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biology-keystones

QuestionAnswer
unlike prokaryotic cells, eukaryotic cells have the capacity to... assemble into multi-cellular organisms
why is water a polar molecule? because the oxygen side is slightly negative and the hydrogen side is slightly positive
cohesion -water tends to stick together ex. droplets of dew on grass
surface tension -the top layer of water is very strong ex. insects can walk on water
adhesion -water tends to stick to OTHER things ex. water sticks to glass after washing
capillary action -movement of water against gravity ex. allows water to rise up narrow tubes in plant stems
high specific heat -water is able to resist changes in temperature ex. helps organisms retain body heat and resist freezing in cold temps.
universal solvent -water can dissolve many things ex. putting sugar in tea
density -the degree of compactness of a substance ex. ice is less dense than liquid water
covalently bonding chemical bond between atoms that results from the sharing of a pair of electrons
dehydration synthesis -monomers are joined together -form water molecules
hydrolysis -polymers are broken down into monomers -use water molecules -splitting of a covalent bond by the addition of water
what are carbohydrates composed of? carbon, hydrogen, and oxygen
what are lipids composed of? carbon, hydrogen, and a little oxygen
what are proteins composed of? carbon, hydrogen, nitrogen, oxygen, and sometimes sulfur
what are nucleic acids composed of? carbon, hydrogen, oxygen, phosphorous, nitrogen, sulfer
carbohydrates include... polysaccharides
polysaccharides contain... disaccharides
disaccharides are composed of two... monosaccharides
lipids include... triglycerides
triglycerides are composed of... fatty acids and glycerol
proteins are composed of... peptides
peptides are composed of... amino acids
nucleic acids include... RNA and DNA
RNA and DNA are composed of... nucleotides
high-energy compounds include... ATP
ATP is composed of... nucleotides and phosphate groups
where is ATP's energy located? the phosphate group
why carbon? -second most abundant element in living organisms -establishes covalent bonds -can share four electrons, therefore it can bond to four additional atoms -have strength, flexibility and can chemically react to other atoms
how does carbon's ability to form bonds make it uniquely suited to form macromolecules? it forms covalent bonds with other carbon atoms
what is the ratio of carbon, hydrogen, and oxygen atoms in a carbohydrate? 1:2:1
monosaccharide one sugar unit
oligosaccharide a short chain of two or more covalently bonded sugar units
polysaccharide a straight or branched chain of sugar units in which there may be hundreds or thousands of the same or different kinds of sugar bonded to one another
what is the structure of a nucleic acid? -five carbon sugar -nitrogen-containing base -phosphate group
why do cells develop metabolic pathways? to maintain, increase, and decrease the concentration of substances
metabolic pathways orderly sequence of reactions with specific enzymes that act at each step along the way
enzymes -catalytic molecules -speed up specific reactions without being used up in the reaction
what 3 special features do all enzymes have in common? 1. do not create processes that would not take place on their own 2. are not permanently altered or used up in reactions 3. catalyzes only one specific type of reaction but can catalyze many of this particular reaction one after another`
substrates molecules that a specific enzyme can chemically recognize and to which it can bind
products substrates that undergo chemical changes to form new substances
lock-and-key mechanism (enzymes) -once the enzyme-substrate is together, the enzyme holds the substrate in a position where the reaction can occur -once the reaction is complete, the enzyme unlocks the product and the enzyme is free to facilitate another reaction
enzyme rate of reaction -the rate of reaction depends in part on the concentration of the enzyme -if the enzyme is diluted, its concentration is lowered, which slows the reaction rate
activation energy -the energy substrates must collide with in order to reach the transition state
enzyme activity of food spoilage bacteria -the enzyme activity is greatly reduced at typical food refrigeration temps -the rate of reproduction is decreased at low temps -typical refrigeration temps are not low enough to kill bacteria
when are enzymes denatured? high temperatures
alcoholic fermentation -makes alcohol and CO2 as byproducts -creates no ATP
lactic acid fermentation -makes lactic acid as the byproduct -creates no ATP
phosphorylation when the appropriate enzyme is present, the terminal phosphate group of an ATP molecule can be transferred to a variety of other compounds
what is the equation for photosynthesis? 6CO2+6H20+sun energy=C6H12O6+602
what are the main reactions of photosynthesis? light reactions, calvin cycle
light reaction -takes place in chloroplasts -light is absorbed by chlorophyll, which uses the energy to split water -oxygen is released to the outside of the cell -"H" part of H2O is carried to the dark reactions with NADPH
calvin cycle -takes place in the stroma -CO2 from the hair combines with hydrogen from the light reaction to form simple sugars
