biology test #1 material

what are the 6 major characteristics of life (organisms)?

1. are composed of cells

2. growth & development

3. regulate metabolic processes

4. respond to stimuli

5. reproduction

6. populations evolve & become adapted to their environment

what is a unicellular life form?

a life form that consist of a single cell

what is a multicellular life form?

a life form that depends on functions of multiple cell that are organized to from tissues, organs / organ systems

what is a prokaryotic cell?

a cell that is exclusive to bacteria & archaea, has simple structures, no nucleus or other membrane organelles

what is a eukaryotic cell?

a cell that contains a variety of organelles w/ a nucleus enclose by membranes

what is biological growth?

an increase in the size of individual cells, number of cells, or both of an organism that includes all changes during an organism’s life

what is metabolism?

chemical activities in an organism like chemical reactions that are essential to nutrition, growth & repair, conversion of energy

metabolic processes are regulated to maintain what?

homeostasis

what is homeostasis?

a balanced internal environment

what is the difference between asexual & sexual reproduction?

• asexual reproduction - offspring that has the same genes as a single parent (variations occur only by mutations)

• sexual reproduction - offspring are produced by fusion of egg & sperm (genes typically contributed by 2 parents)

what are the major levels of biological organization that pertain to organism organization?

1. chemical level

2. cellular level

3. tissue level

4. organ level

5. organ system level

6. organism level

what are the steps of the scientific method?

• observations

• questions

• hypothesis

• predictions that can be tested

• experiments that can be analyzed

• come to a conclusion

how does the scientific method determine the types of questions that scientists ask?

scientists take work done by others and use these steps to help further their research

what is deductive reasoning?

supplied info (premises) & draws conclusions based on info comes from general principles to specific conclusions that help w/ discovering relationships among known facts

what is inductive reasoning?

specific observations & draws a conclusions or general principle that organizes data into categories like conclusions like generalize facts to all possible examples

what is a hypothesis?

an explanation for observations or phenomena

what are the characteristics of a good hypothesis?

1. consistent w/ well established facts

2. capable of being tested, & test results are repeated by independent observers

3. it’s falsifiable (can be proven false)

what are the components of a controlled experiment?

making predictions (deductive, logical consequences of a hypothesis) that can be tested controlled experiments where experimental groups differ from control groups only w/ respect to the variable studied

what is an experimental group?

a group that DOES receive the change or independent variable being tested

what is a control group?

a group that DOESN’T receives the change or independent variable being tested

what sorts of steps can an investigator take to strengthen a hypothesis?

• experiments must be repeatable by other scientists (avoid sampling error)

• researchers must try to avoid bias or preconceived ideas of what should happen

what is a scientific theory?

an integrated explanation of some aspects of the natural world which is based on the number of hypotheses, each supported by consistent results from many observations or experiments by showing relationships among classes of facts which clarifies our understanding of the natural world (explains what)

what is scientific law?

a generalization of a body of observations to which no exception have been bound to explain things, but doesn’t describe time in the manner (explains how)

what is a paradigm?

a set of assumptions or concepts that constitute a way of thinking about reality

what is a paradigm shift?

the changing of their view of reality to accommodate new knowledge

what is an atom?

the smallest portion of an element that retains its chemical properties

what is an element?

a substance that cannot be broken down into a simpler substance by ordinary chemical reactions (the letters on an element square)

what is an atomic number?

the number of protons found in an atom (on the top row of an element square)

what is atomic mass?

the number of protons & neutrons (at the bottom of an element square, calculated in amu)

what is a valence electron?

the electrons farthest from the nucleus that generally have greater energy

what is an electron?

light, negatively (-) charged particles that move around in energy levels (orbitals) surrounding the atomic nucleus

• the smallest of the subatomic particles by 1800x

what is a proton?

heavy, positively (+) charged particle located in the atomic nucleus

what is a neutron?

heavy, uncharged particle located in the atomic nucleus

which particle participates in chemical bond formation?

electrons

what is a chemical compound?

formed when two or more atoms are joined in a fixed ratio through any type of chemical bonding

what is a molecule?

formed when two or more atoms are strongly joined in a fixed ratio through covalent bonding

what is a chemical formula?

describes the types & numbers (subscripts) of atoms present in a compound

• H2O

what is a structural formula?

describes how the atoms of a compound are arranged in space

• O-H-O

what characteristic(s) of an atom determine how it will interact with other atoms and the types of bonds it will form?

