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9.3: Lab 9 Assignment: Collection Register - Biology

9.3: Lab 9 Assignment: Collection Register - Biology


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9.3: Lab 9 Assignment: Collection Register

Making Better Poison Eaters: Metabolic Engineering for Bioremediation

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Space Science Programs Grades K-12

The Virginia Living Museum’s Space Science Programs are out of this world! Inside the digital Abbitt Planetarium theater, students will make important connections to essential space science SOLs as they explore the solar system, travel to distant galaxies and marvel at the mysterious celestial objects in our own night sky.

Length of Session: 45 minutes
Number of Students: 30 maximum
Fee: (includes self guided tour of exhibits)
Contract Schools: Please call for information
Non-contract schools: $12.50 per student ($212.50 minimum September – February, $375 minimum March – June)
Classroom teacher and school staff are free. One chaperone is recommended for every 10 students and is admitted free. Additional chaperones are $18 each.

For more information or to make a reservation, call the Reservations Coordinator at 757-595-9135 Monday-Friday, 9am – 4:30pm or complete the online request form.

Funded in part by Langley Federal Credit Union.

Virginia Skies

Grades K-12
SOLs vary by grade level
Explore the evening skies above Virginia in this classic planetarium presentation. Students view the planetarium’s night sky while a staff astronomer discusses seasonal constellations, visible planets and other celestial happenings around the time of your visit. This program can be tailored for any grade level and is especially effective for introducing kindergarteners to the planetarium experience.

Day and Night

Grades K-1
Science SOLs K.8, K.10, 1.6, 1.7
Discover the importance of Earth’s shadow as a staff astronomer takes you on a journey from Day to Night.

Stacey Stormtracker

Grades 2-4
Science SOLs 2.6, 2.7, 3.8, 3.9, 3.11, 4.6, 4.7
Journey through the solar system and learn all about the forces behind our home planet’s weather.

The Skies of Jamestown

Grades 2-4
History and Social Science SOLS 2.2, 2.6, VS.1, VS.2, VS.3
Discover the dangers of ocean travel in the early 1600s and learn how important the stars were to two cultures.

Assignment Earth

Grades 3-4
Science SOLs 3.8, 3.9, 3.11, 4.8
See the Earth through alien eyes as we learn about Moon phases, tides, Earth motions, seasons, and more.

Reasons for the Seasons

Grades 3-4
Science SOLs 3.8, 3.11, 4.8
Witness the power of the tilt of the Earth as one of our staff astronomers helps you explore the reasons for the seasons.

Worlds in Motion

Grades 4-6
Science SOLs 4.7, 4..8, 6.8
Explore why objects move across the skies of Earth, why Pluto is no longer a major planet, how fast you are moving when you’re sitting still and other amazing topics…all connected by these worlds in motion.

Two Small Pieces of Glass

Grades 5-12
Science SOLs 5.3, 6.8, PS.9, ES.3
Originally produced in celebration of the 400th anniversary of Galileo’s groundbreaking work with his telescope, this program takes your students on a journey through the history of telescopes, how they are made, and how they have helped astronomers make so many astounding discoveries about the universe. A brief look at the current night sky is included.

Oasis in Space

Grades 6-12
Science SOLs 6.8, ES.3
Discover the uniqueness of our home planet as we tour through the solar system, seeking that most basic necessity for life – water. Does water exist elsewhere in the solar system? Can life survive beyond the confines of Earth? These questions and more will be discussed in this visually stunning program about the origins and nature of the worlds that surround us.


