Lecture 2 Flashcards
Chapters 1b and 2a
are K+ and Na+ same or different?
K+ is bigger in every way
more protons, neutrons, electrons). They have the same charge when dissolved in water (+1
What person advanced the field of neuroscience the most?
Charles Darwin
what was Charles Darwin’s idea
All animals in the world, all cells in the world have a lot in common, because they all are descendants of a common ancestor.
The current diameter of our observable universe is what
91 billion light years
The current diameter of our observable universe is 91 billion light years,
but this limit exists simply because why
of the slow speed of light.
The size of the entire universe might be 1023times this amount (no one knows).
when did the universe expand
abou 14 billion years ago
All the ordinary matter of the universe is made from what
the elements on the periodic table
Achemical elementis what
an atom
how long did inflation last?
less than a second but not sure how much
Atoms have a specific number of what
protons
when 2 atoms come together what is this called
a compound which makes a molecule
if a molecule or singular atom has an electrical charge this is called what
an ion
what is an ionic bond
when the charted particles come together
what happens when an ion is dropped in water
breaks apart and dissolves
Atoms held together by ionic bonds are called what
salts (like the table salt NaCl).
A chemical reaction is what
when chemical bonds (chemical compounds) are formed, broken, or modified
chemical reactions often involve what
These reactions often just involve a rearrangement of the electrons around the atoms involved
The likelihood of a chemical reaction depends on many factors. Living entities (life) regulate chemical reactions to do what
create order, grow, and accomplish things.
Planet Earth was formed when
4.5 billion years ago
life as we know it formed when
Sometime in the 1st billion years
The main elements of cells (of life on Earth) are:
The acronymCHNOPS, which stands for carbon, hydrogen, nitrogen, oxygen, phosphorus,sulfur, represents the six most importantchemical elementswhose covalent combinations make up mostbiologicalmoleculeson Earth
what % of Hydrogen in the elements of cells (of life on earth) and what is the number of protons
59% Hydrogen (H, the element with 1 proton)
what % of Oxygen in the elements of cells (of life on earth) and what is the number of protons
24% Oxygen (O, the element with 8 protons)
what % of Carbon in the elements of cells (of life on earth) and what is the number of protons
11% Carbon (C, the element with 6 protons)
what % of Nitrogen in the elements of cells (of life on earth) and what is the number of protons
4% Nitrogen (N, the element with 7 protons)
what % of Others in the elements of cells (of life on earth) and what is the number of protons
2% Others (phosphorus, sulfur, …)
the CHNOPS are classified as what
non metals but reactive
The CHNOPS elements come together in different combinations to form a handful of different types of molecules such as: (5 of them)
Water Sugar Lipid Nucleic acid Amino acid
Almost everything found in a cell is one of these molecules or it is made up of a chain of these molecules (i.e., a chain of sugars or a chain of lipids, etc.)
what are lipids
the fat that makes o the cell wall
what are Nucleic acid
Amino acid
made up of the same 6 elements but slightly diff orientation
everything in cell that is not sugar water or fat is going to be made up of nucleic acid or amino acid
all molecules in a cell are what
long chains!
how many atoms are in any given part of the chain is the question
30-50 kinds of atoms in on blink but then you can get up yo million when looking at the longer chains
70% of total cell mass is what
water
Beside water (70% of total cell mass), cells are made up of:
15% Sugars (strings of sugar molecules are called carbohydrates)
10% Lipids (cell membrane, fat)
15% Nucleic acids (DNA & RNA are strings of nucleic acids)
50% Amino acids (proteins are strings of amino acids; the instructions for how to make proteins are found in the DNA)
10% Other organic molecules
strings of sugar molecules are calledwhat
carbohydrates
strings of nucleic acids are what
DNA & RNA
strings of amino acids are what
proteins
the instructions for how to make proteins are found where
in the DNA
what is plasma membrane
cell wall
The prokaryotic cell consist of a plasma membrane (cell wall) filled with what
cytoplasm
what is cytoplasm
which is mostly salt water
what was the first cell to appear on earth
prokaryotic
The prokaryotic cell consist of a plasma membrane (cell wall) filled with cytoplasm (which is mostly salt water). Floating in the cytoplasm are what
Loose strings of nucleic acids (DNA and RNA) - labeled chromatin
and
Proteins (made up of amino acids), which perform most of the functions within a cell.
