Module 1

Question 1

Biology

Answer 1

is the scientific study of living things

Question 2

science

Answer 2

is a collection of facts, a process, by which we can examine and learn about the natural world around us.

Question 3

in order to be informed citizens…

Answer 3

You need basic knowledge about your health, nutrition, and the environment

Question 4

how do biologists define living

Answer 4

scientists define life through a set of observable characteristics or properties: (1) possess order & organization (2) regulation (3) growth and development (4) perform energy utilization (5) respond to stimuli (6) reproduction (7) undergo evolution (8) are made up of at least one cell, the smallest unit of life that can function independently

Question 5

All cells have these three components

Answer 5

(1) DNA (2) cytoplasm (3) Cell membrane

Question 6

Atoms make up….. which make up….which combine together to make up…. these then make up …. which make up…. which then make up…!

Answer 6

molecules, cells, tissue, organs, organ systems, organism

Question 7

regulation

Answer 7

living things can control their internal environments despite frequent and drastic changes in their external environments.

Question 8

growth and development

Answer 8

living things have genes (made up of DNA) that control the growth and development of each individual

Question 9

perform energy utilization

Answer 9

(metabolism): living things can break down food molecules and utilize them for energy.

Question 10

In ____, the sequencing of the entire human genome (i.e. all of our ______ genes) was completed

Answer 10

2001, 20,000-25,000

Question 11

Cytoplasm

Answer 11

gel-like substance inside the cell (it holds the organelles)

Question 12

cell membrane

Answer 12

regulates what goes in and out of the cell.

Question 13

DNA

Answer 13

the molecule of heredity, for it is the substance that makes up genes

Question 14

prokaryotic

Answer 14

small, no nucleus, no membrane-bound organelles like a nucleus. Examples include bacteria & Archaea Approx. 50% have flagella which are used for movement all have DNA, cell walls, cell membranes, and ribosomes.

Question 15

eukaryotic

Answer 15

has a nucleus and membrane-bound organelles. Example: all other cells (i.e. fungi, plant and animal cells, including human cells)

Question 16

two general types or categories of cells on our planet

Answer 16

(1) Prokaryotic (2) eukaryotic

Question 17

autotrophs

Answer 17

self-feeders” (“auto”=self) that can make their own food, like plants

Question 18

heterotrophs

Answer 18

“other” feeders (“hetero”=other) that need to eat other things, like most life forms on the planet.

Question 19

Classification categories (Dapper King Phillip Came Over For Good Sex)

Answer 19

Domain Kingdom Phylum Class Order Family Genus Species ( Dapper King Phillip Came Over For Good Sex)

Question 20

genus

Answer 20

(1) The genus and species of an organism is equivalent to its scientific name (2)The genus is always capitalized, and both the genus and specific epithet (the second word in the scientific name) are either underlined or italicized (i.e. Homo sapiens is also correct)

Question 21

All living things on the planet are now classified using a three-domain scheme

Answer 21

(1)Domain Bacteria (2)Domain Archaea (3) Domain Eukarya

Question 22

Domain Eukarya

Answer 22

all are eukaryotes (their cells contain a nucleus and membrane-bound organelles)

Question 23

Domain Archaea

Answer 23

Members are all unicellular prokaryotes and all are autotrophs. Most are “extremeophiles” who love living in many different extreme environments such as Yellowstone hot springs (hotter than boiling water!) and around deep sea vents one or more miles below the surface of the ocean. Non-extremeophile archaea such as “methanogens” are found in the intestines of humans (Fig. 13-18) and, especially, in herbivores like deer, cattle, elk, etc. – that’s why these animals (and humans, too!) occasionally expel methane gas. None cause disease that we know of. Most archaea are chemolithotrophs (Fig. 13-9), utilizing inorganic molecules (ammonia, iron, various gases, etc.) for energy (i.e. they are chemosynthetic as opposed to photosynthetic because they make food from chemicals rather than the sun). The enzyme from one archaean (Thermus aquaticus, see Fig. 13-2) is used in biotechnology because it is heat-stable, and others are used in bioremediation (cleaning up) of oil spills (Fig. 13-19). These prokaryotes (as well as some species of bacteria) helped to clean up some of the millions of gallons of oil leaked into the Gulf of Mexico from the BP oil spill.

Question 24

Domain Bacteria

Answer 24

Members are all unicellular, prokaryotic and most are heterotrophs (though some are photosynthetic). Examples include the microbes that cause strep throat, staph infections, chlamydia (an STD), gonorrhea, syphilis, anthrax and E. coli. Actually, less than 1% of bacteria cause disease; most do good things such as recycle nutrients; degrade oil spills or leaks (like the one off the Gulf Coast in 2010), pesticides, and other toxic chemicals; and serve as starter cultures to make cheese and yogurt. some are pathogens (disease-causing agents; p. 522). Bacterial diseases include tuberculosis (TB), bubonic plague, anthrax (these two can be used as bioterrorism weapons), syphilis, gonorrhea, Lyme disease, bacterial meningitis (you hear about this one on the news sometimes regarding high school or college students), strep throat (caused by Streptococcus), staph infections (caused by Staphylococcus), and some food poisonings (caused by Staphylococcus, Salmonella and Escherichia coli, aka E. coli). We all have a normal strain of E. coli in our intestines (Fig. 13-2). The problem occurs when we ingest food such as hamburger, unpasteurized milk or apple juice, or various veggies that have been contaminated with a particularly nasty strain of the bug– O157:H7. This strain of E. coli occurs normally in cattle but can cause serious disease and even death in humans. If any food we eat inadvertently gets contaminated with cow fecal material (during the butchering process or from cow poop on the ground), therein lies the problem! There are up to 20,000 cases of food poisoning due to E. coli O157:H7 each year in the U.S., some of which are fatal. Certain strains of so-called “bad” bacteria occur in some humans, so if people simply washed their hands properly after going to the bathroom, there would be fewer such issues!

