Atoms and Elements The Periodic Table The nucleus is the very small center core of an atom. –The nucleus is made up of a group of smaller particles called protons and neutrons. Protons have a positive electric charge (+). Neutrons have no charge. They are neutral. (0) Electrons move rapidly around the nucleus and have a negative electric charge. An electron is shown by the symbol e-. (-) –Moves in the space outside the nucleus. Bill Nye the Atoms in my Life video

Element Each element consists of atoms that differ from the atoms of all other elements. An element can be identified by the number of protons in the nucleus of its atoms.

Biology Periodic Table

What data can I find about an element?

Compounds –Compounds do not have the same properties as the matter that formed it. –The compound is a new substance with new properties. – Sodium is an explosive solid and chlorine is a poisonous gas. When the two combine, they form a compound, salt, that is safe enough for us to use every day to season our food.

Brain Break Look on p.149 of your textbook. Write the following chart in your composition Notebook and fill in the answers using the periodic table on page 149. ElementChemical Symbol Atomic Number Compound that uses that element Hydrogen Carbon Oxygen

MACROMOLECULES PHYSICAL, CHEMICAL, AND CELLULAR BASIS OF LIFE

Carbohydrates Glucose Glucose - Song by Science Groove

Carbohydrates: OH H H HO CH 2 OH H H H OH O Energy molecules

Carbohydrates Building block molecules = sugar sugar - sugar - sugar - sugar - sugar sugars

sucrose Carbohydrates Function: –quick energy –energy storage –structure cell wall in plants Examples –sugars –starches –cellulose (cell wall) glucose C 6 H 12 O 6 starch

Sugars = building blocks Names for sugars usually end in –glucose –fructose –sucrose –maltose OH H H HO CH 2 OH H H H OH O glucose C 6 H 12 O 6 sucrose fructose maltose -ose

Building carbohydrates Synthesis | glucose | glucose 1 sugar = monosaccharide 2 sugars = disaccharide | maltose mono = one saccharide = sugar di = two

Building carbohydrates Synthesis | fructose | glucose 1 sugar = monosaccharide | sucrose (table sugar) 2 sugars = disaccharide How sweet it is!

BIG carbohydrates Polysaccharides –large carbohydrates starch –energy storage in plants »potatoes glycogen –energy storage in animals »in liver & muscles cellulose –structure in plants »cell walls chitin –structure in arthropods & fungi »exoskeleton poly = many

Building BIG carbohydrates glucose + glucose + glucose… = starch (plant) glycogen (animal) energy storage polysaccharide

Digesting starch vs. cellulose starch easy to digest cellulose hard to digest enzyme

Cellulose Cell walls in plants –herbivores can digest cellulose well –most carnivores cannot digest cellulose that’s why they eat meat to get their energy & nutrients cellulose = roughage –stays undigested –keeps material moving in your intestines

Different Diets of Herbivores Cow can digest cellulose well; no need to eat other sugars Gorilla can’t digest cellulose well; must add another sugar source, like fruit to diet

Helpful bacteria How can cows digest cellulose so well? –BACTERIA live in their stomachs & help digest cellulose-rich (grass) meals Eeeew… Chewing cud?

Let’s build some Carbohydrates! EAT X

Brain Break In your composition notebook. Write the following and fill in the answers. Try not to use your notes. 1.What are carbohydrates? Give two examples 2.What are three functions of carbohydrate molecules? 3.What elements make up a Glucose molecule? 4.What is the difference in a monosaccharide and a disaccharide?

Proteins

Proteins: Multipurpose molecules

collagen (skin) Proteins insulin Examples –muscle –skin, hair, fingernails, claws collagen, keratin –pepsin digestive enzyme in stomach –insulin hormone that controls blood sugar levels pepsin

Proteins Function: –many, many functions hormones –signals from one body system to another –insulin movement –muscle immune system –protect against germs enzymes –help chemical reactions

Proteins Building block = amino acid amino acid – amino acid – amino acid – amino acid – —N——N— H H H | —C— | C—OH || O variable group amino acids  20 different amino acids There’s 20 of us… like 20 different letters in an alphabet! Can make lots of different words

Amino acid chains Proteins –amino acids chained into a polymer Each amino acid is different –some “like” water & dissolve in it –some “fear” water & separate from it amino acid

Water-fearing amino acids Hydrophobic –“water fearing” amino acids –try to get away from water in cell the protein folds

Water-loving amino acids Hydrophillic –“water loving” amino acids –try to stay in water in cell the protein folds

pepsin For proteins: SHAPE matters! collagen Proteins fold & twist into 3-D shape –that’s what happens in the cell! Different shapes = different jobs hemoglobin growth hormone

It’s SHAPE that matters! Proteins do their jobs, because of their shape Unfolding a protein destroys its shape –wrong shape = can’t do its job –unfolding proteins = “denature” temperature pH (acidity) folded unfolded “denatured” In Biology, it’s not the size, it’s the SHAPE that matters!

Let’s EAT some Proteins!

Brain Break Which elements make up amino acids?

