Introduction to Biochemistry

Unit 3, Lesson 1

C-Scope

Organisms are composed of elements, in combinations called compounds

Living organisms are composed of matter, which is anything that occupies space and has mass (weight).Matter is composed of chemical elements.An element is a substance that cannot be broken down to other substances.

A compound is a substance consisting of two or more different elements in a fixed ratio.Compounds are more common than pure elements.Sodium chloride, table salt, is a common compound of equal parts of sodium (Na) and chlorine (Cl).

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Elements

92 occur naturally ( some are man-made) 25 essential to living organisms C,H,O,N make up 96% of a human body Carbon, Hydrogen, Oxygen, and Nitrogen make up

Carbohydrates, Fats, Proteins, and DNA and RNA-which make up YOU!

This Burmese woman has Goiter, a symptom of Iodine deficiency. Iodine is an essential ingredientof a hormone produced by the thyroid gland. Iodine deficiency is also linked to mental retardation.We get our iodine from iodized salt on our foods or from eating SEAFOOD!.

Some trace elements are required to prevent disease.Without iron, your body cannot transport oxygen.An iodine deficiency prevents production of thyroid hormones, resulting in goiter.

Trace elements are common additives to food and water

Fluoride is added to municipal water and dental products to help reduce tooth decay.

Several chemicals are added to food to help preserve it,make it more nutritious, and/or make it look better.

Check out the “Nutrition Facts” label on foods and drinks you purchase.

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Periodic Table

Atomic Number (number of protons) Atomic Mass (total of protons and neutrons in the nucleus) Electrons are so lightweight that their weight only adds up

with their increasing numbers on the Periodic Table. Isotopes – different number of neutrons C 14 is used for radioactive Carbon dating of fossils

12.001

Atoms Nucleus

– Protons (positive charge)– Neutrons (no charge)

Energy levels– Electrons (negative charge)– 1st level holds up to two electrons– 2nd level holds up to eight electrons– 3rd level holds up to eight electrons (needs 8 to be

stable) 2-8-8 - Octet Rule

The rows on the Periodic Table tell you how many shells to use!

The columns will tell you how many electrons you have in the outermost shell. These are called leftover or VALENCE Electrons.

The number of electrons in the outermost shell determines the chemical properties of the atom.Atoms whose outer shells are not full tend to interact with other atoms, participating in chemical reactions.

Atoms - All Atoms want to be stable

– Atoms have no electrical charge when

the Number of proton and electrons are equal

But an atom wants to fill its outermost shell to be stable. It can do this by Covalent or Ionic Bonding to another atom

Sodium (Na) + Chlorine (Cl) = Table Salt (NaCl)

Elements combine to form compounds or molecules.

EXPLOSIVE !

Molecule– Has covalent bonds

(shared electrons)– bond is strong

Ionic Compound– Has ionic bonds

(+ and – atoms pulled together by their differences in charge-like a magnet

– Bond is weak

Molecules vs. Compounds

Covalent vs. Ionic Bonding Covalent bonding is where atoms share electrons to fill

their outermost shells….Like a marriage

Ionic bonding is where atoms give away or take electrons to fill or dissolve their shells….. Like a Divorce

Covalent Bonds

Two or more atoms held together by covalent bonds form a molecule

Atoms in a covalently bonded molecule continually compete for shared electrons.The attraction (pull) for shared electrons is called electronegativity.More electronegative atoms pull harder.

Ionic BondsAn ion is an atom or molecule with an electrical charge resulting from gain or loss of electrons.When an electron is lost, a positive charge results.When an electron is gained, a negative charge results.Two ions with opposite charges attract each other.When the attraction holds the ions together, it is called an ionic bond.Salt is a synonym for an ionic compound.

Cl

Na

Hydrogen bonds-weak bonds

Because the positively charged region is always a hydrogen atom, the bond is called a hydrogen bond.

Hydrogen, as part of a polar covalent bond, has a partial positive charge.The charged regions on molecules are electrically attracted to oppositely charged regions on neighboring molecules.

Hydrogen bond

Hydrogen bond

Life on Earth is tied to WaterLife’s chemistry is tied to water.Life first evolved in water.All living organisms require water.The chemical reactions of your body occur in cells consisting of 70–95% water.

Water has atoms with different electronegativities.Oxygen attracts the shared electrons more strongly than hydrogen.So, the shared electrons spend more time near oxygen.The oxygen atom has a slightly negative charge and the hydrogen atoms have a slightly positive charge. The result is a polar covalent bond.Because of these polar covalent bonds, water is a polar molecule.

