Ch 1-3 Flashcards
the study of life; “bios” = life
characteristics of life
- living organisms reproduce
- living organisms grow and develop
- organisms process energy
- regulation
- organisms interact
- composed of cells
- evolutionary adaptation
Living organisms reproduce
they produce copies of themselves; pass on genetic information to the future
Living organisms grow and develop
growth and development
growth
increase in size and number
development
change during life cycle (infant-child-adolescent-adult)
organisms process energy
allliving organisms live at the expense of their environment; they must extract energy and materials from the environment; convert energy from another source (ex: plants from sun and animals from food they eat)
regulation
organisms maintain their interval environment within limits that sustain life; ex: sweating, jackrabbit has blood vessel in ears to maintain body temp.; have to eat right food, balanced pH
organisms interact
interact with one another and their environment, responding to stimuli (ex: venus fly trap)
composed of cells
order; all living things exhibit complex organization
evolutionary adaptaino
over many generations, individuals with inheritied traits best suited to their local environment tend to pass these traits on to their offspring
“to know”; science is a way of knowing (one way, not the only way)
is to better understand the natural world; looking for empirical evidence; supernatural is outside of the realm of science
to approaches to science
- discovery science
2. scientific method
discovery science
- verifiable observations and measurements
- describe life in a variety of ways
- aka “descriptive science”
- looks at physical characteristics (what we see, hear, smell, taste, and feel)
- observe behaviors
- dissections
scientific method
- formal process of inquiry
- series of steps
- begins with observations (discovery science)
- asks questions and seek answers (forms hypothesis)
scientific hypothesis
- a proposition that can be tested by careful observation or experiment (more than an educated guess)
- “if ___ occurs, then ___ will result”
- has to be potentially falsifiable which means it has to be able to be proven false
- controlled experiment
with a control group, only one variable changed in each ofthe experimental groups; not always possible for practical and ethical reasons (es: global warming and testing drugs on children)
results of the scientific method
- scientists do not tend to prove hypothesis, but support hypothesis with evidence
- lots of evidence in support is considered “proof”
- if the tests supports the hypothesis, move on to another question
- if test does not support the thesis go back and provide another hypothesis to explain it
scientific fact
an observation that has been repeatedly confirmed and for all practical purposes is accepted as true (ex: cells have membranes, egg and sperm contain DNA)
Scientific Theory
a well substantiated explanation for some aspect of the natural that can incorporate facts, laws, inferences and tested hypothesis (ex: theory of evolution); lot of evidence behind it;
science is not set in stone
- understandings can change as we learn more
- the body of knowledge grows and science adapts to this new knowledge
- science can change (# of planets changes, we can’t entirely stop disease with antibiotics because bacteria evolves extremely fast)
science tends to be self-correcting
- scientists publish their findings in “peer-reviewed” journals and conferences
- other scientists repeat their procedures to see if they get the same results and come to the same conclusions
- over time, incorrect conclusions will usually be corrected
strengths of science
- scientists strive to be free of bias and coercion in order to obtain objective answers and results
- use controlled experiments when possible]
- findings are reported in peer-reviewed journals with methods and results (helps for replication and self-correcting)
limitations of science
- it isn’t always possible to do controlled experiments for practical and ethical reasons (climate change, testing drugs on kids)
- science is reductive (looks at ever smaller parts, separate from the whole so it may not give an accurate picture of how the parts function within the whole)
- the objective, value-free approach of good science cannot determine if something is good/bad, ethical/unethical, and cannot answers about the spiritual/supernatural (basically, it is only one facet of knowledge)
binomial nomenclature
- scientific names (2 names)
- italicized
- genus and species
genus
begins with a capital letter (first word)
species
begins with a lower case letter (second word)
common name
both names are capitalized
three domains
domain bacteria
domain archaea
domain eukarya
domain bacteria
- prokaryotic
- unicelular
- no nucleus
- some (not all) cause disease
domain archaea
- prokaryotic
- unicellular
- do not cause disease
- some can do photosythesis
- some can live in extreme environments (hot, salty, acidic…)
Domain eukarya
- eukaryotic
- some multi and some unicellular
- 4 kingdoms
Domain Eukarya Kingdoms
kingdoms…Protista, plantae, fungi, and animalia
Kingdom protista
- protists
- eukaryotic
- unicellular
- more complex and larger than bacteria and archaea
- some are photsynthetic
Kindom Plantae
- plants
- eukaryotic
- multicellular
- photosynthetic
Kingdom Fungi
- eukaryotic
- most are multicellular
- do not photosynthesis
- decomposers (live off dead things)
Kingdom Animalia
- animals
- eukaryotic
- multicellular
energy flows
- almost all energy on the earth comes from the sun
- some energy can be used to do work but much of the rest is lost as heat
- energy has to be continually brought into a system
- slows in and out of a system
- once you use it, its gone (reason we have to eat everyday)
chemicals cycle`
- chemicals are used over and over again
- nature recycles (to be sustainable on this planet we need to learn how to recycle almost everything)
elements that make up 96.3% of our body weight
- oxygen
- carbon
- hydrogen
- nitrogen
fifith element need in molecules of life
- phosphorus
molecules of life
- water (O & H)
- carbohydrates (O,H,C)
- lipids or fats (O,H,C)
- Proteins (O,H,C,N)
- nucleic acids or DNA (O,H, C,N, P)
submicroscopic units of matter, smalles unit of all physical materials; molecules are made up of atoms
Proton
- located in nucleus
- one unit positive charge (+)
Neutrons
- located in nucleus
- no charge
electrons
- revolve around nucleus in shells (shells are energy levels)
- one unit negative charge
- shell closest to nucleus holds 2 electrons; second and third shells hold 8 electrons
atomic number
determined by the number of protons (whereas mass number is the combined number of protons and neutrons)
what does the atomic number tell us?
