Test 1 Review

An observation must:

Look for cause-and-effect relationships or interesting patterns

Urine, with a pH of 6, is _________ times more acidic than seawater, with a pH of 8. • 10 • 8 • 6 • 1,000 • 100

• 100

Of all the elements that occur on earth, how many are found in your body? • 90 • 25 • 4 • 10 • 116

• 25

How many hydrogen bonds are explicitly represented in this figure? • 8 • 4 • 0 • 1 • 10

• 4

Which of the following statements is true about acids and bases? • Acids and bases do not react with each other. • Acids mixed with bases neutralize each other. • Acids mixed with bases make stronger acids. • Acids will neutralize bases, but bases will not neutralize acids. • Bases will neutralize acids, but acids will not neutralize bases.

• Acids mixed with bases neutralize each other.

Which of the following is not an important biological function of lipids? • insulation • regulation of growth and development • energy storage • protection of internal organs and tissues • All of the above are true.

• All of the above are true.

All lipids are: • polymers of fatty acids. • not soluble in water. • triglycerides. • polar. • hydrophilic.

• not soluble in water.

A complex polymer built of monosaccharides is called a(n): • polypeptide. • polysaccharide. • protein. • ketone. • aldehyde.

• polysaccharide.

Glycogen belongs in the class of molecules known as: • amino acids. • monosaccharides. • proteins. • polysaccharides. • nucleic acids.

• polysaccharides.

Well-designed experiments are essential to testing hypotheses because:

Controlling variables makes experiments more powerful

Independent variable vs. Dependent variable

IV: Some measurable entity at the start of a process and can be changed - generally the x-axis DV: Created by the process being observed and whose value cannot be controlled - generally the y-axis

Pseudoscience characteristics:

Individuals make: - Scientific-sounding claims NOT supported by a trustworthy, methodical scientific studies

What is the null hypothesis?

- A negative statement that proposes that there is no relationship between two factors. Example: If I do X, then nothing should change. - Both null and alternative hypotheses are equally valid, but the null is easier to disprove. This is because a single piece of evidence or a single new observation that contradicts a null is sufficient for us to reject it and conclude that an alternative hypothesis must be considered.

What is statistics?

- A set of analytical and mathematical tools designed to help researchers gain understanding from the data they gather. - The more participants, the better if you want to draw general conclusions about natural phenomena. - Statistics can help us identify whether relationships exist between variables. - Because much variation exists in the world, statistics can help us evaluate whether any differences between a treatment group and a control group can be attributed to the treatment rather than random chance.

Common visual displays of data used in biology

- Bar graph - Line graph - Pie chart

Why and when do people develop superstitions?

- Because of anecdotal evidence (seen once or twice but never really been tested). This is often unreliable and untested. - We develop behaviors that we think are necessary for certain outcomes. - This is not part of a natural phenomenon and so it has no part in biology due to its irrationality.

Why do we have to seek to stay away from biases?

- Because they can influence our behavior, including our collection and interpretation of data. - With careful controls, it is possible to minimize such biases.

A hypothesis must:

- Clearly establish mutually exclusive alternative explanations for a phenomenon - Generate testable predictions

What is another hallmark of an extremely well-designed experiment?

- Combing blind/double-blind strategies in a randomized, controlled, double-blind study.

What does scientific thinking enable us to do?

- Helps us make wise decisions - Statistics also help us make decisions

What are two unifying themes in the diversity of living organisms?

- Hierarchical organization: Life is organized on many levels within individual organisms, including atoms, cells, tissues, and organs. And in the larger world, organisms themselves are organized into many levels: populations, communities, and ecosystems within the biosphere. - The power of evolution: Evolution, the change in genetic characteristics of individuals within populations over time, accounts for the diversity of organisms, but also explains the unity among them.

Difference between hypothesis and theory

- Hypothesis: Proposes an explanation for a phenomenon; leads to testable predictions. - Theory: Hypothesis for natural phenomena that is exceptionally well-supported by empirical data; it has withstood the test of time and is unlikely to be altered by any new evidence. This is often seen as a "fact".

What is a superstition?

- Irrational belief that actions that are not logically related to a course of events can influence its outcome.

Why does visual display of data is important?

- It helps us understand and explain phenomena - It condenses large amount of information into a more easily digested form - It helps readers think about and compare data, ultimately helping them to synthesize the information and see useful patterns

Why are repeated experiments important?

- It increases our confidence - Science can be misleading because once is not enough - We also want to watch out and minimize biases

What are some characteristics of science?

