Using A Microscope 101: Important Microscope Parts & Functions

Can you name all the different parts of a microscope? Knowing how to properly label microscope parts is important so you can communicate clearly and provide detailed instructions when teaching a class of young students. Here is everything you need to know about naming the parts of a microscope.

Using A Microscope 101: Parts Of A Microscope

A microscope is used to magnify small objects. Microscopes are often used in scientific or educational settings to observe objects and living organisms that wouldn’t be visible to the naked eye. It is important to learn about the different parts of a microscope to understand how these devices work.

Why Is Knowing About Microscope Parts Important?

one microscope

Learning about microscope parts provides you with a frame of references. You can use the correct terms to communicate with other scientists or students.

This is crucial when giving instructions. If you are an instructor, you should take the time to teach students about the different parts of a microscope so you can give detailed instructions on how to prepare a microscope and use it safely.

Knowing the correct terms for the different parts of a microscope will also help you troubleshoot problems. You will be able to look up information on a specific part you are encountering issues and figure out how to rectify the issue.

The Basic Components Of A Microscope

microscope diagram

Three microscope parts make up the frame of the device.

Base

The base is the large piece that supports the microscope. You need to keep your microscope steady to get a clear image of what you want to magnify. This is why the base is an important part.

The size of the base depends on how heavy the microscope is. If you need to carry a microscope, make sure you place one hand under the base to support the weight of the device.

Arm

This is the C-shaped section that connects the base of the microscope to the controls and tube. You can typically adjust the angle of the arm to use the microscope more comfortably.

The arm is the first part that young students should learn about. This is the part you would use to safely pick up and transport the microscope. Teach students that they should always grab the arm of the microscope if they need to change the position of the device.

When carrying a microscope, you should hold the device by the arm and have one hand under the base to support its weight.

If you are using a compound microscope, the base, arm, and stage of the device won’t be separate elements. However, these different parts are easily identifiable on most small microscopes with low magnification settings.

Tube

This is a large part at the top of the microscope. The tube is connected to the arm of the microscope.

You will find the turret or nosepiece with the magnifying lenses at the bottom of the tube. However, you don’t directly look down the tube since an eyepiece is mounted on top of the tube.

The tube of a microscope can’t be adjusted. Make sure you teach the name of this part to young students, so they know not to grab a microscope by its tube.

Some microscopes have two tubes and two eyepieces. Most models only have one tube and eyepiece.

How To Magnify An Object

Eight different microscope parts come into play when you use a microscope to magnify an object.

Stage

The stage is the small surface located under the turret or nosepiece of the microscope. This is where you need to place the object you want to magnify.

The stage is equipped with a couple of metal clips that will secure the object you need to magnify to the microscope. You would typically prepare the object or living organism you want to magnify by placing it on a microscope slide and use the stage clips to secure the slide to the stage.

There is a hole called the aperture in the center of the stage. Light comes through the aperture and illuminates the object. You need to make sure the object you want to magnify is aligned with the aperture when attaching it to the stage.

Mirror Or Illuminator

You can’t use a microscope without a light source. The mirror or illuminator is located under the stage and illuminates the object or living organism you want to magnify.

If your microscope is equipped with a mirror, you will need to adjust the mirror to reflect sunlight. Most microscopes are equipped with an illuminator that you simply switch on and off.

You will find a 110v bulb inside of the illuminator. Some microscopes have an iris diaphragm attached to the illuminator that can be used to control how much light comes out.

Turret Or Nosepiece

This is a rotating circle attached under the tube of the microscope. There are different objective lenses attached to the turret of the nosepiece.

The purpose of the turret or nosepiece is to support the different objective lenses and let you select the right one. Microscopes have at least two lenses attached to the turret or nosepiece but can have a lot more.

Eyepiece

The eyepiece is the part mounted on top of the tube. This is where you look into the microscope. The eyepiece usually has a lens with a 10x or 15x magnification power. You can calculate the magnification of a microscope by multiplying the eyepiece lens magnification power by the magnification power of the objective lens you are using.

Stereo microscopes have two eyepieces to create a three-dimensional image of the object. If you are an instructor, you probably won’t be working with stereo microscopes but showing images of these devices to your students could be an interesting way to introduce three-dimensional images and to show them there are different types of microscopes with more features.

Controls

You will find the controls on one side of the arm. Most microscopes use dials or knobs to let you adjust the magnification.

The controls work by bringing the stage closer or further away from the objective lens you have selected. You will usually have a coarse control to make broad adjustments and a fine control for more precise adjustments.

