bio - midterm #1

nervous system

neurons + supporting cells

neurons

cells rhat can send & receive signals in nervous system

neuronal plasticity

the ability to modify nervous system after birth

synapse

small junction/gap between 2 nerve cells where signals pass from one cell to the next

memory

the set of processes used to encode, store & retrieve information over different periods of time

sequence memory

stimulus —> STM —> practice —> encode to LTM —> retrieval —> STM

short term memory

temporary storage system that processes incoming sensory memory. it takes info from sensory memory & connects it to something in LTM

short term memory characteristics

• stored for a very short time —> seconds to minutes

• limited capacity - 5 to 7 thoughts at a time

• released (forgotten if not used)

• a component of working memory

long term memory

continuous storage of information

long term memory characteristics

• activated when info needs to be retained

• infinite duration & capacity (as far as we know)

• can’t be used directly

rehearsal

moves info from short-term to long-term memory

active rehearsal

practice & repeat the ifno to be remembered & moved to LTM

semantic/association networks

concepts that are connected —> arranged hierarchically

explicit memories

we consciously try to repeat/recall remember

episodic memory

information about events we’ve personally experienced

semantic memory

knowledge of words, concepts, language-based knowledge, facts

implicit memory

long-term memories that aren’t part of our consciousness —> remember learning something, but can’t recall it

long-term potentiation

• it has a lasting increase in the strength of synaptic information

• facilitated by: organization, chunking, activity

• neuronal plasticity in a single synapse

• helps retrieval of memmories

evolution

the unifying idea of biology: all organisms are modified descendants of common ancestors. process of gradual change in a population/species over time.

phylogenetic tree

summarizes the evolution of different life forms of Earth

emergent properties

the result from the arrangement & interactions of parts within a system —> whole becomes more than the sum of parts

science

a process of testing hypothesis to develop knowledge

• “to know” in latin

• obsservable & measurable phenomena

• systematic method

Language of Science (steps)

hypothesis, prediction, theory, law

hypothesis

testable proposed explanation for something you want to explain based on available data—> suggested explanation for an event that one can test (educated guess)

prediction

expected outcome when testing a hypothesis - IF the hypothesis is true, THEN this is the expected outcome. Something that must be true if your hypothesis is accurate

theory

broad explanatory framework; tested and confirmed explanation for observations/phenomena

law

statement of what occurs under specific conditions s

scientific method

method of research w/defined steps including experiments & careful observation

steps of the scientific method

observation & pattern —> background —> generate your hypothesis —> generate prediction —> experiment/observation —> evaluate —> repeat/revise until results are the same over numerous trials —> share findings —> ask a new question

background

research topic, context, what’s been studied, ensure you’re not repeating something

generate prediction

what you’re evaluating, make sure you actually prove your hypothesis

experiment/observation

see if your hypothesis is proven/disproven

humans are made of

65% oxygen, 18% carbon, 10% hydrogen, 3% nitrogen

atom

smallest unit fo matter retaining all the element’s chemical properties

protons

positively charged

neutrons

no change; contributes to atom weight but not charge

nucleus

the center of the atom & contains protons & neutrons

electrons

negatively charged. move rapidly around the nucleus & look like a cloud

potential energy

energy based on capacity/change —> stored energy —> work needs to be done to restore energy

valence electrons

electrons in the valence (outermost) shell

molecule

compound of 2 or more atoms held together by chemical bonds c

chemical bonds

result of how many atoms share electrons

electronegativity

ability of elements to attract electrons (often hydrogen) acquiring partial negative changes in molecules & acquiring partial negative charges in molecules & partial positive charges in hydrogen atoms

covalent bond

sharing electrons between atoms - share 1,2,3, pairs of electrons

types of covalent bonds

polar covalent bond, nonpolar covalent bond

nonpolar covalent bond

equal sharing of electrons in the bond due to equal/similar electronegativity

polar covalent bond

equal sharing due to unequal electronegativity resulting in partial (+) or partial (-) charged regions.

ionic bonds

attraction between ions (charged atom) due to the gain/loss of electrons. based due to highly unequal electronegativity

Vander Waals

short-lived, relatively weak interactions due to e- position & motion. strong in large numbers.

hydrogen bonds

interaction between partial charges formed when H bpnds strongly bond with electronegative atoms (oxygen or nitrogen)

types of bonds strongest —> weakest

covalent bond (nonpolar & polar) —> ionic bond —> Van der Waals interactions —> hydrogen bonds

emergent properties of water

cohesion, adhesion, high-specific heat due to cohesion, expands when frozen, “universal” solvent

cohesion of water

attraction between water molecules. molecules stay together at water-air interface

adhesion

attraction between water molecules & other substances

capillary action

occurs when water molecules are attacted to charges on inner surfaces of narrow tubular structures like glass tubes drawing water molecules to the tubes sides

high-specific heat of water

you need lots of energy to increase heat. high boiling point of water

water expands when frozen

forms crystals w/greater distance betweenn molecules/liquid. each has 4 hydrogen bonds