Proteins are made by what
ribosomes
what are ribosomes made of
nucleic acids and proteins
Ribosomes form proteins how
by linking together amino acids (the building blocks of proteins) in the order dictated by the DNA genetic code.
what are proteins
Proteins are what do things in cells
are there lots of different types of proteins?
hell yes
what are Enzymes
Enzymes are proteins that perform (catalyze) chemical reactions
what are Receptors
Receptors are proteins that sense things and react accordingly
what make up the scaffolding and roads of a cell
Proteins are also what make up the scaffolding and roads of a cell. They also mediate transport and storage. They also serve as messengers
when did complex eukaryotic cells form
Sometime in next 2 billion years
what is required for a cell to move
ATP
what is ATP
energy
prokaryotic cells are always starved for what
energy
how are eukaryotic cells thought to have formed
there was a small bacteria (single cell) and some bigger ones
the bigger ones engulfed the smaller ones
normally would break it down to smaller parts but then it realized if it didnt break it down it would keep having energy and this formed a symbiotic relationship (the mitochondria was the cell that was engulfed and then not broken down)
The eukaryotic cell is similar, but it…
Organizes the DNA into a nucleus, from which the DNA cannot escape
and
2) It also 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 the nucleus form
organized place to hold DNA
what do lysosomes do
garbage removal
A chromosome is a strand of what
DNA
A gene is what
a section (a functional unit) of a chromosome. It is a section of DNA unit that encodes a specific protein
When a gene is active (being read), copies of it are made (transcribed) into what
RNA
This RNA leaves the nucleus, where a ______ _______ into a protein.
ribosome translates
The genome of a cell (of an organism) refers to what
all the DNA sequences in the soma. The genome provides the information necessary to synthesize all the proteins for a particular organism.
Humans have about 20,000 protein-encoding genes in their genome.
Note, however, that genes can often be read in “alternative” ways, which can result in there being different versions of one type of protein. These protein variants are known as what
protein isoforms. Often several protein isoforms are made from a single gene
The Eukaryotic Cell Body is called what
Soma
The soma of a cell is where the what is located
nucleus is located
The nucleus houses what
the strands of DNA (the chromosomes) within a cell
Neurons are typically defined by what
where their soma are located (e.g. hippocampal neurons).
what is Cytoplasm
a gelatinous, semi- transparent fluid in which organelles are suspended.
what is Membrane
defines the outer boundary of the cell. It consists of lipids and is embedded with proteins that have special functions.
what are Microtubules
allow for rapid transport of material throughout the neuron.
like a highway system through the cell to move things efficiently
There are dozens of instances throughout history were collections of eukaryotic cells came together to form multicellular organisms.
Once multicellular organisms were formed, cells began to specialize, and the structure and function of life became almost limitless. Organisms known as animals first appeared when
around 650 million years ago
Nerve cells evolved when
600 million years ago
Nerve cells haven’t changed that much in the last hundreds of millions of years. So, to understand how human neurons work, you can study what animal
squid
The 1963 Nobel Prize was awarded for what (in relation to the squid)
describing how neurons transmit electrical signals, i.e. the action potential
The 2000 Nobel Prize was awarded for describing the neuronal basis of learning and memory.
This work was done on what
a sea slug
In the mammalian kingdom, brain structure is highly ______ between species
similar
why are rodents the dominant group of species used in neurobiology research
40% of the mammalian species alive today are rodents. 20% are bats.
Rodents are evolutionarily closer to humans than cats, dogs, bats, sloths, elephants, etc.
Because of the genetic and behavioural similarities between humans and rodents, as well as their small size, rodents have become the dominant group of species used in neurobiology research.
By learning what makes mice feel hungry or sexual, depressed or anxious, motivated or tired at the neuronal level what do we gain
we can get a very clear idea of how similar processes work in the human brain.
humans and chimpanzees share what percent of their DNA
98.8
After birth, the human brain continues to_____ __ ____ in a dramatic fashion
grow larger and heavier
do neurons keep producing
Production of new neurons almost ceases at birth, but those that are already present grow and establish connections with each other, and other types of brain cells, which protect and support neurons, begin to proliferate
what is Neoteny
extended youth – Prolongation of maturation
when does human brain reach its adult size of approximately 1400 g—about four times weight of newborn’s brain
Not until late adolescence
Given the properties of planet Earth, how likely was the formation of life and evolution of intelligent, verbal beings?
Was this process fairly inevitable given the billions of years, or was it highly improbable?
Were we just lucky?
it was just a matter of time and evolution
mAYBE the development of language was a lucky thing because we are the only species with this complexity
what is the Fermi Paradox
where is everybody?
Within our galaxy, the Milky Way, there is estimated to be about 40 billion planets that could support life (earth-like planets).
The Milky Way galaxy is over 13 billion years old, so some earth-like planets may be much older than our relatively young planet earth.
