Bio Unit 2

**concentration gradient**

a difference in the concentration of solute across a membrane

Ch 7 : Structure and function of cellular membranes

%%Function%% : keep outside out and inside in ( this is b/c selective permeability)

^^Structure^^ : phospholipid bilayers

Ch 7 : fluid mosaic model

describes structure of cell membrane

• fluid phospholipid bilayer

• mosaic of embedded / attached proteins

Ch 7 : Amphipathic

Hydrophilic and hydrophobic regions

ex: phospholipid

Ch 7 : Diffusion

high to low concentration ( spread evenly ) water and solute move

• No energy

• Down concentration gradient ( passive )

Ch 7 : Selective permeability

Some substances cross more easily than others

* small and non polar molecules are able to cross

Ch 7 : passive transport

across a membrane with no ATP

• concentration gradient provides energy

• down concentration gradient

Tonicity

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

* influenced by solute concentration / membrane permeability

Ch 7 : active transport

the transport of a solute across a membrane against its concentration gradient

• needs atp

• low to high

example : living yeast was able to actively transport dye out of cell

Ch 7 : does moving something against its concentration gradient need ATP , is it active or passive ?

Yes movement against concentration gradient needs atp; it’s active

ch 7 : does moving something down its concentration gradient need atp ? is it passive or active ?

No movement down concentration gradient doesnt need atp ; it’s passive

Ch 7 : osmosis

@@Diffusion of water from@@ high to low solvent concentration

* only water moves

Ch 7 : bulk transport

large molecules ( proteins , carbohydrates) in or out of cell

* active

Ch 7 : turgid

cell wall exerts turgor pressure which stops water from leaving .

• cell is swollen and firm

• pressure works against osmosis ( hypo to hypertonic flow )

Ch 7 : facilitated diffusion

passive high to low transport with help of membrane protein

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Ch 7 : Isotonic

equal ( solute and water concentration )

* equal in and out

Ch 7 : Hypotonic

low solute concentration and high water concentration

* too much water

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Ch 7 : Hypertonic

high solute concentration and low water concentration

* not enough water

ch 7 : exocytosis

%%active transport and bulk transport out of cell%%

* transport vesicles fuse w/membranes

ch 7 : endocytosis

%%active and bulk transport into cell%%

* takes in substance by forming vesicle from plasma membrane
* **entro = inside = endo , transport into cell**

Ch 7 : 3 endocytosis types

Phago , pino , receptor mediated

^^Phagocytosis^^ : cell eating

Pinocytosis : cell drinking ( not picky / specific )

* think of **vino** = wine = drink

%%Receptor - mediated endocytosis%% : receptor proteins help bring more of what’s trying to come in

Ch 7 : Reaction of Animal Cells in (Hypotonic , Isotonic , Hypertonic environments )

Different cell environments :

^^Hypotonic^^ : too much water in cell and low solute

cell swells and burst

%%Isotonic%% : equal solute and water concentration

cell is stable (normal )

==Hypertonic== : low water in cell and high solute

cell shrivels and dies

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Ch 7 : Reaction of Plant Cells in (Hypotonic , Isotonic , Hypertonic environments)

Different cell environments :

^^Hypotonic^^ : too much water in cell and low solute

cell is turgid b/c of the cell wall being pressed against the plasma membrane (normal )

%%Isotonic%% : equal solute and water concentration

cell becomes flaccid

==Hypertonic== : low water in cell and high solute

cell shrivels and dies because the cell wall is pulling away from the plasma membrane

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Ch 7 : Two types of transport proteins and the kinds of transport for each

Channel protein : hydrophilic tunnel thru membrane

• used in facilitated diffusion

Carrier protein : change shape to give their molecules a ride

• used in facilitated diffusion and sodium potassium pump

ch 7 : Sodium potassium pump

Exchanges Na+ for K+ in animal cells

• Na+ is high (outside ) to low (inside)

• K+ is high (inside) and low (outside)

• against concentration gradient = uses ATP ( active transport )