of protons
what does the mass number tells us?
of protons and neutrons
isotopes
have the same number of protons and electrons but different number of neutrons; can be dangerous because some are radio active (nucleus decays, giving off particles and energy); living cells cannot distinguish between radioactive and non-radioactive elements so they take up both and use them (used in carbon dating and medicine)
Danger of isotopes
- uncontrolled exposure to large doses can damage molecules, especially DNA
- it does this by breaking chemical bonds and reforming abnormal bonds
- can cause cancer and other diseases
outer electron shell
number of electrons in outermost shell determines the chemical properties of atom; atoms are considered reactive when their outermost shell is incomplete (these openings are the place where bonds form); atoms bond to fill up their outer shell
unfilled spaces in atoms?
they are the places where atoms can bond to fill up the outer shells; the place where bonds form
ionic bonds
form ionic compounds; ions are atoms or molecules with a positive or negative charge; attractions between ions of opposite charges (ex: NaCl); ionic compounds are held together by attraction of opposite charges
covalent bonds
form molecules; share electrons; share one or more electrons to complete their outermost shell; ability to single bond (H2) and double bond (02); ex: water, carbohydrates, lipids, proteins, nucleic acid
ions
atoms/molecules with a positive or negative charge
what causes the attraction of ions?
the attractions between ions of opposite charge (one negative and one positive)
% of earth’s water is freshwater
less than 3%
% of freshwater available to us
0.5%
what causes water to be a polar molecule?
- water is held together by covalent bonds
- oxygen atoms pulls the 10 electrons much more strongly than the hydrogen atoms so they don’t share the electrons equally
- the electrons spend more time around the oxygen nucleus than around the hydrogen nucleus
- since electrons have a negative charge, the oxygen side pole is slightly negative and the hydrogen side is slightly positive
hydrogen bonds
form between water molecules as they align themselves by opposite charges (oxygen pole which is negative aligns up with the hydrogen pole which is positive of another molecule
hydrogen bond vs. ionic and covalent bond
- hydrogen bonds form a weak bond that is not as strong as ionic bonds, they are much less than a unit of charge
- water stays bonded for only a fraction of a second, but at any given moment, many are bonded
four qualities of water that make it unique
water reacts differently than most other molecules
- liquid water is cohesive
- ice floats
- water moderates temperatures
- water is the universal solvent
liquid water is cohesive
- cohesion- stick together
- hydrogen bonds cause water molecules to stick together and pull each other along
- ex: moving water up trees and other plants
ex: surface tension; water bug on top of water
ice floats
- ice is less dense than liquid water
- when water freezes, hydrogen bonds form between 100% of the molecules, pushing the molecules apart so there is more space between molecules
- lattice like structure
- becomes less dense and thus lighter than liquid water
- vary rare (most substances become more dense as they get cold)
- less dense b/c water molecules are farther apart
water moderates temperatures
- water gains and loses heat slowly***
- the hydrogen bonds must first be broken in order for water to evaporate when heated causing water to heat up slowly
- when water cools the opposite happens; hydrogen bonds have to reform causing water to cool down slowly
- favorable for aquatic life in coastal areas and lakes because the water changes temperature slowly giving organisms time to adapt
- water moderates temp. changes in cells
- evaporative cooling (sweat)
water is the universal solvent
- many materials dissolve in water
- helps materials to move around in cells
- breaks materials down to their components
acids
chemicals that increase the concentration (relative number) of H+ ions; ex - hydrochloric acid in our stomachs
bases
chemicals that increase the concentration of OH- ions; ex - ammonia, household bleach
pH represents…
- each pH unit represents a 10fold change in concentration
- you multiply by 10 (from 1-2,2-3…)
acid precipitation
when water has a pH below 5.6
at what temperature is water most dense?
4 degrees celsius/ 39.2 degrees F
pH biological range
- 7 = neutral
- 6.5 to 8.2 = biological range
pH of pure water
7
Cause of acid precipitation
sulfur and nitrogen oxides, mostly from burning fossil fuels (coal, oil, gasoline)
electron shells
energy levels
nucleus
contains the protons and neutrons; center of atom
bohrs model
know carbon has 4 openings, nitrogen has 3 openings, and oxygen has 2 openings; count the openings in the outer shell and that will give you the answer
similarity b/t ionic and covalent bonds
they bond atoms together
hydrogen bond
bond between water molecules
Where is most of the energy stored in hydrocarbons, carbohydrates and fats
- between the carbon and the hydrogen
- much of the energy stored in organic molecules is stored in these carbon-hydrogen bonds
- this energy is released when the bonds are broken (much of the energy is released as heats)
what is the monosaccharide in fruit
fructose
what are two differences between hydro carbons and carbohydrates?
