Unit 2 The Chemistry of Life

How can this plant digest a frog?

Like other carnivores, the Venus flytrap eats animals to get nutrients that it needs to make molecules such as proteins and nucleic acids. Other chemical compounds made by the plant’s cells enable the Venus flytrap to digest the animals that it eats. These chemicals are similar to the chemicals that allow you to digest the food that you eat. Example from Holt McDougal text

Fun Fact! The Venus flytrap can capture prey even though it has no muscles or nervous system. When one of six tiny trigger hairs is touched, the plant responds by moving water in its cells to change the curvature of the leaves. The convex leaf halves become concave and snap shut in less than .5 seconds.

???????? If plants can make their own food through photosynthesis, why would a plant species evolve a mechanism to capture and eat animals?

The animal must be supplying nutrients that the plant cannot get from other sources.

Venus fly traps grow in swampy areas that have nitrogen poor soil Venus fly traps grow in swampy areas that have nitrogen poor soil. These plants get the nitrogen they need for survival by trapping and digesting animals.

Videos http://www.youtube.com/watch?v=O7eQKSf0LmY http://www.youtube.com/watch?v=ktIGVtKdgwo

Intro. Video http://vimeo.com/83005599

Vocabulary Introduction Using your workbook, write out the definitions and provide an example for each word.

What are all things made up of? They are all made up of ATOMS-> Smallest basic unit of matter.

Atoms are made up of: Protons-> positively charged particles and dense Neutrons-> neutral / no charge Electrons-> negatively charged particles and small Protons and neutrons live in the nucleus (center of the cell) Electrons are in the outer levels= electron cloud

Draw and label the atom

Element A type of atom that cannot be broken down into simpler substances. Can also be a group of atoms of the same type. Ex-> gases such as hydrogen and oxygen. Metals= aluminum and gold.

Atoms are made up of the same types of particles, so what makes one element different from another? Different elements differ in the number of protons they have. Atomic number= number of protons Atomic Mass

How many protons does hydrogen have? Oxygen?

Energy levels Different energy levels can hold a different number of electrons. 1st energy level= hold 2 electrons 2nd level= hold 8 electrons Stable atoms have a full outermost energy level

91 elements 4 that make up 96 % of your body= carbon, oxygen, nitrogen, and hydrogen The other 4% are called trace elements because they are found in little amounts but we need them to survive-> like calcium, iron, potassium

Why does your blood need iron? To transport oxygen in your blood.

Why does your body need chromium? Needed for your cells to break down sugars for usable energy.

Compounds Atoms of elements found in organisms are usually linked or bonded to other atoms= compound. Common compounds= water (H2O), carbon dioxide (CO2)

Ion Atom that has gained or lost one or more electrons. Forms because an atom is more stable when its outermost energy level is full. The gain or lose results in a full outer level. Either positive or negative Atoms with few electrons= lose electrons and becomes more positive Gains electrons= more negative.

NaCl Transfers electron from sodium atom to chlorine atom When sodium loses electron it becomes positive-> full charged because it has a filled outermost energy level. The electron lost goes to the chlorine ion, causing the chlorine to become more negative and have a full energy level.

End product is an ionic bond-> bond that forms when two oppositely charged particles exchange electrical forces. Opposites attract (+ / -)

What determines whether an atom becomes a positive ion or a negative ion? Atoms with few outer electrons tend to lose electrons and form positive ions; atoms with almost full outer energy levels tend to gain electrons and form negative ions.

Covalent Bonds Form when atoms share a pair of electrons. Need 4 electrons to fill its outermost energy level.

CO2= Carbon Dioxide O C O An oxygen atom needs 2 electrons to fill its outer energy level. In Carbon dioxide, carbon makes a double bond, or shares two pairs of electrons with each oxygen atom.

Molecule Two or more atoms held together by covalent bonds.

Waters unique properties allow life to exist on Earth. Properties of Water!!!!! Waters unique properties allow life to exist on Earth.

Polar vs. Nonpolar Polar: Water and some gases In the water molecule, the electrons of the polar covalent bonds spend more time near the oxygen than the hydrogen The water molecule is thus a polar molecule: the overall charge is unevenly distributed Polarity allows water molecules to form hydrogen bonds with each other Nonpolar= liquids, CO2, Oxygen, oils, fats Electrons are distributed more evenly around the outer shell.

− Hydrogen bond + Polar covalent bonds − + − + − + Figure 3.2 Figure 3.2 Hydrogen bonds between water molecules

Life depends on hydrogen bonds Water is polar-> act the same way as the magnetic poles. Have regions with a slight positive and slight negative charge. Waters oxygen atoms are slightly negative and hydrogen is slightly positive= HYDROGEN BOND

Where else can we find hydrogen bonds? DNA Proteins

Properties of Hydrogen Bonds Weakest of the bonds High specific heat= water resists changes in temperature, therefore water must absorb more heat energy to increase temperature. Very important with cells because our cells release a lot of heat and water absorbs that heat which allows us to regulate cell temperatures.

Cohesion Cohesion-> attraction among molecules of a substance. Makes water molecules stick together. Also produces surface tension- makes a skin on the surface of the water. Ex- beads on a car when it is washed Spider walking on top of the water.

Adhesion Adhesion-> attraction among molecules of different substances. Water molecules stick to other things. Ex- upward curve of the surface of the water-> graduated cylinder Ex- plants transport water up their roots to their leaves.

Capillary Action Water molecules stick to tubes of small diameter. Plants transport water from roots to leaves. Water moving up a straw.

Videos http://www.youtube.com/watch?v=0eNSnj4ZfZ8 http://www.youtube.com/watch?v=WpXHpXKZtws http://www.youtube.com/watch?v=8O8PuMkiimg

Many compounds dissolve in water Molecules and ions can’t take part in chemical processes inside cells unless they dissolve in water. Materials such as sugar and oxygen cannot be transported from one part of an organism to another unless they are dissolved in blood, plant sap, or water based fluids.

Solution= mixture of substances that is the same throughout= homogeneous mixture Solvent-> substance that is present in the greatest amount, and is the substance that dissolves solutes. Example= Water Solute-> substance that dissolves. Example= kool aid powder

????? Your plasma (liquid part of your blood) is 95% water. Which is the solvent and solute? Solvent= water; Solute is the other 5% which is made up of proteins, sugars.

Why do solutes such as proteins and sugars dissolve in the water of blood plasma?

Answer Polar= because the attraction between the water molecules and the solute molecules is greater than the attraction among the molecules of the solutes.

ACID / BASE Notes See foldable.

Ph of 7=Neutral-> neither acidic or basic Acids and Bases Acids Releases a hydrogen ion (H+) when it dissolves in water. 0 to 7= acids Bases Removes H+ ions from a solution 7-14= basic Weak base Strong Base Strong Acid Weak Acid Ph of 7=Neutral-> neither acidic or basic

pH Scale (Potential Hydrogen)

How is pH regulated in our bodies? Through buffers-> compounds that can bind to H+ ion when the H+ concentration increases and can release an H+ ion when the H+ ion decreases. Buffer “locks up or stops” the H+ ions in order for our bodies to maintain homeostasis. Example-> normal Ph of blood is 7.35-7.45 (slightly basic), therefore a small change in this could really disrupt your cells and can be fatal.