  • 3 NA leave

• • 2 K enter

Ch 7 : Active transport VS Passive transport

Active : against gradient and needs atp

Passive : down the gradient and doesnt need atp

Ch 7 : Membrane potential

voltage across a membrane , inside cell is - and outside is + .

being inside is boring (-) , being outside is fun (+)

• cations (+ ) diffuse into cell

  • Cats are pawsitive ,

• anions (-) diffuse out of cell

  • anions are anti = negative charge

Ch 7 : Electrogenic pump

^^. transfer^^ ^^(+) charge from inside cell to outside^^ . maintains membrane potential

* Ex: @@Sodium potassium pump ( animal cells ), Proton pumps ( everything else )@@

Ch 7 : Free energy

energy available to perform work when temp and pressure are uniform

• the inside of a cell is uniform

• helps us know if a reaction occurs spontaneously

Ch 8 : Metabolism

all of an organism’s chemical reactions . transforms matter and energy

ch 8 : metabolic pathways

molecules changed in series of steps

two types : catabolic and anabolic

Ch 8 : entropy

measure of disorder/randomness

• the more randomly arranged a collection of matter the greater the entropy

• heat increases entropy

• every energy transfer increases entropy

Ch 8 : What does it mean to be spontaneous ?

Energetically favorable

Ch 8 : Spontaneous process

occurs on its own , no energy , high entropy of universe

* ex- old car rusting

Ch 8 : Anabolic

^^build^^ complex molecules , consume energy , uphill , endergonic

ex: protein synthesis

**Anabolic steroids building muscle**

Ch 8 : Catabolic

==break== down complex molecules , release energy , down hill , are exergonic

ex: cellular res

**think of a catastrophe destroying**

Ch 8 : Exergonic (related to energy )

energy ==outward ,== ==release== of free energy , ==∆ G is neg== (less than 0) , some free energy available , ==spontaneous ,== ==downhill more entropy==

* not all energy is available b/c 2nd law , energy lost to entropy (heat)

Ch 8 : Endergonic (related to energy)

energy %%inward , absorbs%% free energy , %%∆G is pos%% ( greater than 0) , stores free energy in molecules , %%nonspontaneous , up%%hill

Ch 8 : Catalyst

molecule that facilitates a reaction w/o being consumed by reaction

Ch 8 : Substrate

the reactant for that particular enzyme

Ch 8 : Active site

region of enzyme where a substrate binds , shaped so that certain substrates can fit

Ch 8 : First Law of Thermodynamics

Energy CANNOT be created or destroyed ONLY transferred and transformed . Energy of the universe is constant

Ch 8 : Second Law of Thermodynamics

every energy transfer (reaction ) increases entropy

Ch 8 : Gibbs free energy ∆G

energy for a system

Ch 8 : Formula for ∆G

∆G = G final state - G initial state

Ch 8 : Equilibrium

lowest ∆G

• valley of free energy

• only spontaneous and can perform work when it is moving towards equilibrium

• never spontaneously move away from equilibrium

Ch 8 : Activation energy

%%energy%% needed to change molecules into an unstable transition state %%so that “downhill “ can occur%%

* acts as a barrier

Ch 8 : Energy coupling

using energy from exergonic for endergonic reaction

Ch 8 : How does ATP work ?

powers cellular work by %%energy coupling%% (exergonic reactions to endergonic reactions) performs work through %%hydrolysis%%

Ch 8 : ATP cycle

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Ch 8 : What are enzymes and how do they work ?

a protein that works as a catalyst ( facilitates reaction w/o being consumed by reaction )

• lowering the activation energy barrier without being consumed by reaction .

