Biology UCC Flashcards
Give some examples of Colloids What are colloidal systems Give an example State the properties of colloidal systems What are sols and gels What is an emulsion Emulsions can be what or what? What’s an emulsifying when made up of State the classification based on the state of the two substances(as in liquid or solid or gas
Milk Foam Detergents Fog smoke Blood Cosmetics Sol: a fluid colloidal system composed of two or more components example protein sol,gold sol,emulsion sol
Emulsion: liquid droplets or crystals dispersed in a liquid. The droplets often exceed the usual limits for colloids in size. An emulsion is denoted by the symbol O/W if the continuous phase is an aqueous solution and by W/O if it is an organic liquid
Latex: an emulsion or sol in which each colloidal particle contains a number of macromolecules
Foam: a dispersion in which a large proportion of gas (by volume) in the form of gas bubbles ,is dispersed in a liquid,solid ir gel
Aerosol: these are dispersions in gases
Colloidal systems:
Colloidal dispersion- system in which particles of colloidal size of any nature (solid,liquid or gas) are dispersed or suspended in a continuous phase of a different composition or state . Ie. Overall mixture
A colloidal system has a dispersed phase (the suspended particles ) and a continuous phase (the medium of suspension)
Example- egg white foam ie. Air bubbles (disperse phase) are trapped in the egg white (continuous phase) resulting in the foam
Properties:
Possession of two phases : dispersed and continuous
The mixture must not settle or should take a very long time to settle considerably for it to be called a colloid
Sols and gels are both liquid loving (lyophilic ) colloids. A sol is a liquid colloid or mixture in which solid particles are dispersed in a liquid phase. The disperse phase is attached to molecules of the continuous phase
Sometimes the mixture needs to the heated and stirred
When this solution cools the sol chnages into a gel which resembles a solid rather than a liquid
Both protein and starch CAn be used in the formation of a sol or gel
Emulsions: when water and oil are shaken together they form an emulsion
This emulsion is unstable
If left to stand the oil will form a separate layer in top of the water
The two liquids are immiscible (they will not mix together)
A stable emulsion is formed when two immiscible liquids are held stable by a third substance called an emulsifying agent
Emulsions may be oil in water (o/w) in which case small oil droplets are dispersed through water example milk , or water in oil (w/o) in which case small water droplets ar w dispersed through oil example butter
Emulsifying agent is made up of two parts
One is hydrophilic(water loving) and the other is hydrophobic (water hating)
The emulsifier holds the disperse phase within the continuous phase
This result in the emulsion becoming stable
Medium phase gas(dispersed medium) in the
Dispersed phase : in the form of gas it’s still gas. In the form of liquid ,gas in the dispersed phase is liquid aerosol example fog,cloud,mist,hair spray
In the form of solid,gas in the dispersed phase is solid aerosol . Example smoke,ice cloud,atmospheric particulate matter
Medium phase liquid(dispersed medium) in the dispersed phase : in the form of a gas in the dispersed phase, liquid becomes foam an example is whipped cream ,shaving cream
In the form kf liquid in the dispersed phase the liquid becomes an emulsion. Example milk(fat fraction),mayonnaise,hand creams,latex
In the form of solid in the disperse phase,the liquid becomes a sol example is milk(protein fraction),blood,pigmented ink
Medium phase solid (the dispersion medium) in the the dispersed phase,in the form of a gas the solid becomes solid foam example aerogel,styrofoam
In the form of a liquid,the solid becomes a gel. Example an agar,gelatin,jelly
In the form of a solid,the solid becomes a solid gel. Example cranberry glass
Explain classification of colloids based on the interaction between the two phases (hydrophobic and hydrophilic)
Lyophobic (hydrophobic) or irreversible sols :
Weak forces of interaction exist between colloidal particles and the liquid
Less stable as the particles are surrounded only with a layer of positive or negative charge
Addition of small quantities of electrolytes by heating or shaking can cause particles to precipitate which do not regain their original state
The particles resist solvation and dispersion in the solvent
Exampl gold in water and Iron(III) oxide-hydroxide
Lyophilic or hydrophilic or reversible sols or solvent attracting:
The dispersion medium can be separated form the collide using physical methods such as evaporation
The particles in the lyophilic system have great affinity for the solvent
If Water is the dispersion medium ,it is often known as hydrosol or hydrophilic
Readily solvated (combine chemically or physically with the solvent) and dispersed,even at high concentrations
Example sols of starch ,gum,etc
What are the main types of colloidal systems in food ,state the disperse phase,continuous phase and the product
Explain the classification of colloids according to the particle diameter of the dispersed material
System: Sol
Disperse phase of Sol is solid
Continuous phase of sol is liquid
Product is uncooked custard,under jelly
System: gel
Disperse: liquid
Continuous: solid
Product: jelly,jam,blancmange
System: emulsion
Disperse: liquid
Continuous: liquid
Product: milk,mayonnaise
System: solid emulsion
Disperse: liquid
Continuous: solid
Product: butter,margarine
Foam
Gas
Liquid
Whipped cream,whisked eggs white
Solid foam
Gas
Solid
Meringue,breads
1. Molecular dispersions (<1 nm ) Particles are invisible in EM Particles don’t settle down on standing Pass through semi permeable membranes and filter paper Undergo rapid diffusion Example ordinary ions ,glucose
- Colloidal dispersions (1nm - 0.5 micrometer)
Particles are detected by EM (electron microscope)but are not resolved by LM
Pass through filter paper but not through semi permeable membrane
Particles are made to settle by centrifugation
Diffuse very slowly
Example colloidal silver sols,natural and synthetic polymers - Coarse dispersions(>0.5micrometer)
Particles are visible under LM(light microscopy)
Do not pass through filter paper or semi permeable membrane
Particles settle down under gravity
Do not diffuse
Example emulsions,suspensions
Explain the classification of dispersed systems based on size
What’s the application of colloidal solution
Explain aggregation and sedimentations
Molecular dispersion: size (<1nm) example oxygen gas,glucose,ordinary ions
Colloidal dispersion: 1.0 nm to 0.5 micrometer
Example : silver sols,natural and synthetic polymer
Coarse dispersion: >0.5 micrometer
Example sand ,pharmaceutical emulsions and dispersions,red blood cells
Applications:
Therapy-example silver colloid in germicidal agents
Blood clotting- blood is a colloidal solution and is negatively charged. On applying a solution of FeCl3 ,bleeding stops and blood clotting occurs as Fe3+ neutralizes the ion charges on the colloidal particles
Stability- example lyophobic colloids prevent flocculation in suspensions
Colloid dispersion or gelatin is used in coating over tablets and granules which upon drying leave uniform dry film over them and protect them from adverse conditions od the atmosphere
Photography: a colloidal solution of silver bromide in gelatin is applied on glass plates or celluloid films to form sensitive plates in photography
Coagulation leading to aggregation prevents stabilization
I’m aggregation particles occur in clusters
Aggregation results from the sum of interactions of forces between particles
-Higher attractive forces (example van der waals forces$ than repulsive forces (example electrostatic force)
Sedimentation arises from difference in the density of the dispersed and the continuous phases.
