Biology Midterm 2-12 Paletzki

Many of water’s unique properties are due to its

polarity

Polar molecule

A molecule with an uneven distribution of charge, electrons are shared between the Oxygen and Hydrogen atoms.

How does the polarity of water contribute to its unique properties

Hydrogen bonds enable water to be attracted to itself and other polar molecules

Cohesion

water molecules attracted to themselves

adhesion

water molecules are attracted to other polar substances

capillary action

water can creep up thin tubes

Water resists..

temperature change

water expands…

when it freezes

solution

when one substance is dissolved in another

solute

substance being dissolved in the liquid

solvent

substance doing the dissolving

acid

a substance that forms higher concentrations of H+ ions in a solution than water does (therefor lower concentrations of OH-)

base

a substance that forms lower concentrations of H+ ions in a solution than water does (therefore higher concentrations of OH-)

H+

hydrogen ion

OH-

hydroxide ion

pH scale

the concentration of H+ ions measured

properties of acids

taste sour, neutralize bases, corrode metal,

properties of bases

slippery, neutralize acids, also known as alkaline

macromolecules

very large molecules composed of carbon and other atoms

living organisms depend on __ to survive

macromolecules

there are many types of organic compounds because

carbon can bond easily with itself and other atoms

macromolecules are polymers…

made of smaller units called monomers (mono=one, poly=many)

polymers can…

be made of only one type of monomer or several different types

4 major groups of macromolecules

carbohydrates, lipids, proteins, and nucleic acids

carbohydrates

commonly known as sugars, monomers: simple sugars like glucose, fructose, and galactose, polymers: starch, glycogen, and cellulose

carbohydrates function

provide structural support and quick energy, plants use a complex sugar (cellulose) to build leaves and stems, sugar can be stored in complex carbohydrates to be broken down later for energy

lipids

fats, steroids, oils & waxes, insoluble in water because their molecules are hydrophobic

lipids are comprised of

1 glycerol molecule and 1,2, or 3 molecules of fatty acids

function of lipids

provide long term energy storage, form membranes within cells, used as messengers between cells

nucleic acids

made of nucleotide monomers, each nucleotide contains a sugar, a phosphate group, and a nitrogen base

function of nucleic acids

stores genetic information in cells in the form of a code

proteins

contain not only carbon, hydrogen, and oxygen, but also nitrogen atoms, proteins are composed of long chains of amino acids

function of proteins

regulate cell processes, form bones and muscles, and transport materials

the 4 macromolecules are…

polymers made of simple units called monomers and each contains a different proportion of elements

what happens during a chemical reaction

the molecules in living organisms aren’t stagnant. they are constantly being formed and changed through chemical reactions. chemical reactions always involve breaking or forming bonds between atoms.

two types of chemical reactions

energy-releasing reactions & energy-absorbing reactions

energy releasing reactions

can occur spontaneously

energy absorbing reactions

require activation energy to get them started

enzymes

proteins that act as catalysts, speeding up the rate of a chemical reaction by reducing the amount of energy needed to start it - a special type of protein that changes one molecule (substrate) into another (product) with less activation energy than if the reaction had occurred on its own

substrate

the substance on which an enzyme acts

2 major types of reactions caused by enzymes

synthesis & decomposition

synthesis

when molecules are joined together to form a larger product

decomposition

when molecules are broken apart to form smaller products

examples of reactions using enzymes

lactase - breaks down lactose (milk sugars) during digestion, helicase - unwinds DNA strands for copying during cell division

tonicity

the ability of a solution to cause a cell to gain or lose water

isotonic solution

the amount of solute is the same inside the cel as it is outside - water flows equally in and out of the cell

hypertonic solution

a higher amount of solute than the cell does - water will flow out of the cell towards the environment

hypotonic solution (think hypo- hippo)

the amount of solute particles is lower than inside the cell - water will flow into the cell

active transport

movement from low to high - DOES require energy, like rolling a ball up a hill

protein pumps

allow substances to move from low concentration to high concentration (opposite of the normal concentration gradient)

passive transport

movement from high to low - does NOT require energy, like rolling a ball down a hill

bulk transport

moving large molecules in and out of the cell

endocytosis

using vesicles to move very large substances into the cell

exocytosis

using vesicles to move very large substances out of the cell

autotrophs

make their own food from photosynthesis

heterotrophs

need to consume other organisms for food

where does photosynthesis occur

chloroplasts

inside chloroplasts

are stacks of sac-like thylakoids, space surrounding stacks is called stroma

when light energy is absorbed..

by chlorophyll, it adds energy to electrons. these high-energy electrons are transported between the light-dependent reactions and the light-independent reactions on a transport molecule: NADP+

Autotrophs require 4 resources for photosynthesis

sunlight, carbon dioxide (CO2), water (H2O), chlorophyll

The full equation for photosynthesis

6CO2 (carbon dioxide) + 6H2O (water) + light —chlorophyll→ C6H12O6 (sugar/glucose) + 6O2 (oxygen)

cellular respiration

the process by which all organisms break down glucose to gradually produce energy in the form of ATP

The inputs of photosynthesis are..

the outputs of respiration and vice versa - scientists say that photosynthesis is the “opposite” of cellular respiration

major steps of cellular respiration

glycolysis, the krebs cycle, the electron transport chain

where does cellular respiration occur?

glycolysis occurs in the cytoplasm and the krebs cycle and ETC occur in the mitochondria

how much ATP does cellular respiration yield if oxygen is available to the cell

about 36 (aerobic respiration)

how much ATP does cellular respiration yield if oxygen is NOT available to the cell

2 ATP (anaerobic respiration)

do i want to kill myself thanks to mr paletzki

yes

cellular respiration occurs in…

ALL organisms to produce energy from glucose

what are stem cells

unspecialized cell that can divide indefinitely and become many different types of cells

differentiation

the process of forming specialized cells

multicellular organisms begin..

as one cell that divides into a small clump of cells called an embryo

totipotent

cells that can differentiate into any cell in the body

as the organism continues to develop…

the cells specialize and have a more limited potential to differentiate

how are stem cells used

stem cells can be used to replace damaged tissues or repair organs destroyed by disease (known as stem cell therapy or regenerative medicine)

what role does dna play in differentiation

each specialized cell uses the sections of DNA that create proteins it needs to function