Final Flashcards
how many cells are formed mitosis vs meiosis
mitosis- 2 new cells are formed
meiosis- 4 new cells are formed
what kind of cell (hap/dip) is formed mitosis vs meiosis
mitosis- diploid
meiosis- haploid
does replication of chromosomes happen in meiosis or mitosis?
both
are tetrads formed in meiosis or mitosis
meiosis
what kind of cell (funct) is formed mitosis vs meiosis
mitosis- body/somatic cells
meiosis-sex cells/gametes
are identical copies of parent cells made in meiosis or mitosis
mitosis
how many times do original cells divide meiosis vs mitosis
mitosis- once
meiosis- twice
does chromosomes moving to cell equators happen in meiosis or mitosis
both
does crossing over take place in meiosis or mitosis
meiosis
name the stages of mitosis
prophase, prometaphase, metaphase, anaphase, telophase
name the stages of meiosis
prophase I, metaphase I, anaphase I, telophase I with cyokinesis I,prophaese II, metaphase II, anaphase II, telophase II (with cytokinesis II)
duplication
when there is extra of a gene on a chromosome
deletion
when a gene on a chromosome is missing
inversion
when a gene sequence on a chromosome is flipped
translocation
when chromosomes switch parts
what kind of mutation causes a gamete to be (n+1) or (n-1)
nondisjunction
what is PCR used for
to make 100 billion identical copies of a SNA sequence within a few hours (helps diagnose diseases, identify bacteria and viruses, match criminals to crime scenes, even wjen a very small DNA sample was found at the scene
what is gel electrophoresis used for
to sort and measure DNA strands, especially good to match up individuals at crime scenes, for paternal tests, etc. (DNA is negatively charged so it moves toward the positively charged end of the gel, with shortest strands moving the farthest)
describe the goal of gene therapy
to put a corrected copy of a gene in a person (usually delivered through a vector) to replace a flawed one, in other words, to fix genetic problems at their source
end product of artificial embryo twinning
identical twins. the two babies are clones of each other
end product of somatic cell nuclear transfer
in somatic cell nuclear transfer, the baby that is born is a clone of a living person (the somatic cell donor)
what are vortexes used for
to mix samples in the lab
what are centrifuges used for
to “spin down” samples and separate out contents (most dense on bottom, least dense on top)
DNA structure
made up of nucleotide building blocks which are composed of a sugar, a nitrogenous base, and a phosphate group. the shape of DNA is a double helix.
gene
basic unit of heredity. genes are on chromosomes
shape DNA vs RNA
DNA- double helix
RNA- single stranded
sugar DNA vs RNA
DNA- deoxyribose
RNA- ribose
base pair rules DNA vs RNA
DNA- A&T, C&G
RNA- A&U, C&G
key function of DNA
holds all genetic material, or code (“secret of”) of lifel the code is universal
key function of RNA
tRNa, rRNA, mRNA, help with making proteins
the steps of transcription
- ) RNA polymerase binds to a promoter; DNA unwinds [initiation]
- ) one side of DNA is used as a template & RNA polymerase adds free nucleotides (using complementary base rules for RNA) [elongation]
- ) RNA polymerase reads terminator; new RNA is released [termination]
the steps of translation
- ) codon on mRNA molecule attaches to a ribosome
- ) tRNA molecules carrying specific amino acids, approach the ribosome
- ) tRNA anticodon attaches to mRNA codon
- ) ribosome slides to the next codon on the mRNA molecule and repeats the process
- ) as amino acids are added to each other, peptide bonds link the amino acids together
- ) chain of amino acids continues to grow until ribosome reaches a stop codon on the mRNA strand. this signals tat no more amino acids should be added and protein is complete
P and A sites on ribosomes
P site (left) holds the growing chain of amino acids, A site (right) is where next amino acid is brought in
what is the difference between a codon and an anticodon
both consist of a set of three bases (“triplets”) but a codon is on mRNa and an anticodon is on tRNA (the anticodons correlate with the codons so each tRNA will bring in the correct amino acid)
name the main evidences for evolution
molecular biology, comparative embryology, fossils, biogeography, comparative anatomy
molecular biology
evidence for evolution. comparing DNA, RNA, amino acids in proteins in different organisms (more similarities means probably more closely related)
comparative embryology
evidence fr evolution. seeing how organisms develop and comparing these early life stages to help determine relatedness
fossils
evidence for evolution. use superposition, relative age and absolute age to determine historical fossil sequence in strata. good for hard parts of animals, rich in minerals, though soft parts and soft organisms rarely fossilize.