“universal” solvent - anything polar dissolves in water

hydrophilic: polar, absorbs in water

hydrophobic: non-polar, won’t dissolve in water

organic compounds

carbon + hydrogen or nitrogen or oxygen

hydrocarbons

organic macromolecules consisting entirely of carbon & hydrogen, such as methane. they are nonpolar & uncharged —> ionic!

aliphatic hydrocarbons

hydrocarbons consisting of a linear chain of carbon atoms

aromatic hydrocarbons

hydrocarbon consisting of closed rings of carbon atoms

functional groups

groups of atoms attaching to carbon & replacing hydrogen

names of the functional groups

hydroxyl, carbonyl, carboxyl, amino, phosphate, methyl

hydroxyl

• chemical form: -OH

• consists entirely of carbon & hydrogen

• polar, hydrophillic, found in alcohols

• methane

• does not ionize

carbonyl

• polar

• hydrophillic

• found in sugars

• chemical formula - C=O

• does not ionize

carboxyl

• carbonyl group + hydroxyl group

• acidic

• hydrophillic

• ionizes

• C=O-O-H

amino

• basic

• hydrophillic

• found in amino acids

• ionized form is NH3+

• electron acceptor

• NH2

phosphate

• acidic

• hydrophilic

• found in phospholipids, nucleic acid, ATP, etc.

• release one or 2 H+ when ionized/not-ionized

• Chemical formula: PO4(2-)

macromolecules

large molecules built from smaller organic molecules

polymers

macromolecules made w/chains of monomers using covalent bonds

monomers

identical/similar repeating building blocks of polymers.

dehydration synthesis

reaction that builds larger molecules by removing H20

hydrolysis

reaction that breaks up larger molecules into smaller ones by adding H20 to separate a polymer (H on one side, H0 on the other one)

carbohydrates

polymers of sugars made from CH20 —> carbon + hydrogen + oxygen

used for cell identification

monosaccharides

monomers (usually 3-6 C)

i.e. glucose, galactose, fructose

main function: fuel/structural

end with “-ose”

polysaccharides

polymers made of hundreds to thousands of monosaccharides. monomers connected with glycosidic linkage.

main function: storage & structur

glycosidic linkage

bond formed by a dehydration reaction between 2 monosaccharides by eliminating a water molecule

disaccharide

2 monosaccharides combined by a covalent bond

lipids

diverse, hydrophobic macromolecules, not polymers. non polar.

dissolves in nonpolar solvents

uses ester bonds to build

main functions: store energy, provide insulation, building blocks of hormones

fats

the most abundant lipid. 9 cal/gram. long-term energy

made of glycerol + fatty acids

energy storage

i.e. triglycerides

phospholipids

major pasma membrane constituents comprising a cell’s outermost layers, comprosied of fatty acid chains attached to glycerol/sphingosine backbone.

glycerol + fatty + phosphate

amphipathic

steroids

fused-ring structure, hydrophobic, insoluble

membrane structure & signalling

i.e. cholesterol

protein

the most diverse macromolecules. polymers of amino acids.

amino acids

monomers of proteins that have diverse function but the same fundamental structure. there are 20. connected via peptide bonds (covalent bond between carboxyl & amino groups) resulting in polypeptides

parts of amino acids

central carbon, hydrogen, carboxyl group, amino group, R group/side chain (changes based on the amino acid).

primary structure of protein

amino acids’ unique structure in a polypeptide

secondary structure of proteins

local folding of the polypeptide —> A helix & B helix

part of the backbone - eveyrthing but side chain. H-bonds, localized

tertiary structure of proteins

polypeptide’s unique 3d strcutre. large folds

quaternary structure

interactions between multiple polypeptides

denaturation

process in which proteins/nucleic acids lose their 3-d fold due to external stressors - causing them to unravel or change shape. you can regain function by reversing the condition

functions of proteins

everything but genetics! structure, signalling/communication, enzymes, defense, transport

nucleic acid

DNA/RNA. the most important macromolecule for the continuity of life, they carry the cell’s genetic institutions for its functioning

abiogenesis

appearance of first cells

abiotic synthesis

molecules had to form successfully

steps of abiogenesis

1) abiotic synthesis of monomers

2) formation of organic macromolecules

3) protocell formation

4) appearance of self-replication

conditions for abiogenesis

1) low free oxygen - loves electrons, grabs electrons to break things down

2) e source - solar, radiation, geothermal, hydrothermal, volcanism

3) chemical precursors & lots of time

4) hypotheses - Oparin-Haldane (shallow water & esource = first cell born), Iron Sulfur: life formed AI warm water deep sea vent

Formation of organic macromolecules

form on clay/rock surfaces. facilitated by metal ions (they catalyze polymerization

formation of protocells

occurs spontaneously

vesicle

fluid-filled compartments surrounded by lipid membrane. functions: storagetransport

vesicle membrane can fuse w/plasma membrane or other membranes