PreAP Biology - BIOLOGY JUNCTION

Mastering GCSE Biology: Key Concepts Every Student Should Know

Biology is a key subject in the UK’s secondary school curriculum, covering essential topics that form the foundation for further study in science. Whether preparing for exams or aiming to improve understanding, many pupils seek additional support to strengthen their grasp of complex topics. While schools provide structured lessons, some individuals find that extra guidance enhances their confidence and knowledge.

With a well-organised approach and access to expert advice, learners can easily tackle challenging areas. Many resources are available to help clarify difficult concepts, offering structured revision techniques that align with national exam boards.

Here’s how you can stay on top of your biology exam prep:

Understanding the GCSE Biology Syllabus

The curriculum in the UK is designed to develop a strong foundation in scientific principles, ensuring that pupils acquire theoretical and practical knowledge. Different exam boards, including AQA, Edexcel, and OCR, structure their content to assess various skills, from knowledge recall to critical thinking.

Key areas of study include cell structure, human body systems, genetics, ecology, and practical investigations. Laboratory work plays a significant role in helping individuals understand real-world applications of biological processes. Developing a systematic revision plan that covers all core topics can help improve recall and confidence when answering exam questions.

Expert Support for GCSE Biology Pupils

Many learners benefit from additional academic guidance outside the classroom. If you’re looking for specialised biology tutoring UK has several digital platforms with experienced teachers who provide tailored assistance and help individuals refine their understanding of difficult concepts.

Structured sessions focus on key subject areas, offering in-depth explanations and exam techniques to boost performance. Various study formats, including flexible lesson schedules, allow participants to fit extra practice into their routines. With expert input, learners can develop effective strategies for problem-solving and gain a deeper appreciation of scientific ideas.

Cell Biology: The Foundation of Life

Cells are the basic units of life, forming the building blocks of all living organisms. Understanding how they function is crucial to grasping more advanced biological concepts.

There are two primary cell types: prokaryotic and eukaryotic. Prokaryotic cells, found in bacteria, lack a nucleus, while eukaryotic cells, present in plants and animals, contain a nucleus and other specialised structures.

Key cellular functions include respiration, protein synthesis, and reproduction. Mitosis and meiosis are essential processes that enable growth, repair, and genetic variation. Mastering these principles is vital for tackling the topics of genetics, physiology, and ecology later in the syllabus.

Human Body Systems and Their Functions

The human body consists of interconnected systems that work together to maintain overall health. Each system has a specific role, ensuring that essential functions such as respiration, digestion, and circulation operate efficiently.

The circulatory system transports oxygen and nutrients to cells, while the respiratory system facilitates gas exchange. The digestive system processes food, breaking it down into absorbable components, and the nervous system transmits signals between the brain and body.

Understanding how these systems interact provides insight into human physiology and medical advancements. Recognising the importance of lifestyle choices, including a balanced diet and regular exercise, can also enhance knowledge of health and disease prevention.

Genetics and Evolution: Understanding Heredity

Genetics explains how traits are passed from one generation to the next. DNA, the molecule carrying genetic information, plays a fundamental role in inheritance, influencing characteristics such as eye colour and height.

Gregor Mendel’s work on pea plants laid the foundation for modern genetics, demonstrating how dominant and recessive traits are inherited. Understanding Punnett squares and genetic probability helps explain patterns of inheritance.

Evolution, driven by natural selection, shapes the diversity of life. Organisms with advantageous traits are more likely to survive and reproduce, passing on beneficial characteristics to future generations. Studying these principles helps explain biodiversity, adaptation, and species survival over time.

Ecology and the Environment

The natural world is made up of interconnected ecosystems, where organisms depend on each other and their surroundings for survival. Understanding ecological relationships helps explain how species coexist and adapt to environmental changes.

Biodiversity plays a key role in maintaining balance within ecosystems. When habitats are disturbed due to deforestation, pollution, or climate change, species struggle to survive, leading to population declines and ecosystem instability. Conservation efforts aim to protect endangered species and restore damaged environments.