- the higher the differences in density the faster the particle settles
What is the structure of micelles
Explain stabilization in colloids or peptization and the mechanisms of stabilization against aggregation
A stable colloid does not have aggregation and sedimentation while an unstable one has rhat . A slurry, emulsion, or dispersion is said to be colloidally “stable” if it remains as individual particles. By contrast, an unstable mixture coagulates during the time of observation.
True or false
Colloidal stability relates to particle size change (e.g. aggregation or agglomeration). If particles are not subject to size variation, the dispersion is considered colloidally stable
True or false
Explain gel network stabilization
An aggregate of surfactant molecules with particle diameter of 5-100nm dispersed in a liquid colloid
In an aqueous solution a Micelle can form an aggregate with the hydrophilic head regions in contact with surrounding solvent while sequestering the hydrophobic single tail regions in the micelle center
So I’m an aqueous solution the hydrophilic head is outside the micelle while the hydrophilic tail is inside the micelle
They’re usually approximately spherical in shape
Stabilization:
Marked by particles remaining suspended in the colloidal system
It is achieved through the activities of forces which cause interaction between colloidal particles
Example electrostatic interaction force
.Mechanisms of stabilization against aggregation:
Electrostatic stabilization -Electrostatic stabilization of Colloids is the mechanism in which the attraction van der Waals forces are counterbalanced by the repulsive Coulomb forces acting between the negatively charged colloidal particles.1
Steric stabilization
ie. Covering the particles in polymers which prevents the particle from getting close in the range of attractive forces. Steric stabilization is the process by which adsorbed nonionic surfactants or polymers produce strong repulsion between particles and droplets in a dispersion.
Gel network stabilization:
Principal way to produce colloids stable to aggregation and sedimentation
It involves adding to the colloidal suspension a polymer that is able to form a gel network and characterized by shear thinning properties
Example Xanthan and guar gum
This prevents settling by stiffness of the polymeric matrix where particles are trapped
The long polymeric chain can provide steric and electrostatic stabilization
Aggregation and sedimentation is prevented by steric stabilization and dispersion in a gel network (network of polymer chains characterized by mechanical strength)
What is the plasma membrane and what does it consist of ,what are phospholipids,what are plasma membrane proteins
How are transport processes categorized and state the categories
Fragile, transparent barrier that separates contains of cell contents from surrounding environment
Consists of
two phospholipid (fat) layers arranged “tail to tail,” with cholesterol
floating proteins scattered among them
Some phospholipids may also have sugar groups attached, forming glycolipids.
phospholipids are polar molecules
The charged end interacts with water, and the fatty acid chains do not
Phospholipids:
Heads contain glycerol & phosphate and are hydrophilic (attract water)
Tails are made of fatty acids and are hydrophobic (repel water)
Make up a bilayer where tails point inward toward each other
Can move laterally to allow small molecules (O2, CO2, & H2O to enter)
Plasma membrane proteins:
Proteins help move large molecules or aid in cell recognition
Peripheral proteins are attached on the surface (inner or outer)
Integral proteins are embedded completely through the membrane
The plasma membrane is effective as a barrier
conditions inside the cell can be much different from conditions outside the cell
Transport processes are categorized according to the mechanism involved:
diffusion
carrier-mediated transport
Vesicular transport
What is diffusion
State five factors that influence diffusion rates
How can an ion or molecule diffuse across a plasma membrane?
What molecules can enter cells easily through simple diffusion and why
Which molecules cannot easily pass and why? How else can they pass through the plasma membrane?
What factors determine the ability of an ion to cross a membrane channel?
Diffusion is a passive process that results from the random motion and collisions of ions and molecules
The movement of molecules is both passive and random
Substance move from an area of higher concentration to an area of lower concentration
The difference between the high and low concentrations is a concentration gradient
Diffusion tends to eliminate that gradient
Diffusion is important in body fluids, because it tends to eliminate local concentration gradients
Several important factors influence diffusion rates:
Distance. The shorter the distance, the more quickly concentration gradients are eliminated
Molecule Size. The smaller the molecule size, the faster the rate of diffusion.
Temperature. The higher the temperature, the faster the diffusion rate
Concentration Gradient. The steeper the concentration gradient, the faster diffusion proceeds
Electrical Forces. Opposite electrical charges (+ and –) attract each other, and like charges (+ and + or – and –) repel each other
Plasma membranes acts as a barrier that selectively restricts diffusion
An ion or a molecule can diffuse across a plasma membrane only by
(1) crossing the lipid portion of the membrane by simple diffusion or
(2) passing through a membrane channel
Simple Diffusion
Alcohol, fatty acids, and steroids can enter cells easily,
because they can diffuse through the lipid portions of the membrane
Lipid-soluble drugs, dissolved gases (O2 and CO2) and water molecules also enter and leave our cells
by diffusing through the phospholipid bilayer
Channel mediated diffusion:The situation is more complicated for ions and water soluble compounds, which are not lipid-soluble
These substances must pass through a membrane channel
very small passageways created by transmembrane proteins
Whether an ion can cross a particular membrane channel depends on many factors, including
the size and charge of the ion,
the size of the hydration sphere, and
interactions between the ion and the channel walls
Leak channels or passive channels, remain open and allow ions to pass across the plasma membrane
What is osmosis and what are the basic characteristics of osmosis
Osmosis is a special case of diffusion true or false
At equilibrium what happens to two different solutions in a selectively permeable membrane for osmosis
How can osmosisbe prevented?