Question 25

Kingdom Protista

Answer 25

unicellular autotrophs and heterotrophs. Many of these protists such as Paramecium and Amoeba are found in pond water or in the ocean. A few cause diseases such as malaria.

Question 26

Kingdom Fungi

Answer 26

unicellular and multicellular heterotrophs. Fungi include molds, mildews and mushrooms. Yeasts are the only unicellular fungi. They are used to make beer and wine, and a few strains of yeast cause yeast infections (eek!)

Question 27

Kingdom Plantae

Answer 27

plants! They are multicellular autotrophs (they make their own food via photosynthesis), but a few such as the sundew and Venus fly trap (found in the Carolinas) can also eat insects and, therefore, can be heterotrophs as well.

Question 28

Kingdom Animalia

Answer 28

birds, cats, dogs, humans, etc. We all are animals, and we all are multicellular heterotrophs.

Question 29

scientific method can be applied only to …

Answer 29

objective, observable phenomena, and cannot be applied to religion, politics, art, morals, etc. or anything else of a subjective nature.

Question 30

Steps of the Scientific Method (7)

Answer 30

1. Make an observation – you observe (or have heard) that some people feel that taking the plant extract Echinacea reduces their cold symptoms (Fig. 1-8). 2. Formulate a hypothesis, which is an educated guess or proposed explanation for what you observed (see Fig. 1-8). 3. Develop a testable prediction, which is basically a re-statement of the hypothesis, commonly in a “if X happens, then that means Y…” format (Fig. 1-9 and p. 11). 4. Perform one or more experiments to test your prediction (Fig. 1-10). It is extremely important that experiments be well-designed and have proper controls (p. 16-17). Such an experiment contains a treatment group/experimental group which would be the people taking Echinacea (the treatment) and the control group who are treated exactly the same except that they are taking a placebo (a pill that looks identical but contains no active ingredient – see p. 12) instead of the Echinacea. Variables – any differences between the experimental and control group other than the specific treatment (Echinacea, in this example) - need to be controlled (minimized) as best as possible. A good experiment needs to be replicated/reproduced/repeated (p. 19-20) many times by the same researchers and by other objective researchers before we can be confident in their results. 5. Draw conclusions, make revisions - the results obtained from the experiments may not support the hypothesis, in which case the original hypothesis must be revised and new experiments performed to determine the validity of the revised hypothesis (Fig. 1-13). 6. publish (a major responsibility of many scientific jobs, including professors at universities); and, in rare cases maybe even 7. formulate a theory

Question 31

difference between hypothesis and theory

Answer 31

A theory in science is a verified while a hypothesis is just a guess

Question 32

pseudoscience

Answer 32

scientific sounding claims that are not supported by trustworthy methodical scientific studies E.G. astrology

Question 33

Matter

Answer 33

the “stuff” everything on the planet is made up of, whether it’s solid, liquid, or gaseous

Question 34

Elements

Answer 34

Matter occurs as elements - 92 are naturally-occurring (like gold, silver and carbon) and the rest are human-made.

Question 35

elements that are found in living things in the greatest amounts: “See Hopkins Cafe? They have Mighty Good Salt”

Answer 35

C=carbon, H=hydrogen, O=oxygen, P=phosphorus, K=potassium, I=iodine, N=nitrogen, S=sulfur, Ca=calcium, Fe=iron, Mg=magnesium, Na=sodium, Cl=chlorine (chloride) C HOPKINS Ca Fe Mg Na Cl

Question 36

__% of your body is made up of

Answer 36

96%, oxygen, carbon, hydrogen and nitrogen.

Question 37

trace elements

Answer 37

include iodine (found in your thyroid hormones) and copper as well as weird things like selenium and molybdenum which our bodies need in very small (“trace”) amounts for metabolic processes.

Question 38

atoms

Answer 38

smallest unit of matter that gives the element its properties (and cannot be subdivided without losing those properties)

Question 39

protons

Answer 39

Positively charged, found in nucleus

Question 40

neutrons

Answer 40

no charge, found in nucleus

Question 41

electrons

Answer 41

negatively-charged electrons which circle around the nucleus

Question 42

atomic number

Answer 42

The number of protons in an atom which gives that particular element its properties (i.e. the number of protons in a given element will never change. As an example, carbon has an atomic number of 6; if that changes then the element is no longer carbon!)

Question 43

atomic mass

Answer 43

sum of the number of protons and neutrons in the nucleus of an atom

Question 44

By definition,

Answer 44

By definition, an atom has no charge, so in atoms of a particular element, the # of protons = the # of electrons. So, an atom of carbon has 6 protons and 6 electrons; the 6 positive charges from the protons cancel out the 6 negative charges from the electrons, so the atom is uncharged.