- It is curious - Asks questions about how the world works - Seeks answers

What is science?

- It is not simply a body of knowledge or a list of facts to be remembered - Science is an intellectual activity, encompassing observation, description, experimentation, and explanation of natural phenomena (does not deal with supernatural)

Devising a testable prediction

- Keep in mind several possible explanations could be true - Devise a prediction from your hypothesis

What is pseudoscience?

- Literally means "false science" - Pseudoscience and misleading anecdotal evidence may obscure the truth

Controlling variables

- Most important feature of a good experiment - The attempt to minimize any differences between a control group and an experimental group other than the treatment itself

What does the scientific thinking consist of?

- Observe a phenomenon - Propose an explanation - Test the explanation with experiments

What are the limits of science?

- Science is not the only way to understand nature - Science cannot address every question posed by man - Cannot prove/disprove God's existence, cannot objectively determine elegance or beauty - Cannot give us insights into the generation of value judgments and other types of non-quantifiable, subjective information.

Characteristics of statistics

- The greater the difference between two groups & the smaller the variation, the more confident we are about our conclusion - We may find positive correlations - Statistical analyses can help us organize and summarize information

What is the scientific method/thinking?

- The process of examination and discovery - This is a flexible, adaptable, and efficient pathway to understanding the world because it tells us when we must change our minds.

What is one of the most common functions of visual data?

- To present the relationship between two variables, such as in a graph

The goal of a prediction is

- To propose a situation that will give a particular outcome if your hypothesis is true, but that will give a different outcome if it is not - To use "if" and "then" types of statements (scientific thinking)

The 4 elements common to most experiments are:

- Treatment: Experimental condition applied to research subjects - Experimental group: A group of research subjects who are exposed to a particular treatment - Control group: A group of research subjects who are treated identically to the experimental group with the one exception that they are not exposed to the treatment (aka, placebo group) - Variables: Characteristics of your experimental system that are subject to change

What is biological literacy?

- Uses the process of scientific inquiry to think creatively about real-world issues - Communicates thoughts to others so that it makes sense - Integrates these ideas into your decision making

How do we understand the world?

- We wonder why something is the way it is, and then we decide to try and find out the answer

How do you know if it is true?

- You have to ask questions about the things you see, and the things that are advertised: does it have scientific proof or evidence? - You got to think scientifically

How do we correctly draw conclusions?

-It is essential to hold constant all those variables we are not interested in. - Control and experimental groups should differ only with respect to the treatment of interest. - Differences in outcomes between the groups can then be attributed to the treatment.

The 4 areas of focus of the 2 major themes are:

1. The chemical, cellular, and energetic foundations of life 2. The genetics, evolution, and behavior of individuals 3. The staggering diversity of life and the unity underlying it 4. Ecology, the environment, and the subtle and important links between organisms and the world they inhabit

What is the alternative hypothesis?

A statement that is contrary to the null hypothesis. Example: If I do X, then there was a change. -It is, however, impossible to prove a hypothesis is absolutely true. You can prove it right but not 100%.

If you wanted to test if antibacterial soap worked better than regular soap, which answer has the strongest experimental design? D.

A. Have people in the experiment wash with antibacterial soap first and later with regular soap and compare. B. Have two groups of people wash with either antibacterial soap or regular soap and compare. C. Have two groups of people wash with either antibacterial or regular soap, without knowing which type of soap is being used, and compare. D. Have two groups of people wash with either antibacterial or regular soap, with neither the researchers nor the groups knowing which type of soap is being used, and compare. -This helps us get away from biases.

What is an experiment?

An experiment is devised to show that if the hypothesis is not true, our experimental results will cause us to reject the hypothesis - Use previous knowledge during the critical experiment

Anecdotal evidence: Characteristics

Based on only one or a few personal observations, people conclude that there is or is not a link between two things.

Drawing conclusions from the experiment

Based on the results of experimental tests, we can revise a hypothesis and explain the observable world with increasing accuracy. A great strength of scientific thinking, therefore, is that it helps us understand when we should change our minds.

Why is the scientific thinking empirical?

Because it is based on experience and observations that are rational, testable, and repeatable.

Experimental designs

Blind experimental design • The experimental subjects do not know which treatment (if any) they are receiving. Double-blind experimental design • Neither the experimental subjects nor the experimenter knows which treatment the subject is receiving.

Placebo effect

Phenomenon in which people respond favorably to any treatment Placebo effect highlights the need for comparison of treatment effects with an appropriate control group.

How are pseudoscience and anecdotal evidence similar?