9.3: Lab 9 Assignment: Collection Register - Biology

There are four grain phenotypes in the above ear of genetic corn: Purple & Smooth (A) , Purple & Shrunken (B) , Yellow & Smooth (C) and Yellow & Shrunken (D) . These four grain phenotypes are produced by the following two pairs of heterozygous genes ( P & p and S & s ) located on two pairs of homologous chromosomes (each gene on a separate chromosome):

Dominant Genes Recessive Genes
P = Purple p = Yellow
S = Smooth s = Shrunken

The following Table 1 shows a dihybrid cross between two heterozygous parents ( PpSs X PpSs ). The four gametes of each parent are shown along the top and left sides of the table. This cross produced the ear of genetic corn shown at the top of this page. Table I is essentially a genetic checkboard called a Punnett square after R.C Punnett, a colleague of William Bateson who devised this method. In 1900, English Geneticist William Bateson had Gregor Mendel's original 1865 paper on the genetics of garden peas translated into English and published. Thus Mendel became known to the entire scientific world. Bateson is also credited with the discovery of gene linkage in 1905.

Table 1. This table shows four different phenotypes with the following fractional ratios: 9/16 Purple & Smooth (blue), 3/16 Purple & Shrunken (red), 3/16 Yellow & Smooth (green), and 1/16 yellow and shrunken (pink). There are nine different genotypes in the table: PPSS (1), PPSs (2), PpSS (2), PpSs (4), PPss (1), Ppss (2), ppSS (1), ppSs (2) and ppss (1). You can easily calculate the number of different phenotypes and genotypes in a dihybrid cross using the following formulae:

2. Sample Chi Square Problem

Chi Square Problem: An ear of corn has a total of 381 grains, including 216 Purple & Smooth, 79 Purple & Shrunken, 65 Yellow & Smooth, and 21 Yellow & Shrunken. These phenotypes and numbers are entered in Columns 1 and 2 of the following Table 2.

Your Tentative Hypothesis: This ear of corn was produced by a dihybrid cross (PpSs x PpSs) involving two pairs of heterozygous genes resulting in a theoretical (expected) ratio of 9:3:3:1. See dihybrid cross in Table 1.

Objective: Test your hypothesis using chi square and probability values. In order to test your hypothesis you must fill in the columns in the following Table 2.

1. For the observed number (Column 2), enter the number of each grain phenotype counted on the ear of corn.

2. To calculate the observed ratio (Column 3), divide the number of each grain phenotype by 21 (the grain phenotype with the lowest number of grains).

3. For the expected ratio (Column 4), use 9:3:3:1, the theoretical ratio for a dihybrid cross. The fractional ratios for these four phenotypes are 9/16, 3/16, 3/16 and 1/16.

4. To calculate the expected number (Column 5), multiply the number of each grain phenotype by the expected fractional ratio for that grain phenotype.

5. In the last column (Column 6), for each grain phenotype take the observed number of grains (Column 2) and subtract the expected number (Column 5), square this difference, and then divide by the expected number (Column 5). Round off to three decimal places.

6. To calculate the chi square value, add up the four decimal values in the last column (Column 6).

7. Degrees Of Freedom: Number of phenotypes - 1. In this problem the number of phenotypes is four therefore, the degrees of freedom (df) is three (4 - 1 = 3). In the following Table 3 you need to locate the number in row three that is nearest to your chi square value of 1.80.

8. Probability Value: In the following Table 3, find the number in row three that is closest to your chi square value of 1.80. In this table 1.85 (shaded in yellow) is the closest number. Then go to the top of the column and locate your probability value. In this case the probability value that lines up with 1.85 is .60 (shaded in yellow). This number means that the probability that your hypothesis is correct is 0.60 or 60 percent. The probability that your hypothesis is incorrect is 0.40 or 40 percent.

3. A Chi Square Problem For Credit

Chi Square Problem: A large ear of corn has a total of 433 grains, including 271 Purple & Smooth, 73 Purple & Shrunken, 63 Yellow & Smooth, and 26 Yellow & Shrunken. These numbers are entered in Columns 1 and 2 of the following Table 4.

Your Tentative Hypothesis: This ear of corn was produced by a dihybrid cross (PpSs x PpSs) involving two pairs of heterozygous genes resulting in a theoretical (expected) ratio of 9:3:3:1. See dihybrid cross in Table 1.

Objective: Test your hypothesis using chi square and probability values. In order to test your hypothesis you must fill in the columns in the following Table 4.