The Important Properties of Water

Cohesion is related to surface tension—a measure of how difficult it is to break the surface of a liquid.Hydrogen bonds give water high surface tension, making it behave as if it were coated with an invisible film.Water striders stand on water without breaking the water surface.

The tendency of molecules of the same kind to stick together is cohesion.Cohesion is much stronger for water than other liquids. Most plants depend upon cohesion to help transport water and nutrients from their roots to their leaves

Adhesion of Water Molecules and Capillary Action

Capillary action

The tendency of two different kinds of molecules to stick together is adhesion.

Plants rely on Adhesion and Cohesion to getWater up from the Roots and into the Stems and Leaves.

Because of hydrogen bonding, water has a greater ability to resist temperature change than other liquids.Heat is the energy associated with movement of atoms and molecules in matter.Temperature measures the intensity of heat.Heat is released when hydrogen bonds form.Heat must be absorbed to break hydrogen bonds.

Water’s Hydrogen Bonds Moderate Temperatures on the Earth

When a substance evaporates, the surface of the liquid that remains behind cools down, in the process of evaporative cooling.This cooling occurs because the molecules with the greatest energy leave the surface.

WATER Makes Earth Liveable!

*Water can exist as a gas, liquid, or solid.*Water is less dense as a solid than a liquid because of hydrogen bonding.*When water freezes, each molecule forms a stable hydrogen bond with its neighbors. *As ice crystals form, the molecules are less densely packed than in liquid water. Because ice is less dense than water, it floats..

This also helps to insulate the oceans thus regulating the temperatures at the poles.

Water is the Solvent of Life

A solution is a liquid consisting of a uniform mixture of two or more substances.The dissolving agent is the solvent.The substance that is dissolved is the solute.An aqueous solution is one in which water is the solvent.

Water’s versatility as a solvent results from the polarity of its molecules.Polar or charged solutes dissolve when water molecules surround them, forming aqueous solutions.

How water dissolves salts and other ionic compounds:

Like a Magnet, the oppositeends of the water moleculesand the ions attract each other and pull the ions Na+ and Cl – apart in the solution. “Dissolves”

Water is Essential to Living Things Most abundant substance in your body Needed for digestion Chemical reactions in your body

require water….yes even brain activity like THINKING!

Suspensions and Colliods Suspension – mixture in which materials

do not dissolve. Particles in a suspension are larger than those in colloids or solutions; they are visible under a microscope, and some can be seen with the naked eye. Particles in a suspension precipitate out if the suspension is allowed to stand undisturbed. Ex: Dirt and water

Colloid-Colloids are mixtures whose particles are larger than the size of a water molecule but so small that they can’t be seen with the naked eye. Ex: Milk, butter, jello, mayo, whipped cream, blood

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Acids and Bases

pH 0-14 Acids

– less than 7 pH– High concentration of hydrogen ions (H+)

Bases– greater than 7 pH– High concentration of hydroxide ions (OH-)

pH of 7 is neutral (water)

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Chemical Reactions

Reactants- The molecules that combine Products- Molecules formed from the reaction

Catalyst-Chemical that speeds up a reaction Metabolism-All the chemical reactions in an

organism from the building and breaking of the bonds forming the molecules.

C6H12O6 + 6O2 6CO2 + 6H2O + energy

6CO2 + 6H2O + energy C6H12O6 + 6O2

The Molecules of Life

Carbohydrates (sugars)Lipids (fats)ProteinsNucleic Acids (DNA, RNA)

Organic Compounds (Contain Carbon and Hydrogen) Monomers (single units or building blocks) Like one train

car…. Monomers can be glucose, a fatty acid, an amino acid, or a

nucleotide Polymers (units joined together)

Like a whole train

Examples: Starch, Cellulose,

Glycogen, cholesterol, hormones.

ligaments, tendons, hair, nails,

genes and chromosomes

Carbohydrates

Used for Energy by cells Monosaccharides (simple sugars)

– Glucose-needed by our cells for energy

– Fructose – sugar in fruits– Galactose-Sugar found in milk

Made up of C, H, and O usuallyin the (C H2 O) Chemical Formula

All sugars will be broken back down into glucose!