Human activity has a direct impact on the planet, influencing air and water quality, weather patterns, and resource availability. Learning about sustainability, recycling, and conservation measures can help individuals make informed choices that reduce environmental harm.

Photosynthesis and Respiration

Plants use photosynthesis to convert sunlight into energy, providing the foundation for life on Earth. This process takes place in chloroplasts, where carbon dioxide and water, in the presence of light, produce glucose and oxygen.

Respiration, on the other hand, allows organisms to release energy stored in food. Aerobic respiration requires oxygen and occurs in cells to produce energy for movement, growth, and repair. Anaerobic respiration, which happens when oxygen is scarce, provides a short-term energy source but also leads to the production of lactic acid in animals.

Both processes are essential for survival. Photosynthesis supports life by generating oxygen and food, while respiration ensures energy is available for essential biological functions.

Homeostasis and Response

The body maintains a stable internal environment through homeostasis. This regulation is essential for processes such as temperature control, blood sugar regulation, and hydration balance.

The nervous system and endocrine system work together to respond to changes in the body. For example, the brain detects fluctuations in temperature and signals the skin to adjust accordingly. The pancreas regulates glucose levels by releasing insulin and glucagon as needed.

Reflex actions, such as pulling away from a hot surface, demonstrate how the nervous system reacts quickly to external stimuli. Understanding these mechanisms helps explain how the body adapts to different conditions and maintains overall stability.

Understanding biology at this level provides a strong foundation for further study in science and related fields. By developing knowledge of key topics, practical skills, and exam techniques, learners can approach assessments with greater confidence.

With the right study strategies and support, complex topics become more manageable. Engaging with the subject beyond textbooks through experiments, discussions, and real-world applications can also deepen understanding.

A well-rounded approach to science education not only prepares pupils for exams but also helps them develop critical thinking skills that are valuable for the future.

Is AP Biology a Hard Class? Tips and Insights to Help You Succeed

Advanced Placement (AP) Biology is a course that challenges high school students with college-level material. While many find it demanding, it’s also incredibly rewarding for those interested in science and biology-related fields. With the right approach, you can navigate the course’s challenges and achieve success. The skills and knowledge gained from AP Biology can also provide a solid foundation for future academic and career pursuits. Here’s everything you need to know about AP Biology, including whether it’s hard and how to succeed.

What Is AP Biology?

AP Biology is a college-level biology course offered in high school, designed to provide a deeper understanding of biological concepts.

What do you learn in AP Biology? Students delve into topics such as evolution, cellular processes, genetics, ecology, and the interactions between organisms and their environments.

This course includes hands-on lab experiments, which are vital for grasping the concepts discussed in class. These labs encourage critical thinking and problem-solving skills, allowing students to approach biological challenges like scientists.

Labs range from examining cell structures to studying ecosystems, helping students connect theory to real-world biology.

Who Should Take AP Biology?

AP Biology is ideal for students who:

● Are genuinely interested in exploring science and biology.

● Are considering a career in health, medicine, or research.

● Feel comfortable with challenging coursework and independent study.

Choosing to take AP Biology is a big step, and it’s natural to wonder if it’s the right fit for you. Instead of overthinking, ask yourself, “Can you write me an essay explaining why I’m excited to take this course?” If the answer highlights your passion for science and eagerness to learn, AP Biology could be the perfect opportunity to grow academically and earn college credits.

Understanding the Difficulty of AP Biology

Is AP Biology hard? Many consider AP Biology one of the toughest AP courses due to its demanding curriculum and in-depth topics. However, the difficulty depends on your background, study habits, and dedication.

Exam Focus and Demands

The AP Biology exam is comprehensive, requiring a strong grasp of numerous biological concepts. It includes multiple-choice questions, grid-in calculations, and free-response essays. You’ll need to analyze experimental data, interpret results, and apply your knowledge to unfamiliar scenarios.

