Ch.2Ch.2

The chemical basis of lifeThe chemical basis of life

What is this picture What is this picture illustrating?illustrating?

Spider capturing a Spider capturing a mothmoth

What does the male What does the male moth do for the moth do for the female?female?

It receives chemicals It receives chemicals that repel the spiderthat repel the spider

What level does What level does everything in biology everything in biology begin at?begin at?

Everything in biology Everything in biology starts at the chemical starts at the chemical levellevel

What molecules make What molecules make up muscle?up muscle?

Actin and myosinActin and myosin

Which four elements Which four elements do we need the most do we need the most of?of?

O,C,H, and NO,C,H, and N What are trace What are trace

elements?elements? Elements that we Elements that we

need in very small need in very small amountsamounts

What is causing the What is causing the bulge in her neck?bulge in her neck?

A lack of iodine in her A lack of iodine in her dietdiet

How much do we How much do we need each day and need each day and where do we usually where do we usually get it?get it?

0.15mg and it is 0.15mg and it is added to saltadded to salt

What two elements What two elements combine to form the salt combine to form the salt crystals on the far right?crystals on the far right?

Na and Cl combine to Na and Cl combine to make the compound NaCl make the compound NaCl or table saltor table salt

Define a compoundDefine a compound Two or more elements in Two or more elements in

a fixed ratioa fixed ratio Is H2O a compound?Is H2O a compound? Yes, it has 2 Hydrogens Yes, it has 2 Hydrogens

for every oxygen all the for every oxygen all the timetime

What do we call the What do we call the center of the atom?center of the atom?

NucleusNucleus What particles are in the What particles are in the

nucleus?nucleus? Protons and NeutronsProtons and Neutrons What is around the What is around the

outside of the atom?outside of the atom? ElectronsElectrons What are the charges of What are the charges of

protons, electrons and protons, electrons and neutrons?neutrons?

Protons are +, electrons Protons are +, electrons are - and neutrons have are - and neutrons have no charge.no charge.

Sodium in waterSodium in wateractin actin and myosinand myosin

What is an isotope?What is an isotope? An atom with a An atom with a

different number of different number of neutronsneutrons

What is a radioactive What is a radioactive isotope?isotope?

An isotope that gives An isotope that gives off particles and off particles and energyenergy

What is the glowing What is the glowing area showing?area showing?

Cancer picked up by Cancer picked up by a radioactive isotope.a radioactive isotope.

What information does What information does the atomic number give?the atomic number give?

The number of protons The number of protons and the number of and the number of electronselectrons

How many electrons does How many electrons does oxygen need to complete oxygen need to complete its outer shell?its outer shell?

2, the outer shell can hold 2, the outer shell can hold eight but only has sixeight but only has six

Why is the sodium atom giving Why is the sodium atom giving up an electron?up an electron?

To complete it’s outer shell it To complete it’s outer shell it would need 7 more electrons, would need 7 more electrons, it is easier to give it to chlorine.it is easier to give it to chlorine.

Why is chlorine willing to take Why is chlorine willing to take it?it?

To complete it’s outer shell it To complete it’s outer shell it needs one more electronneeds one more electron

What kind of bond (attraction) What kind of bond (attraction) is this?is this?

IonicIonic

What is keeping the What is keeping the sodium and chloride sodium and chloride together?together?

The charged particles The charged particles are attracted to each are attracted to each other forming an ionic other forming an ionic bondbond

How are the attractions How are the attractions between these molecules between these molecules different from ionic different from ionic bonds?bonds?

The atoms are sharing The atoms are sharing electrons instead of electrons instead of transferring them.transferring them.

What are these bonds What are these bonds called?called?

Covalent bonds involve Covalent bonds involve sharing electronssharing electrons

What is this picture What is this picture showing?showing?

In a water molecule the In a water molecule the oxygen pulls the oxygen pulls the electrons toward itself electrons toward itself making the oxygen making the oxygen negative and the negative and the hydrogens positivehydrogens positive

What type of bond is this?What type of bond is this? A polar covalent bond A polar covalent bond

What are the dashed What are the dashed lines representing?lines representing?

A hydrogen bond A hydrogen bond between one water and between one water and anotheranother

What causes these bonds What causes these bonds to form?to form?

The attraction between The attraction between the negative oxygen of the negative oxygen of one water and the one water and the positive hydrogen of positive hydrogen of anotheranother

What are the 3 states What are the 3 states of water?of water?

Solid, liquid and gasSolid, liquid and gas What allows for this What allows for this

property?property? Hydrogen bondingHydrogen bonding

What allows this What allows this insect to walk on insect to walk on water?water?

Hydrogen bonding Hydrogen bonding between water between water molecules creates molecules creates surface tensionsurface tension

What makes it difficult to What makes it difficult to heat up water?heat up water?

It takes a lot of energy to It takes a lot of energy to break the hydrogen break the hydrogen bonds bonds

What happens when we What happens when we sweat?sweat?

The hottest water The hottest water molecules evaporate molecules evaporate leaving the cooler ones leaving the cooler ones behind, (evaporative behind, (evaporative cooling)cooling)

What are some other What are some other properties of water?properties of water?

Large bodies of water Large bodies of water can store huge can store huge amounts of heat.amounts of heat.

Water molecules stick Water molecules stick together (cohesion)together (cohesion)

water and icewater and ice

Why does ice float?Why does ice float? The hydrogen bonds The hydrogen bonds

are stuck in place are stuck in place making it less dense making it less dense so it floatsso it floats

Does this look familiar?Does this look familiar?

What do you think What do you think was going on in this was going on in this demonstration?demonstration?

The solution on the The solution on the right is not liquid right is not liquid water but something water but something that is less dense that is less dense than icethan ice

What happens to salt What happens to salt in water?in water?

It dissolvesIt dissolves Does it disappear?Does it disappear? No, the ions are No, the ions are

attracted to the attracted to the different parts of the different parts of the water molecule, water molecule, breaking the ionic breaking the ionic bondsbonds

What are solutes and What are solutes and solvents?solvents?

The solute is what The solute is what dissolves in a solution, dissolves in a solution, the solvent is the solution.the solvent is the solution.

What do you see as the What do you see as the difference between an difference between an acid and a base?acid and a base?

Acids have more H ions Acids have more H ions and bases have more Oh and bases have more Oh ionsions

What has happened What has happened to this statue?to this statue?

Acid rain has caused Acid rain has caused it to deteriateit to deteriate

What causes acid What causes acid rain?rain?

Sulfur and nitrogen Sulfur and nitrogen oxides produced in oxides produced in factoriesfactories

CC66HH1212OO66 + ____ O + ____ O22 -------> ___ CO -------> ___ CO22 + __ H + __ H22OO

CC66HH1212OO66 + 6O + 6O22 -------> 6 CO -------> 6 CO22 + 6 H + 6 H22OO