1. For the observed number (Column 2), enter the number of each grain phenotype counted on the ear of corn. [Note: These numbers are already entered in Table 4.]

2. To calculate the observed ratio (Column 3), divide the number of each grain phenotype by 26 (the grain phenotype with the lowest number of grains).

3. For the expected ratio (Column 4), use 9:3:3:1, the theoretical ratio for a dihybrid cross.

4. To calculate the expected number (Column 5), multiply the number of each grain type by the expected fractional ratio for that grain phenotype. The fractional ratios for these four phenotypes are 9/16, 3/16, 3/16 and 1/16.

5. In the last column (Column 6), for each grain phenotype take the observed number of grains (Column 2) and subtract the expected number (Column 5), square this difference, and then divide by the expected number (Column 5). Round off to three decimal places.

6. To calculate the chi square value, add up the four decimal values in the last column (Column 6).

7. Degrees Of Freedom: Number of phenotypes - 1. In this problem the number of phenotypes is four therefore, the degrees of freedom (df) is three (4 - 1 = 3). In the following Table 5 you need to locate the number in row three that is nearest to your chi square value.

8. Probability Value: In the following Table 5, find the number in row three that is closest to your chi square value. For an explanation of how to find and interpret the probability value, go back to the previous example.

4. Chi Square Table Of Probabilities

5. Chi Square Quiz # 1 Scantron Questions

1. What is the chi square value? [Use Chi Square Choices]

2. What is the probability value? [Use Probability Decimal Choices]

3. Is There a GOOD or POOR fit between your hypothesis and your data? I.e. is the probability value within acceptable limits?

4. What is the percent probability that your hypothesis is correct? I.e. the observed ratio of grains in the ear of corn represents a dihybrid cross involving two pairs of heterozygous genes (PpSs X PpSs). [Use The Percent Probability Choices]

5. What is the percent probability that the observed ratio of grains in the ear of corn deviates from the expected 9:3:3:1 due to an incorrect hypothesis? I.e. your ear of corn does NOT represent a dihybrid cross involving two pairs of heterozygous genes (PpSs X PpSs). [Use The Percent Probability Choices]

6. The following question refers to a cross involving linkage, where the genes P & s are linked to the same chromosome, and the genes p & S are linked to the homologous chromosome. Refer to Section 7 below. What percent of the grains from this cross will be purple and smooth? [Use The Percent Probability Choices]

6. Chi Square Quiz # 1 Scantron Choices

7. Possible Reasons For Incorrect Hypothesis

Reasons For Incorrect Hypothesis: If your probability value is .05 (5%) or less, then your ear of corn deviates significantly from the theoretical (expected) ratio of 9:3:3:1 for a dihybrid cross. A probability value of 5% or less is considered to be a poor fit. One possible reason for a poor fit is that your original ear of corn was not produced by a dihybrid cross (PpSs X PpSs). The original parents may have had different genotypes, such as PpSS or PPSs. These genotypes when crossed together will not produce a 9:3:3:1 ratio typical of a true dihybrid cross. Another reason for an incorrect hypothesis might be due to linkage (autosomal linkage), where more than one gene is linked to the same chromosome. For example, what if the genes P & s are linked to a maternal chromosome and the genes p & S are linked to the homologous paternal chromosome. Since they occur on the same chromosomes, these linked genes will also appear together in the same gametes. They will not be assorted independently as in dihybrid cross shown in Table 1 above. The following Table 7 shows a genetic corn cross involving linkage:

There are three different phenotypes in the offspring from this cross: 1/4 Purple & Shrunken (blue), 2/4 Purple & Smooth (red) and 1/4 Yellow & Smooth (green). There are also three different genotypes: 1/4 PPss (blue), 2/4 PpSs (red) and 1/4 ppSS (green). Compare the phenotypes and genotypes in this table with the original 9:3:3:1 dihybrid cross shown above in Table 1.