Question 45

isotopes

Answer 45

different forms of element, positive or negative charge

Question 46

radioactive

Answer 46

(isotopes) the nuclei of their atoms are unstable because of the extra neutrons. In the process of attempting to eject these extra neutrons, lots of energy (radioactivity) gets emitted

Question 47

Radioactivity can be used and measured for these things:

Answer 47

a. dating fossils- b. medicine - radioisotopes such as cobalt-60 are used in radiation treatment of cancerous tumors. Other radioisotopes such as radioactive iodine are used in bone scans and PET scans. c. research - Phosphorus-32 and Sulfur-35 are routinely used in research labs working with DNA. These radioisotopes can attach themselves to the DNA, allowing scientists to locate DNA in a cell, sort of like a molecular Global Positioning Device. d. energy sources – uranium and plutonium are used in nuclear reactors in nuclear power plants to generate electricity. Although nuclear energy generates very little greenhouse gas emissions, accidents at these power plants can be fatal, such as the one at Chernobyl, Ukraine about 25 years ago. Other very serious issues can occur from natural disasters such as earthquakes, tsunamis, etc. – there are still tremendous concerns about the nuclear reactors in northern Japan following the March, 2011 tsunami. FYI, the half-life of uranium-235 is about 700 million years – yikes! These isotopes can also be used to make bombs, of course, as we know from WW II.

Question 48

radiometric dating

Answer 48

Radioisotopes (radioactive isotopes) have half-lives, that is they decay (break down) to a more stable form in a known time frame. As an example, it takes 5,730 years for half of a given quantity of carbon-14 to break down to a more stable form. By determining the ratio of carbon-14 (which will radioactively decay) to the more common carbon-12 (which does not break down) in a fossil such as an ancient bone, scientists can tell pretty closely how old that bone is. There are several different isotopes that are used to determine the age of rocks, geological formations, etc…

Question 49

“2,8,8” rule

Answer 49

When electrons fill the shells surrounding a nucleus, they fill the innermost shell first; this shell can hold a maximum of 2 electrons. The next shell holds a maximum of 8 electrons, and the third (outermost) shell can hold a maximum of 8 electrons.

Question 50

An atom is only stable if …

Answer 50

its outer shell is completely full of electrons or completely empty.

Question 51

atom of hydrogen has

Answer 51

one proton and one electron. Is this atom stable? No, because there needs to be 2 electrons in the outer shell for stability. Hydrogen is very unstable (reactive). The Goodyear blimp, balloons, etc. are filled with helium instead of hydrogen because of the potential explosion problem with hydrogen. what hydrogen can do to gain stability is jettison that electron so that now it becomes basically a proton.

Question 52

Ion

Answer 52

When an atom gains or loses electrons ions are charged atoms If an atom gains one or more electrons it becomes a negatively-charged ion, whereas if it loses one or more electrons it becomes a positively-charged ion.

Question 53

way hydrogen can gain stability

Answer 53

to share that missing 2nd electron with another atom of hydrogen (forming a hydrogen molecule = H2) or any other atom, such as hydrogen and oxygen, forming water (H2O).

Question 54

In your blood (which is mostly water) you can find hydrogen both as an

Answer 54

ion (H+) and as a molecule (H2O).

Question 55

Molecules

Answer 55

are groups of atoms held together by chemical bonds.

Question 56

chemical bonds

Answer 56

made up of energy and serve as a sort of molecular glue, holding the atoms together in a particular configuration. Energy is stored in these bonds, so when you eat a hamburger, as an example, the bonds in the protein, fat and carbohydrate in the burger get released, providing energy (calories) for your body.

Question 57

3 common types of bonds that hold atoms together:

Answer 57

1. covalent bonds —are very strong bonds and occur when two or more atoms share one or more electrons. Carbon is very versatile because it can share 4 electrons with other atoms. We are carbon-based life forms probably because of the myriad of bonds that carbon can make with other atoms, forming larger biological molecules such as proteins, carbohydrates and lipids that make up our bodies. 2. ionic bonds— form between oppositely-charged ions, such as the sodium and chloride ions, forming a compound (table salt). In this case an electron is actually donated from one ion (like sodium) to another (like chloride). 3. hydrogen bonds— can form between molecules when one of the molecules contains a hydrogen atom. The most common example is the hydrogen bond between individual molecules of water – there is an attraction between the slightly positively charged hydrogen atom of one water molecule and the slightly negatively charged oxygen atom in the other water molecule. Individual hydrogen bonds are weak, but collectively (holding together all the water molecules in Jordan Lake, as an example) they are very strong (more about this shortly).

Question 58

cohesion

Answer 58

molecules of water like to cling to each other

Question 59

a thin film of water can act like a solid because

Answer 59

of its hydrogen bonds

Question 60

Water is a good temperature … and good…

Answer 60

moderator (i.e. it has a large heat capacity). ex) Early in the summer it’s a little cooler at the beach than in Raleigh, and in the winter it’s a little warmer at the beach, all because the ocean, a huge body of water, holds in warmth from summer heating and coolness from the winter, slowly moderating the adjacent land temperatures. When you sweat, the liquid evaporates from your skin, taking some of your body heat with it. solvent

Question 61

pH

Answer 61

a measure of the amount of H+ (hydrogen ions) it contains

Question 62

pH

Answer 62

a measure of the amount of H+ (hydrogen ions) it contains Notice that the pH scale is logarithmic. Beer with a pH of about 5.0 is 10 times more acidic than urine with a pH of 6.0 and 100 times more acidic than pure water with a pH of 7.0.