The term osmosis for the movement of water, and the term diffusion for the movement of solutes
Basic characteristics of osmosis:
Water molecules diffuse of across a selectively permeable membrane
Osmosis takes place across a selectively permeable membrane that is freely permeable to water, but not freely permeable to solutes
Water flows across a selectively permeable membrane toward the solution that has the higher concentration of solutes
Osmosis eliminates solute concentration differences more rapidly than solute diffusion
Water molecules can also cross a membrane through abundant water channels called aquaporins,
which exceed the number of solute channels, through which water can also pass
This difference results in a higher membrane permeability for water than for solutes
At equilibrium,the soluble concentrations on the two sides of the membrane are equal. The volume of solution B (the one that had the higher conc at first before equilibrium) increased at the expense of solution A(the one with lower conc at first)
Osmosis can be prevented by resisting the change in volume. The osmotic pressure of B then becomes equal to the amount of hydrostatic pressure required to stop osmotic flow
Bioenergetics
For a biochemical reaction ,aA + bB ➡️
⬅️ cC + dD
the change in free energy (delta G) is related to what?
State the formula for equilibrium constant
The value of delta G is zero when the system is at equilibrium. True kr false
https://www.web-formulas.com/Formulas_of_Chemistry/Chemical_Equilibrium.aspx
Check to understand better
Delta G naught is the standard change in free energy between reactants and products. This value refers to the difference in free energy between reactants and products in their standard states at a specified temperature.
True or false
When a reaction system is at equilibrium, it is in its lowest-energy state possible (has the least possible free energy). If a reaction is not at equilibrium, it will move spontaneously towards equilibrium, because this allows it to reach a lower-energy, more stable state.
True or false
Concentrations of the substrates and products,change in the standard free energy of the reaction at pH 7 (delta Gnot). The change in the standard free energy of the reaction at pH 7 is determined by the chemical bonds that are being broken and formed.
NB: reactions with a negative delta G proceed spontaneously,those with a positive delta G do not
If delta G = 0,the reaction is at equilibrium
Keq = [C] raised to the power c x [D] raised to the power d divided by [A] raised to the power a x[B] raised to the power b
The c,d,a,b are the numbers in front of each substance in the chemical equation or the moles of their respective substances in the chemical equation
The square brackets show concentration in moldm raised to the power -3
Keq= [products] raised to the power number of moles divided by [reactants] number of moles
Example : if 2NO + Cl subscript 2 ➡️ 2NOCl
Note:If 2NOCl has been first on the reactant side and the other two on the product side,the other two will be on top and 2NOCl will be at the bottom instead .
[NOCl] raised to the power 2 divided by [NO] raised to the power 2 x [Cl] raised to the power 1
Or the right hand side of the equation is always at the top and the left side is always at the bottom
Where,the substrates and products are at their equilibrium(eq ) concentrations .
Therefore delta G naught = -RT in Keq
Where R is the gas constant with a value of 8.314 J K-1mol-1. T is the temperature of the reaction in Kelvin.
What Is the formula for change in free energy
Energy available for doing useful work at a constant P and T:
Delta G= delta H-TdeltaS
Where delta G-change in free energy Delta H-change in enthalpy Delta S-change in enthropy T-temperature in K At equilibrium,delta G= G naught + RTIn( [C] raised to the power c x [D] raised to the power d divided by [A] raised to the power a x [B] raised to the power b)
If delta G= 0 then
delta G naught = -RT In [C] raised to the power c x [D] raised to the power d divided by [A] raised to the power a x [B] raised to the power b
NB- Keq = [C] raised to the power c x [D] raised to the power d divided by [A] raised to the power a x [B] raised to the power b
Therefore,delta G naught = -RT InKeq
NB
using changes in Gibbs free energy to predict whether a reaction will be spontaneous in the forward or reverse direction (or whether it is at equilibrium!).
True or false
At constant temperature and pressure, the change in Gibbs free energy is defined as :
ΔG=ΔH−TΔS
When
Δdelta G, ,is negative, a process will proceed spontaneously and is referred to as exergonic.
The spontaneity of a process can depend on the temperature.
Spontaneous processes
In chemistry, a spontaneous processes is one that occurs without the addition of external energy.
True or false
How do we know if a process will occur spontaneously? The short but slightly complicated answer is that we can use the second law of thermodynamics. According to the second law of thermodynamics, any spontaneous process must increase the entropy in the universe.
Luckily, chemists can get around having to determine the entropy change of the universe by defining and using a new thermodynamic quantity called Gibbs free energy.
energy: Gibbs free energy=G=H−TS where H is enthalpy, T is temperature (in kelvin, K)and S is the entropy. Gibbs free energy is represented using the symbol G and typically has units of kJ divided by mol-rxn
The change in Gibbs free energy for a process is thus written as ΔG which is the difference between Gfinal
(the Gibbs free energy of the products), and G initial, (the Gibbs free energy of the reactants.) ΔG=Gfinal−Ginitial
Another thing to remember is that spontaneous processes can be exothermic or endothermic. That is another way of saying that spontaneity is not necessarily related to the enthalpy change of a process,
ΔH
What’s the sign of delta G used to find out?
. extra close attention to units when calculating ΔG from ΔH and ΔS
Although ΔH is usually given in
kJ divided by mol-reaction, ΔS is most often reported in J divided by mol-reaction
True
We can use the sign of
ΔGto figure out whether a reaction is spontaneous in the forward direction, backward direction, or if the reaction is at equilibrium.
When ΔG<0 the process is exergonic and will proceed spontaneously in the forward direction to form more products.
When ΔG>0, the process is endergonic and not spontaneous in the forward direction. Instead, it will proceed spontaneously in the reverse direction to make more starting materials.
When
ΔG=0 the system is in equilibrium and the concentrations of the products and reactants will remain constant
When is delta G negative and what things does deltaG depend on
For a sequence of reactions with common intermediates ,delta G naught is additive.Explain Delta G naught being additive and give example
Under relevance of free energy changes,
The rage of a reaction is not related to it’s free energy change
A reaction with a large negative free energy change does not necessarily proceed rapidly
The speed of a reaction depends on the properties of the enzyme that catalyzes the reaction
An enzyme increases the rate at which a reaction reaches equilibrium
It does not affect Keq
Most biochemical reactions exist in pathways; therefore other reactions are constantly adding substrates and removing products.