biogeography
evidence for evolution. studying distribution of animals around the world, ex: finding closely related organisms adapted to different environments in nearby regions, seemingly unrelated organisms may have similar adaptations to similar environments in regions that are far apart (think pangea for this one)
comparative anatomy
evidence for evolution. study homologous, analogous, and vestigial structures and transitional species to determine ancestry and relatedness
name the process of descent with modification using the points of natural selection
1.) overproduction 2.) genetic variation 3.) struggle to survive 4.) differential reproduction
overproduction
more offspring are produced than can survive in the environment (ex: more baby lions are always born than would ever survive past age one)
genetic variation
individuals have different traits because they receive different alleles from their parents, some traits are better than others and provide a favorable adaptation, while others don’t receive beneficial traits
struggle to survive
organisms compete for the limited resources; those who outcompete others generally are those with the best adaptations while the others die out
differential reproduction
those with the more successful adaptations survive longer and reproduce more. over time, the favorable traits become the most frequent alleles in the population, as the other alleles die out (assuming natural selection is still working, by chance, in favor of these same “favorable traits”)
homologous structure
is derived from a common ancestor, is structurally similar/same to common ancestor, but is used in different way (different function) ex: forelimbs of humans, bats, cats, and whales
analogous structure
is not derived from a common ancestor, is not structurally similar, but are used in the same/similar way (same function) ex: wings of birds, bees, bats
vestigial structure
is derived from a common ancestor, is structurally similar/same to common ancestor, but is not useful to the current organism ex: small hind leg and foot bones in whales
hierarchy of life from most broad to most specific
life, domain, kingdom, phylum, class, order, family, genus, species
what does it mean to be fit in the theory of evolution
ability to survive long enough to produce fertile offspring (your offspring must also be able to have viable offspring of their own)
define and describe genetic drift
genetic drift is a change in the gene pool of a population due to chance and it’s especially impactful in smaller populations such as populations that have undergone a bottleneck effect or a founder effect
bottleneck effect
an event such as an earthquake or flood that drastically reduces population size
founder effect
colonization of a new location by a small number of individuals
stabilizing selection
average form of a trait is slected for (and it’s the most common) while either extremes are selected against
the graph is low on either side and goes high in the middle
disruptive selection
both of the extreme forms of the trait are selected for, while the average is selected against double humps (hump, then dip down, then hump)
directional selection
one of the extreme forms of a trait is selected for while the other extreme form and the average is selected against.