Question 63

hydrophobic

Answer 63

Some things like fats, oils and plastics do not dissolve in water

Question 64

water tends to split into …

Answer 64

H+ and OH- (hydroxyl) ions

Question 65

acid

Answer 65

. A solution containing more H+ than OH- is called an acid and has a pH< 7.0. ex) beer, soda, stomach acid, grape juice

Question 66

neutral

Answer 66

A solution containing equal amounts of H+ and OH- is considered neutral and has a pH of 7.0. ex) water and blood

Question 67

basic (alkaline)

Answer 67

A solution having more OH- than H+ ions is basic (alkaline) and has a pH> 7.0. ex) ammonia and bleach

Question 68

pH of your blood

Answer 68

approx. 7.4 and doesn’t vary much (or else you could die)

Question 69

buffer

Answer 69

one or more chemicals (like bicarbonate) that regulates pH and keeps the level where it should be

Question 70

Biological molecules

Answer 70

(proteins, fats, etc.) are all made up of many atoms, and because they are large, complex molecules, they are called macromolecules. These macromolecules are polymers (“many-parts”) which are made up of building blocks, also known as monomers (“one-part”).

Question 71

four groups of important biological macromolecules

Answer 71

carbohydrates, lipids, proteins and nucleic acids

Question 72

Carbohydrates

Answer 72

this term literally means “water-of-carbon”. The molecular formula for carbs is (CH2O)n where “n” is any number. In other words, the structure of a carb is such that for every carbon and oxygen atom there are two hydrogen atoms. An example of a carbohydrate is glucose: C6H12O6. carbs constitute short-term energy sources. The carbs that you eat get used pretty quickly for your energy needs, unless you eat too many of them (!) Some biological structures (plant cell walls, as an example) are also made up of carbs.

Question 73

types of carbs

Answer 73

A. Monosaccharides B. Disaccharides C. Polysaccharides

Question 74

Disaccharides

Answer 74

made up of two monosaccharides linked together. Examples include: 1. sucrose – this is common table sugar you put in your coffee and tea and use in baking. It comes from sugar cane (grown in Florida & Hawaii) and sugar beets (grown in states out west like Colorado). When you eat sucrose, your body digests it into the monosaccharides glucose and fructose, meaning that your digestive enzymes can break apart the bond that holds the 2 monosaccharides together, releasing them as simple sugars. 2. lactose - this is milk sugar. What is lactose intolerance? See p. 70. This occurs when your body can’t digest this sugar (which may happen because of age or genetics), meaning that your body is not making enough chemicals called enzymes that break the bond between the 2 monosaccharides that make up lactose. If you can’t break down the lactose, it can’t enter your cells to provide energy, so the lactose stays in your lower intestine, where normal, resident bacteria try to break it down. This process releases various gases, which may cause discomfort (gas pains), cramping, and flatulence - look up that word if you don’t know what I mean.

Question 75

Polysaccharides

Answer 75

made up of hundreds and thousands of monosaccharides (primarily glucose) all linked together by chemical bonds. Examples include: 1. starch - makes up pasta, bread, rice (any grain), potatoes, veggies, etc. It is the form in which plants store their energy. When you hear the word starch you usually think of potatoes, right? When we eat this complex carb we digest it (break it down) primarily into glucose. Since nearly all carbohydrates end up in your body as glucose, why on earth do nutritionists say it’s better to eat complex carbs than simple carbs? Why is it better for you to eat veggies and brown rice rather than a Krispy Kreme donut? Because it takes a much longer time to digest the complex carbs, resulting in a nice, slow and steady release of glucose into the blood. Plus these foods also contain vitamins, minerals, perhaps some protein, etc. A Krispy Kreme donut gets digested almost immediately into glucose, resulting in a “sugar high” that goes quickly to the brain but leaves you feeling hungry very soon thereafter. Plus, the last time I checked, a Krispy Kreme donut doesn’t contain many vitamins or minerals; it’s basically just sugar and fat, both of which most of us need to eat less of! 2. glycogen - this is the form in which your body (or any animal’s body) temporarily stores excess sugar (Fig. 2-23). As an example, if you eat 3 Poptarts and “burn off” (use up the calories from) only one Poptart, the sugar in the other 2 Poptarts will get stored as glycogen in your liver. If you don’t eat for several hours, your body will call for sugar (energy), and the liver will convert the stored glycogen back into glucose, which will enter the bloodstream and then enter your cells to provide energy. 3. cellulose - this is a structural polysaccharide. It is a polymer of glucose that makes up plant cell walls. We cannot digest cellulose, so when you eat veggies, salads, etc., the cellulose in the plant cell walls passes through your system. It serves as fiber or roughage (Fig. 2-27) which keeps your digestive plumbing in shape by helping to move foods through your system. Herbivores (vegetarian animals) like cows, deer and elk (and termites) can digest cellulose because their intestines contain bacteria and protists that can break down the cellulose into glucose. Another structural polysaccharide is chitin (Fig. 2-26) – it makes up the outer covering of insects, lobsters and crabs.

Question 76

Monosaccharides

Answer 76

(simple- or single-sugars) - these are the monomers of carbohydrates. Simple carbs are made up of just one or 2 monosaccharides, while complex carbs are made up of many monosaccharides linked together by chemical bonds. Examples include: 1. glucose (C6H12O6)- most living things on our planet can utilize this sugar for energy. It is the main building block of most of the carbs that you eat. Regardless of whether you eat pasta, potatoes, rice, an apple, a muffin, a piece of pie or a candy bar, you will digest (break down) the carbs in these foods into the simplest carb, glucose. The glucose then goes into your blood (“blood sugar”) and then enters your cells where it gets converted into energy (calories) which get burned during your daily activities (Fig. 2-21). When dissolved in water, glucose forms the “ring” structure as indicated in Fig. 2-21. 2. fructose (C6H12O6) - this is another simple sugar, commonly found in fruits (along with glucose). Notice that it has the same chemical formula (C6H12O6) as glucose. So, why are they different molecules? Notice that these molecules are 3-dimensional, and that some of the C, O, and OH atoms are arranged in space a bit differently from glucose, making it a different simple sugar. Have you heard about high fructose corn syrup (HFCS)? This stuff is added to lots of processed foods and drinks to sweeten them up.

