bio unit 2

endothermic reaction

1. absorbs energy

2. ΔG > 0 (positive, so creates products w/ higher free energy)

3. decreases entropy (disorder of surroundings) in system

4. non-spontaneous

ex. photosynthesis

exothermic reaction

1. releases energy

2. ΔG < 0 (negative; creates products w/ lower free energy)

3. increases entropy (disorder of surroundings) in system

4. spontaneous

5. ex. cellular respiration

anabolic pathways

process of metabolism that constructs large, complex molecules from smaller simpler ones (small to large)

• ENDERGONIC (requires & absorbs energy)

• ex. amino acids → polypeptides → protein

catabolic pathways

process of metabolism that breaks down large, complex molecules into smaller simpler ones (large to small)

• EXERGONIC (releases energy)

• ex. glucose → CO2 & H2O, protein digestion

define metabolism

the sum of all the chemical reactions that continuously occur within each cell of a living organism

• converting food into energy!!

• operates through 2 main processes: catabolic & anabolic pathways

define system

a group of interacting, chemical components that work together (doesn’t include surroundings)

define kinetic energy & examples

energy in motion/used currently / ability of an object in motion to do work

ex. mechanical, sound, electrical, light, thermal energy

define potential energy & examples

the capacity of stored energy, but could be used (not currently)

relates to position of shared electrons in covalent bonds (polar vs. nonpolar)

ex. chemical (like a battery), gravitational, nuclear, elastic

fill in the blank: polar covalent bonds are (strong/weak), (short/long), (high/low) in potential energy —> why?

strong, short, low due to unequal pull b/c it has less “potential”/likely to break

fill in the blank: nonpolar covalent bonds are (strong/weak), (short/long), (high/low) in potential energy —> why?

weak, long, and high in potential energy b/c they have the “potential”/possibility to break

• ex. methane or glucose b/c its C-C & C-H nonpolar bonds

define the 1st law of thermodynamics

energy cannot be created nor destroyed — only transferred & transformed

what 2 factors determine a reaction will occur spontaneously?

when the products have:

1. lower potential energy

2. lower entropy

compared to the reactants

when does entropy increase in a system?

when a reaction is spontaneous or when energy/molecules become disordered/spread out

left:

• less entropy b/c pretty ordered: one side mostly (-), another side mostly (+) molecules

• more potential energy to change: (+) attracted to (-), so want to attach tgtr and move

right:

• more entropy b/c disordered: both sides a random mixture of (+) & (-)

• less potential energy to change: no pull to switch sides

define cell theory

foundational scientific principle w/ 3 principles

1. all living organisms are made of cells

2. cells are the basic units of structure and function

3. all cells come from pre-existing cells

traits of prokaryotic cells

1. lack membrane-bound organelles (ex. true nucleus)

2. DNA located single circular chromosome in nucleoid region (since no membrane bound nucleus)

3. reproduce through binary fission

trait of eukaryotic cells

1. possesses membrane-bound organelles

2. contains a nucleus w/ DNA chromosomes

3. reproduces w/ mitosis and meiosis

5 traits living organisms share

1. made of cells

2. self-replication (mitosis or binary fission)

3. process genetic information

4. gain and use energy

5. undergo evolution

nucleus function

• stores genetic information (chromosomes; dictates cell activity)

• handles ribosome assembly

• structural support (nuclear lamina)

nonexistent in prokaryotic cells

ribosomes function

translates genetic code from messenger RNA —> protein synthesis

• larger in eukaryotic than prokaryotic

function of rough endoplasmic reticulum

protein synthesis & processing

function of smooth endoplasmic reticulum

lipid synthesis & processing

golgi apparatus

protein, lipid, & carbohydrate processing

lysosomes function

digestion & recycling

vacuoles function

storage, digestion, & recycling

peroxisomes (made of & function)

made of catalase (processes peroxide); oxidation (break down) of fatty acids to provide energy

mitochondria function

ATP production

chloroplasts (made of & function)

made of pigments; produces sugar via photosynthesis

cytoskeleton (made of & function)

actin filaments (protein fibers); structural support, movement of materials

ATP is formed when ___ & ___ combine

ADP & phosphate

Oxidation

loss of electrons or H atoms from a particle

O - Oxidation

I - is

L - Loss

• can only occur if reduction also occurs

• ex. organisms extract energy from fuel molecules by oxidizing them

• a molecule’s potential energy decreases after oxidation!!