Chemistry resources for high schools impacted by COVID-19

  • Open Learning Initative (OLI) General Chemistry I and II are complete online courseware for AP and college level chemistry. Each module includes short amounts of text, interactive worked examples, scaffolded practice problems, and assessments. The integration of these components provides a seamless and interactive learning experience for your students. The courseware also provides instructors with data on student performance, which they can use to adapt their instruction to student needs.
  • NGSS Chemistry Modules These online materials for a first course in chemistry aim to teach and reinforce chemistry concepts in the context of real-world scenarios, while incorporating virtual lab activities and strengthening student application of NGSS practices.
  • ChemCollective virtual labs The virtual labs hosted here allow students to design and carry out their own experiments. You can provide experimental procedures to your students or allow them to invent their own. The autograded labs create unknowns and provide feedback on students answers. Please contact for information on how to best use these with your students.

A recording from our webinar on March 16 is available here. A discussion of the virtual lab starts at about 29:00. The earlier portions give an overview of the OLI General Chemistry I and II courseware. We also created an editable google doc to provide additional information on virtual labs, and help instructors collaborate on use of these labs.


Popularity of Programming Language Worldwide, Jul 2021 compared to a year ago:

`
Rank Change Language Share Trend
1 Python 30.32 % -1.8 %
2 Java 17.79 % +1.0 %
3 Javascript 9.03 % +1.1 %
4 C# 6.55 % -0.2%
5 C/C++ 6.02 % +0.3 %
6 PHP 5.94 % +0.0 %
7 R 3.96 % -0.0 %
8 TypeScript 2.26 % +0.3 %
9 Objective-C 2.24 % -0.3 %
10 Swift 1.78 % -0.4 %
11 Kotlin1.75 % +0.3 %
12 Matlab 1.72 % -0.2 %
13 VBA 1.38 % +0.1 %
14 Go 1.28 % -0.1 %
15 Rust 1.26 % +0.3 %
16 Ruby 1.01 % -0.2 %
17 Visual Basic 0.76 % -0.1 %
18 Ada 0.74 % +0.3 %
19 Scala 0.72 % -0.3 %
20 Dart 0.61 % +0.1 %
21 Lua 0.54 % +0.1 %
22 Abap 0.44 % -0.0 %
23 Perl 0.38 % -0.0 %
24 Julia 0.36 % -0.0 %
25 Groovy 0.34 % -0.1 %
26 Cobol 0.3 % -0.1 %
27 Delphi/Pascal 0.27 % -0.0 %
28 Haskell 0.24 % -0.0 %

TIOBE Index for June 2021

Jun 2021 Jun 2020 Change Programming Language Ratings Change
1 1 C 12.54% -4.65%
2 3 Python 11.84% +3.48%
3 2 Java 11.54% -4.56%
4 4 C++ 7.36% +1.41%
5 5 C# 4.33% -0.40%
6 6 Visual Basic 4.01% -0.68%
7 7 JavaScript 2.33% +0.06%
8 8 PHP 2.21% -0.05%
9 14 Assembly language 2.05% +1.09%
10 10 SQL 1.88% +0.15%
11 19 Classic Visual Basic 1.72% +1.07%
12 31 Groovy 1.29% +0.87%
13 13 Ruby 1.23% +0.25%
14 9 R 1.20% -0.99%
15 16 Perl 1.18% +0.36%
16 11 Swift 1.10% -0.35%
17 37 Fortan 1.07% +0.80%
18 22 Delphi/Object Pascal 1.06% +0.47%
19 15 MATLAB 1.05% +0.15%
20 12 Go 0.95% -0.06%

[ Want to contribute to Python exercises? Send your code (attached with a .zip file) to us at w3resource[at]yahoo[dot]com. Please avoid copyrighted materials.]