Enzymes: “Helper” Protein molecules

Flow of energy through life Life is built on chemical reactions

Chemical reactions of life Processes of life –building molecules synthesis –breaking down molecules digestion ++

Nothing works without enzymes! How important are enzymes? –all chemical reactions in living organisms require enzymes to work building molecules –synthesis enzymes breaking down molecules –digestive enzymes –enzymes speed up reactions “catalysts” ++ enzyme We can ’ t live without enzymes! What are enzymes video

Examples synthesis digestion ++ enzyme

Enzymes are proteins Each enzyme is the specific helper to a specific reaction –each enzyme needs to be the right shape for the job –enzymes are named for the reaction they help sucrase breaks down sucrose proteases breakdown proteins lipases breakdown lipids DNA polymerase builds DNA Oh, I get it! They end in -ase

Enzymes aren’t used up Enzymes are not changed by the reaction –used only temporarily –re-used again for the same reaction with other molecules –very little enzyme needed to help in many reactions enzyme substrateproduct active site

It’s shape that matters! Lock & Key model –shape of protein allows enzyme & substrate to fit –specific enzyme for each specific reaction

1 2 3

What affects enzyme action Correct protein structure –correct order of amino acids –why? enzyme has to be right shape Temperature –why? enzyme has to be right shape pH (acids & bases) –why? enzyme has to be right shape

Enzyme vocabulary Enzyme –helper protein molecule Substrate –molecule that enzymes work on Products –what the enzyme helps produce from the reaction Active site –part of enzyme that substrate molecule fits into

Order of amino acids Wrong order = wrong shape = can’t do its job! DNA chain of amino acids folded protein right shape! wrong shape!

Temperature Effect on rates of enzyme activity –Optimum temperature greatest number of collisions between enzyme & substrate human enzymes –35°- 40°C (body temp = 37°C) –Raise temperature (boiling) denature protein = unfold = lose shape –Lower temperature T° molecules move slower fewer collisions between enzyme & substrate

37° Temperature temperature reaction rate What’s happening here?! human enzymes

How do cold-blooded creatures do it?

pH Effect on rates of enzyme activity –changes in pH changes protein shape –most human enzymes = pH 6-8 depends on where in body pepsin (stomach) = pH 3 trypsin (small intestines) = pH 8 Acids and Bases Have Two Different Faces video

The pH Scale

7 pH reaction rate stomach pepsin intestines trypsin What’s happening here?!

For enzymes… What matters? SHAPE!

Brain Break Please write in your composition book: 1.What are substrates? 2.What is the pH range for most enzymes? 3.What affects enzymes?

Lipids: Fats & Oils

Lipids Concentrated energy molecules

Lipids Examples –fats –oils –waxes –hormones sex hormones –testosterone (male) –estrogen (female)

Lipids Function: –energy storage very concentrated twice the energy as carbohydrates! –cell membrane –cushions organs –insulates body think whale blubber!

Structure of Fat not a chain (polymer) = just a “big fat molecule”

Saturated fats Most animal fats –solid at room temperature Limit the amount in your diet –contributes to heart disease –deposits in arteries

Unsaturated fats Plant, vegetable & fish fats –liquid at room temperature the fat molecules don’t stack tightly together Better choice in your diet

Saturated vs. unsaturated saturatedunsaturated

Other lipids in biology Cholesterol –good molecule in cell membranes –make hormones from it including sex hormones –but too much cholesterol in blood may lead to heart disease

Other lipids in biology Cell membranes are made out of lipids –phospholipids –heads are on the outside touching water “like” water –tails are on inside away from water “scared” of water –forms a barrier between the cell & the outside

Brain Break Please write in your composition book: 1.What elements make up lipids? 2.What is the difference in saturated and unsaturated fats?

Nucleic acids: Information molecules

Nucleic Acids Examples –DNA DeoxyriboNucleic Acid –RNA RiboNucleic Acid RNA DNA music video

DNA Nucleic Acids Function: –genetic material stores information –genes –blueprint for building proteins »DNA  RNA  proteins transfers information –blueprint for new cells –blueprint for next generation proteins

A A A A T C G C G T G C T Genes (DNA) are needed to run bodies every day … to make you and me … to make new cells … to make babies!

Nucleic acids Building block = nucleotides  5 different nucleotides  different nitrogen bases  A, T, C, G, U nucleotide – nucleotide – nucleotide – nucleotide phosphate sugar N base Nitrogen bases I’m the A,T,C,G or U part!

Nucleotide chains Nucleic acids –nucleotides chained into a polymer DNA –double-sided –double helix –A, C, G, T RNA –single-sided –A, C, G, U phosphate sugar N base phosphate sugar N base phosphate sugar N base phosphate sugar N base strong bonds RNA

DNA Double strand twists into a double helix –weak bonds between nitrogen bases join the 2 strands A pairs with T –A :: T C pairs with G –C :: G –the two strands can separate when our cells need to make copies of it weak bonds

Copying DNA Replication –copy DNA –2 strands of DNA helix are complementary they are matching have one, can build other have one, can rebuild the whole

Copying DNA –pairing of the bases allows each strand to serve as a pattern for a new strand Newly copied strands of DNA DNA replication DNA Video

Watson and Crick … and others… 1953 | 1962 The Atom Song Video

Brain Break Look on p.167 in your textbook. Concepts in Motion activity.