concentration gradient (pumping the molecules "uphill"), they require energy input usually supplied by ATP. The sodium/potassium (Na/K) pumps in your nerve cells are a good example.
- Bulk transport: larger molecules such as proteins and carbohydrates are transported across cell membranes by endocytosis (in) and exocytosis (out).
- Endocytosis (transport in) is where the cell membrane - or a vacuole membrane - surrounds and traps molecules-of-interest, and encapsulates them. Then it can move them around and digest them or do whatever it's going to do with them.
- Exocytosis (transport out) is where the cell builds a membrane-bound vesicle around molecules-of-interest, and transports the whole 'package' out to the plasma membrane where it is emptied out onto the surface of the cell.
Cell Membrane videos
We will view some of these in class. Watch the rest of them on your own! They are short, just a few minutes each, and will give you a mental picture of what is going on in the cell membrane.
We will view some of these in class. Watch the rest of them on your own! They are short, just a few minutes each, and will give you a mental picture of what is going on in the cell membrane.
Sheep's heart dissection lab
The lab report for the heart dissection involves taking *very good pictures* and then presenting them in an organized portfolio, with certain features identified with labels, boxes, and arrows. See the lab report instructions. Due date is on Canvas.
Important: Bring to the lab
The lab report for the heart dissection involves taking *very good pictures* and then presenting them in an organized portfolio, with certain features identified with labels, boxes, and arrows. See the lab report instructions. Due date is on Canvas.
Important: Bring to the lab
- A camera, or a smart phone with a camera.
- The lab handout below.
- The lab report instructions below.
| Lecture Slides: The Heart and Circulatory System |
| 4._heart_dissection_lab_handout_2021.pdf |
| 4._heart_dissection_lab_report_instructions_2021.docx |
Diagnosing Diabetes lab
Diabetes serves as an excellent launching pad for understanding cells & membranes, signaling molecules, and membrane transport mechanisms.
Diabetes serves as an excellent launching pad for understanding cells & membranes, signaling molecules, and membrane transport mechanisms.
| Diagnosing_diabetes_complete_lab_handout.pdf |
"Cell Factory" assignment
Look at the student examples from prior years. DO YOUR OWN WORK.
Look at the student examples from prior years. DO YOUR OWN WORK.
| 3._cell_factory_assignment_2021.docx |
| cell_city-factory-student_exemplars_.pdf |
| More cell city_student_exemplars_.pdf |
| cell_planet_student_exemplar.pdf |
Cardiology Virtual Lab
Simulation: www.biointeractive.org/classroom-resources/cardiology-virtual-lab
Instructions:
- Complete the virtual lab. Turn in the completed quiz which is contained in the simulation.
- Turn in the completed heart quiz, below.
| _heart_quiz_.pdf |
Virtual Heart Surgery lab (Note: as of 1/1/2021 Adobe Flash is blocked on all major browsers, so this simulation is temporarily inactive)
Complete parts 1 and 2 and turn-in together
Complete parts 1 and 2 and turn-in together
- Virtual Heart Surgery
- Heart quiz (you can use the Internet and all the resources on this page to complete this - Khan Academy video, heart lecture slides below, etc)
| _virtual_heart_surgery_assignment1.docx |
"Heart & Circulatory System" presentation
Presentation topic: "The Heart and Circulatory System".
This is to be a 5-6 minute PowerPoint presentation which you will give at an upcoming class. You can use PowerPoint, Google Slides, Prezi, and so on.
Read the detailed instructions for "class presentations" posted in Canvas under the "Heart and Circulatory System" assignment. I'm not going to repeat these for each & every presentation we do in this class, so bookmark them or copy them somewhere so you can refer back to them.
Your presentation should be suitable for a Biology class. Use correct Biology terms. Examples: you can make your presentation on things such as heart disease, pacemakers, artificial hearts, blood-borne infectious diseases (HIV, hepatitis B or C), how smoking and alcohol affect the heart, how SARS CoV-2 affects the heart and circulation, how the Covid-19 vaccines might affect the heart, recent developments in heart valves, how heart muscles work, the heart’s electrical system, cardiac tissue engineering, Sickle Cell Anemia, Leukemia, other diseases of the blood, new drugs or drugs under development, and so on.
Presentation topic: "The Heart and Circulatory System".
This is to be a 5-6 minute PowerPoint presentation which you will give at an upcoming class. You can use PowerPoint, Google Slides, Prezi, and so on.
Read the detailed instructions for "class presentations" posted in Canvas under the "Heart and Circulatory System" assignment. I'm not going to repeat these for each & every presentation we do in this class, so bookmark them or copy them somewhere so you can refer back to them.
Your presentation should be suitable for a Biology class. Use correct Biology terms. Examples: you can make your presentation on things such as heart disease, pacemakers, artificial hearts, blood-borne infectious diseases (HIV, hepatitis B or C), how smoking and alcohol affect the heart, how SARS CoV-2 affects the heart and circulation, how the Covid-19 vaccines might affect the heart, recent developments in heart valves, how heart muscles work, the heart’s electrical system, cardiac tissue engineering, Sickle Cell Anemia, Leukemia, other diseases of the blood, new drugs or drugs under development, and so on.
| Heart & Circulatory System presentations - student examples |