biopsychology exam 1

abiogenesis

under the right circumstances, amino acids could spontaneously synthesize (early earth conditions)

how do multicellular organisms form over time

they self-organize into a membrane of a cell and over time, they mutate/evolve into multicellular organisms

steps to a complete living cell

1. small organic molecules

2. monomeric biomolecules

3. biomacromolecules

4. a complete living cell

when was the first form of life found

3.5 billion years ago

miller and Urey experiment

• wanted to recreate early earth conditions in order to create spontaneous synthesis of amino acids

criticism of miller and Urey experiment

• miller and Urey didn’t include oxygen and oxygen may have been present on early earth

other possible (low oxygen) places for abiogenesis (counter arguments for miller and Urey criticisms)

• hydrothermal vents in the ocean

• mineral rich tidal pools

• from space on a meteor

early protolife

• self replicating RNA

• proteins and DNA organized into a cell (cell membranes self-align)

what are the characteristics of a cell membrane ?

• lipid bilayer

• channel proteins

• semipermeable membrane

lipid bilayer

• hydrophilic head

• hydrophobic tail

hydrophilic head

phosphate ion attracted to water

hydrophobic tail

not attracted to water - repels water

channel proteins

• small things like oxygen and carbon dioxide and anything that is fat soluble diffuses right across the membrane

• facilitate transport across the cell membrane

• ligate gated ion channels

• voltage channels

ligate gated channels

open when a chemical ligand such as a neurotransmitter binds to the protein

voltage channels

open and close in response to changes in membrane potential

example of stuff that can diffuse across the membrane

vitamin A, oxygen, carbon dioxide

examples of things that CAN’T diffuse across the membrane

• vitamin C is not fat soluble —> the body only takes what it needs and excretes all the extra

• cations (+) and anions (-) —> don’t diffuse across membrane unless there’s a channel

semipermeable membrane

some things can cross freely, others can not

DNA

• sugar phosphate backbone

• nucleotides

• genes/alleles on segments of DNA

• genotype

• phenotype

what do genes make up

chromosomes

genotype

genes

phenotype

physical/behavioral expression of the gene, how it manifests in the organisms

• ex: hair color, eye color

RNA

causes ribosomes to build, repair, transport, and facilitate reactions

epigenetics

• experiences and behaviors that interact or affect our genes and change the genetic expression

example of epigenetics

• exposed to tuberculosis bacteria causes some genes to turn off and weakens immune system

• pregnant women smoking can cause toxic changes to the epigenetic affects of a fetus

natural selection

the mechanism that drives evolution; traits that lead to better ability to reproduce (fitness) are more likely to be expressed in the next generation

5 premises of natural selection

• there is trait variation within the population - genetic variation leads to phenotype variation

• organisms over reproduce (competition for survival)

• organisms compete for survival

• organisms with certain traits have a survival advantage

• modifications by descent

modifications by descent

organisms are changed over generations and new species emerge after thousands of years of change

phenotypic expression

not just genes, but behaviors can cause phenotypic expression —> relationship between environment and genes = phenotypic expression

• ex: Darwin’s finches —> over time the beak features were expressed

role of behavior in survival

• physical attributes can help with natural selection but behaviors can fill in the gaps to help with survival

• behaviors can help us communicate and adapt to different environments

physical evidence for evolution

• homologous structures

• biogeography

• embryological development

• fossil record

homologous structures

• similar structures across species

• vestigial structures

vestigial structures

structures that have no purpose due to evolution

ex: coccyx bone —> evolutionary bone from tail that ancestors had

biogeography

similar climates will have similar animals and similar plants —> adapted to environment

embryological development

start out looking the same and then develop into different looking fetuses

fossil record

can see where species lived

direct observation of evolution

• selective breeding

• insect changes

• drug resistant bacteria

• virus mutations

selective breeding

picking the mates artificially

insect changes

insect lifespan is really short so their evolutionary clock goes by a lot faster —> respond to changes in environment

drug resistant bacteria

evolutionary clock moves faster and becomes resistant to drugs

virus mutations

ex: covid-19 evolved to become less deadly

genetic evolution (primate evolution)

• 99% genetic overlap with chimpanzees

• evidence for evolution with genetic overlap with primates

how does genetic variation (within a species) happen?

• sexual reproduction

• genetic drift

• gene flow

• mutations

sexual reproduction

involves fusion of gametes from 2 different parents, resulting in offspring with a unique combination of genes due to crossing over and independent assortment

genetic drift

• bottleneck effect —> drastic change in population to decrease it —> serving individuals genes make up the next generation

gene flow

• geographic movement of genes across the globe

  • ex: birds migrating and reproducing with birds from another species

mutations

can create new traits that can help an organism reach sexual maturity and reproduce or vice versa and it is less advantageous

is there a genetic basis for race? (human genome variation)

• no race gene

• more genetic variation WITHIN races than BETWEEN races

more genetic variation WITHIN races than BETWEEN races explanation

• 3 million base pairs on DNA

• no 2 humans (except monozygotic twins) have the same DNA

• within a population: 85-90% genetic variation; between populations: 10-15%

• chimpanzees have more variation than humans

• race defined phenotypes make up very small amounts total DNA

ancestry (genetic) vs race (social construct)

• health disparities among races are not biological but can be epigenetic —> toxic environments

eugenics

• natural selection, applies to human population to improve it

• galton late 1800s, popular until 1960s

problems with eugenics

• fallacious (mistaken belief) premise

• what traits do we select?