the graph just looks like the regular bell curve has been shifted to one side
allopatric speciation
a speciation event that results after a geographic isolation (ex: canyon, river, etc. forms separating the population into different species over thousands perhaps the two populations can no longer interbreed- 2 different species)
sympatric speciation
a speciation event that results after reproductive isolation (ex: maybe they live in the sam area but have different niches & only breed with those of the same niches over time they maybe can’t breed together any more
define and describe adaptive radiation
the evolution of many new species from a common ancestor introduced to a new and diverse environment
example of adaptive radiation
14 finch species in the galapagos islands likely evolved from a single small population of ancestral birds that colonized one of the islands
commensalism
one organism benefits, the other neither is helped nor harmed
mutualism
both organisms mutually benefit
parasitism
one organism benefits (the parasite) while the other is harmed (the host)
list the ecological hierarchy from biggest to smallest
biosphere, ecosystem, community, population, organism
biosphere
the thin layer of Earth where life exists
ecosystem
biotic (living) and abiotic (nonliving) components in an area and their interactions
community
only the living organisms in an area
population
all members of a single species living at the same place and time
organism
a single individual member of the species
density-dependent limiting factors
affect the population dependent on how dense the population is. ex: dense populations can much more easily transfer communicable disease through the population faster, predators do better when more prey is available but once they strain the prey population and thin out their density the prey goes down in number, also causing the predator to do poorly.. as predators do poorly then prey starts doing better, but then in return predators start doing better, etc. (their success directly depends on the other organisms’ success
density-independent limiting factors
impact dense and not very dense populations the same proportionally. for instance, hurricanes, tornadoes, floods, or maybe even global warming.
how overpopulation affects world
global warming:more people= more burning of fossil fuels = more greenhouse gases.
global: also affects health and sanitation worldwide with more waste produced and greater food supply needed
how deforestation affects world
global warming: less forests = less vegetation to remove CO2 from air = higher quantities of greenhouse gases
global: hurts land fertility, causes erosion, affects oxygen levels
some effects of global warming
sea levels rise from melting glaciers and ice caps, weather patterns will change, diseases will spread, crops won’t grow in their normal locations affecting food supply, changing climates also means more migration, more extinction, etc. its effects are massive and global
how ozone depletion affects world
as more UV radiation also affects food supply/ crops get damaged, and can affect human health (skin cancer)
how is it thought that global warming is taking place
humans burn too many fossil fuels and as a result release too much CO2, a greenhouse gas. therefore when the natural greenhouse effect takes place, the greenhouse gases are in higher concentration so even greater amounts of hear are trapped and radiated back down to earth, warming it (too much)
the greenhouse effect
sin shines down, heats earth, heat escapes to space while some gets trapped in greenhouse gases and is radiated back down to Earth, warming it
how is it thought that the hole in the ozone happened
humans made products that release ozone-depleting chemicals. for example, CFCS were commonly used in air conditioners, refrigerators, hair spray cans, etc. and when released into the air, the CFCs go up into the atmosphere, when light strikes, bringing UV radiation, a CFC molecules i broken and a chlorine molecule released. the chlorine then attaches to an ozone (O2) molecule, breaking it into chlorine monoxide and O2. then when an atom of oxygen attaches to clo, the p is released as O2, leaving the Cl left to do it all over again
what does a graph of population growing exponentially look like
j-shaped graph
what does the graph of a logistic growth model look like
it looks like a stretched out j that continues in a straight line when population hits carrying capacity
which graph is representative of the current human population
currently, human population is growing exponentially (esp. bc we used to be hunters/gatherers), then we learned to grow crops and raise animals in the agricultural revolution, followed by 1800s industrial revolution, and there increased lifespan (lower death rates but still high birth rates)
demographic transition
a model that many developed countries follow. it is like a logistic growth model that instead of hitting carrying capacity, the population is stabilizing (low growth) based on choice– choosing to have less children. developing countries don’t have access to contraception, birth control, good health/sanitation/medicine so many are still growing exponentially
the cell cycle
involves growth, replication, and division of a eukaryotic cell
two main phases of cell cycle
interphase and M phase
interphase