Pseudoscience and anecdotal observations often lead people to believe that links between two phenomena exist, when in fact, they don't.

Science vs. Technical innovations and development

Some things seem scientific, but they are not. Rather, some things are technical innovations and developments (such as construction of new engineering marvels or the heroic surgical separation of conjoined twins). While they frequently rely on sophisticated scientific research, they represent the application of research findings to varied fields such as manufacturing and medicine to solve problems.

Null and alternative hypothesis example

Statement: Echinacea reduces the duration and severity of the symptoms of the common cold. - Null: If I take echinacea while I have the common cold, then nothing should happen; all symptoms will remain the same - Alternative: If I take echinacea when I have the common cold, then the severity and symptoms will be reduced.

What are the basic steps in the scientific thinking?

Step 1: Make observations. Step 2: Formulate a hypothesis. Step 3: Devise a testable prediction. Step 4: Conduct a critical experiment. Step 5: Draw conclusions and make revisions. - This process proceeds in a straight line. Conclusions, for example, lead to new observations and refined hypothesis.

What is scientific literacy?

This is - Thinking scientifically - Using knowledge to make wise decisions - Important in our lives - Important in matters of biology because it looks at how things affect you

Positive correlations

When one variable increases/decreases, so does the other variable

What is a randomized study?

When subjects are randomly assigned into experimental and control groups.

Which of the following statements about cellulose is FALSE? • The cellulose we eat passes right through our digestive system unused. • Cellulose has a slightly different three-dimensional structure from starch. • Although it is not digestible, cellulose is still important to humans' diets. • Cellulose and starch are made from similar molecules. • All of the above statements about cellulose are TRUE.

• All of the above statements about cellulose are TRUE.

Carbohydrates: • act as a relatively quickly available source of fuel. • serve as carbon skeletons that can be rearranged to form other molecules that are essential for biological structures and functions like nucleic acids. • in the form of oligosaccharides are often covalently bonded to proteins and lipids on the outer cell surface, where they serve as cell recognition signals. • are a good source of sustained energy when they come in the form of polysaccharides. • All of the above.

• All of the above.

__________ is the smallest chemical unit of a type of pure substance. • An atom • A proton • A molecule • An amino acid • A cell

• An atom

Which statement about phospholipids is FALSE? • They are hydrophilic at one end. • They contain glycerol linked to fatty acids. • They are a major constituent of cell membranes. • They are hydrophobic on one end. • Because their phosphate groups repel each other, they are used as organisms' chief form of short-term energy.

• Because their phosphate groups repel each other, they are used as organisms' chief form of short-term energy.

Which of the following is NOT a property of water? • It is less dense when frozen than when it's a liquid. • It is a good solvent because both polar and nonpolar molecules dissolve in it. • It takes a lot of energy to raise the temperature of water. • Water molecules stick to each other. • A lot of energy must be withdrawn from water in order to lower its temperature.

• It is a good solvent because both polar and nonpolar molecules dissolve in it.

Why do coastal areas have milder, less variable climates than inland areas? • Because water is a good solvent, it is able to dissolve the photons in light, reducing their ability to heat or cool the land. • Large bodies of water have high salt concentrations and salt absorbs a large proportion of the light energy that would have warmed the land. • Coastal areas are concentrated near the equator, which varies less than other parts of the globe in the angle at which the sun's light hits it. • Large bodies of water, especially oceans, can absorb huge amounts of heat from the sun during warm times of the year, reducing temperature increases on the land. Similarly, during cold times of year the ocean slowly cools, giving off heat that reduces the temperature drop on shore. • None of the above. No one knows why coastal areas have milder, less variable climates than inland areas.

• Large bodies of water, especially oceans, can absorb huge amounts of heat from the sun during warm times of the year, reducing temperature increases on the land. Similarly, during cold times of year the ocean slowly cools, giving off heat that reduces the temperature drop on shore.

Which of the following molecules is NOT formed by covalent bonding? • NaCl • H2 • H2O • CH4 • O2

• NaCl

Which of the following is a common role that sterols play in the human body? • They are used as energy storage molecules. • They are important components of cell membranes. • They are used as primary fuel molecules for cellular metabolism. • When eaten in the diet, they help prevent heart disease by lowering blood pressure. • None of the above is true about sterols.

• None of the above is true about sterols.

What is missing from this cell of the periodic table? • The atomic number for nitrogen, 7 • The atomic number for nitrogen, 6 • The atomic number for nitrogen, 8 • The atomic number for nitrogen, 14 • The atomic number for nitrogen, 28

• The atomic number for nitrogen, 7

A chemical compound that releases OH- into a solution is called: • a base. • a salt. • a solvent. • a hydroxide ion. • an acid.