• Lower barrier by lining up substrates to bend towards transition state

optimum condition: where enzyme shows the most activity

Ch 8 : Induced fit

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Entry of a substrate changes active site so it binds better to substrate

* low activation energy and takes the barrier from activation energy away

Ch 8 : Competitive inhibitor

looks like substrate , occupies active site making it unavailable

* increases substrate concentration

Ch 8 : Noncompetitive inhibitor

binds to another part of enzyme , changes shape of active site so enzyme can’t bind there

Ch 8 : Cofactor

non protein helpers

• Inorganic/organic

• bound permantly / loosely to enzyme

Ch 8 : Coenzyme

organic cofactors

Ch 8 : How are enzymes involved in regulating metabolism ?

lower activation energies of chemical reactions

* high activation energy prevents reactions from acting spontaneously

Ch 8 : Allosteric regulation

a protein’s function is controlled by a regulatory molecule at a separate site , not active site

* may inhibit or stimulate activity

Ch 8 : Feedback inhibition

end product of pathway

==**off switch for enzyme**==

* form of allosteric regulation

Ch 8 : How do enzymes facilitate a reaction ? What do they do specifically?

lower the activation energy barrier , they do not change ∆G

Ch 8 : How are metabolic pathways organized ?

organized by :

• time ( inhibition (off ) or activation (on) )

• space ( in membrane and organelles)

ch 9 : redox reactions

a type of chemical reaction that involves a transfer of electrons . this is how catabolic reactions release energy

ch 9 : LEO the lion says GER

(LEO): Loses Electron Oxidation

(GER ) : Gains Electron Reduction

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ch 9 : oxidation

loses electron , increases charge ( more +)

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ch 9 : reduction

gains electrons , decreases charge (-)

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ch 9 : oxidizing agent

electron acceptor , cause of something oxidation

ch 9 : reducing agent

electron donor , cause of something being reduced

ch 9 : aerobic cellular respiration

• final electron acceptor

• is efficient ? ( yes or no )

• electrons transferred down or up ?

• uses o2 as final electron acceptor

• more efficient , more energy

• uses electron transport chains to transfer electrons down to o2

ch 9 : anaerobic cellular respiration

• o2 needed ( yes or no )

• initial electron acceptor

• Efficient ( yes or no )

• inorganic final electron acceptor ( stronger or weaker than o2)

• no o2 needed

• initial electron acceptor NAD + w/o air life

• less efficient , less energy

• uses an inorganic molecule (not o2 ) as final electron acceptor , this acceptor won’t be as electroneg. as o2

ex: fermentation

ch 9 : fermentation

• O2 needed ( yes or no )

• Initial electron acceptor

• ETC ? does that change the final electron acceptor

Catabolic

no o2 to make ATP from glucose by letting glycolysis happen over and over .

NAD+ is initial electron acceptor .

uses a different final electron acceptor b/c no ETC .

Alcoholic fermentation

• NADH becomes NAD+ with acetaldehyde as electron acceptor

Lactic acid fermentation

• NADH becomes NAD + with pyruvate acting as acceptor

ch 9 : glycolysis

• location

• input

• output

glucose oxidizes to pyruvate without using o2

ATP made thru substrate phosphorylation

location : cytosol

Input :1 glucose

Output

2 pyruvate

2 ATP

2 NADH

ch 9 : pyruvate oxidation

• location

• input

• output

pyruvate oxidizes (loses electrons ) to become acetyl coA

location

Eukaryotic- mitochondrial matrix

Prokaryotic - cytosol

Input :2 pyruvates

Output :

2 Acetyl CoA

2 CO2

2 NADH

ch 9 : citric acid cycle ( Krebs cycle )

• location

• input

• output

**Acetyl CoA delivers the acetyl into the citric acid cycle , 2 carbons from Acetyl CoA continue to be oxidize ( lose electron ) and leave as Co2**

__location__

Eukaryotic -mitochondrial matrix

Prokaryotic - cytosol,

%%__Input__%% : 2 Acetyl CoA

==__Output__== ( for 1 turn per glucose molecule )

one ATP by substrate phosphorylation

2 CO2

3 NADH

FADH2

ch 9 : oxidative phosphorylation

• location

• input

• output

ETC and chemiosmosis

ATP synthesis from adding inorganic phosphate to ADP

^^most atp in cellular respiration^^

__location__: Inner membrane of mitochondria

%%__Input__%% :10 NADH and 2 FADH2

==__Output__== : 26 to 28 ATP

ch 9( how atp is made ) :substrate level phosphorylation

substrate level : makes atp by adding phosphate group from substrate to ADP

* used in glycolysis and citric acid cycle

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ch 9 (how atp is made) : oxidative phosphorylation

oxidative : makes atp by adding an inorganic phosphate to ADP

• makes the most atp

• also the last step in cellular respiration

ch 9 : function of NAD +

initial electron acceptor , oxidizes

becomes NADH when it has electrons

Ch 9 : NADH

electron donator , reduces

becomes NAD when loses electrons

ch 9 : how an ETC moves electrons in general

electrons passed down the chain as the carriers alternate b/w reduced and oxidized states .