Disaccharides (double sugars)

Maltose (glucose + glucose)

Lactose – (glucose + galactose)

Sucrose – (glucose + fructose)

Sucrose-Table Sugar

Lactose-Milk sugar

Polysaccharides (complex carbs)

Starch- Starch is a long (100's) polymer of Glucose molecules, where all the sugars are oriented in the same direction. Plants store starch for energy.Starch is one of the primary sources of calories for humans.

Cellulose (fiber) - Cellulose is a long (100's) polymer of Glucose molecules. However the orientation of the sugars is a little different. In Cellulose, every other sugar molecule is "upside-down". This small difference in structure makes a big difference in the way we use this molecule. Human can’t digest cellulose, but certain bacteria can, which is found in cow and termite stomachs.

Glycogen (animal starch)

Glycogen is another Glucose polymer. Glycogen is a stored energy source, found in the Liver and Muscles of Humans. Glycogen is different from both Starch and Cellulose in that the Glucose chain is branched or "forked“ and Temporarily stored for quick energy.

All three are composed only of Glucose.

Glycogen is stored in Liver and Muscle Cells in humans.

Cellulose fibersStarches

Chitin- Carb that forms the exoskeletons of insects and fungi

It is the main component of the cell walls of fungi,

the exoskeletons of arthropods such as crustaceans

(e.g., crabs, lobsters and shrimps) and insects, the radula

or tongues of mollusks, and the beaks and internal shells

of cephalopods, including squid and octopuses.

In terms of structure, chitin may be compared to the polysaccharide cellulose. The English word "chitin" comes from the French word chitine, which first appeared in 1821 and

derived from the Greek word chiton, meaning coveringcovering. In its unmodified form, chitin is translucent, pliable, resilient, and quite tough.

In its pure form, chitin is leathery. Chitin's properties as a flexible and strong material make it favorable as surgical thread. Its

biodegradibility means it wears away with time as the wound heals called Dissolvable sutures. Moreover, chitin has some unusual properties that accelerate healing of wounds in human.

Chitin is used in industry in many processes. Chemically modified chitin in food processing include the formation edible films and as an additive to thicken and stabilize foods and pharmaceuticals. It also acts as a binder in dyes, fabrics, and adhesives. Chitin is used to size and strengthen paper.

High-Fructose Corn Syrup

What is it? The main carbohydrate

in corn is starch. Industrial processing

hydrolyzes starch into monomers of

glucose producing corn syrup. Glucose isn’t sweet like sucrose,

so an enzyme is used to rearrange the glucose atoms into fructose that is sweeter than sucrose. The mixture is added back to regular corn syrup (55% fructose and 45% corn syrup or glucose). It is cheaper than sucrose (table sugar) and easier to mix into drinks and processed foods.

Why is it so bad for you?

It is linked to obesity in Americans who consume high quantities of

HFCS. Also linked to type 2 diabetes, high blood pressure, and other

chronic diseases associated with weight .

Isomers-same chemical formula but a different arrangement Isomers (Molecules having the same number and kinds of atoms, but

different chemical properties because of the difference in the ARRANGEMENT of the atoms.)

Discovered in 1976, sucralose is 600 times sweeter than sugar and does not metabolize to produce energy, thus it does not contain calories. It is the only low calorie sweetener that is made from sugar, which has been changed, so it passes through the body unchanged and unmetabolized. How? By Substituting for three alcohol groups on the sugar molecule with three chlorine atoms, this creates sucralose.

Lipids (Fats, Oils, and Waxes)

Long term energy storage (C-H bonds) Fats are nonpolar, so water can’t attach

and break them apart. Plant lipids have light-absorbing

pigments that give them all their beautiful colors and greenery

Found in – Hormones, like steroids– Cholesterol acts like antifreeze in your cell

membranes. Insulation and cushions vital organs Protective covering

Acts as lubricants for muscles as well as waterproofing birds and our eardrums

-Lipids acts as a boundary in your cell membranes that surrounds and contains the watery contents of your cell.

-Water avoiding molecules are said

to be HYDROPHOBIC !

Triglycerides (Fats and Oils) Composed of

– three fatty acids “tails”• hydrocarbon chain (nonpolar)

• carboxyl group(polar)

– Glycerol “head”

Triglycerides are both manufactured by our bodies and obtained from the food that we eat. We cannot help lower the triglycerides that are produced by our bodies. But, we can certainly control the food and beverages that we consume in order to check our triglycerides count.