How long is the AP Biology exam? The exam lasts 3 hours, testing your ability to think critically and synthesize information quickly. With its breadth of content and time constraints, it’s no wonder some students ask, “Is the AP Biology exam hard?” Understanding how to study for AP Biology exam effectively is key to managing its demands and improving your performance. Proper preparation can significantly enhance your chances of success.

How to Succeed in AP Biology

Success in AP Biology requires consistent effort, effective study habits, and active engagement in class. Try these practical tips to boost your performance.

Develop Strong Study Habits

Strong study habits are essential to succeed in AP Biology. Here’s how to study for AP Biology:

● Start early: Begin reviewing notes and concepts as soon as the course starts. Cramming the week before the exam won’t work for a course of this depth. Consistency is key, so make studying a regular part of your routine.

● Use resources: Leverage textbooks, online tools, and AP Biology prep books to reinforce your understanding. Don’t hesitate to explore videos or interactive platforms that explain complex topics in a more visual way.

● Practice exams: Get comfortable with the structure and question types featured in the AP Biology exam. Practice regularly to build confidence. Review your mistakes thoroughly to identify areas that need improvement.

Make the Most of Class Time

Maximizing your class time is one of the best ways to grasp difficult material. Here’s how:

● Participate actively: Participate actively by asking questions, joining discussions, and clarifying difficult concepts. Engaging in class helps you retain information and demonstrates your commitment to learning.

● Stay organized: Keep a dedicated notebook for notes, diagrams, and important terms. This will be your go-to resource during exam prep. Adding color coding or tabs can make finding key information quicker and more efficient.

● Collaborate with peers: Study groups can help you learn from others and fill in gaps in your understanding. Working with classmates also gives you the opportunity to explain concepts, which reinforces your own learning. With these strategies, you’ll have a strong foundation and know how to study for AP Biology effectively.

Is AP Biology Worth Taking?

So, is AP Biology worth it? The answer depends on your goals.

If you’re passionate about science and considering a career in biology, medicine, or environmental studies, AP Biology can give you a significant head start. The skills and knowledge you gain in this course can also strengthen your college applications, showcasing your academic commitment.

The course not only helps you develop critical thinking skills but can also earn you college credits, saving time and money later.

Even if science isn’t your career focus, AP Biology provides a valuable understanding of the natural world, which can be beneficial in any field. Plus, it can give you a deeper appreciation for the scientific processes that impact everyday life.

The time and effort you dedicate to this course can create opportunities and sharpen your academic abilities.

Conclusion: Just How Hard Is AP Biology?

So, is AP Biology a hard class? The answer depends on your preparedness and mindset.

While it’s undoubtedly a challenging course, it’s also incredibly rewarding for students who approach it with dedication and the right strategies. The sense of accomplishment you’ll feel after tackling such a demanding course is well worth the effort.

By focusing on consistent study habits, making the most of class time, and leveraging available resources, you can overcome the hurdles and succeed. Success in AP Biology can boost your confidence in handling future academic challenges.

Whether your goal is to earn college credits, prepare for a science-related career, or simply explore your passion for biology, AP Biology is a worthwhile challenge that can set you up for future success.

What You Need to Know About Becoming a Biology Major

People choose to major in Biology for reasons that go beyond a fascination with living organisms. So, what’s so special about that? In essence, it satisfies a deep curiosity about life and answers fundamental questions about the natural world. And, that’s not it. On top of that, many are motivated by a desire to make a meaningful impact. There are various ways to do that, whether through medicine, conservation, or research. However, this field is very complicated. Thanks to its challenges, people can experience a sense of accomplishment. At the end of the day, mastering complex topics fosters resilience and growth. But the question is “How to handle those challenges successfully?” Read a simple answer below.