stage where most of cell’s life is spent. during interphase, a cell’s chromosomes are duplicated, but no cell division is occuring
M phase
includes mitosis and cytokinesis. the end result is two cells that are genetically identical to the parent cell
during mitosis
the nucleus of a cell divides into two daughter nuclei that each contain the same number of chromosomes as the parent nucleus
cytokinesis
the two nuclei formed during mitosis are separated into two identical daughter cells during this
meiosis
not directly involved in the cell cycle. a process where the cell undergoes two successive nuclear divisions. produces haploid daughter cells with half the species’ usual number of chromosomes. the result is gametes which aid the organism in sexual reproduction
how is cell division triggered
as cells become too large to efficiently import nutrients and export wastes across their cell membrane. this occurs because as a cell grows larger, its volume grows more rapidly than its surface area
what stops cell growth (dividing over and over)
as cells grow, they fill whatever medium they are in. once the cells have spread so much that two cells contact each other, they can signal each other to stop dividing through process called inhibition
prophase I
homologous chromosomes pair and become tetrads (2 chromosomes or 4 chromatids). crossing over between homologous chromosomes occurs at this stage
metaphase I
after crossing over occurs, homologous chromosomes line-up along the equator
anaphase I
whole chromosomes separate from the tetrad formation and move to opposite sides of the cell. each chromosome still has two sister chromatids
telophase I
nuclear membrane forms around each set of chromosomes. each cell now has one set of chromosomes and is haploid (n)
prophase II
sister chromatids become short and thick
metaphase II
the chromosomes migrate to the center of the nucleus and line-up along the equator
anaphase II
sister chromatids are pulled apart by microtubules to opposite poles
telophase II
a nuclear envelope forms around each set of chromosomes and meiosis II is complete
cytokinesis of meiosis
cells divide to create 4 haploid cells
genetic variation
during meiosis, crossing over can occur during prophase I when two chromosome pair up and exchange parts of their DNA. this provides genetic diversity. genetic variation can also occur when alleles are randomly sorted during meiosis, since each offspring receives a different combo of alleles from parents, phenotypic diversity occurs. errors or mutations can also result in genetic variaiton
organization of genetic material from smallest to biggest
gene —> DNA molecule —-> chromosome —-> genome
gene is one piece of DNA molecule, DNA molecule is packaged and carried by chromosome, genome is organism’s complete genetic makeup and includes the organism’s entire set of chromosomes
how many chromosomes do humans have
46, 23 from mom and 23 from dad
homologous pair
in cells of sexually reproducing organism, a pair of similar chromosomes with same gene in the same location is known as homologous pair. every norman human body cell contains 22 homologous pairs of autosomal chromosomes and 1 pair of sex chromosomes
DNA replication
- )two original strands of DNA are separated with help of enzymes known as DNA helicases. they break hydrogen bonds holding nucleotide bases together.
- ) DNa polymerases add complementary nucleotides to each strand.
- ) 2 DNA molecule identical to original DNA molecules form. each consists of two strands of DNA, one from parent, and one built using parent molecule as template
where does process of transcription occur
in nucleus of cell, but mRNA that is created travels into cytoplasm once it is made
where does process of translation occur
mRNA is delivered to ribosome in cytoplasm, where translation takes place
endoplasmic reticulum and protein synthesis
aids in transporting proteins out of cell or to other organelles within the cell. some proteins are synthesized by ribosomes found on rough ER. these proteins are destined for other organelles or to be secreted by cell. the ER also plays part in folding and modifying some proteins
golgi apparatus and protein synthesis
golgi is responsible for sorting, modifying and packaging proteins. plays important role in sorting and tagging proteins which aid in their transportation to the correct location
law of dominance
when an organism has two or more alleles for a trait, the allele that is expressed over the other allele is dominant. the others are considered recessive.
law of segregation
different alleles for same trait separate when gametes are formed (ex: mother with Bb could wither pass B or b onto offspring)
law of independent assortment
when pairs of alleles separate, they do so independently of each other. thus, allels for hair color and alleles for eye color in humans are not inherited together
incomplete dominance
when neither allele is completely dominant over the other there is a blending of traits
codominance
when two alleles are equally dominant, and alleles are expressed simultaneously resulting in organisms with a mixed pattern
polygenic inheritance
when particular phenotype may be determined by more than one gene
nondisjunction
occurs when chromosomes do not separate correctly during cell division. the resulting daughter cells will either be missing o have an extra copies of chromosomes.