Question 77

Types of lipids

Answer 77

fats, oils & cholesterol (steroids). Fats are hydrophobic and are needed for long-term energy storage (whale & seal blubber), insulation (same examples) and cushioning (women have some fat in the abdominal region to protect and cushion the uterus). We need lipids in our diet every day for certain “lipid-soluble” vitamins (A, D, E & K) to be absorbed, and the lipid cholesterol is a key component of bile and our cell membranes.

Question 78

Fats and Oils

Answer 78

made up of monomers called fatty acids (long chains of carbon and hydrogen – Fig. 2-29) and they both basically have the same structure, except that fats are solid at room temperature and oils are liquid at room temperature. Why is this? Fats are made up of fatty acids that are straight (Fig. 2-31), while fatty acids in oils (found in oily fish like salmon) have kinks/bends in them; these kinks and bends make the oil liquid at room temp. Also notice that some of the carbon atoms in fats are full of hydrogen atoms (they are saturated), whereas the carbons in oils have one or more double bonds (where the bends are) and fewer hydrogen atoms; they are considered unsaturated . Fats are used for long-term energy storage in animals while oils are used for long-term energy storage in plants.

Question 79

saturated vs. unsaturated fats

Answer 79

Saturated fats (found in meats like steak, chicken fat, cheeses, etc.) tend to cling to your blood vessels (you may have heard of plaque build-up) which can lead to heart attacks and strokes. Unsaturated fats (found in oils like canola and olive oil) are much healthier for you and do not stick to your arteries. When you eat out, it’s much healthier for you to dip a piece of bread into olive oil than to slather butter or margarine on it. In general, it is much healthier for us to get our lipids (fatty acids) from oils rather than from fats.

Question 80

trans fats

Answer 80

start off as perfectly healthy oils like corn oil which are made up of unsaturated fatty acids. Chemists at food companies then add more hydrogen atoms (this process is called hydrogenation; Fig. 2-32) to their unsaturated fatty acids, converting them to unhealthy saturated-like fats called trans fats. This is primarily done in the baking industry to produce a “better”, longer-lasting product. When you bake cookies you probably use butter or Crisco, not Wesson oil, right? Crisco is hydrogenated corn oil (the oil has been converted into a solid), and, thus, contains trans fats and is much less healthy for you than the corn oil it came from. Foods containing trans fats (check out boxes of cookies, crackers, pies, donuts, most margarines, etc. and fried foods) really should be avoided as much as possible, because we have recently learned that these trans fats may be even worse for you than butter!! Our bodies have evolved with saturated fats like butter and know how to process them (unless we eat too much; therein lies the problem), but our bodies don’t know how to process trans fats, which end up clogging arteries to a greater degree than do saturated fats.

Question 81

Fatty Acids

Answer 81

make up several plant oils (found in nuts, avocados, flax seeds, etc.) and in fish oils, called omega-3 fatty acids, are VERY beneficial for many of our organ systems – these are lipids we need to eat more of. They appear to reduce inflammation so they may be helpful for people with heart disease and arthritis.

Question 82

Steroids

Answer 82

(or Sterols) (p. 61) - yes, this is a general class of lipids! The steroids you hear about in the news (possibly abused by body-builders and some athletes) are anabolic or “tissue-building” steroids that can lead to tumors, masculinization of females and feminization of males if abused. (Yikes - is that the former governor of California in Fig. 2-34??) Because it is a synthetic form of testosterone, it can cause excessive hair growth, deepening voice, and loss of feminine characteristics in females, while in males excess testosterone gets converted into estrogen, causing loss of masculine attributes (need I say more?!) and tumor growth. Steroid drugs found in topical creams, inhalers, etc. are catabolic rather than anabolic and are not harmful when used as directed. ex) sex hormones (estrogen and testosterone) and cholesterol

Question 83

Cholesterol

Answer 83

We need cholesterol for bile (the green stuff found in your gall bladder and needed to digest fats), and for our cell membranes. So, if a person is a strict vegetarian (a vegan who eats no meat, cheese or eggs), how do they get their needed cholesterol? It turns out that our livers (many cells in our bodies, in fact) can make cholesterol, so we really don’t need to eat it. Excess cholesterol, like saturated fats, can stick to arteries, causing plaque build-up. Not all forms of cholesterol are bad for you. LDL cholesterol is the bad kind that sticks to your arteries, whereas the good HDL cholesterol minds its own business

Question 84

Proteins

Answer 84

used primarily for structural things such as muscle, hair, the lens of your eye, antibodies that fight infections, hemoglobin (binds oxygen) in red blood cells, enzymes that digest your food, spider webs (silk), fingernails, horns on sheep, etc. (Fig. 2-36). Their monomers are amino acids (Fig. 2-37). The proteins that you eat, such as meat, fish, beans, chicken and dairy products are made up of hundreds or even thousands of amino acids linked together by chemical bonds. Your body digests the proteins you eat into their constituent amino acids and then re-arranges these amino acids into human proteins such as those listed above. Think of a protein like a pearl necklace, with each pearl being an amino acid.