Test your Python skills with w3resource's quiz


Background

Originally, physicists made measurements by hand we measured lengths with rulers, counted events by penciling in tick marks, and timed events with stopwatches. But as the experiments became more sophisticated, hand and eye techniques failed they were too slow, too inaccurate, and too imprecise. Experiments began making measurements electronically. In some experiments, the measurements are intrinsically electrical for instance:

  • Measurements of the charge collected on a plate from a cosmic ray.
  • Measurements of the resistance of a semiconductor.
  • Measurements of the radio signal from a pulsar.
  • Measurements of the potential across a nerve cell.

Other experiments produced data that is not intrinsically electrical, but are best measured by converting the data to an electrical signals. Devices which convert a non-electrical measurements to an electrical signal are called transducers, and some typical examples include:

  • A spectral line converted to an electrical signal by a photomultiplier tube.
  • The passage of an energetic particle converted to an electrical signal in a spark chamber.
  • The separation between two masses in a gravity wave experiment measured by light interferometry and converted to an electrical signal with a photocell.
  • The temperature of a liquid helium bath converted to an electrical signal by measuring the resistance of a semiconductor.
  • The pressure in vacuum chamber measured with an ion gauge.

Perhaps the last important non-electrical observations were photographs of astronomical images, and particle tracks in bubble chambers. Now even astronomical “photos” are taken electronically with CCD cameras, and bubble chambers have been replaced by silicon detectors.

Computerized Data Acquisition

For many decades, it was sufficient to read the signal on a meter, or display the signal on an oscilloscope. Sometimes hybrid methods were used for my Ph.D. thesis, I took about ten thousand photographs of oscilloscope screens, and analyzed the information on the photos with calipers. Nowadays, most data is collected by computer. Computers have become astonishingly powerful, and data acquisition hardware has become cheap, fast and accurate. Data acquisition by computer has many advantages over hand collection:

  • It is generally more precise and accurate.
  • The much larger data sets that can be collected by computers are far more amenable to sophisticated analysis techniques.
  • It is much less tedious.
  • When properly programmed, there are no recording errors.

Noise, Signal Processing, and Data Acquisition

Unfortunately, it’s a rare experiment that produces noise-free data. Noise comes from many sources. Some are intrinsic, like the Johnson Noise discussed later in these Background notes, while others are extrinsic, like the 60Hz harmonics picked up from the power lines. It is always best to minimize noise before collecting data, but inevitably we would like to “see into the noise”…to recover a valid signal from a noisy signal. Powerful signal processing techniques, like filtering, averaging and Fourier Transforms, have been developed to do this. Most of these techniques require extensive data sets. Frequently, computerized data acquisition is the only way to acquire enough data.

Modern instruments like oscilloscopes, signal sources, and digital multimeters can often send their measurements to computers. The most common hardware interface protocol is called the GPIB bus, sometimes known as the HP-IB or IEEE bus. Powerful in its time, the GPIB interface is slow, expensive, difficult to use, and archaic. Recently, some instruments have been designed to communicate over Ethernet or USB. Whatever the bus, each instrument has its own set of programming commands, and recovering data from the instrument is generally painful.

Standalone instruments are often the best choice for very high end applications, but many applications are well served by data acquisition cards placed inside standard computers. These cards are quite cheap and powerful, and can be much easier to use than standalone devices.

The data acquisition card in the 111 lab computers.

Data Acquisition Environments

Standalone instruments can be used independently via their front panel interfaces, but data acquisition cards must be used in a data acquisition environment. Most cards come with a debugging interface that may be used in as a simple data logger, but is insufficient for more sophisticated applications. Ideally, the data acquisition environment should be:

· Easy to learn, use, and debug.

· Robust and stable (doesn’t crash.)

· Efficient (uses computer resources wisely.)

Some familiar programs provide data acquisition environments. For instance, with add-ins, Excel can be used to collect data, but it has very limited functionality, execrable graphs, is utterly undocumentable, and is inefficient. Add-ins are available for both Mathematica and Matlab, and both produce beautiful graphs. Matlab, in particular, has powerful data analysis capability. But their data acquisition functionality is limited, both are obscure and difficult to learn, have pathetic, 1970’s style user interfaces, and Mathematica is inefficient.