Some microscopes have an additional control mounted on the eyepiece. This is a diopter control to adjust the magnification of the lens you look into.

Some microscopes have an additional control attached to the base so that you can adjust the brightness of the illuminator.

Rack stop

The rack stop is a safety feature that prevents you from bringing the stage too close to the objective lens and accidentally damaging it. The rack stop is a small screw that is mounted next to the stage.

You shouldn’t have to adjust the rack stop of your microscope. The default setting will prevent you from getting the stage too close to the objective lenses.

If you are teaching young students how to use a microscope, make sure they know what the rack stop is and understand why they shouldn’t touch it. It is possible to loosen this screw and get the stage closer to the objective lenses, which could result in some damages to the lenses.

Objective Lenses

These lenses are attached to the turret or nosepiece and hang directly above the stage. Microscopes can have two, three, four, or five lenses depending on their magnifying power.

The magnification power of a lens typically ranges from 4x to 100x depending on how performing the microscope is.

The objective lenses are the most important and most fragile microscope parts. They are protected by small tubes, but students should be aware of how fragile the lenses are.

Condenser lens

Not all microscopes have a condenser lens. The purpose of the condenser lens is to focus the light on the object you want to magnify.

A condenser lens is often used with high magnifications since it gives a sharper image of the object. You can upgrade your microscope by adding a condenser lens, but this is something you might not need if your microscope only has low magnification settings.

The condenser lens is mounted on the stage and will concentrate light on the object.

How To Teach Students About Microscope Parts

children using a microscope

There are different ways to help students remember the different parts of a microscope. Here are a few ideas:

  • Bring a microscope to class and point to the different parts.
  • Have the students label a diagram of a microscope.
  • During activities that involve microscopes, make sure you ask each student to name a few parts.
  • Ask students to explain how they would prepare a slide or transport a microscope. Make sure they use the correct names for the different parts they mention.
  • Ask students to name the parts that come into play when magnifying an object.
  • Ask students what the purpose of a specific part is.
  • Have students try out different lenses and calculate the magnification power for each one.

Knowing the names of the different parts of a microscope is important because it helps you communicate clearly with students or colleagues. Remembering the different parts is easy if you keep a labeled diagram with you and make sure you always use the proper terms when referring to the different parts of a microscope.

Amino Acids: Definition, Charts, and Study Guides

Finding an excellent amino acid chart that is also a good reference and well suited for your needs can be a challenge. However, there are great charts and study guides available that use diagrams, videos, and text to quickly deliver information in a succinct and organized manner.

Amino Acids

Learning about amino acids and finding good charts and study guides can be a challenge, but there are reliable resources available. Our list includes some of the best reference charts and most diverse study guides to fit a variety of learning styles and other preferences.

Whether you are a beginner or a more advanced user, these charts and guides can be helpful in accelerating learning and testing the knowledge that you already possess. For those studying for the MCAT, having these tools at your disposal can help supplement your other materials and verify your knowledge by presenting content in alternative forms.

What Are Amino Acids? What Do They Do?

Amino acids are a class of organic compounds that include at least one carboxyl group, and one amino group. Amino acids are one of 20 different components that go into assembling proteins and are frequently referred to as “building blocks.”

There are a total of seven amino acids which are called “essential” because they must be obtained from the diet and the human body is unable to manufacture them. They include:

7 Amino Acids

  • Isoleucine
  • Leucine
  • Lysine
  • Valine
  • Tryptophan
  • Threonine
  • Phenylalanine

Amino acids are also procured from a healthy diet, and many can be taken as an oral supplement as needed. The proteins that amino acids create are an essential part of just about every biological process in your body.

Amino acids are responsible for carrying out bodily functions and making cells such as muscles and other tissues in the body. They also help give those cells structure and play vital roles in the transference and storage of nutrients to different parts of the body.

How your organs, tendons, arteries, and glands function also depend on different amino acids. Wound healing, tissue repair, and skin and hair growth are also related to how amino acids perform in the body.

Amino acids are responsible for building and transporting many substances within the body, but they also work to remove waste and other deposits that are produced as part of the body’s functions and metabolism.

Having an appropriate quantity of the needed amino acids also helps to regulate the body’s metabolism in different ways and can prevent disease, tissue damage, organ damage, and other health issues.

Helpful Reference: Amino Acid Chart

Amino acid charts

There are many different amino acids, and the way that they can combine leads to an even more significant number of potential compounds. In addition to that, each amino acid has a 3-letter symbol, 1-letter symbol, formula, molecular weight, and structure.

Different charts present information about amino acids in different ways, and our list of amino acid charts offers a variety of different formats to suit different needs. Having an amino acid chart on hand may help save time and prevent mistakes.