• valence electrons

• electronegativity

• chemical equations

what leads to the formation of ions from uncharged atoms?

the atoms (ions) gained or loss

what is an cation?

an ion formed when atoms w/ 1,2,or 3 valence electrons lose electrons to other atoms & become positively charged (+)

what is an anion?

an ion formed when atoms w/ 5,6,or 7 valence electrons gain electrons to other atoms & become negatively charged (-)

what is a covalent bond?

a bond formed when atoms share electrons to form molecules (they are the strongest)

what is an ionic bond?

a bond formed when one atom gives up electrons to another atom (they are strong & dissolve in water)

ionic compounds do what?

they are (solutes) that dissolve in water (solvent)

what is a hydrogen bond?

a bond formed when a slightly negatively charged atom in one polar molecule w/ a hydrogen bound to an electronegative atom in another molecule (these bonds are weak & results in uneven charge distribution)

what is a van der waals interaction?

are temporary interactions resulting from the movement of electrons in different atoms that are close to each other (the weakest & no longer called a bond)

what are the properties of water?

• cohesive : water molecules stick to each other

• adhesive : water molecules stick to other substances

water dissolves what kind of compounds?

polar water molecules dissolves hydrophilic compounds, but not hydrophobic compounds

what does hydrophilic mean?

• ”water-loving”— interact easily with water

  • polar and ionic compounds are hydrophilic

what does hydrophobic mean?

• “water-fearing”— not soluble in water

  • non-polar compounds are hydrophobic

what are the properties of carbon that contribute to its central role in the formation of organic compounds?

• a hydrocarbon backbone (chains or rings)

• can complete its valence shell by forming a total of four covalent bonds

• bonds are strong & not easily broken (but can be)

• produce a variety of 3D shapes

• permit freedom of rotation, allowing organic molecules to be flexible

what is an isomer?

molecules with the same molecular formula but different structures

what is a structural isomer?

compounds that differ in covalent arrangements of atoms that usually large compounds that differ in the covalent arrangement of their atoms

what is a geometric isomer?

compounds identical in arrangement of covalent bonds but different in space that often contain double or triple C-C bonds or carbon rings

• can be cis (on the side) or trans (across)

what is an enantiomer?

isomers that are mirror images of each other

• the central carbon is asymmetrical b/c it’s bonded to four different groups b/c of their 3D structure

be able to recognize the types of functional groups.

check slides

what is a macromolecule?

organic molecules that are made of thousands of atoms

what is a monomer?

a small, single molecule that links together w/ other monomers to make a polymer

what is a polymer?

chemical substances made of repeating monomers

what is hydrolysis?

the disconnection of 2 monomers

what is condensation / dehydration?

the joining of 2 monomers

what are the characteristics of a carbohydrate?

• a polysaccharide monomer

• joined together by glycosidic bonds

what are the types of carbohydrates?

• starch - energy in plants

• glycogen - energy storage in animals

• cellulose - most abundant carb that is a polysacc in plants

what are the characteristics of a lipid?

• not “true” polymers : no repeating monomer units

• contain fatty acids - long, unbranched hydrocarbon chains w/ a carboxyl group @ one end

what are the different types of fatty acids (FAs) ?

• saturated - contain the maximum number of hydrogen atoms, solid @ room temp.

• unsaturated - includes 1+ pairs of carbon atoms joined by a double bond, liquid @ room temp.

what are triglycerides (TGs) ?

a glycerol molecule + 3 (FAs) that are linked by ester linkages

what is a phospholipid?

a glycerol molecule + 2 FAs + a phosphate group attached to an organic molecule w/ the basic components of cell membranes

what is a sterol?

a structure that contains 4 rings

• ex: bile salts, reproductive hormones

what is a protein?

• a diverse group of molecules made of amino acids that are liked through a peptide bonds

• monomer, dipolar ions

what is an amino acid?

a carbon bound to a hydrogen, amino group, carboxyl group, & a side chain that react w/ the amino group which causes the release of a H2O molecule & the formation of a covalent bond

what are the 4 protein structures?

• primary

• secondary

• tertiary

• quaternary

what is a primary protein structure?

the sequence of amino acids in a polypeptide chain that are specified by instructions in a gene

what is a peptide bond?

covalent carbon-to-nitrogen bonds that link amino acids together to form a chain

what is a secondary protein structure?

results from hydrogen bonds between different amino acids within a small region of the polypeptide chain backbone

• α–helix (helical coil)

  • H bonds

  • basic structural unit of fibrous, elastic proteins

• β-pleated sheet

  • H bonds

  • proteins are strong and flexible, but not elastic

what is a tertiary protein structure?

determines the overall 3-D shape of a polypeptide chain that results from interactions among R groups of amino acids within different areas of the same polypeptide chain

what are the four factors in a tertiary structure?