Handling Challenges in Education

What is a Biology major path? To be fair enough, the academic journey is as demanding as it is rewarding. If you want to become a Biology major, you must understand that this path will be filled with challenging courses and rigorous research projects. And of course, this overwhelming workload can lead to intense reactions to stress. So, if you don’t want to face the negative consequences of that, you should learn how to balance work, exams, and writing assignments. The best way to do that is by using additional support. For me personally, the best solution was to pay someone to write my essay so that I could submit it on time without sacrificing sleep. Thanks to Edubirdie which provides online academic assistance, I could keep my passion for Biology alive and manage all my responsibilities. But it’s far not everything that you must know. Read more about this educational journey below.

Confronting the Boundaries of Control

If you think about what lessons biology teaches us, it would be a lot about control. It shows us that life is governed by forces beyond our control, such as evolution, genetic inheritance, and ecological interactions. Sometimes, it can feel frustrating but it’s better to learn this lesson as soon as possible. While pursuing a major in Biology, many young people come up against the limits of human influence and are reminded of the fragility that underlies all living systems. Of course, this can evoke discomfort, but it’s worth facing. This is a necessary confrontation with reality that forces a deeper recognition of what it means to be alive. It forces a deeper recognition of what it means to be alive, so we can keep our hearts soft and open.

Searching for Meaning in Complexity

Any Biology student would confirm that the allure of this science lies not in its simplicity but in its intricacy. To be more accurate, the field doesn’t shy away from the messiness of life; rather, it delves into it. Researchers bravely accept the challenges presented by this field and delve into the messiness of life. They dedicate huge amounts of time to examining the interconnections between organisms and their environments. They also explore the emergence of consciousness, and the process of decay and renewal, which are so exciting for curious minds. By the way, have you ever thought that there is often an underlying need to find meaning amid this complexity for those drawn to this major? Just reflect on that and you’ll notice how you not just seek answers but strive for understanding your place in a world where change is the only constant. Thus, Biology becomes a way of coming to terms with the ever-changing nature of life.

Growth Through Tension and Struggle

If you study Biology, you must be prepared for the fact that this path is fraught with challenges. Just imagine yourself in a laboratory and recall all the failed experiments, difficult concepts, and unexpected outcomes. Sounds pretty scary, isn’t it? Yet, these struggles are not just obstacles to overcome. If we look at them from another perspective, they are the very ground upon which growth takes place. Without setbacks, we wouldn’t progress that much. In general, each setback invites reflection and each obstacle demands adaptation. This is an exciting ongoing process where you come to realize that growth is forged through moments of tension. It’s a valuable life lesson that Biology can teach you. Hence, the pursuit of understanding biology, then, is a lived experience of questioning and reimagining what is possible.

Final Thoughts

So, is biology hard? Definitely, yes. But it should not scare you away. If you pick a Biology program, you will not regret it. In fact, you need to know about both rewards and challenges before applying for a major in Biology. Hopefully, this article has inspired you to follow your passion!

Author’s BIO

Mattew Stoll is a personal tutor and content writer. He works with high school graduates and college students to help them achieve outstanding results in their education. Matthew believes that we all need to explore our full potential in academic settings, so his mission is to help with that.

Conquering Your Biology Paper Starts with Smart Preparation

When you sit down to write a biology paper, it can be scary. So many science terms, so much research, so many expectations. But it doesn’t have to be that hard. If you start with smart preparation, you’ll find that the writing process goes a lot more smoothly, and you’ll feel more confident writing about the most challenging subjects. Let’s break it down into easy steps to ace your Biology paper.

Writing Biology Papers

1. Choose a Focused Topic

A good first step in smart prep is to select a topic that’s relatively narrow and manageable. The subject of Biology is so vast that to succeed, you’ll have to narrow your focus. Your topic will be too broad if you don’t know where to start your search and don’t know when you’ve covered enough. You can overcome these problems by zeroing in on a specific question or issue. For example, instead of “The Human Immune System”, consider “The Role of T-Cells in Fighting Viral Infections”. A narrow topic makes it easier to stay on track and allows you to go deeper in your research.

2. Conduct Thorough Research

Now you have chosen your topic, it is time to get down to business – research! For any good biology paper, your sources always need to be robust. That means peer-reviewed journal articles, books, and academic websites. Be sure to organize your research as you go. Keep a notebook or digital document handy for saving quotations, studies, and other facts that you plan to use in your paper. This will help you avoid a frantic search once you’re ready to put pen to paper.