DTU Bioinformatics

The amino acid chart provided on the DTU Bioinformatics website is straightforward and offers up the 1-letter symbol, and the DNA codons. It lists 20 amino acids found in proteins, along with the 64 available 3-letter symbols that correspond to each respectively.

Although this table is somewhat bare-bones, it’s easily printed and hung up where it is convenient for reference. If all you need is some basic information about amino acids, then this chart is ideal for you.

This chart may not have all of the information necessary for an introduction to the subject, but it succinctly provides essential information without frills, distracting colors, icons, or logos, and comfortably fits on one page.

Oregon State

The amino acid chart provided by Oregon State is a color-coded table that makes it possible to translate different parts of mRNA code into a sequence of amino acids. The simple 3 step directions indicate that you first need to select the nitrogenous base, and then match it to the first letter on the table.

After that, you follow the row until it leads you to the second and third letter required for the sequence, and each letter is color coded in black, blue, red, or green.

Although the table looks complicated at first, once you go through the steps a few times it becomes a rather quick way to look up an amino acid sequence without needing to do an online search each time.

The table also does a great job of narrowing down the available options, so if you are unsure of one of the bases, you can at least get an idea of what the possible options are which may be all you need to figure it out.

This table is also relatively compact, and provided you have access to a color printer it could be beneficial to have printed out and on hand for when you need it.

Sigma- Aldrich

The amino acid charts provided by Sigma-Aldrich are much more extensive and present the information in both chart and structure format. You can quickly look up the drawn structure of an amino acid complete with different side chains, or you can scroll down to the tables that have more information about the amino acid properties.

This page has a wealth of information about the amino acids and lists them in different groupings and categories for convenience. You can peruse the chart that talks explicitly about properties such as symbols, weights, molecular formula, or residue formula, and you can also view them based on how hydrophobic they are.

The bottom of the page also lists some relevant technical articles that relate to amino acids, and there is a link that allows you to read the abstracts from those papers. This website also features a wealth of other information and charts related to medical science, biology, genetic research, and life science.

GenScript

The GenScript website offers some clean and easy to read charts that detail amino acid related information such as symbols, formula, weights, isoelectric points, and structure. There are small illustrative diagrams for the various structures, and each chart categorizes the amino acids according to type.

There are also links on the page that will navigate to other helpful charts, formulas, and calculators and the site offers many different genetics related reference charts. The page details universal genetic codes along with 20 standard residues that can be found in nature.

SmartDraw

SmartDraw is a unique website that isn’t specifically science oriented but offers a wide variety of charts and visual illustrations for reference material. It covers a wide range of topics, but the amino acid charts are both easy to see and can be uploaded into the SmartDraw website for customization.

The templates offered are fully editable, so you can make your own custom notes, color code, and make other customizations easily. It’s also possible to make a chart of your own with the information of your choosing.

a girl studying

Study Guides and Resources

An amino acid chart is somewhat quick to find, but a reliable study guide that is easy to use can be harder to locate. Luckily there are a few good sources available that offer just enough information to be helpful, without weighing you down with opaque content.

Albert

This site offers some helpful study tips when it comes to learning about amino acids, and even includes helpful diagrams and a complete study guide. If you like to learn by reading and viewing visual pictures, this site may be beneficial for you.

At various parts of this site, you’ll find summaries, and the content is broken up with practice questions to help you test your understanding. Everything is well organized and ideal for beginners looking to learn quickly.

Sporcle

Sporcle is a site specifically for quizzing yourself about amino acids and other content created by users in the community. While this would not be ideal as your only source of information and exposure to amino acids, the fun quizzes can help accelerate learning in a fun way.

There are a number of quizzes related to biology, and other sciences that are free for visitors to take. In the end, you get a score out of a total of 20 points which can help you track your progress as you learn.

Cliffs Notes

Cliffs Notes on amino acids don’t contain many diagrams, so this may be a better source for those that like to read exclusively. However, it does provide a good summary of the relevant information related to a number of different scientific categories.

In fact, there are well-categorized chapters available that discuss many different biological and other scientific concepts, and many of these come directly from books, or classroom approved study guides.

Khan Academy

Khan Academy offers a wealth of lectures, videos, diagrams, and other content that is posted by some of the brightest minds at the most well-renowned universities. The topics are widespread and feature a number of different categories included study guides specifically for amino acids, MCAT, and other science-related subjects.