OIL RIG stands for:

O - Oxidation

I - is

L - Loss

R - Reduction

I - is

G - Gain

• one cannot occur w/o the other

• processes that involve both are Redox reactions!!!!

Reduction

gain of electrons or H atoms from a particle

R - Reduction

I - is

G - Gain

• can only occur if oxidation also occurs

• a molecule’s potential energy increases after reduction

phosphorylation

the addition of a phosphate group to a molecule by the enzyme “kinase,” which acts as a protein on-off switch to control cell activity

A + B + ATP → A + BP + ADP (molecule B phosphorylated)

dephosphorylation

the removal of the phosphate group from a molecule

define energy coupling

the process where cells use energy released from an exergonic reaction (releases energy) to power an endergonic reaction (requires & absorbs energy)

primarily driven by ATP

enzyme

a protein that serves as a biological catalyst

• reduces activation energy by temporarily binding the substrates to the active site

catalyst

a substance that greatly accelerates a chemical reaction w/o being a reactant in reaction (so doesn’t become a product)

substraces

reactants of catalyzed reactions

induced fit

the process where the binding of a substrate to an enzyme’s active site causes the enzyme’s structure to change to mold to the precise shape of the substrate in order to maximize the catalyst’s effectiveness

what factors influence enzymatic activity aka catalytic rate?

concentration (amount) of substrates, temp, pH, competitive & allosteric inhibitors, & feedback inhibition

how does pH & temperature affect enzymes’ catalytic rate?

if outside the peak range, pH can disrupt an enzyme’s ability maintain its shape of the active site —> hinders a substrate’s ability to bind

allosteric regulation

control of an enzyme’s activity through the sites that aren’t the active site (aka Allosteric sites)

• may cause Allosteric Activation

allosteric sites

sites that are distinct from the main, active site; an effector molecule can influence enzyme’s activity (change or turn on-off)

Allosteric Activation / positive effector

after an effector molecule binds to an allosteric site, there’s an increase in attraction of the enzyme’s active sites for substraces, which leads to → an increased rate in enzyme activity & reaction

• graph w/ x=substrate concentration & y=reaction rate: goes from s-shape to hyperbolic (almost square) curve

Allosteric Inhibition / negative effector

a process when after an effector molecule binds to an allosteric site, there’s an decrease in attraction of the enzyme’s active sites for substraces, which leads to → an decreased rate in enzyme activity & reaction

which is an allosteric activator, inhibitor, and w/o either?

• green = activator

• gray = w/o effector molecule

• red = inhibitor

competitive inhibition

a process where a molecule (inhibitor) blocks an enzyme’s active site, preventing the normal substrate from binding → no reaction

feedback inhibition

type of control that occurs when high amounts of product in a metabolic pathway inhibits the regulatory sites of a enzyme early in the pathway, halting the pathway

• ex. in glycolysis, if ATP concentrations (amounts) is high → starts to bind to allosteric/regulatory sites → ATP becomes an allosteric inhibitor → halts whole cellular respiration

coenzymes

organic molecules (higher presence of C-H)

cofactors

inorganic helper molecules (little to no presence of C-H) that help increase the function of enzymes/molecules

glycolysis

1st stage of cellular respiration

catabolic

redox reactions

aka reduction-oxidation reactions

photosynthesis

• located in the chloroplast

• consists of light-dependent & light-independent (Calvin Cycle) reactions

• series of redox reactions

• producing sugar and O2 from CO2 & H2O

carbon fixation

turning inorganic CO2 from air into useful organic molecules like sugars that contain more chemical energy than the reactants

• requires mucho energy input (anabolic)

light-dependent reactions

• reactants: sunlight, water, NADP+, & ADP

• products: heat, O2, ATP and NADPH

• located in the thylakoids

Calvin Cycle aka light-independent reactions

• use ATP & NADPH as energy sources to build carbohydrate molecules

• 3 phases

Photophosphorylation

the process that plant cells use to use light energy (sunlight) to convert ADP and a phosphate group to ATP