Test 1 Flashcards
What is consciousness?
the state or quality of awareness- awareness of our thoughts, perceptions, memories, and feelings
What is a frontal lobotomy?
used to treat psychosis, depression, anxiety, etc. (experimental)
- Cuts off pieces of the brain
What is the split brain operation?
- Used to cure severe epilepsy, when both sides of the brain exhibit excessive and uncontrolled neural activity
- An outdated approach that involves cutting the corpus callosum, the bundle of nerve fibers that connect the left and right sides of the cerebral cortex
Patients cannot verbalize any stimuli directed to their _____ brain
Right
Which hand is always consistent with conscious awareness?
The right hand
What is the corpus callosum?
- A bundle of fibers that interconnects the two cerebral hemispheres
- Enables both hemispheres to share information with each other
- If it is cut, the two hemispheres cannot directly talk to each other, but they can send information down the spine and to the lower brain
What is the function of the spine and lower brain?
They help with balance and coordinating body movements
Where is our comprehension of language and our ability to talk and write is generally located in?
The left cerebral cortex
What is Gazzaniga’s interpreter theory?
he argued that our ability to communicate and make up stories might have given rise to our ability to think and be aware of our own existence; the evolution of speech gave rise to storytelling, which in turn gave rise to consciousness
What is mind-body dualism?
while the body may be a mechanical device and the world deterministic, the mind is something else, something immaterial that exists outside of the body
What are the main elements of cells?
H, O, C, N
- we breathe mostly O and N
What is RNA?
A strand of a certain type of nucleic acid, specifically ribonucleic acids
- it easily breaks apart
- not much diversity
- sections of DNA are transcribed in RNA
What are RNA-based enzymes?
They can catalyze chemical reactions
What is a phospholipid bilayer?
- Strands of fat with a phosphate cap
- Lipids interact with each other, while phosphate groups prefer to interact with water
What are micelles?
Shaken up phospholipids
What are liposomes?
- When micelles explode
- Diffusion through the membrane is limited
- The interior is full of saltwater
What floats in the cytoplasm of a prokaryotic cell?
Chromatin, ribosomes, proteins
What is chromatin?
consists of loose strings of nucleic acids (DNA)
What are ribosomes?
Consist of nucleic acids (mostly RNA) and proteins
- Function: make proteins by linking together amino acids in the order dictated by the DNA genetic code
What are proteins?
- Catalyze all chemical reactions (specifically enzymes)
- Receptors are proteins that sense things and react accordingly
- Proteins make up roads of the cell and mediate transport and storage
- Serve as messengers
What is different about a eukaryotic cell?
- The loose chromatin DNA is compacted into a nucleus, which is called a chromosome
- It has mitochondria, which are responsible for extracting energy from nutrients
- This energy is typically stored in the molecular bonds of the molecule ATP
What is a neutron typically defined by?
Where the soma (cell body) is located
What is a gene?
Section of a chromosome that encodes a specific protein
• When a gene is being read, copies of it are made (transcribed) into DNA
What is the genome of a cell?
Refers to all the DNA sequences in the soma
- Provides the info necessary to synthesize all the proteins for a particular organism
What are isoforms?
Genes can often be read in alternative ways, resulting in there being different versions of one type of protein
What is neoteny?
extended youth- prolongation of maturation
What is a kinesin motor protein?
uses ATP to walk and carry information
What is a crystal structure?
aggregates of one kind of molecule
What are processes?
The parts of the neutron that extend out of the soma
What are dendrites?
branched extensions responsible for sensing the external world
What are axons?
varies in length and communicates info through action potential (faster than other forms of transport)
What is electrical potential?
Potential for electricity to flow
What is the charge difference?
The difference between inside and outside of the cell
- Solution outside of cell: ground (0 mV)
- Solution inside cell: # of mV
What is the difference between a cation and an anion?
Cation: positive charge
Anion: negative charge
What is electrostatic pressure?
Attractive force between molecules that are oppositely charged (- and +) or repulsive force between molecules that are similar charged (+ and +)
What are ion channels?
Specialized protein molecules that sit in the cell membrane
- They have a pore (hole) in them through which specific ions can enter or leave cells
What is a leak channel?
an ion channel protein that is in the membrane and has a pore that is always open
What is the 2% “others” composition of cells is made up of?
