Why Do cells need motors to move "stuff" around the cell?

(4 reasons)

-*diffusion is inefficient over long distances or large cargoes

- *motors specificy the directionality of motion

-the cell shape is in constant flux

-the movement of the whole cell is relative to the enviroment

What is the function of Motor Proteins?

(3 answers)

1. *Power cell movements

2. power movement of subcellular components

3. create local forces--> which will lead to changes in cell shape (i.e) muscle contration

key words: power/ forces

What are Motor Proteins

(give example of one)

Motor proteins are a class of molecular motors that are able to move along the surface of a particular substrate.

-driving force behind

1.active transport of proteins and vesicles in the cytoplasm

example: myosin in muscle contraction

How are Protein motors powerd?

ATP!!!

What are the 3 families of protein motors?

1. Myosins actin microfilaments

2. Kinesins

3. Dyneins

hint: myoanoise kan cause dyeath!

ignore the spelling you' ll remember it!

Microtubules characterestics in "road system" terms.

1. direction of movable motors

2. characteristics of tubules extending out to cell

-Similar to high way system, has a forward and reversed direction

-Microtubules are stiff, arranged radially

radially- think about a central point of light like the sun "radiating" outward

def of Radially

radially- think about a central point of light like the sun "radiating" outward

Characteristics of actin in terms of roads.

How is Actin oriented in cell?

Actin in terms of roads can be compared to as "local road", they are extremely limited in the amount of distance motors can travel

Actin is oriented like noodles in soup, unconnected and random  in cellular cytosol

Characteristics of ATPase motors

1. Each motor has a HEAD and  TAIL

2. Head- converter

3. Tail- anchors motor protein to Cargo/ cell membrane/ or other tails (ex. Muscle myosins)

4. Needs ATP hydrolysis (ATP-ADP+Pi)  to move motor on tracks

5. polarized fibers

Function of ATPase motor head?

converter: ATP--> ADP+ Pi

Function of ATPase motor tail?

ANCHORS motor protein to:

-cargo

- cell membrane

- tails (ie muscle myosins)

What results in the movement of motor on tracks?

Hydrolysis of ATP (ATP-->ADP+Pi), which "charges" myosin head like a battery providing energy for action

What allows the directionality of ATPase motor proteins?

Fiber is polarized

- Meaning that the fiber has a positive and negative end, this allows the MP ( motor proteins) to differentiate the differing directions

MP Myosin associates with only which tracks? 

All myosins associate with

actin/microfilaments

What is the direction of MP Myosin on Actin/Microfilament tracks?

 Movement toward end (+) from neg

More specific characteristics of Myosin head.

(3 characteristics)

1. Site of ATP hydrolysis

2. Responsible for creating FORCE

3. Site responsible for binding to ACTIN or track

What regulates the activity of Head domain in Mysoin MP?

Ligh Chain regulates activity of head domain

What usually serves as "light chain" for most cystolic myosin?

Calmodulin serves as light chain for some cytosolic

myosins

If heads of myosin is regulated by the light chain and the Light chains are made up of Calmodulin then what is Calmodulin dependent on?

CALCIUM!!!!

Remember the Calmodulin is a ca binding protein that enables ca to target specific targets at long distances

key:    myosin head< light chain< calmodulin< ca

Functinon of Myosin Tail??

Tail (effector) domain

• Contains binding sites for cell membrane or other tails (muscle)

What is unique to Myosin motors?

 ***Tail is unique for the myosin type

4 Steps to Myosin Movement?

1.       Binding of ATP to Myosin head; releasing myosin head from actin

2.       Hydrolysis of myosin headà Cocked position (preparing to hit golf ball with club)

3.       Leaving of pi from ADPà golf ball gets hit ball club

4.       ADP replaced by ATP cycle begins again

3 Common Classes of Myosin

1. Membrane Endocytosis

3. Contraction 

2. Organelle transport

What are the 3 types of muscle cells?

1. smooth

2. skeletal

3. cardiac

think: a rib going through a heart duet to trauma, bones are smooth, must pierce through the skeletal muscle layer towards the heart

myofibers

parallel arrangement of

muscle cells

myofibrils

multiple myofiber 

sarcomeres

 highly ordered linear chains structures of

actin and myosin

Structural and functional

unit of contraction

Sarcomere

Contractions are all or

nothing!!!