Additionally, we can take supplements to lower the triglycerides in our body. Fish oil works wonders as far as triglycerides are concerned. EPA and DHA, the two types of omega-3 fatty acids are effective in lowering triglycerides. They are ideal to control the level of triglycerides and help lead a healthy life. 

Types of Triglycerides

Saturated– C-C bonds (hard to break)

– animal fats, tropical oils– raises cholesterol level

Mono-unsaturated– one C=C bond (“kink” where it will break)

– plant oils– lowers cholesterol level

Types of Triglycerides Polyunsaturated

– more than one C=C bond

– plant oils

Hydrogenated fats– H added to unsaturated fats

– found in junk foods– Trans-fatty acids are manufactured fats

created during a process called hydrogenation. Hydrogenation aims to stabilize polyunsaturated oils to prevent them from becoming rancid and to keep them solid at room temperature. Trans-fatty acids may be particularly dangerous for the heart and may pose a risk for certain cancers.

Hydrogenated fats are used in stick margarine, fast foods, commercial baked goods (donuts, cookies, crackers), processed foods, and fried foods.

Dietary Fats: The Good, the Bad, and the Worst In the culinary arts, one simple fact is this: fats make food taste good. In the medical arts, it isn't so simple. Some fats, namely saturated and trans fats, aren't so good for long-term health. Other fats, namely mono- and polyunsaturated fats, are good for long-term health.While fats affect many systems in the body, from energy production to maintaining healthy skin, nutritionists are mainly interested in their effects on the heart and blood vessels. Healthy muscles and blood vessels need some saturated fats and even some cholesterol—but not too much. A diet rich in saturated and trans fats can cause one type of fat- and protein-carrying particle known as low-density lipoprotein (LDL, or bad cholesterol) to accumulate in artery walls. These pockets, known as plaque, can enlarge to the point where they block blood flow. Even worse, they can break apart and ooze their contents into the bloodstream. When this happens, blood clots that form to stop the leakage can block a blood vessel. When this happens in an artery that feeds the heart, a heart attack ensues. When it happens in the brain, it triggers a stroke.

Did you know that yellow grease collected from restaurants is used in biofuels, cow feed, chicken feed, furnace and boiler fuels in factories, and suppression of dust during construction of roads and while drilling !

Cholesterol Benefits

Needed in making steroid hormones like Testosterone and Estrogen (the sex hormones)

Makes up part of cell membranes. Makes up the nerve cell’s protective

coating, and part of your brain and skin.

Some forms of cholesterol act as antibodies to fight diseases

Cholesterol can be changed to Vitamin D in the presence of sunlight.

Bile salts are modified cholesterol and needed for the digestion of fats.

Bad vs. Good Cholesterol

You add to what your liver naturally produces when eating fatty foods. When you eat too much fatty food, your liver slows down making the good cholesterol and more cholesterol- transporting lipoproteins will enter your blood. Lipoproteins are substances that transport cholesterol. There are two kinds of lipoprotein carriers, HDL and LDL. HDL-High Density “Happy” Lipoprotein and LDL-Low Density “Lazy” Lipoprotein. HDL will carry the cholesterol to the liver for breaking it down, but LDL will dump it anywhere, like arteries and body tissues where it is deposited as plaque.

Proteins

Composed of amino acids (C,H,O,N)– 20 amino acids

Used as building blocks– Cell parts are mostly proteins

– Enzymes-speed up chemical reactions

– Transport Ex: hemoglobin in blood transports oxygen, other proteins transport molecules across cell membranes

– Signaling and receiving chemical signals in cell membranes Ex: Insulin controls sugar levels

– Defense-antibodies are proteins that destroy cells

– Movement-contractile proteins allow cells to move which allows muscles to move

R may be a hydrogen or an organic group and determines the properties of a particular amino acid

Amino Acids are the Monomers (base) of Proteins

Amino acids are joined together by a peptide bond (a covalent bond ) and water is given off. Peptide bonds are polar so hydrogen can attach. If water is added, the bond will be broken.

Some proteins may have small numbers of amino acids, like Ribonuclease, which breaks down RNA .It has a little over 100 Amino Acids in it’s chain. But Titan, is part of your muscle structure and contains over 33,000 amino acids! The Shape of the protein determines the Function of the protein.

Nucleic Acids Used to store information Composed of nucleotides

Examples– DNA - stored information– RNA - uses information in protein synthesis

Nucleotides make up Nucleic Acids. They are the MONOMERS.

