CHAPTER 8 ENERGY AND ENZYMES

Endergonic= energy input (+ G) NOT THE SAME as enderthermicΔExergonic= energy output (- G) NOT THE SAME as exothermicΔThis equations shows how much energy is being put into OR released from the system

G= H-T S (net= gross – taxes)Δ Δ ΔS is entropyΔH is enthalpyΔ

-food is like the fuel of cars but with peopleRedox Reaction- Na+ClNa+ Cl-Elector donor=reducing agentElectron receptor= oxidizing reagentLEO says GER = lose electron oxidized, gain electrons reduced

NAD+ (+) 2[H] NADH + H+ --------- NADH has 2 electrons

Enzymes: Catalytic Protein, bonds with weak bonds like ionic and hydrogenEnzyme Activity

1) Temperature- increase activity until denaturing occurs2) pH change in 3D shape due to interaction to the R-groups (denature)3) other molecules

-Cofactors- non-organic, vitamans-CoEnzymes- organic-losely bond, may change

4) Regulation -simulation/activation-Inhibition

-competitive inhibition – competing for the active site, may turn enzyme on or off so it is revserable

-Non compeditive – molecule binds to regulatory site to change active site, Still reversable

Allosteric reluaioton- turns on OR turns off the enzyme- still non-compeditive

-feedback inhibition- end product binds to regulatory site on enzyme to shut down (most common) or enhance the enzyme (EX blood clotting)

-In temperature graph, slope up until a point then rapidly drops off (left skewed)-In pH the graph is approximately symmetricalpepsin is in the stomach and cleaves peptide bonds (low pH)tripson is in gut and neutralizes acids from stomach

PHOTOSYNTHESIS-mass in wood comes from CO2 (THE AIR)

-90% of water leaves though leaves

-Organisms that are capable of photosynthesis: Bacteria, algae, protists, plants-Photosynthesis takes CO2 and turns it into glucose (using light as a source of energy)

-light energy chemical energy

KNOW HOW TO DRAW2 Stages of Photosynthesis ( BOTH OCCUR DURING THE DAY)

1) Light Reactions – takes place in thylakoid membrane -Covert solar energy into chemical energy2) Calvin cycle (AKA dark reaction but name is misleading)- takes place in stroma

-Carbon Fixation

-ATP ADP + Pi + energy (doesn’t make energy, merely transforms it)-ADP + Pi + catabolic energy ATP

-ATP powers cellular work by coupling exergonic reactions to endergonic reactons (transfers Pi to another molecule)

PIGMENTS

-two types of chlorophyll: chlorophyll A and Chlorophyll B –different structures but aborb different light wavelengths

-also found in chloroplasts are carotenoids which help chlorophyll-outside of the chloroplasts- anthocyanin – purple pigment in pansies.. stored in central vacuole act like sunscreen

Reaction center is ALWAYS chlorophyll A and is surrounded by CA CB and C pigments-light comes in and “bounces” electrons to excite them to a higher energy level

Photosystem II first then Photosystem I-I- makes ATP which is catalyzing energy-II- NADPH which helps build bonds

ATP and NADPH are like rechargeable batteries: charged by light

Stoma= singular (contains guard cells and a pore)Stomata= many

-CO2 enters and O2 leaves

P680 or P700- describes the different wavelengths that the photosystems absorb-Water gives electrons to PII

-H20 is broken down into ½ O2 and 2H+-“Hill” (electron transport chain) is made by proteins which transfer electrons and also move protons from the Stoma to the inner thylakoid space creating a low pH inside

-Protons than move down their Proton gradient (Called chemiosmosis) out back into the stroma and they power ATP synthase (produce 1 ATP) as they leave.

PI Doesn’t require water because electrons are provided by PII-NADP+ reductase makes 1 NADPH at end of PI (NADPH and ATP amount are =)

Light reactions pathway is also called “z pathway”

-cyclic light Cycle- PI electrons travel back down ETC entering halfway down-This means that: PI can make ATP and NADPH-BUT PII can only make ATP

-ATP make in the light reactions drives the Calvin Cycle-O2 is waste productCALVIN CYCLE- 3 stage process (MAKES PYRUVATE)

1) carbon fixation2) Reduction (reverse of glycolysis)3) Regeneration (of CO2)

KNOW WHAT GOES IN/OUTC3 Cycle (normal) –takes place in the stroma-sun goes up.. stomata open and when sun goes down…stomata close

-RuBP- 5 carbon chain (combines with 1 carbon CO2)-Rubisco- enzyme that puts together RuBP and CO2

-most abundant protein/enzyme on earth-Fixes carbon

-New chian cant stay 6 carbons because it is unstable so it falls apart to…-3PG which is rearagned to form G3P and that is stable and has high energy

5/6 G3Ps STAY IN CYCLE-only one G3P leaves cycle as output as sugar-this occurs because there is FREE ENERGY from the sun

