1
Q
Nucleus
A
The cell’s genetic control center. House and copy DNA to pass onto daughter cells
2
Q
Endomembrane system’s function and parts (EGVL)
A
To regulate protein assembly and traffic within cell
-Endoplasmic Reticulum, Golgi apparatus, Vesicles, Lysosomes
3
Q
Endoplasmic reticulum
A
Protein folding and assembly
4
Q
Golgi Apparatus
A
Modifying and sorting protein for destination
5
Q
Vesticles
A
Sacs made of membrane. Intra (within) cellular that transport btwn organelles
6
Q
Lysosomes
A
Contain digestive enzymes that break down matter to be recycled
7
Q
Some membranes in the Endomembrane system…
A
are physically connected or remotely connected via vesicles
8
Q
Endomembrane system and gene expression process
A
DNA uncoils to mRNA, which leaves the nucleus and is fed into ribosome in endoplasmic reticulum. The ribosome translates the mRNA into a specific amino acid chain, which forms the protein
9
Q
Transport of proteins from ER
A
Proteins in ER enter the Golgi bodies and are wrapped for shipment. Each protein is attached to a motor molecule and moves along to one of 2 destinations. Either its incorporated into the membrane or excreted from the cell by exocytosis
10
Q
What is the purpose of neuronal membranes’ Non-polarity?
A
Prevent polarized/charged atoms (ions) from crossing the membrane unless through a specific channel
11
Q
How do small molecules cross the membrane?
A
-Passive Transport (Diffusion and Facilitated). No energy in needed to enter or leave
-Active Transport- is ATP-Driven
12
Q
ATP
A
Adenosine triphosphate. 3 charged phosphates attached, which can be released. Used for a lot of cellular energy
13
Q
Diffusion vs Facilitated Diffusion
A
Non-polarized molecules vs polarized/charged molecules (which cannot pass through non-polarized membrane, thus requires a transport protein)
14
Q
3 forms of Passive transport
A
Selective permeability- some substances are able to cross membranes more easily than others
Passive transport- diffusion of molecules across a membrane with no energy expended
Diffusion- Spontaneous movement of a substance DOWN from High concentration to low concentration (aka down the concentration gradient)
15
Q
Water and dye metaphor for diffusion
A
Molecules of dye as Oxygen. It can easily diffuse through the membrane ( since its not polarized) through Net diffusion, When all sides of water are equal in dye, they have reached Equilibrium
16
Q
Dynamic Equilibrium
A
Constant movement of substances, but it is equal, and there is no net change of concentration
17
Q
Diffusion with 2 types of molecules
A
Depending on concentration, substances move opposite of each other to reach equilibrium
18
Q
Concentration Gradients equals…
A
Potential Energy- energy stored waiting to be released
19
Q
What lines the Transport Protein channel? What do they do?
A
Charged proteins that pass along polarized ions
20
Q
What is Active transport and why does it require energy?
A
Cell expends energy to move a solute against its concentration gradient (aka from a less concentrated are to a more concentrated one) which is called Active Transport
21
Q
Compare Diffusion, Facilitated Diffusion, and Active Transport on polarity, energy, protein transport, and their concentration gradient
A
Diffusion: Small and non polar. Doesn’t require energy, doesn’t transport required proteins and goes down the concentration gradient
Facilitated Diffusion: Small and polarized molecules. Doesn’t require energy, does transport required proteins. and goes down concentration gradient
Active Transport: Requires energy, does transport required proteins and goes against concentration gradient
22
Q
Why do we need Active Transport?
A
Allow cells to maintain specific concentrations of molecules
23
Q
Ligand
A
Molecule that binds to a specific site on a protein (ex: Glucose molecule)
24
Q
3 main types of Transmembrane transport proteins
A
Channel: Transport proteins that are always open. Ions move from higher concentration to lower concentration (passive)
Gate/Gated channel: Open and close, allow substances to pass through on some occasions but not others (ex: ligand-gated) (passive)
Pump: Active, moves substances against concentration gradient
25
Sodium Potassium Pump
Very important source of potential energy. Require ATP. Pump 3 sodium out for every 2 potassium brought in
26
Phospholipid bilayer?