The relative activities of the enzymes that catalyze the individual reactions of a pathway differ
Some reactions are near the equilibrium (delta G= 0) . Their direction can readily be altered by small chnages in the concentrations of their substrates or products
Other reactions are far from equilibrium . Allosterjc factors that alter the activity of these enzymes can change the overall flux through the pathway
true or false
the change in enthalpy ΔH system
the temperature T
the change in entropy ΔS system
Temperature in this equation always positive (or zero) because it has units of K .Therefore, the second term in our equation, TΔSsystem, will always have the same sign as ΔS system
When the process is exothermic (ΔHsystem<0), and the entropy of the system increases (ΔSsystem>0), the sign of ΔG system is negative at all temperatures. Thus, the process is always spontaneous.
When the process is endothermic,ΔHsystem>0, and the entropy of the system decreases, ΔSsystem<0,the sign of
Delta G is positive at all temperatures. Thus, the process is never spontaneous.
For other combinations of ΔH system and ΔS system,the spontaneity of a process depends on the temperature.Exothermic reactions (ΔHsystem<0) that decrease the entropy of the system (ΔSsystem<0) are spontaneous at low temperatures.Endothermic reactions (ΔHsystem>0) that increase the entropy of the system (ΔSsystem>0) are spontaneous at high temperatures.
In General Chemistry 1, section 5.7.1, Hess’s Law we noted that if we coupled two reactions the energy is additive, and this principle also holds for other state functions like Gibbs Free Energy. That is, Free Energies of Reactions are additive. What this means is that a nonspontaneous process (ΔG>O) can become spontaneous if it is coupled to a second spontaneous process (ΔG
Under ATP
Solve this question:
Consider the ff reaction catalyzed but fumarase:
Fumarate + H2O ➡️ malate.
Fumarase was added to a solution that finally contained 20 micrometer fumarate. After the establishment of equilibrium,the concentration of malate will be ??
State the properties of ATP
State the functions of ATP
ATP is produced from adenosine diphosphate and inorganic phosphate (Pi) mainly by the process of oxidative phosphorylation.
The free energy released when ATP is hydrolyze is used to drive the reactions that require energy
ATP can transfer phosphate groups to other compounds such a glucose,forming ADP.
ADP can accept phosphate groups from compounds such as phosphocreatinine,forming ATP
Functions:
ATP is constantly being consumed and regenerated
It is consumed by processes such as muscular contraction,active transport,biosynthetic reactions
It is regenerated by the oxidation of foodstuffs
The free energy released when ATP is hydrolyzed is used to drive reactions that need energy:
ATP can be hydrolyzed to ADP and inorganic phosphate or to AMP and pyrophosphate (PPi)
ATP,ADP,and AMP are interconverted by the adenylate kinase reaction(termed myokinase in the muscle) ATP + AMP ➡️⬅️ 2ADP.
Other nucleosides triphosphates (GTP(guanosine triphosphate. ),UTP(uridine 5’ triphosphate) , and CTP(Cytidine 5′-triphosphate (CTP) is a pyrimidine nucleoside triphosphate that is analogous to the better-known ATP, but with cytidine as the base instead of adenine. It is a substrate in the biosynthesis of RNA. ) ) are sometimes used to drive biochemical reactions .
They can be derived from ATP and have the same Gibbs free energy of hydrolysis as do the two high energy bonds in ATP.
For the hydrolysis of ATP to ADP and Pi, delta G naught = -7.3 kcal/mol
The anhydride bonds of ATP are often called (high energy bonds)
The delta G naught is large however not because a single bond is broken but because the products of hydrolysis are more stable than ATP
ATP can transfer phosphate groups to compounds such as glucose,forming ADP.
ADP can accept phosphate groups from compounds such as phosphoenolpyruvate,phosphocreatinine, or 1,3-bisphosphoglycerate, thus forming ATP
What’s the components of Adenosine 5’-triphosphate or ATP
Under electron carriers and vitamins state some examples of processes that generate energy for the production of ATP
Give examples of cofactors that help in the processes that help with generation pf energy for ATP production
Name some examples of cofactors derived from water soluble or vitamins that are involved in many metabolic reactions
ATP is composed of D-ribose, a five-carbon sugar, three phosphate groups(with high energy phosphate bonds between them), and adenine , a nitrogen-containing compound (also known as a nitrogenous base)
Certain cofactors of enzymes are involved in the transfer of electrons from foodstuffs to oxygen,a process that generates energy for the production of ATP.
NAD+ (from niacin) and FAD(from riboflavin) pass electrons to the electron transport chain.
In this chain,flavin mononucleotide (FMN) and coenzyme Q(CoQ;ubiquinone) pass the electrons to heme-containing cytochromes ,which transfer the electrons to oxygen.
This results in ATP production
For cofactors in the generation of ATP from food:
As food is oxidized j to carbon dioxide and water,electrons are transferred mainly to NAD+ and flavin adenine dinucleotide(FAD)
The nicotinamide ring of NAD+ is derived from the vitamin niacin(nicotinic acid) and to a limited extent from the amino acid tryptophan
FAD accepts two hydrogen atoms (with their electrons). FAD is reduced and the substrate is oxidized.
So now FAD + RH2 becomes FADH2 + R
FAD is a better oxidizing agent than NAD+ and is frequently involved in reactions to produce a carbon carbon double bond
FAD is derived from vitamin riboflavin
Other cofactors include:
Coenzyme A(CoA; synthesized from the vitamin pantothenate)
Thiamine pyrophosphate (synthesized form vitamin thiamine)
Lipoic acid
Cofactors derived from water solubke vitamins: NADPH(from niacin) Biotin Pyridoxal phosphate(from vitamin B6) Tetrahydrofolate (from vitamin folate) Vitamin B12 Vitamin C
The fat soluble vitamins are also involved in metabolism
What are the components of the electron transport chain
State some inhibitors of electron transport
Explain the electron transport chain
NADH and FADH2 , transfer electrons to the electron transport chain located in the inner mitochondrial membrane. The chain consists of a number of protein complexes.