Positively charged: monovalent cations (1 charge) and divalent (2 charges)
Negatively charged: monovalent anions (1 charge)
- Na, Ca, Mg, Cl: more abundant outside of cell
- K: more abundant inside of cell
What does equal concentration on either side of the membrane mean?
Outside the cell = 0 mV
Inside the cell = 0 mV
What is a sodium-potassium transporter?
It requires ATP, concentrates sodium and potassium outside and inside the cell
- Pumps K+ ions in and Na+ ions out of the cell
- 30x more K+ on inside and 15x more Na+ on the outside
• This never changes, unless the cell dies
What causes the concentration gradient within the membrane?
Because of the force of diffusion, K+ wants to leave, but it can’t because of the bilayer, so it causes a potential energy (concentration gradient)
What are leak potassium channels?
Always open, the number of these channels determines the resting membrane potential
- With the freedom to cross the membrane whenever they want, K+ ions start to leave the cell because of the force of diffusion
- Very few K+ leave because whenever it leaves, it creates an imbalance in the charges –> a negative charge builds up
- *The more K+ leak channels = the more permeable it will be to K+ **
What is electrochemical equilibrium?
when the concentration gradient and electrical force are EQUAL due to more potassium leak channels
What is membrane potential?
electrical charge across a cell membrane; difference in electrical potential inside and outside the cell
What is resting potential?
Membrane potential of a neuron when it is not being altered by signalling molecules that cause excitatory or inhibitory postsynaptic potentials
- At rest: membrane potential ranges between -40 mV and -90 mV across different types of neurons
Why does Na+ build up on the outside of the cell?
Because both diffusion and electric pressure are pushing it
- This desire for sodium to come in will launch an electrical signal
What is depolarization?
When the membrane potential of a cell becomes less negative than it normally is at rest
- Ex: an acute influx of positive ions such as Na+
What is hyper polarization?
When the membrane potential of a cell becomes more negative than it normally is at rest
- Ex: an acute influx of negative ions such as Cl-
What are voltage-gated ion channels?
They have an electrically charged door (pore) that can be opened or closed by graded changes in the membrane potential
- This gives rise to ACTION POTENTIAL if the change is strong enough
What are the 2 proteins that set up the resting membrane potential?
Sodium potassium transporter and leak potassium channels
What is the voltage-gated sodium channel?
Function: to initiate and propagate the action potential
What is the voltage-gated potassium channel?
Function is to restore the resting membrane potential
What is the voltage-gated calcium channel?
Located in the axon terminal; triggers release of neurotransmitters
• These channels open when the axon terminal becomes depolarized
• Calcium is 1000x more concentrated outside the cell than in
• The calcium that enters through these channels and binds to proteins that control the release of neurotransmitters and activates vesicle release machinery
When are the voltage-gated sodium channels closed?
When the membrane potential os more negative than -40 mV
What is action potential?
• It is a brief electrical impulse that provides the basis for conduction of information along the axon
- It is a rapid change in the membrane potential that is caused by the active opening and closing of ion channels
What is the threshold of excitation?
The value of the membrane potential that must be reached to produce an action potential
What is synaptic transmission?
Transmission of messages from one neuron to another via the presynaptic release of a chemical (neurotransmitter) that crosses the synapse and binds to receptors located on the post-synaptic membrane
What is the all-or-none law?
States that the action potential occurs or does not occur, and once triggered, will propagate down the axon without growing or diminishing in size
What is the rate law?
States that the strength of the stimulus is represented by the rate of the firing axon
What is a hydration shell?
An atom surrounded by water
Why can only K+ get through K+ ion channels even though Na+ is smaller?
- There are carbon-oxygen molecules sticking out into the pore that provide the perfect way for K+ to get through
- The water shell naturally separates because the K+ charge is perfectly balanced by the atoms in the pore
- The Na+ is too small for optimal interaction with the atoms
What is a promoter?
a region of DNA that initiates transcription of a particular gene
What are neuroglia/glial cells?
- Found all around neurons and even physically encapsulate some parts of them
- They help traffic nutrients and maintain molecular (ionic) stability in the extracellular space
- They support many functions of the nervous system
- They outnumber neurons in the brain
- They DON’T have action potentials
What is an astrocyte?
Glial cell that provides physical support and cleans up debris in the brain through phagocytosis
- They control the chemical composition of the surrounding environment and help nourish neurons