LSB231.1 Cellular Physiology Student Version Slides

8/8/2019 LSB231.1 Cellular Physiology Student Version Slides

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LSB231- Physiology:

Lecture 1.

Part A: The Cellorganelles

cytos e eton

www.invitrogen.com



LSB231- Physiology:

Lecture 1.

Part B: The Plasma Membranemembrane structure

membrane roteins

www.smbs.buffalo.edu/bch/Labs/Kosman/research.htm

membrane transport



LSB231- Physiology:

Lecture 1.

Part C: Metabolism and Energy

t es of metabolism

role of ATP

www.invitrogen.com



LSB231- Physiology:

Lecture 1.

• Part A: The Cell

– organelles

– cytoskeleton

•

– membrane structure

–

– membrane transport

– types of metabolism

– ro e o

– sources of ATP



LSB231- Physiology:

Lecture 1.

Learning Objectives – Part A

• escr e t e unct on o eac organe e

• Identify the major intracellular structural proteins

which make u the various c toskeletal structures

intracellular cytoskeletal structures



component of the.

Organ Tissue Cells



component of the.

• Bounded by plasma

mem rane.



component of the

.

• Bounded by plasma

mem rane.• Intracellular fluid is

called the

cytoplasm.• Contains functional

subunits called

organelles.



• Membrane bound.• Analogous to organs

found within the

body.• Each serve s ecific

functions.

• cytoskeleton.



• Nucleus• Endoplasmic

reticulum

• Golgi apparatus•

• Lysosomes

• erox somes



• Bounded by nuclearenve ope w pores.




• Contains DNA in the

form of chromatin.





form of chromatin.• Ma dis la

nucleolus.





form of chromatin.• Ma dis la

nucleolus.

•

m

• Site of transcription.



• Outer membrane

continuous withnuclear envelope.



• Outer membranecon nuous w

nuclear envelope.

• May be characterisedas either

– “smooth” or

– “rough”• depending upon

resence of

ribosomes.



• Rou h ER RER

– site of translation for

proteins that are aatransported out of the

cell or into other

organe es.

– Synthesis of phospholipid.



• moo

– lipid metabolism – c o estero /steroi

synthesis

– rug me a o sm ver

– calcium storage

of skeletal muscle cells)

Ca2+



• Receives packages of

proteins from RER.• Modifies proteins:

– ost-translational

modifications.– Glycosylation.

• Sorts and packages

roteins:– vesicles delivered to other

or anelles or lasma

membrane.



• Produce energy source:– Adenosine Triphosphate

(ATP).



Outer membrane


(ATP).

• Consist of inner and outermembranes, surrounding a

fluid matrix.

Matrix

Inner membrane




(ATP).

• Consist or inner and outermembranes, surrounding a

ui matrix.

• Contain mitochondrial DNA– mitochondrial disorders may

therefore be maternally

inherited.



• Bound by singlemem rane.

• Contain acidic

environment.• Serve di estive function.

• Contain acid hydrolases.

– , .

• Especially abundant in

.

– eg. NeutrophilsNeutrophil leukocyte



• Bound by singlemem rane.

• Contain enzymes required

for metabolism of toxins.• Peroxisomal Disorders:

– Can cause serious

developmental andneurological defects.

– eg. X-linked Peroxisomes in liver cell



• Internal scaffold of cells.

•

• Controls cell transport.

• ons s s o :

– microfilaments (actin

– microtubules (tubulin

– intermediate filaments

.

Keratins).

in fibroblasts





• Composed of

polymerised actin.

or = G-actin (monomer)

• Associated with

numerous actin-

binding proteins, eg.myosin.

F-actin (polymer)



• ompose o

polymerised actin.• Associated with

numerous actin-


• Essential for

re ulatin chan es in

•Human Neutrophil seeksbacteria

•for ermanentcell shape.

– Amoeboid motilit

relationship•Enjoys food and long

– Muscle contraction.

the body



• Composed of

polymerised actin.• Associated with

numerous actin-


• Essential for

re ulatin chan es incell shape.

–

Movie of Leukocytes huntingbacteria

’

– Muscle contraction.

...

lecture you don’t get to seethe movie!!



• Composed of po ymer se u u n.




• Associated with motor

proteins eg. kinesin.




• Associated with motor

proteins eg. kinesin.• Su ort cell structure.

• Provide paths for

transport.

– -. .



• Composition variesaccor ng o ce ype.

• Less dynamic than

microfilaments andmicrotubules.

• “Tough” insoluble

fibres.







fibres.• Example:

–

cells.







fibres.• Example:

–

Human corneal epithelialcells stained with antibody

cells.

to keratin 3



–

• Describe the structure and identify the various components of the

• Describe the general roles of transmembrane or integral proteins

• Describe the processes of membrane transport, diffusion and osmosis

• Understand and describe osmolarity

• Describe and understand the difference between facilitated diffusionand active transport

• Describe the fluid composition of some common ions inside andoutsi e t e ce



• Double layer of p osp o p an

cholesterol.

Non-polar




cholesterol.




cholesterol.

• Highly dynamic.




cholesterol.

• Highly dynamic.• Accessor

molecules:

– roteins• integral

• peripheral

– carbohydrates





• Communication.• Provide receptors for

soluble ligands.

• eg. ormones.



• Communication.

– Provide receptors for

soluble ligands.

• rov e receptors or

other cells.



• Communication.

– Provide receptors for

soluble ligands.

– rov e receptors or

other cells.

–

between cells.

• between muscle cells.



• The plasma membrane is a semi-permeable

arr er.