For those that are stuck in their learning and want to speed up the process, the free content on Khan Academy can help liven up your studies with fun and interactive learning that you can take on at your own pace. The videos are generally very high quality and easy to watch, and the instructors are typically quite good at dissecting a topic, so it’s easy to understand.

8 Lesson Plan Template Resources for Biology Teachers

A lesson plan template can help save time but can also assist with creating an engaging and thought-provoking opportunity for students to learn. Using customizable templates, our list offers up multimedia content resources suitable for all grade levels and biology subjects.

8 Lesson Plan Template Resources for Biology Teachers

Lesson plan templates can help save teachers time and also improve their ability to successfully teach students without the hassle of starting from scratch for every lesson. Teachers around the world have grouped to share content on various platforms, and now students and educators alike can reap the benefits.

Lesson plans are also an excellent way to organize ideas and plan subject matter out in advance without having to memorize lectures or assemble multiple lists of resources. Creating a sound lesson plan complete with links, handouts, and thought-provoking questions can make learning fun, and create time for essential teaching moments.

Effective Use of Lesson Plans

writing on top of the table

Lesson plans can be a helpful guide for delivering engaging and thought-provoking lessons that help students understand the material and take an interest in the subject matter. A well thought out lesson plan also has the ability to serve as a reference to make sure a lecture stays on track and within a preset time limit.

Using a lesson plan template effectively can be a bit more of a challenge since it is likely that you’ll be working with formatting done by another person who may think differently about how to put together an engaging lesson for students.

However, there are many benefits to using a lesson plan template, including:

  • Discovering how other educators organize and deliver information
  • Innovative solutions to common problems
  • Time savings and efficiency

There’s no shame in managing your own time by using a lesson template, and frequently it can help you assess how reliable or efficient different templates can be in a real-world scenario. Lesson plans also can limit the amount of multi-tasking that you’ll be doing while trying to teach students which can simplify and space out learning opportunities.

Clear lesson plans also include enough time for questions, reflection, and opportunities to encourage in-depth student thinking to enhance learning. Assignments can then be coordinated to be purposeful instead of becoming just busy work that doesn’t reinforce the essentials discussed in class.

8 Lesson Plan Template Resources

lesson written on a paper

There are a number of lesson plan template resources available online for a variety of subjects but finding the right one can be time-consuming. Here’s our list of recommended resources to get you started and connect you with content that is both functional and applicable to biology instruction at all grade levels.

The Teacher’s Guide

The Teacher’s Guide may look a little outdated, but the lesson content provided includes free worksheets, lesson templates, and other planning materials that have been created by other teachers. You can view the material by subject, and grade level recommendations are also listed.

Many of the links go to a webpage that includes other helpful information, diagrams, links, and handouts to help you create a more engaging lesson. These pages can easily be copied into a word document, uploaded to google drive, or used on a laptop as is.

Share My Lesson

Share My Lesson is another excellent website where content is provided by other educators for free, and there are comments and ratings to help you navigate among the material.

Finding the best content is easier with the ratings, but there are also descriptions, and lesson tags to help you find what you need more quickly so you can assess your options.

The content itself is also listed by grade level, and you can use the search filter options to see what is available without having to click through countless pages. Many of the lessons include PowerPoints, word documents, handouts, and note how many times the content has been downloaded.

The comments on the page are also a helpful resource that can let you know the thoughts of other educators, and you can share any content you find via the helpful social media buttons located on each page. You can also email the content to yourself or others, and upload documents to google drive.

The Biology Corner

miology corner

This super basic lesson plan template from the Biology Corner is great for planning out your lessons week by week, but it doesn’t offer the same detailed breakdown as other templates. What it does do is provide a simple model that you can download as a pdf or save to google docs and use over and over.

Although it is simple, it can also be edited to have different headings and include more information. It will also save you from having to buy an expensive lesson plan book that you have to lug around day in and day out.

Science Teacher Program.org

The Science Teacher Program website is a treasure trove of templates listed by year and grade for a variety of different subject matter. If you have a specific topic in mind, this cohesive list can help you get a ton of material together and get started on a lesson plan quickly.

Each lesson plan is unique, and many of them include helpful diagrams and details that you can copy and paste into slides as a visual during the less. The lessons are also in a simple webpage format, so they are easy to convert to word documents or view on your laptop as is.

Slide Share

SlideShare is an exciting resource where people can upload presentations and slides on any subject they choose to share with the rest of the web. This website offers up tons of original content that works for other presenters, teachers, educators, speakers, and even conferences.

The wealth of material also provides ample inspiration and many times you can download the slides for your own personal use. Not only can this save you a considerable amount of time when creating your lesson plan, but you can also get new ideas for how to present information.