point mutation
a mutation in a single base pair in a strand of DNA
silent mutation
specific type of point mutation where the mutation has no effect on the polypeptide sequence
nonsense mutaion
changes one amino acid codon into a stop codon. causes normal polypeptide sequence to be shorter
frameshift mutation
a mutation that causes the reading frame of a codon sequence to be shifted. any insertion or deletion of nucleotide base pairs that are not in multiples of three will cause a frame shift mutation
chromosome translocation
caused when material is exchanged between two chromosomes or part of one chromosome becomes fused onto another chromosome
selective breeding
when certain crops or animals are chosen to breed based off of desirable traits
recombinant DNA technology
how genetic engineering can be done. using this, different enzymes can be used to cut, copy, and move segments of SNa. characteristics produced by the segments of SNA can then be expressed when these segments are inserted into new organisms
aerobic
living in presence of gaseous oxygen
anaerobic
living in the absence of gaseous oxygen
endosymbiosis theory
describes evolution of eukaryotic cells from prokaryotic organisms. theory proposes that certain eukaryotic organelles developed from prokaryotic cells engulfed by a host cell. engulfed cells developed mutually beneficial symbiotic relationship with each othe and the host cells
endosymbiosis evidence
chloroplasts and mitochondria have double membranes, have own circular DNA, are similar in size to bacteria, have ribosomes similar to those in bacteria
diversity
either the number of different characteristics present in a population or the number os different species in an area. natural selection resulted in it. on the species level, diversity allows species to survive in changing environment. on community level, a community with biodiversity will not be seriously affected by the extinction of 1 or 2 species. humans affect diversity through selective breeding and genetic engineering
gene flow
the transfer of genetic information from one breeding population to another. can be an important source of genetic variation when unique genetic information from one population is introduced into a different population
biome
geographic region that has a distinct climate
biotic factors
include living organisms and factors from formerly living organisms
abiotic factors
include any nonliving geological, geographical and climatological factors
trophic level
describes the feeding level of an organism. producer, decomposer, primary consumer, secondary consumer, tertiary consumer, quaternary consumer
producers
organisms that are able to synthesize food molecules from inorganic compounds, usually through photosynthesis. green plants, algae and some kinds of bacteria and protists are producers
consumers
organisms that get energy by feeding on producers or other concumers
primary consumers
animals that ear producers. are also called herbivores because they ear only plants
secondary consumers
organisms that eat primary consumers. can be carnivores if they eat only animals. or, they can be omnivores if they eat both animals and plants
tertiary consumers
eat secondary consumers and may be carnivores or omnivores
decomposers
organisms that consume dead organisms. as they break down dead organic matter, they release nutrients back into the soil, water, and atmosphere
role decomposers play in ecosystem
important for carbon, nitrogen, phosphorus and oxygen cycles. nutrients they release are also used by producers to make complex organic molecules
food chain
describes the feeding relationships and energy flow between species within an ecosystem
arrows on food chain
represent the direction of energy flow. arrow points from organism being consumed to the organism that is receiving energy
food web
group of interconnected food chains where organisms can belong to more than one trophic level
energy pyramid
diagram that shows the relative amounts of energy located within each trophic level.
where is most of energy in ecosystem
with plants and other producers. this is bc most of the energy in an energy pyramid is used or lost as heat energy as it moves up the pyramid
predation
type of relationship in which a predator hunts, kills, and eats its prey.
competition
since there are limited amounts of resources in an ecosystem, if one organism gets a particular resource, another does not. this leads to competition as two organisms try to access the same resources.