Form the cell membrane and separates the extracellular fluid from the Intracellular fluid. The boundary is non-polar
27
3 basic questions that underlie a behavioural response to stimulation?
1. How do our nerves detect a sensory stimulus and inform the brain about it?
2. How does the brain decide what response to make?
3. How does the brain command muscles to move?
28
Action Potential? Where does it occur?
The chance of activating an info impulse. Axon Initial segment
29
What is Electricity? Battery?
-The flow of electrons (e-) down their concentration gradient.
-Source of potential energy
30
Voltage vs Current?
Voltage: Difference in charge between 2 points (i.e inside and outside of cell). Measured in millivolts (mV). "Pressure"
Current: Movement of charged particles (electrons and ions). "Flow" Measured in (Amps, A (specifically pA))
31
How do biologists measure Volts?
with milli Volts
32
Use "water tank" analogy to describe charge, voltage, current, and resistance.
Charge = water, voltage=pressure, current=flow, hose width = resistance
33
Relationship between Resistance/Voltage and Current
Higher voltage leads to higher current. Higher resistance leads to lower current
34
Nonpolar molecules _________ across membrane, while Polar molecules need help from ________
diffuse , proteins
35
Voltage/Electrical Gradient and concentration gradient
As the concentration gradient works, it creates a charge in that direction. Voltage gradient activates, moving the charge in the opposite direction as the concentration until it reaches equilibrium. This is Electrochemical gradient
36
What is a membrane potential?
electrical charge difference across the neuron’s plasma membrane (between inside and outside of cell)
37
What is the Resting potential of the inside of a cell.
about -70mV
38
How is resting potential generated?
1. Na+/K+ Pump: Keeps sodium high outside, potassium high inside and more positive charge on OUTSIDE of membrane
2. High A- inside of cell
3. Potassium/K+ leaks OUT through leak channels
39
Otto Loewi and the 2 frog hearts
Won Nobel Prize in 1936 for discovering A, by using 2 frog hearts in seperate beakers with a connection, One with a vagus nerve. When the Vagus heart is stimulated, the other heart also slows down
40
Acetylcholine (ACh) (4)
-1st to be discovered in CNS ad PNS
-Excites skeletal muscles
-Excites OR inhibits internal organs in ANS
-1st Neurotransmitter discovered, works primarily at the neuromuscular junction (including heart)
41
2 modes of synaptic communication (slide 5+6)
-Chemical synapse- Most common. messenger molecules are released when stimulated by an action potential (neurotransmitter)
-Electrical synapse- specialized connections between neurons that facilitate direct ionic and small metabolite communication (gap junction)
42
Neurotransmitter vs Gap Junction
Gap Junction- area of contact between adjacent cells formed by hemichannels composed of connexin proteins
Neurotransmitter- Chemical with an excitatory or inhibitory effect when released by a neuron onto a target
43
When neurons are connected electrically they are...
Electrically coupled
44
Chem vs Electrical- Morphology, Direction, Space between synapse, commonality,
Chemical- Asymmetric, Unidirectional, Extracellular space between synapses (synaptic cleft), most common type
Electrical- Symmetrical, Bidirectional, Cells interconnected via gap junctions
45
Hydrophilic Channels and gap junctions
Gap junctions form hydrophilic channels that ions can pass through freely synchronization of electrical signals between lg. populations of neurons
46
Advantages of Chemical vs Electrical synapse
Chemical- Flexibility, important for learning/memory
Electrical- Instantaneous
47
Why are synapses so important (3)?
