Chapter 3

Hydrophilic

(water-loving) polar or charged molecules that are soluble in water.

Examples of branching in carbon skeleton?

Butane and isobutane (pic above)

Enzymes

a macromolecule that is usually a protein that speeds up chemical reactions.

Examples of different lengths in carbon skeleton?

Ethane and propane

Explain how a protein's shape determines its functions.

Four structures: 1. primary structure: first structure 2. secondary structure: Second level of protein structure. Segments of the chains fold and recoil into this. 3. tertiary structure: 3D shape of a polypeptide due to interactions of the R groups. 4. quaternary structure: Final level.

What is the importance of carbon?

its ability to form large and complex molecules, which build the structures and carry out the functions required for life

Why are people lactose intolerant?

They can't hydrolyze bonds in the sugar lactose because the lack the enzyme lactase.

Organic compounds

a chemical compound containing the element carbon and sometimes hydrogen

Hydrocabon

a compound containing only carbon and hydrogen atoms. hydrocarbons are the major components of petroleum and provide much of the world's energy. Hydrocarbons are rare in living organisms. Found in fat.

Describe the properties of and distinguish between the six chemical groups important in the chemistry of life?

1- Hydroxyl group: hydrogen atom bonded to an oxygen atom. Ethanol is an example (alcohols) 2-Carbonyl group: Carbon atom linked by a DOUBLE BOND to an oxygen atom. Can be located within or at the end of the carbon skeleton. simple sugars contain them 3- Carboxyl group: a carbon double bonded to an oxygen atom AND a hydroxyl group (hydrogen bonded to oxygen). can act as an acid by contributing an H+ to a solution. which makes it iodized carboxylic acids: compounds with carboxyl groups. 4- Amino group: Nitrogen bonded to two hydrogens. amines: organic compounds with amino groups. Amino acids are made of amino and carboxyl groups. 5- Phosphate group: Phosphorus atom bonded to FOUR oxygen atoms. it's usually ionized, as you can see by the negatively charged oxygens. organic phosphates: compounds with phosphate groups. involved in energy transfers 6- Methyl group: Carbon bonded to THREE hydrogen atoms. (DNA)

Examples of double bonds in carbon skeleton?

1-Butane and 2-Butane

List the four main classes of macromolecules important to life.

1. carbohydrates 2. lipids 3. proteins 4. nucleic acids.

Explain why carbon is unparalleled in its ability to form large, diverse molecules.?

A carbon atom has 4 electrons in a valence shell that holds 8. Carbon completes its outer shell by sharing electrons with other atoms in four covalent bonds

Carbon skeleton

A carbon skeleton is a chain of carbon atoms that can differ in length and be straight, branched, or arranged in rings

Macromolecules

A very large organic molecule composed of many smaller molecules joined by dehydration synthesis.

Describe the structures, functions, properties, and types of proteins.

Amino acids: monomers of protein made of a caboxyl group and an amino group. _____________________________________________________________________________ Structure: these functional groups are covalently bonded to a central carbon atom. The other two partners bonded to this carbon are a hydrogen atom and a variable chemical group symbolized by the letter R. In the simplest amino acid (glycine), the R group is just a hydrogen atom. In all others, the R group consists of one or more carbon atoms with various functional groups attached. _____________________________________________________________________________ Function: Proteins are •involved in nearly every dynamic function in your body and regulate virtually all chemical reactions within cells. their most important role is as enzymes, the chemical catalysts that speed and regulate virtually all chemical reactions in your cells. _____________________________________________________________________________ •very diverse, with tens of thousands of different proteins, each with a specific structure and function, in the human body.• Proteins are composed of differing arrangements of a common set of just 20 amino acid monomers.•serve as catalysts and _____________________________________________________________________________ lysozyme: an enzyme found in your sweat, tears, and saliva. Lysozyme consists of one long polymer of amino acids, Lysozyme's general shape is called globular. _____________________________________________________________________________ •Other types of proteins include •transport proteins embedded in cell membranes, which move sugar molecules and other nutrients into your cells, •defensive proteins, such as antibodies of the immune system, •signal proteins such as many hormones and other chemical messengers that help coordinate body activities, •receptor proteins, built into cell membranes, which receive and transmit signals into your cells, •contractile proteins found within muscle cells, •structural proteins such as collagen, which form the long, strong fibers of connective tissues. those making up hair, tendons, and ligaments. 40% of the protein in your body. •storage proteins, which serve as a source of amino acids for developing embryos in eggs and seeds. _____________________________________________________________________________ What happens if a protein doesn't fold correctly? Alzheimer's and Parkinson's and mad cow disease. _____________________________________________________________________________ How are amino acids grouped? Whether the R is hydrophilic or phobic. Hydrophobic amino acids have nonpolar R groups—note the nonpolar C─H bonds in the R group of leucine (abbreviated Leu) shown in the figure. The R groups of hydrophilic amino acids, on the other hand, may be polar or charged. R groups that contain acidic or basic groups are charged at the pH of a cell. see pic below. _____________________________________________________________________________ How are proteins linked? Peptide bonds: covalent bonds between amino acids Polypeptide: Chain of amino acids (polymers) linked by peptide bonds.