Most data acquisition cards also come with windows DLLs that can be called by C and C++ . Properly programmed, C and C++ are efficient and powerful data acquisition environments. But they are very primitive, have neither built-in graphing capability or analysis routines, and are difficult to learn and debug. Both can be documented, but, in the press of time, rarely are.

National Instruments, has developed a quirky graphical programming language called LabVIEW specifically designed for data acquisition, analysis and control. It is easy to learn and use, powerful and flexible, efficient, and self-documenting. It resembles no other significant computer language. You develop a user interface, or Front Panel [l2 ]

You will learn to write LabVIEW programs in this lab. It should be fun and useful to you outside this course almost all the physics labs in Berkeley, and many throughout the world, have adopted LabVIEW as their programming standard, and LabVIEW is widely used in industry.

LabVIEW is not a panacea for simple tasks it is unsurpassed, but, like any programming language, programming complicated applications is difficult. While LabVIEW does not resemble other languages, many of the programming guidelines you may have learned previously still apply: breaking functionality down into subroutines, testing subroutines individually, avoiding side effects like global variables, paying attention to memory management, and using efficient data structures are always worthwhile.

In 1928, J.B. Johnson discovered that the RMS voltage across an isolated resistor is not zero, but, instead, fluctuates in proportion to the square root of the temperature and resistance. Later that year, H. Nyquist showed that the voltage is due to the thermal fluctuations in the resistors, and follows:

,

where R is the resistance, T is the temperature, and is Boltzmann’s constant. The bandwidth B is the band over which one measures the voltage. In other words, if the signal from the resistor is sent through a bandpass filter which passes frequencies between and , the bandwidth is .

The discovery and explanation of Johnson Noise, sometimes called Thermal Noise or Nyquist Noise, was one of the grand triumphs of thermodynamics. It is well worth reading Johnson’s and Nyquist’s original papers, which are available on the lab computers under “U:BSC ShareLAB_9”.

Johnson Noise is of great practical importance it is often the dominate source of noise in an experimental measurement. Normally noise is detrimental and an annoyance, but measuring the noise in a resistor is probably the easiest way to determine . We will perform this measurement in this lab.


Conduction Velocity in a Human Reflex Arc

When the Achilles tendon is stretched after being tapped with a reflex hammer, the induced action potential is conducted up the leg to the spinal cord and back down where it causes the gastrocnemius (calf) muscle to contract. To determine the speed of conduction, the distance that the action potential travels is measured and the time between the tapping of the tendon and the contraction of the muscle is measured using PowerLab and ADinstruments software.

The Reflex Arc: A reflex arc is initiated by stretching a tendon, an action that stimulates stretch receptors in the muscle. Those stretch receptors respond by initiating an action potential in sensory neurons. The action potential travels through those sensory neurons to the spinal cord where they synapse directly with motor neurons. The excitation travels back to the gastrocnemius muscle where it causes contraction of the muscle. Thus the tendon that was initially stretched is returned to its original length through contraction, completing the reflex arc.

The function of this type of reflex arc is to maintain posture. Muscles are continually stretching and returning to their original length without the intervention of the brain. Note that this response is monosynaptic. The sensory neuron synapses directly with the motor neuron in the spinal cord there is no interneuron involved.

The Electromyogram (EMG): is a recording of a muscle contraction that can be taken from the skin above a muscle. An action potential travels down a nerve, through a nerve/muscle junction and into a muscle. In the muscle the action potential spreads throughout the muscle causing contraction of the muscle fibers. The passage of the action potentials can be sensed by electrodes placed on the skin above the muscle, which when amplified (as in the ECG) can be displayed on a computer screen.

The Reflex Hammer: is a percussion hammer used to test reflexes. The hammer that you will use has been modified so that when it hits the tendon, the hammer closes a circuit and generates a small signal. This signal is used to trigger a sweep by the computer.