• The plasma membrane is a semi-permeable

arr er.

• Transport of molecules across membrane is

dependent upon:– relative solubility.

– physical size.

– presence of concentration gradient.– other factors: specialised transport proteins.



• Solubility:

– more hydrophobic/more non-polar

molecules readil dissolve throu h li id

bilayer.



• Solubility:

– more hydrophobic/more non-polar

molecules readil dissolve throu h li id

bilayer.

– More hydrophilic/polar molecules have

poor solubility in lipid bilayer.



• Size:

– certain small molecules can pass through

– examples:.

• Ion channels: tend to be specialised for

each ion.– may be “gated”: open in response to stimulus.



• Basic channels:

– Always open.

– Enable passive

transport o

molecules across

diffusion.

– molecules of certain

physico-chemical

properties.



• Gated channels:

– Normally closed.



• Gated channels:

– Normally closed.

– Open in response to

appropr ate st mu us.

• Hormone

• Ion balance (voltage)



• Diffusion:

– movement of

substance along a

gradient.–

collisions of

particles known asBrownian Motion.



• Diffusion:

– movement of

substance along a

gradient.

– diffusion of water

gradient.



• Diffusion:

– movement of

substance along a

gradient.


gradient.



• Diffusion:

– movement of

substance along a

gradient.


gradient.

–

hydrostatic pressure

within the cell.



• Direction of osmosis is determined by relative

osmo ar y:

– total number of solute particles per litre of

so u on.

• Sometimes use term osmolality:

– total number of solute particles per litre of water.



• Example: for a 0.15 molar solution of

a e osmo ar y s ou e: e .

mosmol.

Na

Na

Dissociates

into two

Cl par c es



• Osmosis occurs when intra-cellular osmolarity is

.• Typical osmolarity within cells is: 300 mosmol.



• Osmosis occurs when intra-cellular osmolarity is

.• Typical osmolarity within cells is: 300 mosmol.

• 300 mosmol solutions are iso-osmotic/iso-tonic.

• >300 mosmol solutions are hyper-osmotic/hyper-

tonic.• <300 mosmol solutions are hypo-osmotic/hypo-

.



• Facilitated diffusion:

– requires

concentration

.

– Involves binding of

transporter protein.




– requires

concentration

.






– requires

concentration

.






– requires

concentration

.






– requires

concentration

.






– requires

concentration

.






– requires

concentration

.






– requires

concentration

.






– requ resconcentrationradient.

– Involves binding of molecule toranspor er pro e n.

– Example: Glucose

proteins (insulinincreases levels of

.



• Pumps:

– Useful for producing

concentration

.

– Working against.

– Requires energy.

•• Ion gradient



• Pumps:


concentration

.



•• Ion gradient



• Pumps:


concentration

.



ATP

– .







• Pumps:


concentration

.

– Working against

P

.


– orientation of

rotein.



• Pumps:


concentration

.

– Working against

P

.


– .



• Pumps:


concentration

.



– .– Protein returns to

P

conformation.



• Pumps: • Calcium-ATPase


concentration

– maintains low intracellular

calcium concentration.

.

– Working against• Sodium/potassium-

ATPase.

– Requires energy.– pumps 3 sodium ions out

for every 2 potassium ions

in.–









• Metabolism:

– that take place within a living structure.

– involve destruction of molecules.





• Energy can neither be created nor

destroyed it simply changes form:

– First Law of Thermodynamics.






•

carbohydrates, fats and proteins.






•

carbohydrates, fats and proteins..






•

carbohydrates, fats and proteins..

• Remainder is stored in the form of

.



• Energy is stored within phosphate

.• Analogous to potential energy stored

w en a spring is compresse .



Carbohydrates Cytoplasm

GlycolysisMuscle

Pyruvate Lactaterea ne

Krebs Cycle

Fats/Proteins

ATP

Fats NADH + H+ and FADH2

ADP

Electron TransportOxygenCreatine-P

Mitochondria



• Conversion of glucose to pyruvate.

• .• Can occur in absence of oxygen

anaero c .

• Net yield: 2 molecules of ATP.

• 1 gram of glucose yields 4 kcal.





• Conversion of glucose to pyruvate.

• .• Can occur in absence of oxygen

anaero c .

• Net yield: 2 molecules of ATP.

• 1 gram of glucose yields 4 kcal.

• Also produces 2 (NADH + H+)

– u se ur ng ec ron ranspor a n.



•

• Pyruvate first converted to Acetyl-CoA.

• ce y - o ena es cyc n o reac ons e weencitrate and oxaloacetate (Citric Acid Cycle).

• Requires aerobic conditions to proceed.

• Net yield for each cycle: 1 molecule of ATP.

Matrix





• -

– protein: in the form of amino acids (via

– Fats: in the form of fatty acids.



O t b



Outer membrane

• Occurs across inner

membrane.

•

essential.• t ses:

– FADH2

– NADH + H+ Matrix

Inner membrane



• Hydrogen ions from FADH2 and NADH + H+

.• Produces a concentration gradient of H+

.

• ATP is generated as the H+ ions flow backacross t e nner mem rane v a an -

synthase.



• Net yield:+– .

– 2 molecules of ATP from each FADH2.



• Muscle cells have an

for producing ATP.



• Muscle cells have anCreatine PiCreatine

for producing ATP.

Creatine Kinase

ADPKrebs Cycle

ETC+ PiATP

Muscle Contraction/Relaxation

See you on Monday morning for your first Prac



See you on Monday morning for your first Prac…

LSB231.1 Cellular Physiology Student Version Slides

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