Describe the health risks associated with the use of anabolic steroids.

Anabolic steroids: synthetic testosterone. Steroid abuse may cause violent mood swings ("roid rage"), depression, liver damage or cancer, and high cholesterol levels and blood pressure. it may also cause the body to stop producing male hormone which causes shrunken testicles, reduced s drive, infertility, and breast enlargement in men. For women their menstrual cycle gets ll messed up and they start having male characteristics. also causes bones and teeth to stop in teens.

Describe the structures, functions, properties, and types of carbohydrate molecules common in the human diet.

Carbohydrates: Macromolecule ranges from one monomer: monosaccharide, two monomers: disaccharide, and polymers: polysaccharide. _____________________________________________________________________________ Monosaccharide: monomers of disaccharide and polysaccharide. C H 2 O. glucose and fructose are types of monosaccharide. Glucose and fructose: Six carbons long building block of polysaccharide and its oxidation in cellular respiration is a major source of ATP. Formula for glucose + fructose = C6H12O6 they are ISOMERS. These differences also make fructose taste considerably sweeter than glucose. Other monosaccharides may have three to seven carbons. Five-carbon sugars, called pentoses, and six-carbon sugars, called hexoses. they form rings Function: Monosaccharides are the main fuel molecules for cellular work. Because cells release energy from glucose when they break it down, an aqueous solution of glucose (often called dextrose) may be injected into the bloodstream of sick or injured patients; the glucose provides an immediate energy source to tissues in need of repair. Cells also use the carbon skeletons of monosaccharides as raw material for making other kinds of organic molecules, such as amino acids and fatty acids. _____________________________________________________________________________ Disaccharides: Sugar molecule made of two monosaccharides linked together by dehydration. Maltase: Two glucose monomers. common in germinating seeds, is used in making beer, malt whiskey, and malted milk candy. Sucrose: Glucose linked to fructose. Transported in plant sap, sucrose provides a source of energy and raw materials to all the parts of the plant. It's table sugar. _____________________________________________________________________________ Polysaccharide: bunch of monosaccharides linked by dehydration. three common types: starch, glycogen, and cellulose. Starch: polymer of glucose. long chains of glucose monomers. molecules coil into a helical shape and may be unbranched (as shown in the figure) or branched. Function: serve as carbohydrate "banks" from which plant cells Human diet: Humans and most other animals have enzymes that can hydrolyze plant starch to glucose. Potatoes and grains, such as wheat, corn, and rice, are the major sources of starch in the human diet. Glycogen: super branched glucose storage for animas found in liver and muscle cells. Cellulose: polysaccharide of plant walls made of glucose monomers linked by hydrogen bonds. we don't have the enzyme to break it down but it's good for our digestive system. It passes uncharged through our digestive tract and are called insoluble fibers. Cows termites and fungi can digest it tho. Chitin: polysaccharide used by insects and crustaceans to build their exoskeleton, the hard case enclosing the animal. Chitin is also found in the cell walls of fungi. Fun fact: Almost all carbohydrates are hydrophilic owing to the many hydroxyl groups attached to their sugar monomers.

Isomer

Compounds with the same formula but different structural arrangements. The different shapes of isomers add greatly to the diversity of organic molecules and their properties.

Compare the processes of dehydration synthesis and hydrolysis.

Dehydration synthesis: A chemical reaction in which two molecules are bonded together by a covalent bond. It happens when the reaction removes a molecule of water and the two molecules are bonded with each other. one monomer (the one at the right end of the short polymer in this example) loses a hydroxyl group and the other monomer loses a hydrogen atom to form H2O. As this occurs, a new covalent bond forms. (look at pic) Hydrolysis reaction: breaking down bonds between two molecules by adding water. Important in breaking down food polymers into monomers during digestion. Why you need to drink water when you eat. the bond between monomers is broken by the addition of a water molecule, with the hydroxyl group from the water attaching to one monomer and a hydrogen attaching to the adjacent monomer.

Describe the structures, functions, properties, and types of lipid molecules.