FMN received electrons from NADH in complex I and transfers them through Fe-S centers to coenzyme Q.
FMN is derived from riboflavin.
Heme is synthesized from glycine and succinyl CoA in humans. It is not derived from a vitamin.
Oxygen ultimately receives the electrons at the end of the electron transport chain and is reduced to water ( a function of complex IV)
Phase 1 of respiration : the oxidation of fuels
Phase 2 of respiration: ATP generation from oxidative phosphorylation
Inhibitors:
If there is a block at any point in the electron transport chain;
All carriers before the block will accumulate in their reduced states
Those after the block will accumulate in their oxidized states
As a result Oxygen will not be consumed.ATP will not be generated and the TCA cycle will slow down owing to the accumulation of NADH
Rotenone,a fish poison,complexes with complex I and causes NADH to accumulate . It does not block the rebadged of electrons to the chain from FADH2.
Antimycins (antibiotics) block the passage of electrons through the cytochrome b-c 1 (check spelling) complex (complex III)
Cyanide and carbon monoxide,poisons commonly used for suicide combine with cytochrome oxidase (complex IV) and block the transfer of electrons to oxygen
State the vitamins and their manifestations of deficiency
Explain the TCA cycle
State the vitamins needed for the TCA cycle
Vitamin A: night blindness and xerophthalmia
D: inadequate bone mineralization,rickets in kids
E: reproductive failure,muscular dystrophy,neurologic abnormalities
K: defective blood coagulation
C: scurvy
Thiamine: beriberi
Riboflavin: oral buccal cavity lesions
Niacin: pellagra(diarrhea,dermatitis,death,dementia)
Vitamin B6 or pyridoxine: convulsions,dermatitis,anemia
Folate: megaloblastic anemia due to impaired cell divisions and growth
Vitamin B12: megaloblastic anemia ,neurologic symptoms resulting from demyelination
Biotin: Anorexia ,nausea,vomiting,glossitis,alopecia,dry,scaly dermatitis
Pantothenic acid: listlessness,fatigue,burning feet syndrome
TCA cycle:
Vitamins: Niacin is used for the synthesis of the nicotinamide portion of NAD
Riboflavin is used for the synthesis of FAD
Alpha ketoglutarate dehydrogenase a multienzhke complex xontains lipoic acid and four other cofactors that are synthesized from vitamins .
Thiamine is used for the synthesis of thiamine pyrophosphate
Pantothenate for CoASH
Riboflavin for FAD
Niacin for NAD+
Who is Gregor Mendel
Explain Mendels pea experiment
Based on Mendels data state the two laws did he formulate?(there are three laws not two . The three laws of inheritance proposed by Mendel include: Law of Dominance. Law of Segregation. Law of Independent Assortment. But I’m UCCs slides it’s 2 so let’s take it like that)
What is reciprocal cross
What’s re the characteristics mendel studied on
Gregor Johann Mendel, OSA was a biologist, meteorologist, mathematician, Augustinian friar and abbot of St. Thomas’ Abbey in Brünn, Margraviate of Moravia. Gregor Mendel was an Austrian monk who discovered the basic principles of heredity through experiments in his garden. Mendel’s observations became the foundation of modern genetics and the study of heredity, and he is widely considered a pioneer in the field of genetics
He is the father of genetics
Around 1854, Mendel began to research the transmission of hereditary traits in plant hybrids. At the time of Mendel’s studies, it was a generally accepted fact that the hereditary traits of the offspring of any species were merely the diluted blending of whatever traits were present in the “parents.” It was also commonly accepted that, over generations, a hybrid would revert to its original form, the implication of which suggested that a hybrid could not create new forms. However, the results of such studies were often skewed by the relatively short period of time.
Mendel performed hybridizations, which involve mating two true-breeding individuals that have different traits. In the pea, which is naturally self-pollinating, this is done by manually transferring pollen from the anther of a mature pea plant of one variety to the stigma of a separate mature pea plant of the second variety.
Plants used in first-generation crosses were called P, or parental generation, plants (Figure 8.3). Mendel collected the seeds produced by the P plants that resulted from each cross and grew them the following season. These offspring were called the F1, or the first filial (filial = daughter or son), generation. Once Mendel examined the characteristics in the F1 generation of plants, he allowed them to self-fertilize naturally. He then collected and grew the seeds from the F1 plants to produce the F2, or second filial, generation. Mendel’s experiments extended beyond the F2 generation to the F3 generation, F4 generation, and so on, but it was the ratio of characteristics in the P, F1, and F2 generations that were the most intriguing and became the basis of Mendel’s postulates.
The law of segregation: A parent contributes only one of its alleles for a trait to each offspring
Law of independent Assortment: Alleles of one gene are passed to offspring independently of the alleles of other genes . This law allows for new gene combinations or genetic recombination.
This law can mathematically predict the possible combinations. Number of possible genotypes= 2 raised to the power n where n is the number of genes or traits considered. Example,considering 100 traits, 2 is raised to the power 100 which is equal to 1.26765x10raised to the power 30.
When Mendel transferred pollen from a plant with violet flowers to the stigma of a plant with white flowers and vice versa, he obtained approximately the same ratio irrespective of which parent—male or female—contributed which trait. This is called a reciprocal cross—a paired cross in which the respective traits of the male and female in one cross become the respective traits of the female and male in the other cross.
The traits that Mendel studied are listed below:
Form of ripe seed (R) – smooth or wrinkled
Color of seed albumen (Y) – yellow or green
Color of flower (P) – purple or white
Form of ripe pods (I) – inflated or constricted
Color of unripe pods (G) – green or yellow
Position of flowers (A) – axial or terminal
Length of stem (T) – tall or dwarf
Why did Mendel choose the pea plant or pisum sativum ?
Explain incomplete dominance
Give an example
Why does it occur?
Explain continuous and discontinuous variation
Why did Mendel choose pea plant for his experiments? Solution: Pea plants were chosen for Mendel’s experiments because they are easy to grow, have a short life period, and produce larger flowers. Pea plants are also self-pollinated. Easy to grow in the garden.
The flowers of pea plants are hermaphrodite, i.e flowers have bisexual characteristics.
Easy to obtain pure breed plant through self-fertilization
The generation time of pea plants is less.
large quantities of garden peas could be cultivated simultaneously
They have excellent disease resistance and have an optimal rate of survival.