Cytosine bonds to Guanine

Guanine bonds to Cytosine

Adenine bonds to Thymine

Thymine bonds to Adenine

Nucleic Acids serve as the blueprint for an Amino Acid chain, which builds proteins.

There are 2 types of Nucleic Acids: Deoxyribonucleic Acid (DNA) -Double Stranded -Contains A,T,C,G - Contains the sugar Deoxyribose Job: BOSS-Carries the instructions

Ribonucleic Acid (RNA) -Single Stranded -Contains A,U,C,G (U= Uracil) -Contains the sugar Ribose Job: Take instructions from DNA and make proteins

These are the molecules which allow organisms to reproduce their complex equipment from one generation to the next. DNA provides directions for its own replication, which is the basis for the continuity of all life on Earth.

What does Human DNA look like? “Spit”

DN

A

DN

A

Gelatin “Jello”

Gelatin is derived from collagen obtained from various

animal by-products. It is commonly used as a gelling

agent in food, pharmaceuticals, photography, and

cosmetic manufacturing. Gummy Bears, candy corn, and

other soft candies have gelatin in them. Elmer’s Glue also

has gelatin in it. Photographic and pharmaceutical grades

of gelatin are generally made from beef bones,

although some beef bone gelatin is used by the

food industry. Gelatin is obtained from the hide of cows and

pigs, as well as bones, tendons and ligaments,

and sometimes the hooves.

Gelatin

Although gelatin is 98-99% protein by

dry weight, it has less nutritional value than

many other complete protein sources.

Gelatin is unusually high in the non-essential amino acids glycine and proline (i.e., those produced by the human body), while lacking certain essential amino acids (i.e., those not produced by the human body). It contains no tryptophan and is deficient in isoleucine, threonine, and methionine. The approximate amino acid composition of gelatin is: glycine 21%, proline 24%, glutamic acid 10%, alanine 9%, arginine 8%, aspartic acid 6%, lysine 5%, serine 4%, leucine 3%, valine 2%, phenylalanine 2%, threonine 2%, isoleucine 1%, methionine and histidine <1% and tyrosine <0.5%. These values vary, especially the minor constituents, depending on the source of the raw material and processing technique.

Enzymes Act as catalysts to speed up chemical reactions.

Can also slow them down.

Made from 100-1000’s of amino acids. So they are PROTEINS! Enzymes are specific as to what it will attach to and react with.

Enzymes can be used over and over again (recycled) Enzymes can work at low temperatures. Enzymes take part in 1000 reactions per second in your body! Enzymes increase the reaction time by at least 1 million times! Thousands of enzymes are known and they all end in “-ase “ .

Ex: maltase breaks down maltose, sucrase breaks down sucrose, protease breaks down proteins…etc…

How Enzymes Work Enzymes attach to a SUBSTRATE (what is to be broken down). Since

enzymes are 3-D and folded, these folds form pockets called ACTIVE SITES. This is where the enzyme attaches. The molecule is broken

apart or fused together. Catabolic reaction-molecule

breaks up in the reaction Anabolic reaction-molecules are built or fused in the

reaction Anabolic steroids are usedIllegially to BUILD muscles

Active site

Enzymes Lower Activation Energy

Without enzymes, Chemical reactions would not occur quick

enough to sustain life on earth.

Enzymes help build new molecules or break them down by reducing the activation energy needed to start the reaction. It takes heat energy to break bonds, but by lowering the energy needed, the reaction can start faster instead of having to “heat up” first.

Bonds have to absorb enough energyto break. That energy is in the form of HEAT.If we had to heat our bodies up to get chemical reactions going, we would kill our cells.Enzymes keep us from having to do that.

Enzymes have a particular environment that they work best in. Enzymes are affected by:

1. Temperature changes

Enzymes do not like high temperatures, but low ones are OK.

2. pH ranges- most enzymes work

best at a pH of 6, but some

like those in your stomach

work at a pH of 3

3.Concentrations of Enzymes

The more “workers” you have,

the faster the job gets done.

Enzymes work in particular environments; Some work best in acidic or basic conditions

Enzymes are engineered to withstand high temperatures,

alkaline (basic),or acidic conditions required for cleaning

and other uses.