stroma -gel-like matrix -contains the ribosomes, DNA, and material foe carbohydrate synthesis
grana -stacks of flattened sacs -contains thylakoids
thylakoids where light-reactions take place
what is the equation for cellular respiration? C6H12O6+6O2=6CO2+6H20+energy
glycolysis -takes place in the cytoplasm -anaerobic process -glucose enters a cell by active transport -glucose is broken down by enzymes into pyruvic acid -produces 2 ATP
Krebs cycle -takes place in the mitochondria -breaks down products of glycolysis -releases 2 ATP and CO2 main function is to move high energy electrons to molecules for the electron transport chain
electron transport chain -takes place in and across the inner membrane of the mitochondria -high energy electrons travel through the proteins and make 34 ATP -releases CO2 and H20
what is released after each step? glucose-->pyruvic acid-->NADH + FADH2-->CO2, H20, 38 ATP
in glycolysis, ATP molecules are produced. what is the net gain of ATP molecules (per molecule of glucose) from glycolysis? 2
ions atom or group of atoms carrying a positive or negative charge
carrier protein protein molecule that combines with a substance and transports it through the plasma membrane
osmosis movement of water from an area of higher concentration of water to an area of lower concentration of water across a differentially permeable membrane
diffusion movement of molecules from a region of higher concentration to a region of lower concentration
hypertonic solution that has a higher concentration of solute and a lower concentration of water
hypotonic solution that has a lower concentration of solute and a higher concentration of water
facilitated diffusion occurs when a carrier molecule embedded in the cell membrane transports a substance across the membrane by means of diffusion
sodium-potassium pump -transport protein in the plasma membrane that moves sodium ions out of and potassium ions into animal cells -important in nerve and muscle cells
endocytosis a process in which a cell surrounds and takes in material from its environment
exocytosis a process by which a cell surrounds and removes materials from inside the cell
bio, logy, cyto, osis meanings -bio=life -logy=study of -cyto=cell -osis=process or action
which molecule provides the greatest amount of energy per gram of mass when metabolized? lipids
what environment change can cause an increase in the rates of chemical reactions in cells? increased temperature -enzymes in organisms must be at the appropriate temp to function -enzymes will work more rapidly as temps increase, until they reach temps at which they become denatured`
what will happen if enzyme concentrations are decreased? -there would be fewer available enzyme molecules to combine with substrate molecules -rate of reaction would decrease -each substrate molecule would have to wait for an enzyme to be freed up after catalyzing a reaction
what will happen if the activation energy was increased? the reaction would be slower because more energy would be required for the reaction to take place
what will happen if the diffusion rates were decreased? decreasing the rate of diffusion of water into and out of the cell would have little effect on the rate of reaction catalyzed by enzyes
what is the purpose of mitosis? -cell growth -repair and replacement of damaged cell parts -asexual reproduction
interphase (mitosis) 1. cell matures and carries on normal activities 2. DNA copied and appears as chromatin 3. nucleolus visible
prophase (mitosis) 1. chromosomes condense and become visible 2. centrioles separate and spindle starts forming 3. spindle forms with aster at each pole 4. nuclear membrane and nucleolus disintegrate 5. centromere of chromosomes attaches to spindle fibers
metaphase (mitosis) 1. chromosomes line up at the equator of the cell attached to kinetochore fibers of spindle
anaphase (mitosis) 1. centromeres split apart 2. homologs move to opposite poles of cell
telophase (mitosis) 1. nuclear membrane forms at each end of cell around the chromosomes 2. nucleolus reforms 3. chromosomes become less tightly coiled and appear as chromatin again 4. cytokinesis begins
cytokinesis (mitosis) 1. cytoplasm of the cell and its organelles separate into 2 new daughter cells
what is the purpose of meiosis? -only occurs in the testes and ovaries -"reduction division": reduces the number of chromosomes to half the normal number so that when fusion of sperm and egg occurs, the baby will have the correct number -PRODUCE GAMETES
what is a cell that undergoes Meiosis 1 called? a primary spermatocyte or oocyte
prophase 1 (meiosis) 1. chromosomes coil tightly and are visible 2. nuclear membrane and nucleolus disintegrate 3. spindle forms 4. synapsis (joining) of homologous chromosomes occurs making tetrads 5. chromosomes in tetrad exchange fragments (crossing over)
metaphase 1 (meiosis) 1. tetrads become aligned in the center of the cell attached to spindle fibers
anaphase 1 (meiosis) 1. homologous chromosomes separate
telophase 1 (meiosis) 1. nuclear membrane forms at each end of the cell around the chromosome 2. chromosomes become less tightly coiled and appear as chromatin again
cytokinesis (meiosis) 1. splits cytoplasm producing 2 cells