Incomplete dominance results from a cross in which each parental contribution is genetically unique and gives rise to progeny whose phenotype is intermediate. Incomplete dominance is also referred to as semi-dominance and partial dominance. Mendel described dominance but not incomplete dominance. Incomplete dominance is a type of inheritance in which one allele is not completely expressed over its paired allele for a specific trait or character. In this, the F1 hybrid have characters intermediate of the parental genes. For example, flower colour. Pink snapdragons are a result of incomplete dominance. Cross-pollination between red snapdragons and white snapdragons result in pink when neither the white or the red alleles are dominant. Incomplete dominance occurs because neither of the two alleles is completely dominant over the other. This results in a phenotype that is a combination of both.
Mendel’s work went virtually unnoticed by the scientific community, which incorrectly believed that the process of inheritance involved a blending of parental traits that produced an intermediate physical appearance in offspring. This hypothetical process appeared to be correct because of what we know now as continuous variation. Continuous variation is the range of small differences we see among individuals in a characteristic like human height. It does appear that offspring are a “blend” of their parents’ traits when we look at characteristics that exhibit continuous variation. Mendel worked instead with traits that show discontinuous variation. Discontinuous variation is the variation seen among individuals when each individual shows one of two—or a very few—easily distinguishable traits, such as violet or white flowers. Mendel’s choice of these kinds of traits allowed him to see experimentally that the traits were not blended in the offspring as would have been expected at the time, but that they were inherited as distinct traits.
What is a gene,allele,homozygous and heterozygous trait,polygenic and monogamist inheritance,genotype and phenotype
Explain Autosomal dominant pattern name six examples of diseases caused by this
Explain Autosomal Recessive pattern and state four examples of diseases caused by this
Gene:
The hereditary information that determines a single trait
Allele: alternate forms of a gene
When an organism inherits two identical alleles for a trait organism is said to be homozygous for the trait and when an organism inherits different allele for one trait the organism is heterozygous for the trait
Polygenic: trait affected by many genes example height,weight,skin color
Monogenic: Traits determined by single gene with two alleles example flower colour in 4’oclock plants
Genotype: genetic makeup of an individual. It is determined by the alleles present for each trait
Phenotype: physical appearance of a trait. It is the expression of the genotype
Autosomal dominant pattern examples: familial hypercholesterolemia,Huntingtons disease,Marfan syndrome,osteogenesis imperfecta,con Willebrands disease,congenital spherocytosis,adult poly cystic kidney disease and neurofribomatosis
One defective copy of the gene on an autosomal (non sex) chromosome produces the disease . A child has 50 percent chance of having the disease if one of the parents is heterozygous. Males and females are affected. Clinical symptoms may not develop until adulthood
Autosomal Recessive pattern :
Two defective copies (alleles) of the gene ,each on an autosomal chromosome ,are needed to produce the disease.
Each child of two heterozygous parents(that is asymptomatic carriers) has a 25percent chance of having the disease(homozygous)
Males and females are affected.
Clinical symptoms usually develop in infancy or childhood and commonly are more severe than in dominant disorders .
Examples:Most inborn errors of metabolism (such as glycogen storage disease,maple syrup Urine disease,phenylketonuria,Tay-Sachs disease ),sickle cell disease,cystic fibrosis,Wilson’s disease and Congenital adrenal hyperplasia
Also called: CAH, adrenogenital syndrome.
Explain X linked recessive pattern and give two examples of diseases caused by this
What are the types of mutations? Define them and give examples
Silent mutations don’t change the result of the protein sequence
Each son of a heterozygous mother who is usually an asymptomatic carrier has a 50 percent chance of being affected
Affected males transmit the abnormal X chromosomes to all their daughters(carriers) but none to their sons.
Heterozygous females may show minor effects but males who have only one X chromosome manifest clinical symptoms.
Examples of such diseases: Duchenne-type muscular dystrophy,Fabrys disease,hemophilia A and B,Hunters syndrome,Lesch-Nyhan syndrome and glucose-6-phosphate dehydrogenase deficiency
Types of mutations
Frame shift: An insertion or deletion involving a number of base pairs that is not a multiple of three, which consequently disrupts the triplet reading frame of a DNA sequence. Frameshift mutations occur in two types - insertion mutations and deletion mutations. A frameshift mutation is produced either by insertion or deletion of one or more new bases. Because the reading frame begins at the start site, any mRNA produced from a mutated DNA sequence will be read out of frame after the point of the insertion or deletion, yielding a nonsense protein. A frameshift mutation can occur if the DNA polymerase leaves out a nucleotide or adds an extra nucleotide to the sequence. Example of diseases that are affected: Crohn’s disease, cystic fibrosis,Tay Sachs
Which of the following mutations is LEAST likely to cause a frame shift? A mutation that removes 6 nucleotides from a sequence.
Missense mutations: In genetics, a missense mutation is a point mutation in which a single nucleotide change results in a codon that codes for a different amino acid. A missense mutation occurs when there is a mistake in the DNA code and one of the DNA base pairs is changed, for example, A is swapped for C. This single change means that the DNA now encodes for a different amino acid, known as a substitution. So for missense the base pairs are swapped but in frame shift the base pair is deleted or a new extra base pair is inserted . missense mutation is a DNA change that results in different amino acids being encoded at a particular position in the resulting protein. So, you can see that frame-shift mutations usually have more significant effects on the final protein than point mutations do.
Example: sickle cell
Nonsense mutation: In genetics, a nonsense mutation is a point mutation in a sequence of DNA that results in a premature stop codon, or a nonsense codon in the transcribed mRNA, and in a truncated, incomplete, and usually nonfunctional protein product. A genetic alteration that causes the premature termination of a protein. The altered protein may be partially or completely inactivated, resulting in a change or loss of protein function. Also called nonsense mutation.
base substitution, called a “nonsense” mutation, results in a stop codon in a position where there was not one before, which causes the premature termination of protein synthesis and, more than likely, a complete loss of function in the finished protein.
Diseases caused by this: Cystic fibrosis (caused by the G542X mutation in the cystic fibrosis transmembrane conductance regulator (CFTR)
Beta thalassaemia (β-globin)
Hurler syndrome.