The are sites of Learning/memory, Drug Action, and Neurological disorders
48
Label a Chemical Synapse Structure and their functions (7)
Presynaptic membrane-Encloses molecules
Synaptic cleft- Small space
Postsynaptic membrane- Contains receptor molecules
Microtubule- Transport structure that carries substances to the axon terminal
Mitochondrion- Provides the cell with energy
Synaptic vesicle- Round, contains neurotransmitter
Storage granule- Large, holds synaptic vesicles
Postsynaptic receptor- Site where neurotransmitter molecule binds
49
Steps of Neurotransmission (5)
1) Synthesis- Neurotransmitters are created from precursor molecules
2) Packaging and storage- Nts moved into vesicles, waiting for an action potential
3) Release- In response to an action potential, transmitter is released through exocytosis
4) Receptor action- Transmitter crosses the synaptic cleft and binds to receptor
5) Inactivation- transmitter either diffuses away, is enzymatically degraded, in taken to neuron terminal, or taken by astrocyte
50
Anterograde (going forward) Synaptic transmission
neurotransmitter is released from the presynaptic side to the postsynaptic neuron
51
*Axomuscular (neuromuscular function) NMS
Directly connects to muscles
52
Name and describe 4 Classes of Biological molecules
-Carbohydrates (cellular fuel)
-Proteins (cell structure and function)
-Nucleic acids (RNA and DNA, transmits/expresses hereditary info)
-Lipids (form cell membrane, smaller)
53
How do Biomolecules define cellular identity?
Each cell has 1000s of different biological molecules, and the particular set of molecules expressed reflects genetic differences
54
How are macromolecules synthesized?
Smaller molecules (monomers) joined into larger chains (polymers) consisting of many small, repeating building blocks
55
What makes up more than 50% of the dry mass of most cells?
Protein
56
Protein is made up of...
polymer of amino acids (monomer)
57
What do Carbohydrates and Proteins have in common?
Both large macromolecules that contain repeating sub units
58
Purpose of R groups?
Distinguishes one amino acid from another
59
__ _______ = confirmation of a protein
3d Shape
60
Polypeptides
Chains of amino acids (51-1000+)
61
Peptides
2-50 amino acids
62
Polypeptide vs protein?
Yarn like structure vs Square. Proteins can function when it has its proper shape
63
The 4 levels of protein structure
Primary- Amino Acid chains
Secondary -form pleated sheets or helices (result of hydrogen bonds along backbone)
Tertiary - Sheets and helicles fold to form a protein (via R groups)
Quaternary - a number of proteins combine to form a complex protein (2 of more different/identical polypeptide chains)
64
Nucleic acids
Store (within nucleus), transmit (daughter cell) and express(production of proteins) hereditary information
65
DNA, RNA and Genes
Deoxyribonucleic acid, ribonucleic acids, segments of DNA that code for
proteins
66
Encoded in the structure of DNA is
the info that programs all of a cell’s activities
67
A,C,T,G
dna
68
A C U G
rna
69
Nucleic acids are made up of chains of
Nucleotides
70
3 nitrogenous bases
Pyrimidines, purines, sugars
71
The flow of genetic information and transcription vs translation
Gene contains dna, turns into rna in the nucleus through transcription, then further changes to an amino acid in the cytoplasm through translation
72
Every ___ nucleotide codes into an _________________
3, amino acid
73
Lipids
Diverse group of hydrophobic (anti-water) compounds like fats, *phospholipids, and steroids
74
Phospholipids form the
Cell membrane
75
Phospholipid bilayer
Characteristic of the cell membrane that separates extracellular fluids from intracellular fluids, which are both aqueous
76
Characteristics of a phospholipid molecule
The head of the molecule has polar regions and is hydrophilic (pro-water), bonding to water, while the fatty tails have no polar regions and are hydrophobic
77
What are Hodgkin and Huxley known for?
Used saline solution to keep a squid giant axon alive in 30s and 40s to study what was the driving change in voltage (action potential)
78
What are voltage-gated ion channels?