prophase 2 (meiosis) 1. DNA is not copied before the cell divides 2. chromosomes condense and become visible
metaphase 2 (meiosis) 1. chromosomes become aligned in the center of the cell attached to spindle fibers
anaphase 2 (meiosis) 1. sister chromatids separate randomly (independent assortment)
telophase 2 (meiosis) 1. nuclear membrane forms at each end of the cell around the chromosomes 2. nucleolus reform 3. chromosomes become less tightly coiled and appear as chromatin again
cytokinesis (meiosis) 1. cytoplasm divides producing 4 cells in males called spermatids 2. spermatids mature and form flagellum to become sperm 3. cytokinesis in females produces an ootid 4. ootids mature to become ovum or egg
meiosis/mitosis type of reproduction meiosis: sexual mitosis: asexual
meiosis/mitosis occurs in meiosis: humans, animals, plants, fungi mitosis: all organisms
meiosis/mitosis genetically meiosis: different mitosis: identical
meiosis/mitosis crossing over meiosis: yes, mixing of chromosomes can occur mitosis: no, crossing over cannot occur
meiosis/mitosis pairing of homologues meiosis: yes mitosis: no
meiosis/mitosis meiosis/mitosis number of divisions meiosis: 2 mitosis: 1
meiosis/mitosis number of daughter cells meiosis: 4 mitosis: 2
meiosis/mitosis chromosome number meiosis: reduced by half mitosis: remains the same
meiosis/mitosis creates meiosis: makes sex cells, eggs and sperm mitosis: makes everything other than sex cells
in order for new cells to pass on the genetic code... DNA must be copied inside of cells
where does replication take place in eukaryotic cells? nucleus
where does replication take place in prokaryotic cells? cytoplasm
replication 1. the double helix is opened up by breaking the weak hydrogen bonds 2. an enzyme (DNA polymerase) comes in and adds new bases to the open strand 3. at the end, two identical strands of DNA are formed
messenger RNA carries the transcripted message fro DN to he ribosome to make proteins
ribosomal RNA a component of the ribosome and the site of protein synthesis
transfer DNA brings the amino acids to the ribosome for protein synthesis
what is DNA composed of? -five-carbon sugar -nitrogenous base -phosphate group
DNA how many rings are purines? 2
how many rings are pyrimidines? 1
how many hydrogen bonds are A and T held together with? 2
how many hydrogen bonds are C and G held together with? 3
what process helps to preserve the genetic information stored in DNA replication? nucleotides lining up along template strand according to base pairing rules
principle of dominance when 2 forms of the same gene are present the dominant allele is expressed
principle of segregation in meiosis two alleles separate so that each gamete receives only one form of the gene
principle of independent assortment each trait is inherited of other traits
diploid an organism with two copies of each chromosome
locus a specific location on a chromosome
why are sex chromosome disorders the most commonly observed type of aneuploidy in humans? because the X chromosome inactivation allows individuals with more than two X chromosomes to compensate for the extra "doses" and survive the condition
monosomy occurs when one chromosome lacks its homolog
trisomy occurs when one extra copy of a chromosome is present
polyploidy occurs when an entire extra set of chromosomes is present
why are sex-linked traits more commonly found on males? because the only have one X, so they cannot mask a negative recessive trait with a second X
incomplete dominance traits in which the heterozygote shows a different phenotype from the homozygous dominant phenotype ex. grey fur
codominant alleles that are fully expressed in the heterozygous condition ex. black and white fur
polygenic traits in which several genes contribute to the overall phenotype
multiple alleles traits that are a result of more than 2 types of alleles
sex-linked traits phenotype of an allele located on a sex chromosome
crossing over -occurs when two chromosomes physically overlap and exchange chromosome material -changes the DNA sequence within each chromosome -results in an endless number of different possible gene combinations
nondisjunction the failure of chromosome pairs to separate properly during meiosis stage 1 or 2, specifically during anaphase
deletion part of a chromosome or sequence of DNA is missing
insertion the addition of one or more nucleotide base pairs into a DNA sequence
translocation transfer of part of a chromosome to a different position especially on a nonhomologous chromosome
duplication there are two or more copies of a gene or of a segment of a chromosome
inversion causes a reversal in the order of a segment of a chromosome within the chromosome of gene
role of RNA -in the process of transcription, RNA transfers the genetic information from DNA to the ribosomes in the cytoplasm -at the ribosomes, the process of translation uses the genetic code on the RNA to form protein from amino acids
how is RNA different from DNA? -single stranded -ribose sugar -uracil
transference when tRNA brings amino acids to the ribosomes, so they can be assembled into proteins
production of proteins role of ribosomes where protein synthesis occurs
production of proteins role of ER -in eukaryotes, ribosomes are attached here -as the proteins build, they are packaged herw