• a base.

A solution's acidity is: • a measure of its negative charge (the stronger the negative charge, the more acidic the substance). • a measure of the number of nucleotide bases in the solution. • a measure of the amount of buffer molecules in the solution. • a measure of the number of all dissolved molecules in a solution. • a measure of the H+ (free-floating protons) in it.

• a measure of the H+ (free-floating protons) in it.

A buffer is a chemical that: • can quickly absorb excess H+ ions to keep a solution from becoming too acidic. • can quickly release H+ ions to counteract any increases in the OH- concentration in a solution. • is identical to baking soda. • restores the pH of a solution to 7.0. • a) and b) are both true.

• a) and b) are both true.

An atom can be changed into an ion by adding or removing: • a neutron. • an orbital shell. • an electron. • a proton. • an isotope.

• an electron.

The number of protons in an element, also called its ____________, identifies the element. • nucleus • atomic number • ion • charge • atomic weight

• atomic number

All matter on earth, both living and non-living, is made up of: • carbohydrates. • atoms. • DNA. • cells. • phospholipids.

• atoms.

Glucose that circulates in your blood has one of three fates: it is used to fuel cellular activities, it can be converted into fat, or it can _______. • be stored temporarily as glycogen • be converted into starch • be converted into fructose and linked together • serve as a buffer • be broken down into simple sugars

• be stored temporarily as glycogen

Certain molecules act like bank accounts for H+ ions because they can absorb excess H+ ions to keep a solution from becoming too acidic and release H+ ions to keep the solution from becoming too basic. Such molecules are called: • catalysts. • buffers. • reducing agents. • oxidating agents. • enzymes.

• buffers.

On food packages, "insoluble fiber" refers to plant material that we can't fully digest but is important for maintaining a healthy digestive tract. This substance refers to a(n): • amino acid. • carbohydrate. • protein. • lipid. • nucleic acid.

• carbohydrate.

Which of the following elements have four electrons in their outer shells? • carbon and silicon • nitrogen and phosphorus • fluorine and chlorine • oxygen and sulfur • boron and aluminum

• carbon and silicon

Which five chemical elements make up 93-97% of the biomass in plants, animals, fungi, and bacteria? • carbon, oxygen, hydrogen, potassium, nitrogen • carbon, oxygen, hydrogen, sulfur, nitrogen • carbon, oxygen, hydrogen, nitrogen, phosphorous • carbon, oxygen, hydrogen, sulfur, phosphorus • carbon, oxygen, hydrogen, sulfur, potassium

• carbon, oxygen, hydrogen, nitrogen, phosphorous

An unsaturated fatty acid is one in which: • carbon-carbon double bonds are present in the hydrocarbon chain. • not all of the carbons in the hydrocarbon chain are bonded to hydrogen atoms. • there are an odd number of subunits in the hydrocarbon chain. • there are an even number of subunits in the hydrocarbon chain. • carbon-carbon double bonds are not present in the hydrocarbon chain.

• carbon-carbon double bonds are present in the hydrocarbon chain.

Which of the following is a polysaccharide? • glucose, the chief cellular energy source • cellulose, the primary component of plant cell walls • fructose, one of the most important blood sugars • insulin, the chief blood sugar regulator • All of the above are polysaccharides.

• cellulose, the primary component of plant cell walls

There are three principal types of bonds that hold multiple atoms together. These are: • hydrogen bonds, ionic bonds, and glycosidic linkages. • covalent bonds, ionic bonds, and hydrogen bonds. • covalent bonds, ionic bonds, and disulfide bonds. • ionic bonds, hydrogen bonds, and ester bonds. • phosphate bonds, disulfide bonds, and hydrogen bonds.

• covalent bonds, ionic bonds, and hydrogen bonds.

Sucrose (table sugar) and lactose (the sugar found in milk) are examples of: • simple sugars. • polyunsaccharide sugars. • disaccharides. • monosaccharides. • naturally occurring enzymes.

• disaccharides.

Relative to protons: • electrons have approximately the same mass. • electrons have a significantly stronger positive charge. • electrons have significantly greater mass. • electrons have significantly less mass. • None of the above; electrons have no mass.

• electrons have significantly less mass.

Saturated fatty acids have _________________ than unsaturated fatty acids, which is why they exist as a ____________ at room temperature. • more carbon atoms; solid • fewer double bonds; solid • more double bonds; liquid • fewer hydrogen atoms; solid • more glycerol molecules; liquid

• fewer double bonds; solid

Lactose is a combination of: • glucose and ribose. • sucrose and fructose. • glucose and galactose. • glucose and maltose. • glucose and fructose.