Channels that open based on voltage/membrane potential changes, selective to a particular ion
79
Where are voltage gated ions located?
Highly connected at Nodes of Ranvier (unmyelinated parts of the axon)
80
How does information move with Nodes of Ranvier?
Saltatory conduction. Jumping from node to node, regenerating as it moves
81
Nodes vs myelin in resistance of current flow
Nodes- low resistance of current flow
Myelin- High resistance of current flow
82
2 conformational states of K+ channels
-Closed at resting membrane potential (-70mV)
-Open at -50mV (depolarization-intracellular fluid becomes less negative as K+ exits)
83
3 conformational states of Na+ channels
-Closed at resting membrane potential
-Open at -50mV (Na+ enters)
-Inactivated at +30mV (inactivation gate closes)
84
TEA and TTX
TEA- Tetraethyl ammonium, Blocks K+ channel, creating an N+ influx
TTX= Tetrodotoxin, Blocks Na+ channels, creating a K+ efflux
85
Neuronal stimulation can result in two different types of responses at the membrane...
Graded potentials and Action Potentials
86
What is a Graded potential and its 2 parts?
-Small voltage fluctuation across cell membrane
1) Hyperpolarization: Inside of a cell becomes MORE negative (outward K+ or inward Cl-)
2) Depolarization: Inside of a cell membrane becomes MORE positive (inward Na+)
87
What is an Action Potential?Fca
the electrical signal neurons use for
communication; a change in
membrane voltage in response to a
stimulus that is transmitted along the
axon towards a synaptic terminal
All or nothing, 1ms
88
What is a Stimulus?
Factor that causes an action potential to be generated like light, sound, chemical signals, etc.
89
Stages of an Action potential (label diagram if possible)
1) Resting Potential
2) Jump to Threshold (?)
3) Depolarization- Membrane potential reverses from negative to positive
4) Repolarization- cell interior becomes negative again
5) Hyperpolarization (extra)-> back to 1
90
Action potential vs Graded potential
Action are all-or-none compared to graded potentials (where amplitude
of voltage deflection depends on stimulus strength)
91
What is the mechanism for the action potential?
Rapid movements of ions across the membrane through voltage gated Na+ and K+ channels
92
What is Absolutely refractory and its 2 components?
A new action potential cannot be elicited
-Depolarization period: Na+ channels already open, no further effects
-Repolarization period: Na+ channel inactivation gate is closed
93
Relatively refractory?
During hyperpolarization, a higher intensity stimulation is required to produce another action potential
-K+ channels are still open
94
Action potentials propagate themselves along ______________. An action potential functions as a ______________________. Starts in __________ to ______________________
the axon. Long distance signal. Axon Initial Segment to Axon terminals
95
Up to ______ in a myelinated axon vs ____ in unmyelinated
120 m/s, 30 m/s
96
Describe Multiple Sclerosis
-Most common autoimmune disease
-Caused by loss of myelin formed by oligodendroglia (in the CNS, controls motor and sensory deficits).
-Hard plaque forms at the site of myelin loss, seen via MRI
-Disrupts action potentials
-Loss of sensation and motor control
97
What is the concentration of Na, Cl, K, and A in/out a cell?
High Na and Cl OUTSIDE, High K and A INSIDE
98
What type of channels maintain the cell’s resting potential?
K leak channels (free to leave and enter), Na channels that are typically closed, and Na + K pumps
99
How do we measure electrical activity in nerve tissue?
Using a voltmeter to record the difference in electrical potential
between two points, we use one electrode to record the outer surface of an axon(0mV) and another to record the inner surface (-70 mV)
99
How do neurons integrate information?
