AP BIO

Water

water distributes the earth 75%

97.5% is salt water

2.5% is fresh water, usually on the surface



FORMATION OF WATER (covalent bonds)

water is a polar molecule due to unablance electrons sharinf between oxygen and hydrogen. There is partial negative energy with oxygen, and partial positive energy hydrogen. When they bond it is called convalent bonding (intramoleculer-from molecule to molecule so hydrogren to oxygen).

  • water is POLAR because of its electronecgativity, oxygen being highest, which why it attracts; hydrogen is drawn to it more. THIS CAN ALSO WORK WITH FON, flourine, oxygen, nitrogen

WATER COMBINING (hydrogen bonds, dipole nature, cohesion)

  • due to its areas of partial charge, water is meant to draw in/attract (dipole nature)

On the other hand, water can combine with other water molecule together through hydrogen bonds (intermoleculer-from between other molecule) This is when a water molecule of hydrogen, connects with another molecule like with oxygen. WHY? they have oppsosite charges. Hygrogen bonds are much weaker because they rely on attractions between partial charges than full on sharing/transfer like covalent bonds


1. Water is a versatile solvent.

WHY? It dissolves in other substances; it can get dissolve! ATTRACT & BREAK APART other polar/ionic substances (for ex: protien, carbohydrates)


2. Water exhibits cohesion and adhesion.

WHY? Cohesion: attaraction to other water molecules (THINK OF HYDROGEN BONDS)

Adhesion: attraction between water molecules to other substances (water + sugar)

BOTH = evapotranspiration (water stick/move together capillary actIon/cohesion through xylem tubes and relsease out leaf by stick on surface of leaf adhesion)


3. Water has a high specific heat capacity.

  • 4.184 joules of energy to raise the temp of 1 gram water by 1 degree c

Formed with hydrogen bonds, when heat is added, it breaks those bonds, causing molecules to move faster. This means that bonds trap heat = has slower heating and cooling affect

WHY MATTERS: regulates climate, body temp


*4. Water has a high boiling point and heat of vaporization.

LIQUID TO GAS

Formed with hydgrogen bonds, but requiere ALOT OF heat, int other to turn into gas/break those bonds


**5. Water is a good evaporative coolant.

Due to high amount of energy to turn liquid to gas. When water evaporates (gas), it takes in thermal energy from its surrounding such as skin/passing air = cause local temp to drop, allowing to remove excess heat


Think of thermoregulation, homeostastis, sweating, qshivering

And Aq And

6. Water has a high melting point and heat of fusion.

SOLID TO LIQUID


7. Water has expansion at freezing (higher density as a liquid than as a solid).

Important because it allows life underwater to not be destroyed by sinking ice .

SOlid has tighter molescules than liquid.

  • water molecules have a lower kinetic energy, allowing more stable hydrogen bonds to form


8. Water is transparent as a liquid.

  • Light penetrates through upper reachers of water due to its structure! it is not absorbed or trapped but RIGHT through


9. Water is a reactant of photosynthesis and a product of cellular respiration in organisms.

CO2 + H20 —> C6H12O6 + O2 (photosynthesis, water is reactant)

C6H12O6 + O2 —> CO2 + H20 + ATP (aerobic cellular respiration, water is product)

  • water splits in a process called photolysis in chloroplasts to serve as a source of protons (H+) and electrons (e-)


Carbs & Lipids i hate my life


4 classes of biomolecules are carbohydrates, lipids, proteins, and nucleic acids


Dehyrdration synthesis: bonds forms, water out (ester bonds 4 lipids)

Hydrolosis: bonds break, water in

both are controlled by enzymes


Carbohydrates:

  • has C, H, O, 2:1 ratio of with H:O

  • Building Blocks: Monosaccharides/Simple sugars (ONE)

    • Fructose, Glucose (used as a source of energy/ATP) , Galactose

  • Disaccharides: combined simple sugars (has more C, H, O)

    • Glucose 2x = Maltose (malta sugar)

    • Glucose + Fructose = Sucrose (table sugar)

    • Glucose + Galactose = Lactose (Milk)


Glycosidic Linkage: covalent bonds between monosaccharides

  • alpha linkage (we can consume better)

  • beta linkage


Polysaccharides: long chains of repeating sugars (MULTIPLE)

  • starch: photosynthesis, bunch of glucose chained through glycosidic bonds

  • celluose: building block of well walls

^^^ energy storage

  • glycogen: animal starch

  • chitin: glucose w/ nitrogren groups

^^^ structural parts


Protein:

  • Amino acids

  • Bulding blocks: amino group + carboxyl group + R group (different r groups is what makes each amino acid different!)


Lipids: fat, non-polar, hydrophobic

  • has C, H, O but more oxygen

  • long term storage

  • heat insulation (blubber, keep warm)

  • padding/protection

  • structural component (lipid bilayer)

  • waterproof (hydrophobic)

  • chemical messenger (steriod/hermone: 4 ring structure gives hydrophobic properties)

  • building blocks:

    • 3 fatty acids, 1 glycerol (triglyceride)

    • 2 fatty acids, 1 glycerol, 1 phosphate group (exception even with sulfer) (phospholipids)


saturated: full of hydrogen, C to C bonds, single bonds (fats, close tightly together, solid)

non-saturated: not full of hydrogen, C to C bonds, has a bend (oil, more spread, liquid)

hydrogenation: adding hydrogen atoms to an unsaturated oil


nucleic acids: CHONP


groups:

  • carboxyl groups in all amino acids

  • methly groups (H3) are non polar = hydrophobic

  • Phosphate groups are charged hydrophilic