There are also ratings, statistics, and other information about how many people have clipped, downloaded, or viewed the slides so you can get an idea for how popular the format is. There are also comments and notes towards the bottom which can provide more detailed information.

NASA

The NASA site is chalk full of information related to science, but lesson plan templates are probably not the first thing that comes to people’s minds when they think about the organization. In fact, the website offers several different files and lesson plan examples for different subjects and a vast number of grade levels.

Each template includes a fillable area for organizing your thoughts and ideas about the lesson contents, and the template allows for a considerable number of notes. Subject matter can efficiently be arranged in a number of different ways based on teaching style, and the headings allow for quick reference during more extended sessions.

Teachers Pay Teachers

Teachers Pay Teachers is an innovative site to get a lesson plan template that has been designed by another teacher. These downloads are often very inexpensive, typically around $1 or so, and offer a preview of the document before you purchase.

There are details about what the template is for, and how it is meant to be used. Many of them indicated a time frame for how many hours and minutes each part of the lesson should take, and the template is completely customizable as well.

Most of the templates are word documents which makes them easy to download and edit. Many of them are also suitable for a wide range of grade levels and include a rating based on the feedback from other teachers who have used the template.

One Note

This Microsoft application is standard as part of the Windows 10 operating system, and the website offers a number of lesson plan templates suitable for different subjects. There are many fun and interactive templates that can be found and downloaded for free, and the tutorials make it a breeze to get caught up on all the features.

The best part about OneNote for teachers is that it allows them to easily save and collate previous lesson plans for reference, so they have all their information and links at their fingertips at all times. For busy teachers working on material for several subjects at a time, they can even have multiple digital notebooks that can each be customized for their intended use.

Additionally, One Note receives regular updates from Microsoft which mean that you can expect regular upgrades to both content and functionality, and the website is full of new material that arrives regularly.

For cutting-edge learning material, and excellent visualizations, you can’t beat One Note which has STEM material, Minecraft, Skype, and other apps that make it the most versatile and customizable option available for free.

If you’re worried about keeping your wealth of material safe, worry no longer because you can create a Microsoft account and backup all of your files as you create them to ensure you’ll always have access even if you don’t have your computer on hand.

You can even share your lessons with others and view pre-made lessons from other educators on hundreds of different topics. There is also a function on OneNote for a virtual career day, a toolkit for school leaders, and specific content for higher education.

Chemistry & Water

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Chemistry & Water
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 1.
Which of these is an example of an organelle?
a.
chloroplast
b.
muscle
c.
epidermis
d.
intestine
e.
maple leaf
 2.
Which of these is a correct representation of the hierarchy of biological organization from least to most complex?
a.
organelle of a stomach cell, digestive system, large intestine, small intestine, intestinal tissue, organism
b.
organelle of an intestinal cell, digestive system, small intestine, large intestine, intestinal tissue, organism
c.
molecule, intestinal cell organelle, intestinal cell, intestinal tissue, digestive system, organism
d.
molecule, small intestine, large intestine, intestinal tissue, digestive system, organism
e.
molecule, digestive system, digestive cell organelle, small intestine, large intestine, intestinal cell, organism
 3.
As a result of photosynthesis, plants release ____ into the atmosphere.
a.
methane
b.
carbon dioxide
c.
water
d.
minerals
e.
oxygen
 4.
Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material?
a.
animal
b.
plant
c.
archaea
d.
A and B only
e.
A, B, and C
 5.
There are approximately ____ identified and named species.
a.
1,800
b.
180,000
c.
1,800,000
d.
18,000,000
e.
180,000,000
 6.
Prokaryotic and eukaryotic cells generally have which of the following features in common?
a.
a membrane-bounded nucleus
b.
a cell wall made of cellulose
c.
ribosomes
d.
flagella or cilia that contain microtubules
e.
linear chromosomes made of DNA and protein
 7.
Which of the following are characteristics shared by members of both domain Bacteria and domain Archaea?
a.
cytosol
b.
nucleus
c.
DNA
d.
A and C only
e.
A, B, and C
 8.
Two species belonging to the same genus must also belong to the same
a.
kingdom.
b.
phylum.
c.
class.
d.
order.
e.
all of the above
 9.
Which of the following is (are) true of natural selection?
a.
requires genetic variation
b.
results in descent with modification
c.
involves differential reproductive success
d.
B and C only
e.
A, B, and C
 10.
Which of these individuals is most likely to be successful in an evolutionary sense?
a.
a reproductively sterile individual who never falls ill
b.
an organism that dies after 5 days of life but leaves 10 offspring, all of whom survive to reproduce
c.
a male who mates with 20 females and fathers 1 offspring
d.
an organism that lives 100 years and leaves 2 offspring, both of whom survive to reproduce
e.
a female who mates with 20 males and produces 1 offspring
 11.
In a hypothetical world, every 50 years people over 6 feet tall are eliminated from the population. Based on your knowledge of natural selection, you would predict that the average height of the human population will
a.
remain unchanged.
b.
gradually decline.
c.
rapidly decline.
d.
gradually increase.
e.
rapidly increase.
 12.
The statement “If you show your dog affection, then your dog will seek your company” is an example of
a.
a statement that can be tested.
b.
a statement derived from a hypothesis.
c.
a prediction.
d.
deductive reasoning.
e.
all of the above
 13.
Which of the following is not a theme that unifies biology?
a.
interaction with the environment
b.
emergent properties
c.
evolution
d.
reductionism
e.
structure and function
 14.
Calcium has an atomic number of 20 and an atomic mass of 40. Therefore, a calcium atom must have
a.
20 protons.
b.
40 electrons.
c.
40 neutrons.
d.
A and B only
e.
A, B, and C
 15.
The atomic number of carbon is 6. Carbon-14 is heavier than carbon-12 because the atomic nucleus of carbon-14 contains ____ neutrons.
a.
6
b.
7
c.
8
d.
12
e.
14
 16.
Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that
a.
an electron may move to an electron shell farther out from the nucleus.
b.
an electron may move to an electron shell closer to the nucleus.
c.
the atom may become a radioactive isotope.
d.
the atom would become a positively charged ion, or cation.
e.
the atom would become a negatively charged ion, or anion.