3. Develop a Clear Thesis Statement

Your biology paper thesis needs to be clear. If your thesis is strong, it will set the direction of your Biology paper while allowing you to focus on the points that you want to make. If we continue with our previous example, a thesis for a biology paper on T-cells could be like this: “T-cells are important because they identify and eliminate infected cells that are infected by viruses, thus preventing the spread of infections”. Your thesis should be concise, specific, and backed by the research you’ve conducted.

4. Create an Outline

An organized outline is perhaps the single most important thing to do when preparing for any paper. Use your outline to map out the order of your essay’s thoughts and arguments so that your ideas flow in a logical manner.

5. Use Visuals to Support Your Argument

Biology papers often grapple with concepts and processes that are hard to describe with words alone. Charts, diagrams, and graphs can help you explain scientific ideas more effectively and make your paper more inviting to read. For instance, if you’re writing about cell division, an easy-to-understand diagram of mitosis can make your explanation easier to follow. Don’t forget to label any visuals you add.

6. Break the Writing Into Sections

Don’t try to write the whole paper simultaneously, as that will leave you frustrated and exhausted. Instead, break up the writing into chunks. Write a paragraph. Or one section. Get that part done well, and then go to the next part of your paper. Having mini-goals makes it less overwhelming and will help you pay equal attention to each part of your paper.

7. Consider Using Essay Writers for Hire

If you have multiple assignments and deadlines to meet, you can get easily stuck and not know what to write first. Or maybe the topic you were assigned is too broad or complex to handle in a given time. In that case, there are services that can help you with this task. Essay writers for hire can help you create a well-researched and well-structured biology paper. This will leave you with some free time for your other projects.

8. Proofread and Edit Your Work

After you have completed your paper, you might be tempted to hit ‘submit’ and call it a day, but take the time to proofread and edit your paper. Your paper should be free of spelling, grammar, and punctuation mistakes, and all of your ideas should flow seamlessly from one section to the next. If you can, you should reread your work after a break with a fresh set of eyes. You may see what you initially didn’t notice.

9. Cite Your Sources Properly

Biology papers rely on a substantial amount of external sources, and they need to be cited properly. Cite the sources using whatever citation style your professor asks for – APA, MLA, or Chicago. Using the correct citation rules gives your work more credibility. If you’re not sure how to cite a source, numerous online tools, such as Citation Machine, can do the formatting for you.

10. Don’t Stress – You’ve Got This!

When you write a biology paper, you don’t have to be afraid. You can be smart about it. You can plan it out. This way, you’ll have your biology paper done in a breeze. Start early. Stay organized. And seek out help when you need it. Remember – you have what it takes to deliver an awesome paper.

Prep Smart, Write Confidently

The key to nailing your biology paper lies in careful preparation, from choosing a specific topic to proofreading the final draft. Every step of the way, your preparation builds on the previous step to a well-researched, effective essay. Preparing well and writing with confidence are the best ways to conquer that college paper. So, grab a pen and get ready to ace your biology paper!

Chapters 1 and 2 PreAP Biology

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Chapters 1 and 2 PreAP Biology

Multiple Choice
Identify the choice that best completes the statement or answers the question.

Biology is the study of

a.	minerals.	c.	the weather.
b.	life.	d.	energy.

All organisms possess DNA. DNA

a.	creates energy for cells.
b.	allows sensitivity to environmental stimuli.
c.	contains information for growth and development.
d.	captures energy from the sun.

Homeostasis means

a.	a change over long periods of time.
b.	keeping things the same.
c.	rapid change.
d.	the same thing as evolution.

The smallest units that can carry on all the functions of life are called

a.	molecules.	c.	organelles.
b.	cells.	d.	species.