Lipids: Organic compound made of carbon and hydrogen atoms linked by a non-polar covalent bond. include fats, phospholipids, and steroids _____________________________________________________________________________ Fats: A triglyceride: three fatty acids linked to one glycerol molecule. glycerol consists of three carbons, each bearing a hydroxyl group (—OH). A fatty acid consists of a carboxyl group (the functional group that gives these molecules the name fatty acid, —COOH) and a hydrocarbon chain, usually 16 or 18 carbon atoms in length. _____________________________________________________________________________ Why are they hydrophobic? The nonpolar C—H bonds in the hydrocarbon chains are the reason fats are hydrophobic. _____________________________________________________________________________ Unsaturated fatty acid: A fatty acid that has one or more double bonds between carbons in the hydrocarbon tail. Each carbon atom connected by a double bond has one fewer hydrogen atom attached to it. These double bonds usually cause kinks (or bends) in the carbon chain. It's liquid. the fats of plants and fishes. _____________________________________________________________________________ Saturated fat: A fatty acid that has no double bonds in its hydrocarbon chain has the maximum number of hydrogen atoms attached to each carbon atom (its carbons are "saturated" with hydrogen) it is sold. Most animal fats are saturated. Their hydrocarbon chains—the "tails" of their fatty acids—lack double bonds and thus pack closely together. _____________________________________________________________________________ Trans fat: dangerous saturated fat that was unsaturated but they artificially made it saturated by adding hydrogen atoms. _____________________________________________________________________________ Function of fat: Energy storage. A gram of fat stores more than twice as much energy as a gram of polysaccharide. _____________________________________________________________________________ Steroids: Lipids that have a carbon skeleton that has four fused rings with various chemical groups. Examples: Cholesterol, testosterone, and estrogen. Cholesterol: Steroid important in animal cell membrane and is the maker molecule for making hormones.

Describe the scientific evidence that suggests that there is a greater health risk associated with the consumption of trans fats than saturated fats.

One study estimated that eliminating trans fats from the food supply could prevent up to one in five heart attacks! Two types of scientific studies: experimental and observational. Two groups one with diets consisting of saturated, unsaturated, and partially hydrogenated fats. Healthy participants were measured in the beginning and end. The trials were short for ethical reasons. The hypothesis of these studies was that trans fats adversely affect cardiovascular health; the prediction was that the more trans fats in the diet, the greater the risk. Many scientific studies about stuff like this are observational because they could last longer, use a more representative population, and measure disease outcomes as well as risk factors. Two set backs are people may not remember and report their dietary histories, and anyone who has already died, say, of a heart attack, is not included in the study. Prospective studies, on the other hand, look forward. Researchers conducting such studies enlist a study group, quantify participants' health attributes, and then collect data on the group over many years. Diet, lifestyle habits, risk factors, and disease outcomes can all be recorded and then analyzed. for each 5% increase in saturated fat, there was a 17% increase in the risk of heart disease and•for each 2% increase in trans fat, there is a 93% increase in risk.(this was nurses study)

Describe the unique structure al properties of phospholipids that make them

Phospholipids: fats that are structurally similar to fats, except that they contain only two fatty acids attached to glycerol instead of three. Function: Biological membrane because they have polar heads and non-polar tails.

Explain why the Food and Drug Administration (FDA) has proposed changes to the nutrition facts on packaged food labels to include grams of added sugars.?

The World Health Organization has recommended that only 5% of our daily calories should come from sugar—about 6 teaspoons a day. no more than 12 teaspoons. The obesity rates in the United States have climbed to 36.5% of adults and 17% of children. 71.4% of U.S. adults get more than the FDA-recommended 10% of their daily calories from added sugars in foods and drinks. those participants who consumed more than 25% of their daily calories from added sugars were almost three times as likely to die as a result of cardiovascular disease. In response to studies such as this, the FDA has proposed changes to the nutrition facts on packaged food labels to include grams of added sugars.

examples of rings in carbon skeleton?

cyclohexane and benzene

Explain the relationship between monomers and polymers.

monomers: subunits that are building blocks of polymers (amino acid is the monomer of proteins) Cells make most of their macromolecules by joining smaller molecules into chains called Polymers (from the Greek polys, many, and meros, part): Large molecule that consists of many monomers joined together by a covalent bond.

Functional group

the portion of a molecule that is active in a chemical reaction and that determines the properties of many organic compounds

Chemical group

two or more atoms bound together as a single unit and forming part of a molecule

Compare the structures and functions of DNA and RNA, noting similarities and differences.

•DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are composed of monomers called nucleotides gene: The amino acid sequence of a polypeptide is programmed by a discrete unit of inheritance known as a gene. •Nucleotides: The monomers that make up nucleic acids. have three parts: 1. a five-carbon sugar called ribose in RNA and deoxyribose in DNA, 2. a phosphate group, and 3. a nitrogenous base. •DNA nitrogenous bases are: adenine (A), thymine (T), cytosine (C), and guanine (G) •RNA also has A, C, and G, but instead of T, it has uracil (U) •RNA is usually a single polynucleotide strand. •DNA is a double helix, in which two polynucleotide strands wrap around each other •The two strands are associated because particular bases always hydrogen-bond to one another •A pairs with T, and C pairs with G, producing base pairs. Nucleoid: non-membrane region in prokaryotes where DNA is suspended. Gene expression: flow of genetic info from genes to proteins.

Describe the adaptive advantage of lactose tolerance in people of East African descent.

•Researchers identified three new mutations in 43 ethnic groups in East Africa that keep the lactase gene permanently turned on.•The mutations•are all different from each other and from the European mutation,•appear to have occurred about 7,000 years ago, and•occurred about the same time as the domestication of cattle in these regions.