Experimental Procedure

  1. Seat the subject on the edge of the lab bench so that her legs are hanging freely. Attach two pre-jelled electrodes to the body of the calf (gastrocnemius) muscle, a bit to the left or right of the midline. The two electrodes should be placed so their outer edges touch in a vertical line on the muscle (See figure below). A third ground electrode should be placed on the ankle bone. Attach the cables to the correct electrodes: green for ground (on the ankle bone) and black and white to the calf muscle.

Fig. 9.1. A, Diagram of a reflex arc in a human. When the stretch receptor is stimulated by the hammer, the action potential travels up the sensory fibers to the spinal cord and synapses on the motor fibers The action potential then travels back down the nerve to cause the muscle contraction we observe as a reflex. B, Two electrodes are placed on the calf, close to each other as shown. The third electrode should be placed on a bony surface, such as the knee cap or ankle. C, LabChart 8 Setup files.

To make an EMG RECORDING:

  1. Open the file: “EMG test settings”. If you cannot find this file on the desktop, ask your instructor.
  2. To collect an EMG: The test subject should be seated and her legs and feet relaxed. Press START in the lower right of the screen. Gently lift the subject's toes to stretch the Achilles tendon on the back of her leg, and firmly rap the Achilles tendon of the subject with the black rubber part of the hammer. Record multiple EMG’s by hitting the black rubber part of the hammer on the Achilles tendon and observing the reflex in Ch. 3. Repeat until you have 3 representative EMGs.
  3. When you have a good set of 3 EMGs (see Fig. 9.2), measure the time with the cursor from the start of the stimulus (at zero) to the middle of the first peak. Repeat on different recordings and average three.
  4. Record data in your lab manual and on the spreadsheet provided by your instructor.
  5. Use the tape measure to measure the distance in centimeters from the point of impact on the subject’s Achilles tendon to the approximate point at which the rib cage meets the spinal column (i.e., the length of the sensory nerve) and then down to the first electrode on the gastrocnemius (i.e., the length of the motor nerve). Refer to PowerPoint slide provided by your instructor for a diagram of how to take this measurement.
  6. Record length and then calculate and record the conduction velocity.

Fig. 9.2. A sample of an EMG recorded on the computer using PowerLab. The trigger signal is on Input 1 (Ch 1) at time 0 and the EMG is on Ch 3 (called Raw Signal). Place the marker "M" at the top of the first peak of the EMG. The time displayed indicates the time elapsed between the trigger signal and the gastrocnemius response, i.e. the time taken by the action potentials to propagate along the sensory neurons of the sciatic nerve to the spinal cord and along the motor neurons to the first (upper) electrode of the gastrocnemius.


Practical Work for Learning

This website is for teachers of biology in schools and colleges. It is a collection of experiments that demonstrate a wide range of biological concepts and processes.

Experiments are placed within real-life contexts, and have links to carefully selected further reading. Each experiment also includes information and guidance for technicians.

Why use practical work in Biology?

Biology is a practical science. Practical activities are not just motivational and fun: they also enable students to apply and extend their knowledge and understanding of biology in novel investigative situations, which can aid learning and memory, and stimulate interest.

Practical Work for Learning

We have published a new set of resources to support the teaching of practical science for Key Stages 3-5. The resources are part of the Practical Work for Learning project, which explores how three different teaching and learning approaches can be applied to practical work. Visit the Practical Work for Learning website to find out more.

Help and support in using the experiments

Unfortunately, we are unable to respond to questions from teachers, technicians or students on how to use the experiments on this website.

  • About Practical Biology
  • Practical Work for Learning
  • Welcome to Practical Biology
  • Topics
  • Standard techniques
  • Animal behaviour
  • Cells to systems
  • Exchange of materials
  • Technology
  • Environment
  • Control and communication
  • Bio molecules
  • Evolution
  • Genetics
  • Health and disease
  • Energy

NCLEX-RN Test Plan

The NCLEX test plan is a content guideline to determine the distribution of test questions. NCSBN uses the “Client Needs” categories to ensure that a full spectrum of nursing activities is covered by the NCLEX. It is a summary of the content and scope of the NCLEX to serve as a guide for candidates preparing for the exam and to direct item writers in the development of items.