• glucose and galactose.

Which of the following are all monosaccharides? • glucose, fructose, and galactose • starch, cellulose, and glycogen • fructuse and cellulose • glucose and maltose • glycogen and glucose

• glucose, fructose, and galactose

The pH of a fluid is a measure of: • its capacity to function as a soap. • how acidic or basic it is. • the amount of adenosine triphosphate (ATP) in it. • its enzymatic stability. • the concentration of phosphate groups.

• how acidic or basic it is.

Water molecules form which type of bond with other water molecules? • disulfide bridges • ionic bonds • hydrogen bonds • covalent bonds • atomic bonds

• hydrogen bonds

The four most abundant elements in living organisms are: • sodium, nitrogen, carbon, and silicon. • carbon, nitrogen, oxygen, and calcium. • carbon, hydrogen, nitrogen, and phosphorus. • carbon, nitrogen, potassium, and oxygen. • hydrogen, nitrogen, oxygen, and carbon.

• hydrogen, nitrogen, oxygen, and carbon.

One important difference between covalent and ionic bonds is that: • in covalent bonds two atoms share electrons while in ionic bonds two atoms of opposite charge are attracted to each other. • ionic bonds only occur among water-soluble elements. • in ionic bonds two atoms share electrons, while in covalent bonds one atom gives one or more electrons to the other atom. • in ionic bonds both protons and electrons can be shared while in covalent bonds only electrons can be shared. • ionic bonds are much stronger than covalent bonds.

• in covalent bonds two atoms share electrons while in ionic bonds two atoms of opposite charge are attracted to each other.

An element: • is a substance that cannot be broken down chemically into any other substance. • is an atom that has lost either a proton or an electron. • must occur naturally on earth somewhere. • is a component of an atom. • All of the above are true.

• is a substance that cannot be broken down chemically into any other substance.

Some atoms of an element contain more neutrons or fewer neutrons than the most commonly found "version" of the atoms for that element. These "alternate versions" of the standard atom are called: • radioactive elements. • atomic variants. • decayed nuclei. • isotopes. • analogs.

• isotopes.

An atom of iron has the atomic number 26. This means that: • it has an atomic mass of 26. • it has 26 protons. • it has 13 electrons. • it has 13 neutrons. • it has 52 protons.

• it has 26 protons.

Helium is not a reactive molecule because: • its first-level shell is full with two protons. • its second-level shell is full with two electrons. • its first-level shell is full with two neutrons. • its first-level shell is full with two electrons. • Helium is a reactive molecule.

• its first-level shell is full with two electrons.

The principal components of cell membranes are: • carbohydrates. • nucleic acids. • lipids. • glycoproteins. • proteins.

• lipids.

Multiple atoms linked together are collectively called a(n): • molecule. • element. • reactant. • substrate. • isotope.

• molecule.

Pure water and aqueous solutions that are neither acidic nor basic are said to be: • buffers. • neutral. • translucent. • transparent. • alkaline.

• neutral.

The nucleus of an atom is usually made up of: • protons, neutrons, and proteins that hold them together. • protons, which have a positive electrical charge, and proteins, which hold them together. • neutrons, which have no electrical charge. • neutrinos, which have no electrical charge. • protons, which a positive charge, and neutrons, which have no electrical charge.

• protons, which a positive charge, and neutrons, which have no electrical charge.

The figure represents which class of chemical compounds? • fats • acids • sterols • carbohydrates • proteins

• sterols

The tendency of molecules to stick together, called cohesion, is stronger in water than in other liquids because: • the polarity of water allows an oxygen atom from one water molecule to form a hydrogen bond with the oxygen atom of another water molecule. • the polarity of water allows a hydrogen atom from one water molecule to form a hydrogen bond with the oxygen atom of another water molecule. • the polarity of water allows a hydrogen atom from one water molecule to form an ionic bond with the oxygen atom of another water molecule. • the polarity of water allows a hydrogen atom from one water molecule to form a hydrogen bond with the hydrogen atom of another water molecule. • the polarity of water allows a hydrogen atom from one water molecule to form a covalent bond with the oxygen atom of another water molecule.

• the polarity of water allows a hydrogen atom from one water molecule to form a hydrogen bond with the oxygen atom of another water molecule.

The most abundant molecule in the cell is: • cellulose. • oxygen. • water. • carbohydrate. • carbon dioxide.

• water.