Photorespiration- a mistake-rubisco accidentally fixes oxygen and not CO2

-In drought stomata close to preserve H2O, O2 concentration increases

Alternate solutions to deal with arid climates..-CAM-C4

-Light reactions and Calvin cycle still occur but process is added before Calvin cycleCAM- think morning (AM) TIME SEPARATION EX is pinapple and catius

-open stomata at night, close in day-Fix CO2 into 4-carbon molecule-Then CO2 can continue to enter the stomata

C4- -pepcarboxylase PHYSICAL SEPARATION EX is Corn and sugarcane

Cellular Respiration is exergonic

Two common processes to produce ATP: Cellular Respiration, Fermentaition

-Cellular respiration- requires O2- produces about 36-38 ATP

-Fermination- used by bacteria beause they don’t have mitochondria- used if no O2 is present, but not effectiant -red blood cells

BOTH USE GLYCOLYSIS- which produces 2 ATP, 2 pyruvate, and 2 NADH TOTALGlycolysis- adds a phosphate to the glucose to prevent from leaving-rearragne and make symetrical with andother phosphate (2ATP invested)

-phosphofructokinase- highly regulated, comitted step to burn sugar though glycolyis

FERMENTAION- purpose is to purpose is to get NAD+ backLactic acid- NO ATP produced

- puts electrons on pyruvate to make lactate (From working) - 2 NAD+ produced- Lactate is waste (lactic acid)

Alcohol- STILL NO ATP produced- releases a CO2 from pyruvate and adds electrons to that molecule

makes ethanol

Cellular Respiration- O-compounds + O2 Co2 + H2O + energy

-Glucose is o-compound normally4 Stages

1-Glycolysis (in cytosol)2- pyruvic Oxidation AKA pre-krebs (in mitochondria)3-Krebs Cycle AKA citric acid cycle4-Electron Transport chain

pyruvic Oxidationlooses electrons so its oxidation

Krebs cycle- (to the right) makes ATP though substrate level phosphoilationTOTAL output PER CYCLE is 1 FAD, 3 NADH, 1 ATP, 2 CO2s (x2 if per glucose)

Electron Transport Chain- ATP made by chemiosmosis (32-34 ATP made)-Chemiosmosis + ETC= oxidative phosphorylation

cristae= membraneAcetyl CoA is a precursor for fat

-Can turn into fat before it reaches the citric acid cycle-SWITCHING POINT

-phosphofuctokinase- ATP inhibits, citrate inhibits, AMP stimulates

Cell Division-Binary fission- simplified mitosis in bacteria cellsa) Reproductionb) Growth and developmentc) Tissue renewal

In order for DNA to replicate, the DNA needs to be relaxed around the histone proteins.

Cell Cycle in Eukaryotes1) INTERPHASE

a. –G1- first step, growing, acquiring nutrients, daily activities, replicates organelles

b. –S – synthesis, replicating DNAc. –G2- second gap, acquires nutrients, check before division

2) Mitotic Phase-Chromosomes- are sister chromatids paired with a centromere

Stages of Mitosis-Interphase Inflate-Prophase- chromosomes are visible package-Prometaphase Polarize-Metaphase Meet at middle-Anaphase (sister chromatids) away-Telephase/cytokinesis terminate, cytoplasm

Cytokinesis: division of cytoplasm + plasma membrane

Animal cells: use actin and myosin, intra cellular skeletonPlant cells: cell plateCtytokinesis and Mitosis overlap

Mitosis: Division of the nuecleous-centrosome-prophase-> packageing for the move, chromotin condences, nuelolus

disappears and nuelasr envelope degrades-plane of division has been set, mechanism of decision is not understood-Prometaphase: polarize

Cell regulationCANCER: uncontrolled cell growth

-contact inhibition-Imortal-Chromosomal abnormalties-Hoard Nutrients-Unable to enter G0 phase

-Normal cells may divide to heal a wound, but they STOP- In cancer, something is happening to the normal stop signals- Cells can break off into the lymphatic and circulatory system in cancer

3 check points-Late G1, G2, and M

-regulated by cyclin dependent Kinases (CdKs)Late G1

-Purpose: Pre-replication DNA, quality control, general cell readiness- most important-Lack of “go ahead” can lead to permanent G0, or temporary G0

-Why wait?-Too Small-DNA Damage-Limited Resourses

G2 checkpoint-Purpose: post-DNA replication, quality check-Activated by MPF (M-phase promoting factor)-triggers mitosis (division of nucelous)

M- checkpoint-Purpose: Halt cell division in anaphase if spindle fibers fail to attach to

kinetochores

CDK + Cyclin = MPF-cylcin turns CDK on, then CYCLIN degrades, marked by ubiquen

DNA Damage checkpoints1)Before cell enters S Phase (a G1 checkpoint)2)During S phase (Check for complete DNA replication)3)After DNA replication (G2 checkpoint)