The content of the NCLEX-RN is organized into four major Client Needs categories which include: Safe and Effective Care Environment, Health Promotion and Maintenance, Psychosocial Integrity, Physiological Integrity. Some of these categories are divided further into subcategories.

Below is the NCLEX-RN test plan effective as of April 2019 to March 2022:

Many questions on the NCLEX are in multiple-choice format. This traditional text-based question will provide you data about the client’s situation and you can only select one correct answer from the given four options. Multiple-choice questions may vary and include: audio clips, graphics, exhibits or charts.

Chart or Exhibit Questions

A chart or exhibit is presented along with a problem. You’ll be provided with three tabs or buttons that you need to click to obtain the information needed to answer the question. Select the correct choice among four multiple-choice answer options.

Graphic Option

In this format, four multiple-choice answer options are pictures rather than text. Each option is preceded by a circle that you need to click to represent your answer.

Audio

In an audio question format, you’ll be required to listen to a sound to answer the question. You’ll need to use the headset provided and click on the sound icon for it to play. You’ll be able to listen to the sound as many times as necessary. Choose the correct choice from among four multiple-choice answer options.

Video

For the video question format, you are required to view an animation or a video clip to answer the following question. Select the correct choice among four multiple-choice answer options.

Select All That Apply or Multiple-Response

Multiple-response or select all that apply (SATA) alternate format question requires you to choose all correct answer options that relate to the information asked by the question. There are usually more than four possible answer options. No partial credit is given in the scoring of these items (i.e., selecting only 3 out of the 5 correct choices) so you must select all correct answers for the item to be counted as correct.

Tips when answering Select All That Apply Questions

  • You’ll know it’s a multiple-response or SATA question because you’ll explicitly be instructed to “Select all that apply.”
  • Treat each answer choice as a True or False by rewording the question and proceed to answer each option by responding with a “yes” or “no”. Go down the list of answer options one by one and ask yourself if it’s a correct answer.
  • Consider each choice as a possible answer separate to other choices. Never group or assume they are linked together.

Fill-in-the-Blank

The fill-in-the-blank question format is usually used for medication calculation, IV flow rate calculation, or determining the intake-output of a client. In this question format, you’ll be asked to perform a calculation and type in your answer in the blank space provided.

Tips when answering Fill-in-the-Blank

  • Always follow the specific directions as noted on the screen.
  • There will be an on-screen calculator on the computer for you to use.
  • Do not put any words, units of measurements, commas, or spaces with your answer, type only the number. Only the number goes into the box.
  • Rounding an answer should be done at the end of the calculation or as what the question specified, and if necessary, type in the decimal point.

Ordered-Response

In an ordered-response question format, you’ll be asked to use the computer mouse to drag and drop your nursing actions in order or priority. Based on the information presented, determine what you’ll do first, second, third, and so forth. Directions are provided with the question.

Tips when answering Ordered-Response questions

  • Questions are usually about nursing procedures. Imagine yourself performing the procedure to help you answer these questions.
  • You’ll have to place the options in correct order by clicking an option and dragging it on the box on the right. You can rearrange them before you hit submit for your final answer.

Hotspot

A picture or graphic will be presented along with a question. This could contain a chart, a table, or an illustration where you’ll be asked to point or click on a specific area. Figures may also appear along with a multiple-choice question. Be as precise as possible when marking the location.

Tips when answering Hotspot questions

  • Mostly used to evaluate your knowledge of anatomy, physiology, and pathophysiology.
  • Locate anatomical landmarks to help you select the location needed by the item.

Want to test-drive the NCLEX? We highly recommend you complete the online tutorial by the NCSBN to help you familiarize yourself with the different question types for the NCLEX.


Watch the video: Practical Immunology Lab 8 u0026 9 (June 2022).


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