Living things

a.	need energy for life processes.
b.	have the ability to reproduce.
c.	are composed of cells.
d.	All of the above

All living things maintain a balance within their cells and the environment through the process of

a.	growth.	c.	homeostasis.
b.	development.	d.	evolution.

A scientist noticed that in acidic pond water some salamanders developed with curved spines. This was a(n)

a.	hypothesis.	c.	observation.
b.	theory.	d.	control.

The English physician Ronald Ross wanted to try to find the cause of malaria. Based on his observations, Dr. Ross suggested that the Anopheles mosquito might spread malaria from person to person. This suggestion was a

a.	prediction.	c.	theory.
b.	hypothesis.	d.	scientific “truth.”

The English physician Ronald Ross knew that the parasite Plasmodium was always found in the blood of malaria patients. He thought that if the Anopheles mosquitoes were responsible for spreading malaria, then Plasmodium would be found in the mosquitoes. This idea was a

a.	prediction.	c.	theory.
b.	hypothesis.	d.	scientific “truth.”

10.

Scientific hypotheses are most often tested by the process of

a.	communicating.	c.	experimenting.
b.	inferring.	d.	analyzing data.

11.

A hypothesis is

a.	a definite answer to a given problem.
b.	a testable possible explanation of an observation.
c.	a proven statement.
d.	a concluding statement.

12.

A unifying explanation for a broad range of observations is a

a.	hypothesis.	c.	prediction.
b.	theory.	d.	controlled experiment.

13.

A hypothesis that does not explain an observation

a.	is known as an inaccurate forecast.
b.	often predicts a different observation.
c.	is rejected.
d.	None of the above

14.

Scientists usually design experiments

a.	with a good idea of the expected experimental results.
b.	based on wild guesses.
c.	in order to develop new laboratory tools.
d.	All of the above

15.

A scientific theory

a.	is absolutely certain.
b.	is unchangeable.
c.	may be revised as new evidence is presented.
d.	is a controlled experiment.

16.

The word theory used in a scientific sense means

a.	a highly tested, generally accepted principle.
b.	a guess made with very little knowledge to support it.
c.	an absolute scientific certainty.
d.	None of the above

17.

observation : hypothesis ::

a.	theory : observation	c.	hypothesis : experiment
b.	guess : hypothesis	d.	theory : control

18.

Which of the following components of a scientific investigation would benefit from communication between scientists?

a.	observing	c.	analyzing data
b.	measuring	d.	All of the above

19.

Scientists share their research results by

a.	publishing in scientific journals.
b.	presenting at scientific meetings.
c.	avoiding conflicts of interest.
d.	Both a and b

20.

Atoms are composed of

a.	protons with a positive charge.
b.	neutrons with no charge.
c.	electrons with a negative charge.
d.	All of the above

21.

The smallest particle of carbon that can retain the chemical properties of carbon is

a.	a carbon molecule.
b.	a carbon macromolecule.
c.	a carbon atom.
d.	the nucleus of a carbon atom.

22.

A substance that is composed of only one type of atom is called a(n)

a.	nucleus.	c.	element.
b.	cell.	d.	molecule.

23.

All matter in the universe is composed of

a.	cells.	c.	atoms.
b.	molecules.	d.	carbon.

24.

The electrons of an atom

a.	are found in the nucleus along with the protons.
b.	orbit the nucleus in various energy levels.
c.	have a positive charge.
d.	are attracted to the positive charge of neutrons.

25.

Atoms that have gained energy

a.	have protons and neutrons that move farther apart.
b.	lose neutrons from the nucleus.
c.	have electrons that move to higher energy levels.
d.	absorb electrons into the nucleus.

26.

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

27.

Because carbon has four electrons in its outer energy level,

a.	it can form bonds with carbon atoms only.
b.	these atoms are naturally chemically stable.
c.	it can react with up to four other atoms to form covalent bonds.
d.	it cannot react with anything other than organic molecules.

28.

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.

29.

Sharing of electrons between atoms of two or more elements

a.	results in the formation of an ion.
b.	results in the formation of a compound.
c.	results in the formation of noble gases.
d.	results in destabilization of the atoms involved.

