C+G Biology - Chapter 3

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why is water polar?

water is polar because the hydrogen and oxygen within water molecules form polar covalent bonds (slightly pos. charge on the hydrogen and slightly neg. charge on the oxygen)

hydrophilic

water-loving

a polar substance (ions/polar molecules) that interacts readily with//dissolves in water

hydrophobic

water-fearing

ex) oil

non-polar things

amphipathic

BIG molecules that are both hydrophilic and hydrophobic (half and half)

what makes liquid water possible?

hydrogen bonds constantly formed and broken as molecules slide past each other (motion, kinetic energy)

gas (steam)

liquid water that is boiled/evaporates

what makes solid water (frozen) possible?

there is not enough energy to break hydrogen bonds and this makes ice less dense than liquid water (molecules pushed further apart when water freezes, less frequent movement/not as tightly packed less weight).

what is specific heat?

specific heat is the amount of energy it takes for 1 gram of a substance to change its temp. by 1 degree celsius

water has high specific heat (it takes a lot of energy to change the temperature of water)

what is the specific heat capacity of water? what does this tell us?

4.184 calories

this is the energy req. to raise 1 gram of water by 1 degree celsius

what is a calorie?

a measure of energy, the amount of heat required to change the temperature of one gram of water by one degree celsius

what is the heat of vaporization?

the amount of energy required to change 1 gram of a liquid substance to a gas

(586 cal. is req. for water)

what is evaporation?

the separation of individual molecules from the surface of a body of water, leaves of a plant, or the skin of an organism

what is evaporative cooling?

sweat evaporates, taking away the heat from your skin

hydration cell/sphere of hydration

ion surrounded by water molecules

when polar water molecules surrounds charged/polar molecules, thus keeping them dissolved and in the solution

water soluble

able to be dissolved in water (insoluble = not)

(universal) solvent

a substance capable of dissolving a vast amount/range of other polar molecules and ionic compounds - it is the liquid doing the dissolving

this is typically water in biology

solute

thing being dissolved

(sugar into coffee)

dissociation

occurs when atoms or groups of atoms break off from molecules and form ions

aqueous solution

solution where water is the solvent

(non-aqueous is where it is not)

cohesion

the ability to stick to the same substance!

water molecules are attracted to each other (bc/ of hydrogen bonding and because they are all polar)

surface tension

the capacity of a substance to withstand being ruptured when placed under tension/stress - how difficult it is to break the surface of a liquid (water has high surface tension)

water has a really high surface tension because of really high adhesion

adhesion

attraction between molecules of different substances

water has really high adhesion to polar things (bc/ polar loves polar!)

capillary action

water moves up the stem of a plant

occurs because water molecules are attracted to charges on the inner surfaces of narrow tubular structures such as glass tubes, drawing the water molecules to the sides of the tubes

• this is how plants pull water from roots up, kind of like a train

• water clings to itself but also the side of a tube and goes up

• cut flowers are an example of this

what is pH?

how acidic or basic a substance is - the amount of hydrogen ions!

as long as we are removing hydrogen ions we are resisting pH change, that is what the body cares about

litmus

pH paper (whats on pH strips) measures concentration of hydrogen ions in a given solution

lots of hydrogen ions means:

low pH number (super acidic)

aka: as pH gets lower the more hydrogen ions are needed

few hydrogen ions:

high pH number (very basic)

aka: as pH rises the fewer hydrogen ions are needed

acid

molecule that donates hydrogen ions and increases the concentration of hydrogen ions in a solution

base

molecule that donates hydroxide ions or otherwise bins excess hydrogen ions and decreases concentration of hydrogen ions in a solution

what do strong acids do?

• more readily donates H+ (bigger concentration)

  ex) hydrochloric acid (HCL) donates more than vinegar

• strong acids COMPLETELY break down

  ex) HCL —→ H+ +Cl-

what do strong bases do?

• strong bases more readily donate OH-

• strong bases COMPLETELY break down

weak acids and weak bases are

reversible

ex.) of a weak acid: H2CO3—→H+HCO3-

pH scale

inverse logarithm

ranges 0-14

below 7.0 = acidic

above 7.1 = basic

what do buffers do?

RESISTS CHANGE IN PH

readily absorb excess H+ or OH- (saves human body and maintains homeostasis)

• allows organisms to ingest highly acidic things w/o dying

• human blood is a buffer

• a buffer is an equation

what do buffers always have, and what in specific does blood have?

buffers always have 2 parts: a weak acid and a conjugate base

human blood has carbonic acid as its weak acid and bicarbonate ion as its conjugate base

acid added means

right to left ←-

base added means

left to right —>

reactants

starting materials (usually on the left side of a chemical equation)

these undergo chemical changes

products/resultants

resulting substances from chemical changes (usually on the right side)

what is the pH of human blood?

7.35

what defines a compound as organic? “organic molecules”

any molecule containing carbon (except carbon dioxide)

hydrocarbons

organic molecules consisting entirely of carbon and hydrogen

• these do not mix with water

• an example of a hydrocarbon is methane (CH4)

• equal sharing, non-polar

adipocytes

act as storage cells for storing energy in the form of fat

albumin

(how fat can be processed in our blood) // protein that solubilizes fats

what observation can be made about the elemental composition of all organisms

all organisms have similar proportions of major elements

solvent

is doing the dissolving

solute

is being dissolved

H+

hydrogen ion/proton

OH-

hydroxide ion

H+ plus OH- =

H2O

describe what happens during the reaction between bicarbonate and carbonic acid

a chemical equilibrium reaction between carbonic acid (H₂CO₃) and its dissociation products: bicarbonate ion (HCO₃⁻) and hydrogen ion (H⁺). This is represented by the equation H₂CO₃ ⇌ HCO₃⁻ + H⁺, where the double arrow indicates that the reaction can proceed in both directions. The equation illustrates how carbonic acid can break apart (dissociate) into bicarbonate and hydrogen ions, or how these ions can recombine to form carbonic acid, depending on the conditions of the solution. This equilibrium is crucial in biological systems like blood pH regulation and plays an important role in ocean chemistry and the carbon cycle.

What does the Bohr effect describe?

the Bohr effect describes how hemoglobin’s affinity for oxygen decreases in the presence of higher carbon dioxide levels and lower pH

the amount of oxygen (O₂) we’re giving our tissues is influenced by pH and CO₂

what is formed when carbon dioxide levels increase in tissues

Carbonic acid (H₂CO₃) is formed, which dissociates into bicarbonate (HCO₃-) and H+ ions.

How does lower pH affect hemoglobin’s oxygen release?

lower pH (more acidic) causes hemoglobin to release oxygen more readily to tissues

what occurs in the lungs regarding CO₂ levels and pH?

in the lungs, CO₂ levels are lower and pH is higher, causing hemoglobin to bind oxygen more strongly