  • positive and negative eugenics

• forces people to give up reproductive autonomy (positive or negative eugenics)

• evolutionary changes are very slow

• selective breeding leads to undesired traits

fallacious premise (eugenics)

the most important characteristics of an organism must be biological

• ignores epigenetic and behavioral affects

positive eugenics

incentivized some groups (European ancestry) —> encouraged these groups to reproduce (institutional racism)

negative eugenics

prevented some from reproducing —> forced sterilization, limited immigration from non-white countries

glial cells characteristics

• glial cells are like the glue

• make up half of your nervous system

• 1/10th of the size of a neuron

• chemical aspect

• myelin sheath

• phagocytosis

• electrical aspect

chemical aspect of glial cells

control the supply of some chemicals that neurons use to communicate (neurotransmitters) —> absorb and release

myelin sheath

insulation of neurons by glial cells

electrical aspect of glial cells

they can affect neural transmission —> can make it easier or harder for a neuron to fire

types of glial cells

• astrocyte

• oligodendrocyte

• Schwann cells

astrocyte

• absorb and release neurotransmitters

• plays a role in blood brain barrier

• help form synapses —> play a role in timing of structuring synapses

• influence connection between neurons

oligodendrocyte

• located in CNS —> brain/spinal cord

• make up myelin

how do oligodendrocytes make up myelin

wraps itself around another cell —> forms a physical barrier

(one oligodendrocyte can make many segments of myelin)

Schwann cells

• peripheral nervous —> network of nerves that run out of your organs, muscles, etc.

• same function as oligodendrocyte but in PNS

• one Schwann cell —> one piece of myelin

• remove injured or dead neurons —> clean up

• guides a nerve’s regeneration

characteristics of neural cell

• intercellular fluid (cytoplasm)

• nucleus —> contains DNA

• mitochondria

• endoplasmic reticulum

• Golgi apparatus

• dendrites

• axons

• axon hillock

• terminal button

• nodes of ranvier

mitochondria

• generates energy in the form of ATP

  • keeping the neuron alive

endoplasmic reticulum

• contains ribosomes

• ribosomes manufacture proteins in the cell, distributes by the ER

Golgi apparatus

helps the neuron pack up neurotransmitters into their own little membranes within the cell —> diffuses down into the neuron and released through the synapse

dendrites

• receive electrical messages from other neurons

  • messages come down towards the soma

axons

• one or none axons (can have many branches of an axon)

• shorter axons don’t necessarily need myelin

• longer axons do —> speeds up the action

axon hillock

where axon and soma meet

terminal button

• end of neuron

  • terminal button and another neuron have a small gap between them called the synapse

nodes of ranvier

gaps between myelin

types of neurons

• receptor neurons

• motor neurons

• interneurons

receptor neurons

• receive information —> physical energy from the environment and they convert it into neural energy

• skin —> spinal cord —> muscles

• afferent nerves

• efferent nerves

receptor neuron example

• eyes have specialized neurons that receive electromagnetic energy from the environment and they transduce it into neural energy

afferent nerves

skin to spinal cord

efferent nerves

spinal cord to muscles

skin —> spinal cord —> muscles example

put hand on hot stove (skin to spinal cord) —> pull hand away from stove (spinal cord to muscles)

motor neurons

• neuromuscular junction —> space between terminal button and muscle fibers —> movement!

  • glandular function, organ function

interneurons

get information from neurons and send information to other neurons

changes in behavior - neurons!

• neurons can change their shape and form over time with use or no use over time

• once neurons die they don’t regenerate

• sprouting of new branches of axons to create new connections —> explains changes in behavior

blood brain barrier

• like a filter

• capillaries (blood vessels in body) made up of endothelial cells —> larger gaps that permit substances in and out of blood

• brain capillaries have much smaller gaps to limit what goes in and out

• active transport systems

active transport system (BBB)

• using energy to pump substances too big to cross BBB into brain from bloodstream

  • ex: glucose —> too big to cross blood brain barrier, using energy (ATP) to pump glucose from bloodstream into brain

electrochemical process (kinda like a cycle)

• pre synaptic neuron (sending out messages)

• post synaptic neuron (receiving messages)

electricity in myelinated neurons

way slower than electricity in wires

• lots of control and stops along the way so its adequate for our bodies

electrodes

small metal discs that are used to detect and measure electrical activity in neurons by picking up the tiny voltage changes generated when neurons fire action potentials

ohms law

v = i x r

what is voltage and resistance measured in?

current (measured in amps) and resistance (measured in ohms)

current

from charged particles moving (cations + and anions -)

• sodium (NA+), potassium (K+) —> charged particles

resistance

• anything that resists movement of electricity

  • lower resistance = more electricity travels through

  • intercellular and extracellular fluids create resistance

resting potential how many milliwatts

-70 milliwatts (voltage)

why is resting potential polarized

it’s negative therefore it’s closer to the negative poll

resting potential conditions

• more negative inside the cell than you have positive charges outside the cell

why is there more negative inside the cell than positive outside the cell in resting potential

• uneven distribution of cations and anions

• protein anions inside of cell —> can’t leave the cell, no way of penetrating the cell membrane

• sodium ions stay outside the cell but they can come inside (slight changes in charges)

what maintains the resting potential

sodium potassium pump

why causes the resting potential to be polarized

• semi-permeable membranes

• sodium potassium pump

semi-permeable membrane (RP)

some things can pass easily through, others can not

• at rest, sodium ions can not pass through easily —> doesn’t pass through easily unless there’s an open sodium ion channel (there can still be leaks)

sodium potassium pump

• 3 sodium ions pumped out, 2 potassium ions pumped in —> uses ATP

• working to create +1 charge outside the cell —> greater concentration of sodium outside the cell

what forces work in opposition to the resting potential to produce the action potential

• diffusion

• electrostatic pressure