Spindle Checkpoints – still being discovered, known checkpoints include:1) detect failure of spindle fibers to attach to kinetochores2) Detect improper alignment of the spindle itself and blocks cytokinesis

-Apoptosis if cell damage is irreversible

Mutations through MEIOSIS are INHEARITEDAsexual organisms replicate through MITOSISThree origins of variability due to MEIOSIS:

1) Crossing over in Meiosis 12) Indepentent assortment in Meiosis 13) Random fertilization

Gene- functional unit of DNALocus-Adress of GeneGerm Cell- 2n (23 total)Gamete- 1nZygote- 1n + 1n = 2n through fertilizationSex chromosomes- XY or XX (1 pair) (Turtles rely on temperature)Chromosomes= 46 total (after anaphase go back to 46 chromosomes)Automomes- 22 pairsKayrotype- ALL TOGETHER (picture)Actin filiments- cleavage furrowMicrotubles- spindle fibers

EVOLUTION IS NOT GOAL ORIENTEDTrisomial 21=down syndromeMeiosis- homolog chromosomes separate first

-sister chromatids separate last

- 4 haploid cells total at end-Girls meiosis pauses sometimes-boys meiosis never stops

prophase 1-chromosome homologs pair up-synapsis- homologs recombine at chiasmta(crossing over occurs here)

-swap genes between homologs-Sister chromatids ay cross but cant see it

Prometaphse 1-tetrads move to poles

metaphase 1-tetrads move to middle

Anaphase 1-sister chromatids STAY together, homologs separate

telephase 1-some may rebuild nuclear envelope and relax DNA other may not

END of meiosis 1--2 HAPLOID daughter cell

Prophase 2- no interphase between-Reverse of telephase 1 (condesnces DNA, Degrade nuclear envelope)

Prometaphase 2-connect microtubules to sister chromatids

Metaphase 2- line up sister chromatids at equator

anaphase 2-separate sister chromatids

Telephase 2-relax DNA, build nuclear envelope-4 daughter cells, in Boys all are =, in girls 3 are polar bodies and 1 is egg (big)

Meiosis occurs in the gonads-called gametogenesis

Three events that distinguish meiosis

Consequences of ERRORS1) aneuploidy: wrong number of chromosomes present2)Translocation: breakage, DNA reattached in wrong place3) Inversion: breakage, DNA reattached in correct place but wrong oder4)Deletion: missing

Nondisjunction in anaphase I results in 2 (n + 1) daughter cells and 2 (n – 1) daughter cells. The law of independent assortment occurs during metaphase I of meiosis. The law of segregation occurs during anaphase I of meiosis

There are 23 PAIRS of chromosomes and 46 TOTAL chromosomesMendel’s Laws-Law of segregation- Focus on same Gene but different alleles (each allele is on a different CHROMOSOME)-Law of independent assortment- Each allele separates independently (from meiosis in CROSSING OVER)

Key features of his work:

1) used numbers and statistics2) Studied “either-or” traits (Clear traits like white or purple)3) Used true breeding plants4) Lucky he chose feature that were determined by allelesCharacter- a heritable featureTrait- varieties of a particular character

MisconceptionsDominant traits are NOT more likely to be inhearitedAlso not more prevalent in the population

Homozygus- 2 of same allele- SS or ssHeterozygous- 2 different alleles- SsGeneotype-what the alleles arePhenotype- what it looks like

Parent Generation (P)- homozygous for each parentFirst generation (F1)- Classically all herozygus crossingTest cross- crossing the F1 generation with the RESSESSIVE P generation-figure out geneoytpe

dihybrid= HrTTBlood is co-cominant (A antibodies, B antibodies, A and B antibodies, O has NONE)(-) or (+) is rhesus factorOO(-) is universal donorAB(+) is universal receiver

epistasis--when the expression of one gene masks the expression of a second gene.

Segrigation- different alleles package on different gametesIndependent assortment- different genes travel different from each otherPlietropy- 1 gene=many traitsPolygenic 1 trait = many genesPhenotype is always a result of environment + gene expression

-enviroment controls what genes get turned on

Ressessively inhearied disorders-cysitic fibrosis- thicker mucus in lungs, causing infections, affects cilia-tay-sachs disease- lack enzyme for digestion for key lipid, early death in childhood-sickle cell anemia- reduced capacity to carry O2-homo res-dies of disease-homo dom- dies of malaria-heteozygous- resistant to malaria and still is able to carry O2

Dominant inhearited disorder- less common, fatal before they are passed to the next generationEXCEPTIONS

-hunningtons- kills in 40s degeneratin of nervous system-not fatal until after reproduction days

-dwarfism-mutation arise in meiosis

-Square are MALE, circles are FEMALE

Linked genes- 2 genes lockated on the same chromosomeSex linkaged:gene carried on a sex chromosome-y is smalled than X chromosome, so only parts cross over, XX cross normally