Use the figure below to answer the following questions.

nar001-1.jpg

 17.
Which drawing depicts the electron configuration of nitrogen (N)?
a.
Drawing A
b.
Drawing B
c.
Drawing C
d.
Drawing D
e.
Drawing E
 18.
What does the reactivity of an atom depend on?
a.
number of valence shells in the atom
b.
number of orbitals found in the atom
c.
number of electrons in each orbital in the atom
d.
presence of unpaired electrons in the outer valence shell of the atom
e.
presence of hybridized orbitals in the atom

Use the information extracted from the periodic table in the figure below to answer the following questions.

nar002-1.jpg

 19.
How many electrons does phosphorus have in its valence shell?
a.
1
b.
2
c.
3
d.
4
e.
5
 20.
Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH3)?
a.
Each hydrogen atom has a partial positive charge.
b.
The nitrogen atom has a strong positive charge.
c.
Each hydrogen atom has a slight negative charge.
d.
The nitrogen atom has a partial positive charge.
e.
There are covalent bonds between the hydrogen atoms.
 21.
What do the four elements most abundant in life-carbon, oxygen, hydrogen, and nitrogen-have in common?
a.
They all have the same number of valence electrons.
b.
Each element exists in only one isotopic form.
c.
They are equal in electronegativity.
d.
They are elements produced only by living cells.
e.
They all have unpaired electrons in their valence shells.

Use the figure below to answer the following questions. .

nar003-1.jpg

 22.
What results from the chemical reaction?
a.
a cation with a net charge of +1
b.
a cation with a net charge of -1
c.
an anion with a net charge of +1
d.
an anion with a net charge of -1
e.
A and D
 23.
The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride?
a.
MgCl
b.
MgCl2
c.
Mg2Cl
d.
Mg2Cl2
e.
MgCl3
 24.
Explains most specifically the attraction of water molecules to one another.
a.
nonpolar covalent bond
b.
polar covalent bond
c.
ionic bond
d.
hydrogen bond
e.
hydrophobic interaction
 25.
In a single molecule of water, the two hydrogen atoms are bonded to a single oxygen atom by
a.
hydrogen bonds.
b.
nonpolar covalent bonds.
c.
polar covalent bonds.
d.
ionic bonds.
e.
van der Waals interactions.
 26.
Which bonds must be broken for water to vaporize?
a.
ionic bonds
b.
nonpolar covalent bonds
c.
polar covalent bonds
d.
hydrogen bonds
e.
covalent bonds
 27.
The formation of ice during colder weather helps moderate the seasonal transition to winter. This is mainly because
a.
the breaking of hydrogen bonds absorbs heat.
b.
the formation of hydrogen bonds releases heat.
c.
the formation of hydrogen bonds absorbs heat.
d.
there is greater evaporative cooling of lakes.
e.
ice is denser than liquid water.
 28.
Recall that when sodium chloride (NaCl) is placed in water the component atoms of the NaCl crystal dissociate into individual sodium ions (Na+) and chloride ions (Cl-). In contrast, the atoms of covalently bonded molecules (e.g, glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest concentration of particles (molecules or ions)?
a.
0.5 M NaCl
b.
0.5 M glucose
c.
1.0 M NaCl
d.
1.0 M glucose
e.
1.0 M MgCl2