Sarcomeres contain what 2 components

lined end to end?

thin filaments (actin) and thick

filaments (myosin II)

I band

light band - thin

filaments = actin

A band

 A band - dark band -

thick filaments =myosin

Z disk

 Z disk is in the middle

of I band

Troponin

"Ca binding site"

What happens when Ca binds to troponin 

troponin is attached to tropomyosin, which is the site for myosin cross-bridge allowing contraction, When ca binds to troponin site for myosin actin cross bridge opens up      --> contraction !!!

Tropomyosin

reveals myosin

binding site

The contraction of skeletal muscle is controlled by what, which differs from smooth and cardiac muscle?

nervous system

*skeletal muscle differs from smooth and cardiac muscle. Both cardiac and smooth muscle can contract without being stimulated

accordion effect

 Sarcomere shortens= contraction 

Where does Ca+ for contraction come from? 

Sarcoplasmic Reticulum !!!

Again, What function does Ca play in contraction?

Ca2+ link action potentials

in a muscle fiber to

contraction.

Cannot have contraction without it 

After flooding of Ca in cytsol my muscle cells how is

Ca+ concentration returned to normal conditions?

ATPases ends contraction by pumping Ca back into SR

What is used to stabilize skeletal muscles on the (+) end

CapZ stabilizes (+) end

 Tropomodulin stabilizes (-) end

What protein stabilizes Actin 

Nebulin, giant protein

What stabilizes Myosin (thick filament)?

Titin 

What is the condition in which muscles are being locked in a state of contraction 

Rigor mortis

What causes Rigor mortis?

 Occurs when ATP is depleted and is not

available to bind to myosin heads.

Lasts for about 3 days after which the muscles

soften due to tissue proteolysis 

What function does ATP play in muscle contraction (myosin) 

ATP binds to myosin head allowing detachment of actin causing a release in contraction 

Function of Myosin V? 

segregates organelles and orients nucleus in

preparation for budding

 Function of Focal adhesions?

anchor spot to allow cell to move forward

and prevent from retracting

4 key steps in cell locomotion 

1. extension 
2. adhesion
3. trans-location 
4. de-adhesion endocytic recycling 

What controls actin organization?

GTPases control actin organization

What causes activation of GTpases?

Growth factors cause

activation of small/monomeric GTPases

Activated receptor brings what to the membrane activating what?

 Activated receptor bring Rho to the membrane and

activate GEF

hint: receptor message causes rhino to bring gefts (gifts) exchanging GDP for GTP!

What controls changes in actin cyotskeleton? 

ex.

Signal Transduction pathways

ex.  Activation of rho – 2 effects

What are the 2 effects of RHINO (Rho) activation?

– Activate assembly of unbranched F-actin

– Activate nonmuscle myosin - contraction

Which two GTPase are associated with inducing "leading edge" in the front? 

Cdc42  and Rac

HINT: Rac like race track--> cars--> moving fwd

GTPase proteins for the back?

function?

Rho- causes contraction of myosin

-inhibits rac

HINT: rhinos chase--> charging behind, and if charging a car on the race track then it will inhibit race

2 themes revolved around microbiology

1. understand basic life processes

2. application of understanding to benefit humans

3 importance of microorganisms

1. oldest form of life

2. largest mass of living mat Earth

3. carry out major processes of biogeochemical cycles

What is the cell?

4 classes of cellular macromolecules

- cytoplasmic membrane

- cytoplasm

-nucleus or nucleotoid and ribosomes

- cell wall

7 characteristics of living systems

1. compartmentalization and metabolism
2. regeneration
3. reproduction
4. differentiation
5. communication
6. movement
7. evolution

define reproduction vs regeneration

reproduction- generation of 2 cells from 1

regeneration- and replacement of components

define differentiation(what is specific to?)

-  synthesis of new structures, to modify the cell ( specific to some microbes)

-  Formation of new cell structure (ie-spore) usually as part of a cellular life cycle

Communication (specific to what?)-ex

What is primarily used for interaction of communication?

o   regeneration of and response to chem signals (no in all microbes)

  Ex. Chorum sensing

§  Cells communicate or interact primarily by mean of chemicals that are released or taken up

example of communication in microrganisms?