Question 85

Enzymes

Answer 85

are proteins that jump-start and speed up chemical reactions in our bodies and pretty much any place else you look on our planet. In Fig. 2-42 you can see how the enzyme lactase (mentioned earlier) in your digestive tract breaks up (digests) the milk sugar lactose into its constituent monosaccharides glucose and galactose. An enzyme is extremely specific about which reaction it will speed up.

Question 86

Nucleic Acids

Answer 86

the main example is DNA, which is the “blueprint of life” that makes up your genes. DNA is a beautiful, double-helix molecule (Fig. 2-45). The monomers of nucleic acids are nucleotides, which are made up of phosphorus (phosphate) & a sugar & a nitrogen-containing base (adenine, guanine, cytosine & thymine, = A, G, C & T). RNA is another nucleic acid.

Question 87

December, 2010, it was reported that scientists discovered

Answer 87

bacteria that have arsenic in their cells in place of phosphorus. You may say “so what?”, but this is a major, substantive discovery, because we are now aware of a life form whose DNA has a sugar-arsenic backbone instead of a sugar-phosphate backbone which all other living things on this planet have. So, if an arsenic-based life form can be found on our planet, who knows what other life forms are out there in our universe?

Question 88

A. van Leeuwenhoek

Answer 88

Dutch amateur naturalist in 1600s; built a new microscope for each specimen he looked at; really the first person to look at lots of different cells and tissues; coined the term “animalcules” for the critters (protists and other small organisms) he saw in pond water, bacteria he found in his mouth, etc. His microscopes and preserved specimens were recently found by the Royal Society of London, and they’ve proven to be of extremely high quality for their time.

Question 89

Robert Hooke

Answer 89

600s British scientist who coined the term “cells” when looking at a slice of cork (cork is bark from a tree; bark is non-living).

Question 90

Cell Theory

Answer 90

formulated in the 1800s by a joint effort of several different biologists; states that all living things are made up of cells and that cells arise from other, pre-existing cells (i.e. “spontaneous generation” – life arising from non-living things - does not occur)

Question 91

Two important factors in determining how good a microscope

Answer 91

magnification (enlarging ability) and its resolving power, the ability to distinguish two objects that are very close together as separate entities.

Question 92

Types of Microscopes

Answer 92

light microscopes (LM) electron microscopes(EM)

Question 93

light microscopes (LM)

Answer 93

glass lenses bend visible light, enlarge the image and transmit it to the eye. Dissecting (aka stereo) and compound microscopes are examples; these are the kinds of microscopes you may have seen or used before. A jeweler uses a stereo microscope to look at gems, the prongs on a ring’s setting, etc.

Question 94

electron microscopes(EM)

Answer 94

a beam of electrons is used to visualize things smaller than 200 nm, such as viruses and cell organelles. Remember the metric system from Lab 1? Electron microscopes have great resolving power, and some can magnify objects up to 200,000 times, significantly more than LMs whose highest magnification is usually 1,000 times

Question 95

two main types of electron microscopes:

Answer 95

a. Transmission Electron Microscope (TEM) – for looking at viruses and the inside of cells. Electrons actually bombard and pass through the specimen. See Fig. 3-3 (lower right) and 3-5 for images produced from a TEM. b. Scanning Electron Microscope (SEM) – for looking at surfaces of cells, insects, etc. – electrons bounce off the specimen, forming a 3-D image of the surface. See human egg photo in Fig. 3-2 (incorrectly labeled TEM 400x) and head louse (ick!) in Fig. 3-1.

Question 96

Plasma membrane

Answer 96

the “gatekeeper” of the cell (Fig. 3-8), it is composed of a phospholipid bilayer with embedded proteins. Phospholipids look like fats and oils except that they have two fatty acids instead of three, plus they contain a phosphate group. See Fig. 3-9. Various kinds of proteins are embedded in/scattered throughout the bilayer (Fig. 3-10), sort of like icebergs. The membrane has the consistency of heavy oil; proteins and lipids can bob and move around in the membrane (they are not set in stone like concrete). Thus, a “fluid mosaic” model best describes the fluid behavior of a membrane (p. 92). The phospholipid portion acts like a fence or barrier around the cell; since many substances are hydrophobic, they cannot easily penetrate the lipid barrier. Because only certain molecules can pass back and forth across a membrane (this is controlled by proteins – see next paragraph), it is considered to be selectively permeable. The membranes of humans and other animals also contain cholesterol which helps to keep the membrane flexible.

Question 97

four main types of proteins found within our membranes

Answer 97

1) Although gases and small molecules can easily pass through the phospholipid bilayer, larger molecules like glucose need help to get through to the inside of the cell. This assistance comes in the form of transport proteins which serve as “gates” in the lipid fence. 2) Enzymes are proteins that speed up the rate of chemical reactions on or within the plasma membrane. 3) Receptor proteins are involved in signaling. They recognize and bind to chemicals such as hormones and drugs in the cell’s external environment and relay their message into the cell, thereby controlling certain processes inside the cell. 4) Recognition proteins act like cellular ID tags/badges, sort of like a cellular fingerprint. Your blood type is determined by these recognition proteins, as are other surface/membrane proteins that have to be “matched” if a person needs an organ transplant (Fig. 3-14).