- all carbohydrates have oxygen in them; hydrocarbons do not
- difference in use, carbohydrates are used for power fuel;
protein structures
primary structure (unique sequence of amino acids, different for each protein); secondary structure (interactions caused by hydrogen bonds); tertiary structure (proteins automatically go into its three dimensional shape as they are being formed in water, no additional energy needed) – 3d shape determines the function of the protein
how many monomers
20 different possibilities
what are two forces that causes proteins to self construct into their three dimensional shape?
hydrogen bonds; hydrophobic/hydrophilic interactions
why is carbon so important for building these organic molecules?
-it can bond in all four directions; you can make all different structures and complexities
what is the difference b/t saturated and unsaturated fats?
- saturated fat is the fatty acids filled with the maximum number of hydrogen atoms on the carbon chain; packs tightly
- unsaturated fat is the fatty acid with less than the maximum of hydrogen atoms on the carbon chain (b/c of double bond) (healthier than saturated)
at room temperature, ___ is ___
saturated fat; solid
polyunsaturated fat
can’t pack tightly together; become liquids at room temperature
“partially hydrogenated oils”
trans fats are present in that food
components of nucleic acids
sugar, phosphate group, nitrogenous base
what forms the backbone of DNA
sugar and phosphate; bases form the bond across
monomers
monosaccharides (carbohydrates), amino acids (protein), nucleotides (nucleic acids)
polymers
polysaccharides (carbohydrates), proteins, nucleic acids
organic molecules that are essential to life
- carbohydrates
- lipids
- proteins
4 nucleic acid
importance of carbon
- carbon can form bonds in four directions
- forms the backbone for all the macromolecules of life
- present in each of the four organic molecules/all have carbon backbones
hydrocarbon
the most simple carbon molecules; made up of hydrogen and carbon only
macromolecules =
organic molecules
polymers
molecules built by linking together a large number of subunits
monomers
the subunits
carbohydrates
- range from small sugars to large polysaccharides
- CHO
- fuel for our bodies (our primary source of energy)
- saccharide
- polar like water
- hydrophilic
monosaccharide
- carbohydrate
- single sugar (monomer)
- glucose
- 3 to 7 carbons long
names of sugars end in ___
ose
disaccharide
- carbohydrate
- two sugar monomers bound together
disaccharide examples
sucrose (sugar), lactose (milk),maltose (beer)
monosaccharide examples
-glucose (plants), fructose (fruit), galactose
polysaccharide
polymers of a few hundred to a few thousand monosaccharides long
polysaccharide examples
starch (food, grains, potatos), glycogen (muscle cells), cellulose (wood, plant cell walls)
hydrophilic molecules
attracted to water
carbohydrates are hydrophilic
- small molecules will dissolve in water (sugar, flour, corn starch)
- large molecules do not dissolve but attract water (wood and cotton)
lipids
diverse compounds that consist mainly of carbon and hydrogen with some oxygen
- no monomers or polymers
- nonpolar
- do not mix with water
- hydrophobic
- ex: fats and oils
hydrophobic
wants to get away from water
fats are made up of…
fatty acid
s
triglceride
three fatty acids linked to glycerol (another name for fat)
fatty acidd
C=O group plus a hydrocarbon
with what are saturated fats saturated with?
hydrogen
why are some fats solid at room temperature adn other liquid?
saturated fats pack tightly and are therefore solid whereas polyunsaturated fats can’t pack tightly so the become liquid at room temperature
trans fats
unsaturated fats that have been partially hydrogenated (hydrogen atoms added)
no kink
look for the line “partially hydrogenated oils”
very unhealthy for you
Protein
- made up of COHN
- the polymers are called proteins
- monomers = amino acids
- unique 3d structure
protein stuctures
primary, secondary, tertiary
primary structure
- unique sequence of amino acids
- different for each protein
secondary structure
-interactions caused by hydrogen bonds
tertiary structure
-proteins automatically go into its 3d shape as they are being formed in water; shape determines function of proteins; happens by itself in water solution
reasoning behind tertiary structure
- hydrogen bonds
- hydrophobic/philic interactinos
- other reactions.
nucleic acids
information storage in cells, COHNP; DNA; RNA
monomers of nucleic acid
nucleotide
components of nucleotide
sugar, phosphate group, nitrogenous base (sugar and phospate bond to form backbone and nitrogenous base extends out from backbone)
major classes of protein
- contractile (muscles)
- structural (hair, tendons)
- signaling (messages within cells)
- enzymes (increase rate of reaction in cells)
how many monomers are in protein?
proteins are made up of 20 amino acid monomers