Cells are a bag of what?

microbial
communities

microbial communities are where microorganisms exist in nature in populations of interacting assemblages

Habitat

Ecosystem

Microbial Ecology

study of microbes in their natural enviroments

Diversity and abundances of microbes are controlled by what?

1. resources= nutrients

2. enviromental condition (temp, pH, O2)

Activities of Microbial communicates can cause what to the enviroment?

species Richness ***

benefits

Total # of species

more beneficial to humans and enviroment, think ( increases genetic diversity which in turn improves the the chances of survival)

species abundance

large amount of proteins specific to one or more species

Which is more beneficial?

1- high species richness, low species abundance

2- low species richness, high abundance

Populations in microbial communities interact in what 2 ways?

1. cooperation
2. competeition 

These are the driving forces of nature due to limited resources and abundant forms of life. even in cooperation the purpose would be to create a larger competitive force to extract resources

(1) Cells can be considered machines that carry out chemical transformation- Enzymes
(2) Cells can also be considered coding devices that store and process information that is
eventually passed on (DNA/RNA)

First forms of bio life?

Bacteria, mosy likey cell replicating, has some genetic material, RNA with ENZYMATIC FUNCTIONS

When did bacteria first arrived? what were its 3 characteristics?

3.8 BYA

1. bact was anoxic
2. anarrobic
3. asexual reproduction

life form 3 BYA, characterisics

Cyanobacteria was oxygenic (uses photosynthesis), uses CO2 to produce oxygen

Where are most microbes cells found? 2 locations

subsurfaces of tessestrial locations and also Oceanic locations

**function of microganism and agriculture

Nodule

function of Rumen in animals

3 elements which microorganisms assist in cycling?

NCS-nation college of science

Nitrogen

sulfur

Carbon

can plants and animal convert N2-Nh3?

*** Basic proccess of Nitrogen fixation in plants

1. Isoflavone produced by plants (plants makes flavored ice cream.
2. Baby (bact) notices ice cream--> produces saliva (chemical)
3. 3. which plants roots hairs notices
4. Bacteria enter root hairs to nodule: convert N2-NH3

ex of biotechnology

insulin development

bioremediation

use organic organs to clean up oil organic

ex of biofuels

corn ethanol used from fermentation

ex of microbiology in food

food preservatives, fermintation are +

food additives, radiation are -

Robert hooke

Ferdinand cohn

trained chemist, discovered that alcholoic fermination was a bio mediated process (though fermentation was purely chemical at time)

- oppsed the theory of spontaneous generation by using nutrient broth with bent tube

- also found vaccine for rabies anthrax, cholera, purepral fever from disproving of spon gen

  hypothesis that living organisms can spontaneously generation through non-living matter (Pasteur disproves this hypothesis)

Koch Robert

- developed link b/w microbes and disea.

-identified ageents: anthrax/ tuberculos

-*koch's postulates

-Developed techniques (solid media) for obtaining pure cultures of microbes.
-Awarded Nobel Prize for Physiology and Medicine in 1905

Koch's postulates

1.    1.   Microorganism must be found in abundance in all org suffering from the disease, but should not be found in healthy org

2.     2.  Microorg. Must be isolated from a diseased org and grown in pure culture

3.     3.  Cultured microorganisms should cause disease when intro into a healthy org

4.     4. Microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent

- not possible to satisfy all postulates for every infectious disease why?

- humans not ethically app to test on

- causative agents of several disease of humans will not cause disease in any exp animal )rickettsias, chlydias)

Sergei winogradsky

concept of ( we are chemotrophic)

- demonstrated that specific bac linked to specific biogeochemical transformation (ie S/N cycles)

1. chemolithotrpy

2.chemoorgan

3. chemoauto trophy

4. chemohetertroph

Virology

are viruses considered cells?

manipulation of genomes--> insulin production

- DNA from one organism can be tranplanted into bacterium and proteins encoded by DNA harvested

study of metabolic expression in cells

a) proteins produced by mRNA translation- glycolysis--> glucose--> = many produc via TCA cycles

 or

they study of the different levels of metabolism