Question 98

active transport

Answer 98

energy is expended by the cell to move molecules across its membrane

Question 99

passive transport

Answer 99

no energy is expended by the cell

Question 100

two kinds of passive transport

Answer 100

diffusion and osmosis

Question 101

Diffusion

Answer 101

the movement of a solid substance (like salt or sugar) or a gas (like oxygen) from an area of high concentration of that substance to an area of lower concentration of that substance. I used to do the “experiment” in Fig. 3-16 in the classroom as a demonstration of diffusion. Gases, amino acids, glucose, etc. (i.e. lots of substances) all move by diffusion across a cell membrane.

Question 102

osmosis

Answer 102

the movement of water across a membrane. In other words, water will also move from an area of high water concentration to an area of lower water concentration, where it’s needed. In other words, water will also move from an area of high water concentration to an area of lower water concentration, where it’s needed.

Question 103

Your cells and their surrounding fluid contain ___% NaCl.

Answer 103

0.9%

Question 104

hypertonic

Answer 104

the concentration of salts, etc. are higher in the extracellular fluid (outside of the cell membrane), then water will move by osmosis out of the cell to equalize the concentration of salt on both sides of the membrane. You can visualize which way water will move by remembering “salt sucks” and “water follows salt”. In the laxative example on p. 100, the laxative causes the interior of your intestines to become hypertonic, causing water to move from the surrounding cells into the intestine, thereby softening the stool (TMI - too much information, perhaps?!). Conversely, if cells find themselves in a hypotonic solution with a lower salt, etc. concentration on the outside, water will move inside of the cell to “dilute out” the excess salt on the inside.

Question 105

isotonic

Answer 105

Under normal/ideal circumstances, cells are bathed in an isotonic solution (Fig. 3-18). In other words, the concentration of salt is equal on the outside (extracellular fluid) and inside (intracellular fluid) of the cell, so there is no net movement of water (i.e. water moves back and forth across the membrane at an equal rate).

Question 106

Nucleus

Answer 106

n a human the nucleus contains 46 chromosomes which are subdivided into genes which code for your characteristics. You do NOT need to know any of the terms such as nucleolus that are not mentioned in this mini-lecture. The nucleus is the genetic control center or brain of the cell; it regulates all of the activities in the cell.

Question 107

Ribosomes

Answer 107

occur in the cytoplasm (gel-like stuff surrounding the nucleus) and serve as workbenches for making proteins.

Question 108

Lysosomes

Answer 108

bag-like structures that contain powerful digestive enzymes. They serve as “stomachs” for many protists by combining with the food they’ve eaten and breaking it down into its monomers (i.e. digestion). In our cells, lysosomes serve as recycling centers or garbage disposals for old or damaged organelles, bacteria, etc.; they digest the organelles or worn-out parts and can re-use the constituent molecules. Finally, lysosomes serve in programmed cell death: when cells need to die and be re-arranged into something else, like a caterpillar changing into a butterfly, the lysosomes perform this function.

Question 109

Mitochondria

Answer 109

cellular respiration (Fig. 4-28) occurs here, a process by which the chemical energy stored in the foods that you’ve eaten is harvested and converted into energy our bodies can use (aka calories) in the presence of oxygen (“aerobic”). On p. 112 note that mitochondria contain DNA, and that mitochondrial DNA is maternally inherited (i.e. it comes from your mother’s side).

Question 110

Cytoskeleton

Answer 110

a network/framework of protein fibers that gives the cell its shape, allows it to creep around (like white blood cells and cancer cells) and allows the organelles to move around inside the cell. The cytoskeleton provides the framework for cilia, which are used in locomotion in some protists like Paramecium. Our respiratory tract is lined with ciliated epithelial cells that help to keep out bacteria and pollutants we might breathe in. Some cells such as sperm and certain bacteria contain a flagellum, a long whip-like extension of the cytoskeleton which is used for locomotion.

Question 111

Central vacuole

Answer 111

these store nutrients, plant pigments in flower petals, waste products and poisons, and provide physical support to the cell. Fluid (water) pressure called turgor pressure inside the central vacuole pushes out against the plant’s cell walls, enabling stems, etc. to stand upright. If you forget to water your houseplants and they wilt, it’s because their cells have lost their turgor pressure. When you then water the plants, you are re-filling their central vacuoles with water, enabling them to stand upright again. Some animal cells contain vacuoles but they are very tiny compared to a plant’s central vacuole.

Question 112

Cell walls

Answer 112

these are made mostly of cellulose and surround and reinforce all plant cells, but they do have pores that allow materials to pass in and out of the cell. Bacteria have cell walls as well, but animal cells DO NOT have cell walls.

Question 113

Chloroplasts

Answer 113

in these organelles photosynthesis (Fig. 4-11) occurs, the process by which the plant or protist (photoautotroph) converts solar energy into chemical energy (sugar) for the rest of the food chain.

Question 114

Viruses are measured in

Answer 114

nanometers

Question 115

Bacteria are measured in

Answer 115

such as E. coli are measured in micrometers (microns)

Question 116

Amoeba are measured in

Answer 116

millimeters (you can see these with the naked eye, but just barely). I like the size comparisons in Fig. 13-1: comparing the size of the flu virus (you’d need a TEM to see one) to an amoeba is like comparing a pinhead to an oak tree – a good visual image.