* electron moved down in energy in controlled way for ATP synthesis ( think of cake down stairs )

ATP synthase

enzyme in mitochondrial membrane

• makes ATP from ADP and inorganic phosphate

• uses energy in form of a H+ concentration gradient ( ions down gradient )

ch 9 : chemiosmosis

redox reactions in membrane to make atp

ex: cellular respiration

ch 9 : difference between an obligate and facultative anaerobe ?

Obligate : can’t use O2

• ex : marine bacteria w/rotten egg smell

Facultative : can go either way ( no o2 or yes o2) depending on conditions

• ex: yeast and muscle cells switch to fermentation when no o2 is present , when o2 is present they use aerobic cellular respiration

Ch 9 : facultative anaerobes at which point is a pathway “chosen” ? what determines that ?

Pathway is chosen at pyruvate point . What determines which pathway is chosen is the presence of o2

• no o2 = fermentation

• yes o2 = aerobic cellular respiration

ch 10 : Autotroph

self feeders

• make organic compounds from inorganic compounds (CO2)

• source of organic compounds for heteroph

locations of cellular respiration of different stages

• Glycolysis

• pyruvate oxidation

• citric acid cycle

• oxidative phosphorylation

why is glycolysis described as having an investment phase and pay off phase ?

==**Investment**== because you have to spend store ATP

%%payoff%% :after spending you make more ATP than you need and net increase in ATP molecules

ch 10 : heterotroph

other feeders

• get organic compounds from autotrophs

• depend on autotroph for food

Ch 10 : draw diagram of how photosynthesis and aerobic cellular respiration fit together to recycle chemical elements and move energy through ecosystem

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ch 10 : why are electrons transferred to in photosynthesis?

what is reduced and what is oxidized

electrons transferred to make O2

• CO2 : reduced ( gains electrons )

• H2O : oxidized ( loses electrons )

ch 10 : source of electrons in photosynthesis

H2O is spilt

hydrogen moves to CO2 to make glucose

ch 10 : %%Compare%% / ==contrast== the processes of chemiosmosis in aerobic cellular respiration and photosynthesis.

%%__Both__%%

use ETC ( and redox reactions )

ATP made from energy of redox reactions

==__Differences__==

Chemiosmosis ( photosynthesis ) : chloroplast

chemiosmosis ( cellular respiration ) : mitochondria

Bio concept : aerobic respiration (mitochondria )

* how does organelle structure relate to function?

@@Aerobic respiration ( use o2 )@@ - in @@mitochondria@@

* double membrane and has folds increase surface area to make more atp

Bio concept : photosynthesis

* how does organelle structure relate to function?

Photosynthesis : in Chloroplast

• double membrane more atp

• contain pigment that takes in sunlight , h2O and CO2 to make glucose and O2

what stage produces the ==Most Co2== in ^^aerobic cellular respiration^^

Citric acid cycle

what stage makes the %%most ATP%%

in ^^aerobic cellular respiration?^^

Oxidative phosphorylation

As electrons flow along etc what happens to the ph of the matrix ?

(increase / decrease )

ph of matrix increases

Ultimate source of the energy released by aerobic respiration ?

light energy from the sun

Immediate source of the energy released by aerobic respiration ?

chemical energy from ATP and heat

Are electrons moved up or down in

• Photosynthesis

• Aerobic cellular respiration

%%__Photosynthesis__%%

moves electrons %%up%% in energy

^^__aerobic cellular respiration__^^

moves electrons ^^down^^ in energy

when in photosynthesis is light energy converted to chemical energy ?

During light reactions