Excitatory postsynaptic potential (EPSP): brief depolarization of postsynaptic
membrane in response to stimulation
Inhibitory post synaptic potential (IPSP): brief hyperpolarization of postsynaptic membrane in response to stimulation
100
Excitatory postsynaptic potential (EPSP)?
brief depolarization of postsynaptic membrane in response to stimulation
101
Inhibitory postsynaptic potential (IPSP)?
brief hyperpolarization of postsynaptic membrane in response to stimulation
102
6 connexins form a hemichannel called a
connexon
103
Excitatory vs Inhibitory synapse structure
Excitatory- Large activation zone, Wide cleft, Round vesicles
Inhibitory- Small active zones, Narrow cleft, Flat vesicles
104
4 criteria for identifying neurotransmitters?
1) Transmitter must be synthesized or present in neuron
2) When released, transmitter mut produce a response in target cell
3) Same receptor action must be obtained when transmitter is experimentally placed on receptor
4) There must be a mechanism for removal after the transmitter's work is done
105
5 Classes of neurotransmitters?
1. Small-molecule transmitters (most common)
2. Peptide transmitters (proteins)
3. Lipid transmitters
4. Gaseous transmitters
5. Ion transmitters
106
Characteristics of small molecule neurotransmitters?
-Quick acting
-Synthesized from dietary nutrients and packaged ready for use in axon terminals
-Once released, are quickly replaced at presynaptic membrane
107
4 major activating systems of brain activity
1. Cholinergic system
2. Dopaminergic system
3. Noradrenergic system
4. Serotonergic system
108
DA: Where is it from in food, What is it responsible for, What disease in it implicated in and why?
Dopamine. From Tyrosine (hard cheeses and bananas)
Coordinates movement, attention, learning, motivation, and reward processing
Implicated in Parkinson Disease. Degeneration of the substantia nigra when DA is below 10% (Brainstem, specifically striatum)
109
Axomuscular/neuromuscular junction?
Motor neuron connected to motor cell
110
6 connexins form a hemichannel called a ...
Connexon
111
5 most important Neurotransmitters in this class?
Acetylcholine(ACh), Dopamine (DA), Serotonin (5-HT), Glutamate (Glu), Gamma-aminobutyric acid (GABA)
112
3 components of Small molecule neurotransmitters?
Quick acting, Synthesized from dietary nutrients and readily packaged in axon terminals, Quickly replaced at presynaptic membrane
113
What are Activating systems?
Neural pathways that coordinate brain activity through a single NT which have a role in synchronizing activity across widespread brain regions
114
What are 4 major activating systems? Which are we focused on?
Cholinergic system, Dopaminergic system, Noradrenergic system, Serotonergic system
115
2 major sources of ACh?
Basal forebrain nuclei and Midbrain nuclei
116
Main NT in Cholinergic System? What is it for?
ACh. Waking behaviour and memory
117
How does Dopamine present in the CNS? What does it do? What happens if there is too much/too little?
Dopaminergic system, through Nigrostriatal pathways. Regulates motor coordination. Too much- schizophrenia, Too little- Deficits in attention
118
Where is DA in the brain?
Substantia nigra and Ventral tegmentum
119
1st symptom of Parkinson Disease?
Shaking, typically in the hands
120
Parkinson is characterized by...
Muscle rigidity and reduced voluntary movement
121
In Parkinson Disease, there is a propensity to...
Lean/run forward to avoid falling
122
As Parkinson progresses...
Essential functions like eating and swallowing are impaired
123
What Causes Parkinson Disease?
Unclear: Several genes have been implicated, with environment possibly playing a role
124
Who is Joy Milne?
Woman who can smell Parkinson Disease on husband 14 years before diagnosis. Woodsy/Musky scent
125
What is Serotonin and what does it do?
Aka 5-HT, it is synthesized from the aa tryptophan (milk, pork, turkey, bananas). Regulates waking activity, mood/aggression, appetite, sleep, memory, respiration, and pain perception
126
Changes in serotonin activity is related to...
OCD, tics and schizophrenia in excess and depression when low
Abnormality in Brainstem-> Sleep apnea and SIDs
127
Where does serotonin appear in the CNS?
Raphe nuclei
128
PSYC 375
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