Use the figure below to answer the following questions:

nar004-1.jpg

 29.
How many grams of the molecule in the figure above would be required to make 1 L of a 0.5 M solution of the molecule?
(Carbon = 12, Oxygen = 16, Hydrogen = 1)
a.
29
b.
30
c.
60
d.
150
e.
342
 30.
Which of the following ionizes completely in solution and is considered to be a strong acid?
a.
NaOH
b.
HCl
c.
NH3
d.
H2CO3
e.
CH3COOH
 31.
Which of the following statements is completely correct?
a.
H2CO3 is a weak acid, and NaOH is a weak base.
b.
H2CO3 is a strong acid, and NaOH is a strong base.
c.
NH3 is a weak base, and H2CO3 is a strong acid.
d.
NH3 is a weak base, and HCl is a strong acid.
e.
NH3 is a strong base, and HCl is a weak acid.
 32.
Buffers are substances that help resist shifts in pH by
a.
releasing H+ in acidic solutions.
b.
donating H+ to a solution when they have been depleted.
c.
releasing OH- in basic solutions.
d.
accepting H+ when the are in excess.
e.
both B and D
 33.

One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3) Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+) Thus,

H2CO3 HCO3- + H+

If the pH of the blood drops, one would expect

a.
a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-.
b.
the concentration of hydroxide ion (OH-) to increase.
c.
the concentration of bicarbonate ion (HCO3-) to increase.
d.
the HCO3- to act as a base and remove excess H+ with the formation of H2CO3.
e.
the HCO3- to act as an acid and remove excess H+ with the formation of H2CO3.

 