Ifinterstellar travelis possible, even the “slow” kind nearly within the reach of Earth technology, then it would only take from 5 million to 50 million years to colonize the Milky Way galaxy.
There is estimated to be over 2 trillion galaxies in our observable universe.
So, where is everybody?
what are Basic structure of the neuron
dendrites terminal buttons synapse myelin sheath soma (cell body
what is Soma (cell body)
contains the nucleus and is the metabolic centre of the neuron.
what are Dendrites
are branched, treelike extensions of the soma. They receive information from other cells and carry it to the soma
what are Terminal buttons
are button-like endings of the axon branch. They release neurotransmitters after receiving an action potential
what is synapse
Terminal buttons are button-like endings of the axon branch. They release neurotransmitters after receiving an action potential.
They connect with another neuron via a synapse, which is the junction between an axon terminal and the membrane of another neuron.
The axon carries information (via an action potential) from the soma to the axon terminals. It is often insulated by what
a fatty myelin sheath, which improves conduction velocity and fidelity
do Neurons have a resting membrane potential? what is it?
yes, -40 to -90 mV
in nerve and muscle
The main elements of cells are:
59% Hydrogen (H) 24% Oxygen (O) 11% Carbon (C) 4% Nitrogen (N) 2% Others (phosphorus, sulfur, …)
what are the Positively charged ions
monovalent cations:
sodium (Na+), potassium (K+)
divalent cations :
calcium (Ca2+), magnesium (Mg2+)
what are the Negatively charged ions
monovalent anions:
chloride (Cl-)
divalent anions :
phosphate (HPO42-)
what is Intracellular fluid
Fluid contained within cells
what is Extracellular fluid
Fluid located outside of cells
Neurons sit in and are full of what
salt water
Neurons sit in and are full of salt water. The salt is mostly what
NaCl and KCl
The lipid bilayer is impermeable to what
ions
If there is an equal concentration of positively and negatively charged ions on either side of the membrane, then:
Outside of cell = 0 mV
Inside of cell = 0 mV
potential is measured how
by comparing 2 things
Two proteins are responsible for setting up and maintaining the resting membrane potential of neurons:
Sodium-Potassium transporter (aka sodium potassium pump)
Leak potassium channels
what is Sodium-Potassium transporter (aka sodium potassium pump)
(requires ATP; concentrates sodium and potassium outside and inside the cell, respectively)
what are Leak potassium channels
(always open; the number of these channels dictates the resting membrane potential)
what happens with With the Sodium-Potassium Pump
K+ is pumped in while Na+ is pumped out
required ATP to spin around a release
with Sodium-Potassium Pump, each is pumped in or out so There is no electrical charge difference yet (membrane potential = 0), since there are similar amounts of positive ions inside and out, but there is what
potential energy
There is no electrical charge difference yet (membrane potential = 0), since there are similar amounts of positive ions inside and out, but there is a potential energy here based on the force of diffusion.
what does this mean
Basically, the K+ ions feel crowded in the cell and want to leave
what is The Force of Diffusion
naturally wants to leave
Diffusion
Movement of molecules from regions of high concentration to regions of low concentration
When there are no forces or barriers to prevent them from doing so, molecules will diffuse from regions of high concentration to regions of low concentration
If you give K+ ions the freedom to leave the cell (by putting open potassium channels in the membrane), they will do so due to the force of diffusion.
These channels are called what
potassium leak channels
what happens if Outside of cell = 0 mV
Inside of cell = -60 mV
The charge inside a neuron can reach -90mV before its electrostatic energy is equal and opposite to the force of diffusion.
The more leak channels a neuron has, the more permeable it is to K+ and the closer its membrane potential will be to the true equilibrium of these forces.
how many potassium ions need to leave the cell for the membrane potential to fall to -60 mV. This amount is actually very small (<0.0001% of the potassium ions inside the cell).
Tens of millions
Neurons vary in their expression of K+ leak channels, and typical resting membrane potentials range from what
40 to -90 mV
it will never actually get to -90… -60 is the typical!
is there always more K+ or Na+ in the cell?
always more sodium out than in and more potassium in than out
basically what is The Membrane potential
Balance of Two Forces
what are Ions
Charged molecule
Cations are positively charged
Anions are negatively charged
what is Electrostatic pressure
Attractive force between atomic particles charged with opposite signs or repulsive force between atomic particles charged with same sign
what are Ion channels
Specialized protein molecule that permits specific ions to enter or leave cells
what is Leak channel
K+ ion channel that is always open
what are the parts to The Force of Electrostatic Pressure
ion
electrostatic pressure
ion channels
leak channels