production of proteins role of Golgi body -modifies and packages proteins from ER into vesicles -can store them for later use
production of proteins role of nucleus contains DNA
nonsense mutation results in a STOP codon being inserted someplace before the end of the gene
silent mutation -point mutations that do not change the amino acid sequence of the protein -these are most likely to have no effect
frameshift mutation -additions or deletions of one or more nucleotides -may result in "garbage genes", as the entire amino acid sequence in the code after the change is devastated -large deletions may remove a single amino acid, or an entire chunk of chromosome
in order for natural selection to occur in a population, several conditions must be met: 1 1. individuals in the population must produce more offspring than can survive 2. those individuals must have different characteristics
in order for natural selection to occur in a population, several conditions must be met: 2 3. offspring must inherit some characteristics from their parents 4. organisms with the best-suited characteristics for their environment are more likely to survive and reproduce
genetic drift the new population does not have the same frequencies or amounts of traits that were previously in the larger population
gene flow organisms of the same species are able to move back and forth between areas to increase the variation of the population through sexual reproduction
homologous structures structures that have the same shape but are used differently
analogous structures structures that have the same function but look different
Hardy-Weinberg Theorem states that the allele frequencies of a gene in a population will remain constant, as long as evolutionary forces are not acting
for a population to be in H-W equilibrium, what conditions must be met? 1. the population is very large; there is no genetic drift\ 2. matings are random 3. there is no mutation 4. there is no migration 5. there is no selection
bottleneck effect -the small surviving population is unlikely to rep. the genetic makeup of the original pop. -in the small remaining pop., some alleles may be overrepresented as some underrepresent and some alleles may be totally absent
founder effect -the smaller the founding pop., the less likely its gene pool will be representative of the original pop.'s genetic makeup -if the new colony survives, random drift will continue to affect allele frequencies until the pop. reaches a large enough size
gene flow -natural pops. may gain or lose alleles by gene flow, since they do not have gene pools which are closed systems required for H-W equilibrium -gene flow tends to reduce between-population differences -extensive gene flow can group neighboring pops->1pop
why would a new mutation increase in frequency? because individuals carrying this allele are producing a larger percentage of offspring in the population due to genetic drift or natural selection, not because mutation is producing the allele in abundance
why is mutation important to evolution? it is the original source of genetic variation, which is the raw material for natural selection
why can organisms that reproduce rapidly fix new traits quickly? because there are many generations in a short time period, and mutations that help the organism are passed on to many more organisms in a short time
theory the summary of a hypothesis or group of hypotheses that have been supported by repeated testing
hypothesis possible explanation for observations or possible answer to a scientific question; educated guess
law generalizes a group of observations for which no exceptions have been found
observation an act or instance of viewing or noting a fact or occurrence for some scientific or other special purpose
fact a truth known by actual experience or observation, something known to be true
principle a fundamental, primary, or general law or truth from which others are derived
inference arrival of conclusions from given information by any acceptable form of reasoning -commonly drawn by deduction//formed by analyzing valid arguments or from accepted premises -induction: a conclusion based on repeated observation of fact
eutrophication -demonstrates how changing nutrient levels affect the organisms in an ecosystem -an increase of nutrients (usually n and p) is added -increases photosynthesis -as the producers die, decomposers come and eat them -lower the oxygen available->many die
population density the number of organisms living in an environment
exponential growth -J shaped -if a pop is provided with ideal conditions, it will increase -healthy organisms reproduce at a rate greater than their death rate -as long as this continues, the pop grows larger
logistic growth -S shaped -as the pop increases, the resources that are available become limited, and the growth of the pop slows and begins to stabilize
density-dependent limiting factors -competition -predation -parasitism -crowding/stress
density-independent limiting factors -weather fire -droughts/floods -human activities
interspecific competition occurs when different species of organisms prey on the same essential resource that is in limited supply
Created by: amandathornton