Question 117

ubiquitous

Answer 117

Microbes are ubiquitous – they can be found pretty much any place on the planet you can think of, such as in jet fuel, on the top of Mt. Everest, in boiling hot watery environments such as hot springs and hydrothermal vents (Fig. 13-2), and covering the insides and outsides of our bodies. Plus, microbes are plentiful; as an example, the number of bacteria living in your mouth right now is greater than the number of people who have ever lived on this planet!! In fact, in Fig. 13-3 you’ll see that approximately 90% of our body cells are actually microbial cells (bacteria), whereas that only 10% are what you would consider normal, human (eukaryotic) cells such as skin cells, muscle cells, etc

Question 118

Common shapes of prokaryotes

Answer 118

cocci (singular = coccus, as in Staphylococcus – they are round), bacilli (rod-shaped, like E. coli), and spiral (which include the corkscrew-shaped spirilli that cause Lyme disease and syphilis).

Question 119

anthrax

Answer 119

It is a relatively rare disease of cattle and sheep and is caused by the bacterium Bacillus anthracis. Farmers or veterinarians may contract the disease from infected livestock in the form of a skin disease. Anthrax bacteria produce very hardy (i.e. resistant to drying, etc.) spores, and if these spores are inhaled (inhalation or pulmonary anthrax), the disease is usually fatal. That’s why anthrax spores are ideal as a bioterrorism agent; they can easily be spread through the air and infect many people and animals.

Question 120

Antibiotics

Answer 120

re chemicals naturally-produced by soil bacteria and fungi. The antibiotic penicillin (from the Penicillium mold) was accidentally discovered by Alexander Fleming in 1928. Organic chemists can now synthesize antibiotics in the lab using the naturally-occurring ones as building blocks. Most antibiotics attack either cell walls or prokaryotic ribosomes, so they work quite well against bacterial infections. Because of over-prescribing antibiotics by the medical community and the use of antibiotics in animal feed, many bacteria have evolved resistance to antibiotics (natural selection at work). Fig. 13-13 does a great job of explaining how bacteria become resistant to antibiotics. The presence of antibiotic-resistant bacteria such as MRSA (methicillin-resistant Staphylococcuc aureus – p. 523) in hospitals, nursing homes, etc. has become a significant and potentially life-threatening issue since the first use of antibiotics during WW II. FYI, when you take an antibiotic, how does it know to kill off the bacterial cells and not harm your body’s cells? Human (animal) cells do NOT have cell walls (so antibiotics cannot harm them), plus human (eukaryotic) ribosomes are different enough from the bacterial (prokaryotic) ribosomes that they also are not harmed.

Question 121

probiotic therapy

Answer 121

eating yogurt, acidophilus milk, etc. that contains beneficial bacteria that will colonize the large intestine to keep us healthy and keep out “bad bacteria”. It is usually a good idea to eat yogurt if you’re taking an antibiotic to replenish the bacteria in your digestive tract that have been killed off by the antibiotic. Our skin is covered with normal bacteria (more “normal flora”) that protect it against bad bacteria.

Question 122

Protists

Answer 122

this very diverse group of mostly single-celled organisms has members that are animal-like (amoebas, Paramecium, etc.), plant-like (algae, seaweed, green pond “scum”) and fungus-like (weird-looking slime molds). Most are harmless (and some are truly beautiful – see Fig. 13-20, 21 and 22), but a few cause some nasty diseases such as African sleeping sickness and malaria

Question 123

Parasite

Answer 123

an organism that lives on or in another organism, called a host, and damages it (and sometimes kills it)

Question 124

Malaria

Answer 124

aused by parasitic protist members of the genus Plasmodium. The malarial parasite is transmitted by a tropical mosquito and can destroy the red blood cells and liver of its human host, resulting in death. Malaria is still one of the most deadly diseases in the world, killing 500,000 to nearly 1 million people each year, mostly young children in sub-Saharan Africa.

Question 125

Acellular Agents of Disease

Answer 125

These pathogens are not made up of cells (hence the name “acelluar”), yet some of them cause some terrible diseases.

Question 126

Types of acellular agents

Answer 126

Viruses (p. 533-539): they are tiny (nanometer-sized) obligate intracellular parasites. All are made up of a protein coat wrapped around nucleic acid (either DNA or RNA; unlike all other genes on the planet, viral genes can be made up of RNA); some have a lipid envelope on the outside as well (Fig. 13-24). Because they are not cells and do not exhibit many of the characteristics of living organisms, they are not considered to be alive, although they can reproduce once they get inside of a host cell. Diseases caused by viruses include the common cold and influenza (Fig. 13-26 - influenza will be discussed in detail in Module 2), AIDS (Fig. 13-29 – HIV/AIDS will also be discussed in Module 2), West Nile virus encephalitis (a brain inflammation), most forms of hepatitis, polio, herpes, mono, warts, cervical cancer, and smallpox, to name a few. Viruses need to infect a host cell in order to reproduce (see Fig. 13-25). They enter a cell, take their protein coats off (like a guest coming into your home), and then proceed to take over the host cell’s replication machinery (ribosomes, nucleic acids, etc.) to make many more copies of themselves. The progeny (offspring) virus particles bud or burst out of the host cell; in the process some viruses pick up bits of the host cell membrane as their envelope. Antibiotics do not work against viruses because viruses lack cellular components such as a cell wall and ribosomes. There are some good antiviral drugs (like AZT for AIDS) which we will discuss when we cover STIs.

Question 127

dengue fever

Answer 127

In 2010, a mosquito-transmitted disease called dengue fever (caused by a virus) that had pretty much been confined to tropical areas of the world appeared in Key West, Florida. The disease is also called break-bone fever because of the severe bone and joint pain involved, so it is disturbing news that this disease is now found in our country.