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Introduction and Chemistry

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Introduction and Chemistry
 

True/False
Indicate whether the statement is true or false.
 1.
The study of biology can help you better understand human reproduction.
 2.
Almost all organisms ultimately get their energy for survival from the sun.
 3.
All living things are composed of chemicals.
      nar001-1.jpg      nar001-2.jpg
 4.
Refer to the illustration above. Both species are multicellular.
 5.
Refer to the illustration above. Both species have DNA in their cells.
 6.
Refer to the illustration above. Reproduction ensures the ongoing success of both species.
 7.
Refer to the illustration above. The sand dollar and paramecium both show organization.
 8.
Refer to the illustration above. Unlike the sand dollar, the paramecium does not have to maintain a stable internal environment.
 9.
Scientists have not discovered any new species on Earth in more than 20 years.
 10.
A scientist who performs an experiment has no idea what the outcome of the experiment is going to be.
 11.
A theory is a hypothesis that has been proven true.
 12.
A theory is an assumption made by scientists and implies a lack of certainty.
 13.
Publication of the results of scientific investigations enables other scientists to verify these results.
 14.
Scientific investigations always follow a series of rigidly defined steps.
 15.
Resolution is a microscope’s power to increase an object’s apparent size.
 16.
The resolution power of an electron microscope is limited by the physical characteristics of light.
 17.
Units of time are not measured in metric units, so time measurements are not accepted for use with SI units.
 18.
The types of particles that are located in the nucleus of an atom are protons and neutrons, and the types of particles that are located in the energy levels surrounding the nucleus are electrons.
 19.
The atomic number of carbon is 6, so it must contain 12 electrons.
 20.
Most elements are stable if their outermost energy level contains an even number of electrons.
 21.
Atoms in a gas move more rapidly than atoms in a liquid or a solid do.
 22.
The products of an endergonic chemical reaction possess more energy than the reactants from which they are produced.
 23.
The amount of energy needed to cause a chemical reaction to start is called activation energy.
 24.
When an enzyme binds with its substrate, the activation energy needed for the chemical reaction to occur is raised.
 25.
Enzymes speed up a chemical reaction by increasing the activation energy of the reaction.
 26.
Without enzymes, chemical reactions necessary for life would not occur at a rate sufficient to sustain life.
 27.
Free hydrogen ions can react with water molecules and form a positively charged ion, the hydronium ion.
 28.
Bases tend to have a sour taste, while acids tend to have a bitter taste.
 29.
Buffers can neutralize acids, but they do not affect bases.
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 30.
Biology is the study of
a.
minerals.
c.
the weather.
b.
life.
d.
energy.
 31.
Instructions for development that are passed from parents to offspring are known as
a.
a species plan.
c.
genes.
b.
organ codes.
d.
natural selections.
 32.
Homeostasis means
a.
a change over long periods of time.
c.
rapid change.
b.
keeping things the same.
d.
the same thing as evolution.
 33.
Which of the following is a means by which heterotrophs can obtain energy?
a.
using water, carbon dioxide, and energy from the sun to produce sugars
b.
using water and carbon dioxide to produce energy-rich compounds
c.
consuming autotrophs
d.
consuming simple chemicals from the environment and using them to assemble complex chemicals and structures needed by the organism
 34.
Which of the following is not necessarily a distinct property of living things?
a.
homeostasis
c.
complexity
b.
metabolism
d.
reproduction
 35.
All organisms are composed of
a.
diatoms.
c.
cells.
b.
cellulose.
d.
None of the above
 36.
Scientific hypotheses are most often tested by the process of
a.
communicating.
c.
experimenting.
b.
inferring.
d.
analyzing data.
 37.
A unifying explanation for a broad range of observations is a
a.
hypothesis.
c.
prediction.
b.
theory.
d.
controlled experiment.
 38.
Most typically, the order in which the steps of the scientific method are applied is
a.
observations, predictions, hypothesis, controlled testing, theory, verification.
b.
predictions, observations, hypothesis, theory, controlled testing, verification.
c.
observations, hypothesis, predictions, controlled testing, theory, verification.
d.
observations, hypothesis, predictions, controlled testing, verification, theory.
 39.
Atoms are composed of
a.
protons with a positive charge.
c.
electrons with a negative charge.
b.
neutrons with no charge.
d.
All of the above
 40.
Which of the following states of matter contain(s) particles that are tightly linked together in a definite shape?
a.
solid
c.
gas
b.
liquid
d.
solid and liquid
 41.
The bond formed when two atoms share a pair of electrons is called a
a.
hydrogen bond.
c.
covalent bond.
b.
nonpolar bond.
d.
water bond.
 42.
An atom that has gained or lost electrons is called a(n)
a.
molecule.
c.
ion.
b.
nucleon.
d.
element.
 43.
Which of the following statements most accurately describes the difference between an ionic bond and a covalent bond?
a.
Atoms held together by ionic bonds separate when placed in water while atoms held together by covalent bonds do not separate in water.
b.
Ionic bonds hold together atoms of two different types, while covalent bonds hold together atoms of the same type.
c.
Electrons are exchanged between atoms held together by an ionic bond, but they are shared between atoms held together by a covalent bond.
d.
Ionic bonds form between atoms that carry opposite charges, while covalent bonds form between uncharged atoms.
 44.
A reaction in which the products have less energy than the reactants is
a.
an endergonic reaction.
c.
a filamentous reaction.
b.
an exergonic reaction.
d.
impossible.
nar002-1.jpg
 45.
Refer to the graph above. Which of these statements is true regarding the graph?
a.
Reaction “2” occurs faster than Reaction “3” because Reaction “2” requires more energy than Reaction “3.”
b.
The difference in the graphs shown for Reaction “2” and Reaction “3” is due to a difference in the activation energy needed for these reactions.
c.
Reactant “A” contains more energy at the beginning of the reaction than Product “C” has after the reaction.
d.
All of the above
nar003-1.jpg
 46.
Refer to the graphs above. Which graph illustrates what happens during an exergonic reaction?
a.
Graph “A”
b.
Graph “B”
c.
Both graphs; they each show a different stage of an exergonic reaction.
d.
Neither graph shows an exergonic reaction.
 47.
Refer to the graphs above. Which graph illustrates a reaction during which reaction energy is released into the environment?
a.
Graph “A”
b.
Graph “B”
c.
Both graphs, since all chemical reactions release energy into the environment
d.
Neither graph, since chemical reactions do not involve energy
 48.
Enzymes
a.
are able to heat up molecules so that they can react.
b.
provide CO2 for chemical reactions.
c.
are biological catalysts.
d.
absorb excess heat so that reactions occur at low temperatures.
 49.
A neutral solution has an equal number of
a.
hydrogen and hydronium ions.
c.
hydrogen and hydroxide ions.
b.
hydroxide and hydronium ions.
d.
oxygen and hydrogen ions.
 50.
Buffers
a.
are of relatively little importance in living things.
b.
are formed when a large number of hydroxide ions are released in a solution.
c.
are formed when a large number of hydronium ions are released in a solution.
d.
tend to prevent great fluctuations in pH.

 

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