Why aren’t memebers of the same species identical?
Solve these questions:
1.The gene that expresses itself and hides the expression of another gene is called?
Dominant gene.
Recessive gene
Expressive gene
Multiple allele
2.The naturally occurring phenotype of a typical species is called ? Wild type Mutated Crossed X-linked
If an organism has two identical gene for a given character it is said to be? Homozygous Heterozygous Dominant Recessive
What is the name for a population in which there are many different alleles,contributing in the phenotype of any number of population ? Recessive alleles Multiple alleles Dominant alleles Gene pool
If the alleles of the gene jn a heterozygote are completely expressed than the pattern of dominance,this is called? Incomplete Codominance Heterozygous Homozygous
For an amino acid,leucine(UUG), if there’s a mutation and UAG is produced what is the name of this mutation? If there’s a mutation and UCG is produced what kind of mutation is this ?
If there’s a mutation and CUG is produced what kind of mutation is it
Genetic variation refers to differences among the genomes of members of the same species.. Genetic variation within a species can result from a few different sources. Mutations, the changes in the sequences of genes in DNA, are one source of genetic variation. Another source is gene flow, or the movement of genes between different groups of organisms. Finally, genetic variation can be a result of sexual reproduction, which leads to the creation of new combinations of genes.
The answer for 2, is wild type. wild type refers to individuals with normal phenotype possessed by the majority of the natural population whereas mutant refers to individuals with a phenotype that varies from the normal populations
UAG- is a stop codon so it’s a nonsense mutation
UCG-missense mutation because instead of a leucine codon(UUG),a serine codon is now produced(UCG).
CUG-Silent mutation because CUG is another codon that can code for leucine thus it didn’t affect the sequence of amino acids(leucine ) that form the protein. Cuz I’m the end leucine was produced still.
Silent mutations are mutations in DNA that do not have an observable effect on the organism’s phenotype.
A silent mutation is a type of substitution, or point, mutation, wherein the change in the DNA sequence of the gene has no effect on the amino acid sequence. For example, AAA (codes for the amino acid lysine, Lys) being mutated to AAG (which also codes for Lys)
Explain Osmolarity and Tonicity
Define isotonic,hypertonic and hypotonic solution
What is crenation
The total solute concentration in an aqueous solution is the solution’s osmolarity, or osmotic concentration
•Osmolarity refers to the solute concentration of the solution, but tonicity is a description of how the solution affects the shape of a cell.
•A solution that does not cause an osmotic flow of water into or out of a cell is called isotonic
you put a red blood cell into a hypotonic solution, water will flow into the cell, causing it to swell up like a balloon
➢The cell may eventually burst (hemolysis), releasing its contents
•In contrast, a cell in a hypertonic solution will lose water by osmosis.
➢As it does, the cell shrivels and dehydrates.
➢The shrinking of red blood cells is called crenation
What is the use of Normal saline in hydration
What is the use of DExtran?
What is carrier mediated transport
Explain the characteristics of carrier mediated transport
Explain facilitated diffusion
It is often necessary to give patients large volumes of fluid to combat severe blood loss or dehydration.
➢Intravenous (IV) administration of normal saline (0.9 g/dL solution of sodium chloride (NaCl)) is used to rehydrate patient
➢It is used because sodium and chloride are the most abundant ions in the extracellular fluid
➢Little net movement of either ion across plasma membranes takes place
An alternative IV treatment involves the use of an isotonic saline solution containing dextran,
➢dextran cannot cross plasma membranes
➢dextran molecules elevate the osmolarity and osmotic pressure of the blood,
➢water enters the blood vessels from the surrounding tissue fluid by osmosis, and blood volume increases
High-molecular weight dextran is a plasma volume expander made from natural sources of sugar (glucose). It works by restoring blood plasma lost through severe bleeding.
Dextrans are chemical sugars obtained from bacteria.
Carrier-mediated transport requires specialized integral membrane proteins
•It can be passive or active,
–Depends on substance transported and the nature of the transport mechanism
•Integral proteins bind specific ions or organic substrates and carry them across the plasma membrane
•In cotransport, or symport, the carrier transports two substances in the same directionsimultaneously, either into or out of the cell
• In countertransport, or antiport, one substance moves into the cell and the other moves out
Characteristics of Carrier-mediated transport
•Specificity
➢Each carrier protein in the plasma membrane binds and transports only certain substanceS
•Saturation Limits
➢The availability of substrate molecules and carrier proteins limits the rate of transport into or out of the cell
➢When all the available carrier proteins are operating at maximum speed, the carriers are said to be saturated
➢The rate of transport cannot increase further, regardless of the size of the concentration gradient
•Regulation
➢The binding of other molecules, such as hormones, can affect the activity of carrier proteins
Facilitated Diffusion
•Many essential nutrients are too large to fit through membrane channels
•These substances can be passively transported across the membrane by carrier proteins in a process called facilitated diffusion
•The molecule must first bind to a receptor site on the carrier protein
•The shape of the protein then changes, moving the molecule across the plasma membrane and releasing it into the cytoplasm
•This takes place without ever creating a continuous open channel between the cell’s exterior and interior
•No ATP is expended in facilitated diffusion
Explain active transport
What is an exchange pump
Explain the sodium potassium exchange pump and name the carrier protein involved
Active Transport
•A high-energy bond (in ATP) provides the energy needed to move ions or molecules across the membrane
•It does not depend on a concentration gradient
•The cell can import or export specific substrates, regardless of their intracellular or extracellular concentrations
- All cells contain carrier proteins called ion pumps, which actively transport the cations sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+) across their plasma membranes
- Specialized cells can transport additional ions, such as iodide (I−), chloride (Cl−), and iron (Fe2+)
Many of these carrier proteins move a specific cation or anion in one direction only, either into or out of the cell
- Sometimes, one carrier protein will move more than one kind of ion at the same time
- If countertransport occurs, the carrier protein is called an exchange pump
The Sodium–Potassium Exchange Pump
•Na+ and K+ ions are the principal cations in body fluids
•Na+ ion concentrations are high in the extracellular fluids, but low in the cytoplasm.