• hydrogen bonds

• ionic bonds

• hydrophobic interactions

• disulfide bridges (strong covalent bonds between sulfhydryl groups of two cysteines)

what is a quaternary protein structure?

a 3-D structure resulting from two or more different polypeptide chains interacting in specific ways to form a biologically active molecule

• only some proteins have this structure

what are the primary functions of a protein?

• enzymes

• strength

• protection

• transport

• motility

• regulation

what are the characteristics of a nucleic acids?

• nucleotides formed by (phosphodiester linkages : phosphate group + covalent bonds that attach it to sugars of adjacent nucleotide)

what 3 parts are nucleotides made of?

• a five-carbon sugar, either deoxyribose (in DNA) or ribose (in RNA)

• one or more phosphate groups

• a nitrogenous base (nitrogen-containing ring compound)

  • some nucleotides have ATP

what is a nitrogenous base?

a base that may be either a double-ring purine or a single-ring pyrimidine

DNA contains?

• four nitrogenous bases:

  • two purines: adenine (A) & guanine (G)

  • two pyrimidines: cytosine (C) & thymine (T)

• consist of 2 nucleotide chains held tgh by hyrdogen bonds in a double helix

• contains instructions for making proteins & RNA

RNA contains?

• four nitrogenous bases:

  • two purines: adenine (A) & guanine (G)

  • two pyrimidines: cytosine (C) & uracil (U)

• usually composed of one nucleotide chain

• used in processes that link amino acids form polypeptides

what is a purine?

a nine-membered large double-ring structure containing four nitrogen atoms

what is a pyrimidine?

a six-membered smaller single-ring structure containing two nitrogen atoms

what is a monosacc?

a single sugar ring or chain that can’t be broken into smaller sugars (very sweet in taste, dissolves easily in water)

• ex: glucose (blood sugar), frutose (fruit sugar), & galactose

what is a disacc?

a two monosaccharides joined together by a chemical glycosidic bond (sweet in taste, dissolves easily in water)

• ex: sucrose, lactose, & maltose

what is a polysacc?

made of three or more monosaccharide units linked in long chains (doesn’t dissolve in water, used to store energy/physical structure in living things)

• ex: starch, glycogen, cellulose

why do phospholipids form bilayers in water environments?

• their molecules have:

  • a strongly hydrophobic region and a strong hydrophilic heads that hydrogen bond to one another

  • their cylindrical shapes that allow them to associate with water most easily as a bilayer

what characteristics of phospholipids make them amphipathic molecules?

• they have amphipathic molecules with distinct hydrophobic & hydrophilic regions

• the two fatty acid chains make up the non-polar, hydrophobic “tail” of the lipid

• the fatty acid tails are bonded to a charged, hydrophilic phosphate group linked to a polar, hydrophilic organic group

what types of molecules make up biological membranes?

the fluid mosaic model shows cell membrane is a fluid lipid bilayer w/ a constantly changing “mosaic pattern” of associated proteins that are ever-changing configuration of molecules embedded in membrane

membranes are primarily comprised of ?

• phospholipids

• proteins

• sterols (cholesterol)

• carbohydrates

what are the types of membrane proteins?

• integral membrane proteins

• transmembrane proteins

• peripheral membrane proteins

what are integral membrane proteins?

amphipathic proteins that span a portion of the bilayer

what are transmembrane proteins?

integral proteins that extend completely through the membrane

what are peripheral membrane proteins?

located on the inner or outer surface of the plasma membrane, usually bound to exposed regions of integral proteins; not embedded in the lipid bilayer

biological membranes are selectively what?

permeable

what are the characteristics of biological membranes?

• allow some, but not all, substances to pass through them

• a membrane may block a particular substance at one time and actively promote its passage at another time

  • a cell controls its volume and its internal ionic and molecular composition

what happens when a membrane has selective permeability?

• biological membranes are most permeable to small non-polar (hydrophobic) molecules

  • ex: O2, CO2

• despite their polarity, H2O molecules are small enough to pass through gaps in the lipid bilayer & slowly cross the membrane

• the lipid bilayer is relatively impermeable to charged ions & most large polar molecules

  • transport proteins move ions, amino acids, sugars, and other needed polar molecules through membranes