population size
the number of individuals within a given population
population density
the number of organisms in the population divided by a regular unit of area or volume
biogeochemical cycles
predictable pathways followed by chemical elements or molecules as the elements or molecules travel through the living and nonliving parts of an ecosystem
carbon-oxygen cycles
are reliant upon each otherphotosynthesis and cellular respiration drive this cycel. each of these processes must take place in order for the other half of the cycle to function properly
nitrogen cycle
the cycle of consumption and regeneration of nitrogen within our environment
how is nitrogen essential
nitrogen is an essential component of amino acids (proteins) and nucleic acids. therefore all organisms require it to survive.
how nitrogen is made usable
microscopic organisms and natural processes, such a lightning, can convert nitrogen in atmosphere to usable forms of nitrogen
nitrogen fixing bacteria
fix atmospheric nitrogen into nitrogen containing compound ammonia. plants can absorb the nitrogen compounds from the soul and use it to form important biological molecules
nitrifying bacteria
convert ammonia into nitrates
denitrifying bacteria
return nitrogen to the atmosphere by converting nitrates to nitrogen
condensation
gas —> liquid (water vapor to water)
crucial for formation of clouds, which form when air contianing water vapor rises and cools.
evaporation
liquid —–> gas
happens usually as result of heat
transpiration
process by which water is carried through plants, from roots to leaves, where it changes to water vapor and is released to the atmosphere
carbon cycle and climate change
when fossil fuels are burned, carbon is transferred to atmosphere. greenhouse gases are released into atmosphere in large quantities when fossil fuels are combusted
how do prokaryotes reproduce
through an asexual reproduction known as binary fission
chromatin
form chromosome exists in for most of the time. this is a mass of long thin fibers, a combination of DNA and proteins
when does a chromosome consist of two identical chromatids
when the cell is preparing to divide and has duplicated its chromosomes but before the duplicates actually separate
what are the three subphases of interphase
G1 phase- begins to grow
S phase-continues to grow, copies chromosomes
G2 phase- grows more and completes preparations for cell division
prophase
- chromatin coils become more tightly coiled and becomes discrete chromosomes in nucleus
- nucleoli disappear
- mitotic spindle begins to form as microtubules rapidly grow out from centrosomes
prometaphase
- nuclear envelope breaks into fragments and disappears
- microtubules reach chromosomes
- chromosomes start moving toward center of cell
metaphase
- mitotic spindle is fully formed
- chromosomes convene on metaphase plate
- microtubules attach to particular chromatid from opposite sides
anaphase
- two centromeres of each chromosome come apart, separating sister chromatids,
- poles are moved farther apart, elongating the cell
- chromosomes get pulled to opposite sides of the cell
telophase
- cell elongation that started in anaphase continues
- nuclei appear at two poles of cell
- nuclear envelopes form around chromosomes
- chromatin fiber uncoils
- nucleoli reappear
cytokinesis
division of cytoplasm occurs with telophase with two daughter cells completely separating soon after the end of mitosis
cleavage
how animal cells do cytokinesis, cleavage furrow pinches cell in two
what bonds are between nucleotides in DNA
covalent bonds
structural difference between deoxyribose and ribose
ribose has additional oxygen atom
what bonds are between nitrogenous bases
hydrogen bonds
how planet traps heat
- solar radiation reaching earth’s atmosphere includes uv radiation and visible light,. ozone layer filters out most of UV, visible light is absorbed by planet’s surface, warming it
- heat is radiated by warmed planet, longer infrared wavelengths are absorbed by gases in the atmosphere which then radiate some of heat back to earth
semiconservative replication
the idea that in each new DNA one strand is from original and one molecule i new
where does DNA replication begin
at origins of replication
mitotic spindle
microtubules (spindle fibers) that guide the separation of chromosomes
cell plate
in plant cytokineses, by vesicles carrying cell wall material collecting at middle of parent cell fusing
germline mutations
occur in sperm and egg and can be inherited
haploid
a cell containing a single set of chromosomes; an n cell
diploid
cell containing 2 homologous chromosomes, one inherited from each parent; a 2n cell
precipitation
how water returns to Earth. when water droplets in clouds condense to become heavy enough that they rain down