• K+ ions are low in the extracellular fluids and high in the cytoplasm
• Leak channels allow Na+ ions slowly diffuse into the cell, and K+ ions diffuse out of cell
• Homeostasis within the cell depends on removing Na+ and recapturing lost K+ ions
•This exchange takes place by a sodium–potassium exchange pump
•The carrier protein involved in the process is called sodium–potassium ATPase
Explain vesicular transport and state the types. Explain the types
In vesicular transport, materials move into or out of the cell in vesicles,
➢small membranous sacs that form at, or fuse with, the plasma membrane
- Because these vesicles move tiny droplets of fluid and solutes rather than single molecules, this process is also known as bulk transport
- The two major types of vesicular transport are endocytosis and exocytosis
Exocytosis
•In exocytosis, a vesicle formed inside the cell fuses with, and becomes part of, the plasma membrane
•The vesicle contents are released into the extracellular environment
•The ejected material may be secretory products, such as
➢mucins or
➢hormones, or
➢waste products, such as those accumulating in endocytic vesicle
Endocytosis
•Endocytosis, involves relatively large volumes of extracellular material
•The three major types of endocytosis are
(1)receptor-mediated endocytosis,
(2) pinocytosis, and
(3) phagocytosis
All three are active processes that require energy in the form of ATP
•The vesicles of endocytosis are generally known as endosomes
•The endosomes may move into the cytoplasm by
➢active transport,
➢simple or facilitated diffusion, or
➢ the destruction of the vesicle membrane
Explain the types of Endocytosis and for each type state the factors affecting the rate and the substances involved
Receptor-Mediated Endocytosis
•Receptor-mediated endocytosis produces vesicles that contain a specific target molecule in high concentrations
•It begins when materials in the extra cellular fluid bind to receptors on the membrane surface
•Most receptor molecules are glycoproteins, and each binds a specific ligand, or target molecule, such as a transport protein or a hormone.
Target molecules bind to receptor proteins on the membrane surface triggering vesicle formation . The factors affecting the rate of this kind of Endocytosis:number of receptors on the plasma membrane and the concentration of target molecules
Substances involved are target molecules called ligands.
So the process: ligand binds to receptors in the plasma membrane. Areas coated with ligands form deep pockets in the plasma membrane surface.pockets pinch of creating endosomes known as coated vesicles.coated vesicles fuse with primary lysosomes to form secondary lysosomes.ligand are removed and absorbed into the cytoplasm.
The lysosomal and endosomal membranes separate. Endosomes fuse with plasma membrane and the receptors are available again for ligand binding .
Pinocytosis
•Pinocytosis or “Cell drinking,” is the formation of endosomes filled with extracellular fluid
•Endosomes formed by pinocytosis are also called pinosomes
•This process requires no receptor proteins
•The target appears to be the fluid contents in general, rather than specific bound ligands
•In pinocytosis, a deep groove or pocket forms in the plasma membrane and then pinches off
•The steps involved are similar to the steps in receptor-mediated endocytosis, except that ligand binding is not involved.
Vesicles form at the plasma membrane and bring fluids and small molecules into the cell. This is called cell drinking
Factors affecting the rate:stimulus and mechanism not understood.
Substances involved:ECF with dissolved molecules such as nutrients
Phagocytosis
•Phagocytosis or “Cell eating,” produces phagosomes containing solid objects that maymbe as large as the cell itself
•In this process, cytoplasmic extensions called pseudopodia surround the object, and their membranes fuse to form a phagosome
•This vesicle then fuses with many lysosomes, and lysosomal enzymes digest its contents
•Phagocytosis is performed only by specialized cells, such as the macrophages, that protect tissues by engulfing bacteria, cell debris, and other abnormal materials
Vesicles form at plasma membrane to bring solid particles into the cell
Factors affecting the rate: presence of pathogens and cellular debris
Substances involved;bacteria,viruses,cellular debris and other foreign material
Eukaryotic cells are more complex that prokaryot cells
State the characteristics of eukaryotes
Kingdom protista has what characteristics
How do organisms in this kingdom reproduce
Membrane-bound nucleus and organelles
•Chromosomes consist of DNA and histone proteins and occur in pairs.
•Protists, fungi, plants & animals are composed of eukaryotic cells.
Eukaryotic •Mostly unicellular •A very heterogeneous group include both heterotrophic and photoautotrophic forms •11 phyla •Lots of disagreements
binary fission splits into two asexually
•multiple fission producing more than two individuals
•sexually by conjugation (opposite mating strains join & exchange genetic material)
State four plant like protists
What are diatoms
State the characteristics of phylum chrysophyta
Dinoflagellates •Diatoms •Euglena •Green algae •Brown Algae •Red algae
Diatom refers to any member of a large group comprising several genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world.
Diatoms
•Phylum Chrysophyta (“diatoms & golden algae”)
Chrysophyta is a phylum of unicellular marine or freshwater protists. Members of this phylum include the diatoms (class Bacillariophyta), golden/golden-brown algae (class Chrysophyceae), and yellow-green algae (class Xanthophyceae).
Characteristics:
•Chloroplast contains
(i) chloropyll a and c
(ii) Golden-brown pigment called fucoxanthin
•Photosynthetic diatoms are important source of food and oxygen for heterotrophs in both marine and freshwater ecosystem.
13,000 species
Diatoms
•Phylum Bacillariophyta: Bacillariophyta A phylum of algae comprising the diatoms. These marine or freshwater unicellular organisms have cell walls (frustules) composed of pectin impregnated with silica and consisting of two halves, one overlapping the other.
•Diatoms have shells that contain silica (SiO2), or glass
•The remains of diatoms called diatomaceous earth accumulate on the ocean floor and are mined for use as filtering agents, sound proofing materials, gentle abrasives, toothpaste, car polish & reflective paint
How do harmful algal blooms occur
What is domoic acid
Harmful algal blooms (HABs)
•occur when colonies of algae grow out of control
•while producing toxic or harmful effects on people, fish, shellfish, marine mammals, and birds
•Foam from ocean algae bloom killing thousands of birds
HABs - Domoic acid
•Domoic acid (DA) is a kainic acid-type neurotoxin
• that causes amnesic shellfish poisoning (ASP).
• It is produced by algae and accumulates in shellfish, sardines, and anchovies
• When sea lions, otters, cetaceans, humans, and other predators eat contaminated animals, poisoning may result