30.

An atom that has gained or lost electrons is called a(n)

a.	molecule.	c.	ion.
b.	nucleon.	d.	element.

31.

Refer to the graph above. Reaction 1 in the graph

a.	is an energy-storing reaction.
b.	requires a greater activation energy than reaction 2.
c.	may use the same initial reactant condition needed to form product Y.
d.	All of the above

32.

Refer to the graph above. Reaction 3 in the graph

a.	probably occurred in the presence of a catalyst.
b.	requires a greater activation energy than reaction 2.
c.	is the same as reaction 1, but faster.
d.	takes longer than reaction 2.

33.

Refer to the graph above. Which of these statements regarding the graph is true?

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 X contains more energy at the beginning of the reaction than product Z has after the reaction.
d.	All of the above

34.

Changing the course or pathway of a chemical reaction so that it requires less activation energy

a.	is a violation of the laws of nature.
b.	requires higher temperatures than those found within cells.
c.	occurs only when reactants are quickly added to the reaction mixture.
d.	is accomplished by the action of catalysts on reactants.

35.

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.

36.

When a molecule gains an electron, it has been

a.	oxidized.	c.	digested.
b.	reduced.	d.	inactivated.

37.

Oxidation-reduction reactions are important in organisms because they

a.	allow the passage of energy from molecule to molecule.
b.	prevent nuclear reactions from occurring.
c.	allow the creation and destruction of energy.
d.	None of the above; oxidation-reduction reactions do not occur in living organisms.

38.

The concentration of a solution is

a.	the number of particles of a substance in a solvent.
b.	the amount of a solvent that is dissolved in a fixed amount of a solution.
c.	the amount of a solute that is dissolved in a fixed amount of a solution.
d.	the ratio of solute to solvent in a solution.

39.

A neutral solution has an equal number of

a.	hydrogen and hydronium ions.
b.	hydroxide and hydronium ions.
c.	hydrogen and hydroxide ions.
d.	oxygen and hydrogen ions.

40.

The terms base and alkaline refer to solutions that

a.	contain dissolved sodium hydroxide.
b.	contain more hydronium ions than hydroxide ions.
c.	contain more hydroxide ions than hydronium ions.
d.	contain more hydroxide ions than hydrogen ions.

41.

A solution with a pH of 11 is

a.	acidic.	c.	neutral.
b.	alkaline.	d.	a buffer.

42.

Acidic solutions have a pH that is

a.	less than 7.	c.	a negative number.
b.	between 0 and 14.	d.	more than 7.

43.

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.

44.

Atoms become more stable when they form compounds because

a.	they always lose electrons when they form compounds.
b.	their outer orbitals become filled when they form compounds.
c.	they always gain electrons when they form compounds.
d.	their nucleus loses extra protons when they form compounds.

45.

A water molecule is polar because its hydrogen and oxygen atoms

a.	both lose electrons.
b.	become ions.
c.	both gain electrons.
d.	do not share the electrons equally.

46.

Polar molecules such as water have

a.	no negative or positive poles.
b.	both negative and positive poles.
c.	only a negative pole.
d.	only a positive pole.

47.

A molecule that has a partial positive charge on one side and a partial negative charge on the other side is called a

a.	nonpolar molecule.	c.	charged molecule.
b.	polar molecule.	d.	bipolar molecule.

48.

Water is a polar molecule because

a.	it contains two hydrogen atoms for each oxygen atom.
b.	it has a charge.
c.	different parts of the molecule have slightly different charges.
d.	it does not have a charge.

49.

Water molecules break up other polar substances

a.	such as salts.
b.	because of the uneven charge distribution that exists in water molecules.
c.	thus freeing ions in these substances for use by the body.
d.	All of the above

50.

Which of the following characteristics of water is not a result of hydrogen bonding?

a.	adhesive strength
b.	capillarity
c.	cohesive strength
d.	All of the above are a result of hydrogen bonding.