Enzymes that Digest your Food

Vitamins R CoEnzymes Vitamin- group of potent organic compounds that are needed in minute quantities for growth and good health Needed in small amounts to maintain growth and metabolism. Vitamins are not used for energy and do not serve as building blocks, but are crucial in helping the body to use those nutrients that do. Without vitamins, all of

the carbohydrates, proteins, and fats that we eat would be useless. Most vitamins function as co-enzymes, that is, they act with an enzyme to accomplish a particular type of catalysis. For example, the B vitamins, riboflavin

and niacin, act as coenzymes (FAD and NAD) in the oxidation of glucose for energy. Except for vitamins D and K, vitamins are not made in the body and must be taken in by the fruits and vegetables that you eat, or by supplements. Vitamin D

is made by ultraviolet irradiation of cholesterol molecules in the skin, and vitamin K is made by the bacteria in your intestine. In addition your body can convert carotene, the orange pigment in carrots, to vitamin A.

The vitamins are lettered based on when they were discovered and their ability to cure certain diseases. For example Ascorbic Acid is also called Vitamin C since it prevents scurvy. It was discovered 3rd and prevents scurvy. Vitamins were only discovered in this century and we are still learning a lot about them.

Fat-soluable vitamins are stored in the body. These are Vitamins A, D, E and K. They bind to fat molecules. Water- soluble vitamins are not stored and must be replaced daily. These are the B-complex vitamins and Vitamin C.

Vitamins A, C, and E have shown to reduced cancer-causing agents and are found in broccoli, cabbage, and brussel sprouts. Vitamin D functions as a hormone and helps in calcium absorption. Vitamin K is essential for blood clot protein formation as well as other proteins made by

the liver. Bruising or bleeding easily might mean a lack of this vitamin. Folic Acid, Biotin, Pantothenic acid, and niacin (nicotinamide- NAD) are also vitamins.

Minerals Approximately 4% of the body's mass consists of Minerals. They are classified as trace minerals (body requires

less than 100 mg/day), and major minerals (body requires more than 100 mg/day). Minerals can be found in water and soil and therefore in root plants and animals.

Trace Minerals The trace minerals are iron, zinc, copper, selenium, iodine, fluorine and chromium. . Iron is essential for the

oxygen- binding protein called hemoglobin and the electron- accepting part of cytochromes. Iodine is required to form thyroid hormones (T3 and T4) which are important in regulating cellular metabolic rates.

Major Minerals The major minerals are sodium, potassium, calcium, phosphorus, magnesium, manganese, sulfur , cobolt and

chlorine. Minerals serve three roles: They provide structure in forming bones and teeth They help maintain normal heart rhythm, muscle contractility, neural conductivity, and acid-base balance They help regulate cellular metabolism by becoming part of enzymes and hormones that modulate cellular activity Daily Requirements Minerals cannot be made in the body and must be obtained in our diet. The daily requirements of minerals required

by the body can be obtained from a well balanced diet. Like vitamins, excess minerals can produce toxic effects. Minerals are found in vegetables, legumes, milk and some meats. Fats and sugars do not have minerals.

Quick Quiz:

1. Fats, Oils, and Waxes (lipids) are Nonpolar so they (a) are not soluable in water (b) form H+ ions in water (c) form OH- ions in water (d) all of these.2. Fats are called TriGlycerides because (a) they have 3 fatty acid “tails” and a glycerol “head”(b) they make your blood pressure go up 3 times higher than normal (c) they are formed from 3 glycerine molecules (d) all of these. 3. Lipids store energy in the (a) C-H bonds (b) O-H bonds (c) C-C bonds (d) C-O bonds. 4. Saturated fats are (a) not soluable in water (b) bad for you because they can be stored as plaque in your arteries (c) are found in palm and coconut oils (d) all of these.5. The type of Lipoprotein “cholesterol” that is good for you is (a) LDL (b) steriods (c) HDL (d) monounsaturated. 6. Lipids are needed in your body for (a) insulation (b) cushioning organs (c) cell membranes (d) waterproofing and lubrication (e) all of these.7.Cholesterol (a) forms steroids which make up your sex hormones (b) keeps your cell membranes from collapsing in on themselves and also from freezing (c) can be changed to vitamin D in sunlight (d) makes up part of your brain, skin, and nerve cell coverings (e) all of these.8. Proteins are made up of C,H,O, and (a) S (b) N (c) Ca (d) Na . 9. The monomer or building block of proteins are (a) amino acids (b) triglycerides (c) sugars (d) nucleotides.10. The above answer makes proteins by being fused together when water is taken out forming a tough (a) hydrogen bond (b) peptide bond (c) ionic bond (d) C-H bond.