Terms in this set (128)
What is the difference between prokaryotes and eukaryotes?
Prokaryotes have circular DNA and no nuclear envelope or organelles, while Eukaryotes have linear DNA and a nuclear envelope as well as other organelles. Prokaryotes also produce using binary fission while Eukaryotes use mitosis and meiosis.
what is the cell wall?
outside of cell used for structure. (not present in all cells)
what is the cell membrane?
it holds everything together
what is the nucleus?
brain of the cell (DNA located here)
what are chromosomes?
they hold genetic material which are composed of DNA and protein
What are ribosomes?
site of protein synthesis/translation
What are spindle fibers?
they are used to pull apart the sister chromatids/homologous chromosomes during division
What is cytoplasm?
the fluid where translation occurs. All organelles are surrounded by it.
what is the human life cycle?
from fertilization>growth (mitosis)>creating gametes (meiosis)>repeat
what is the purpose of mitosis?
to produce genetically identically diploid cells and maintain cell population
what is the purpose of meiosis?
produce genetically unique haploid gametes
Explain the steps of mitosis
prophase (chromosomes condense and spindles form), metaphase (sister chromatids line up in the middle of the cell), anaphase (spindles pull sister chromatids apart), and telophase (nuclear envelope reforms)
explain the steps of meiosis
Meiosis 1: prophase 1 (crossing over between chromosomes within the tetrads), metaphase 1 (homologous pairs (tetrads) are lined up at the center), anaphase 1 (homologous chromosomes are pulled apart by the spindles), telophase 1 (nuclear envelope reforms). Meiosis 2: same as mitosis but it occurs in two cells as once and the outcome is four genetically distinct haploid cells.
explain the similarities and differences between mitosis and meiosis
They both include the same process, but the outcome is very different. Meiosis also divides twice instead of once like mitosis. Meiosis also includes crossing over which mitosis does not.
how does binary fission work?
the circular strand of DNA duplicates and then each one attaches to one side of the cell or the other and then they move apart until the cell is squeezed apart like a balloon/
What does haploid mean?
half the number of chromosomes (n)
What does diploid mean?
containing two complete sets of chromosomes, one from each parent (2n)
What does polyploidy mean?
multiple sets of chromosomes
what does it mean to be a somatic cell?
to be non reproductive
what does it mean to be a gamete?
haploid reproductive cells
What are autosomes?
What are sex chromosomes?
chromosomes that determine the sex of an organism
what is a genome?
All the DNA in one cell of an organism
what is the human ploidy level?
23 pairs of chromosomes/2n (males have xy, females have xx)
what is the basic structure of a chromosome?
a condensed double helix that forms into an X shape with a kinetochore within the centromere that connects the sister chromatids in the X.
describe the steps of the cell cycle
Interphase is 90% of the cell cycle. It includes G1, S, and G2. G1 and 2 are growth phases and S phase is for DNA duplication. Then comes Mitosis. Finally, cytokinesis which divides cytoplasm.
Explain how cancer cells are different from other cells
they don't respond normally to body control systems so they continue to divide when they should stop
How does meiosis create genetic variation?
due to recombination and independent assortment in meiosis, each gamete contains a different set of DNA
how does meiosis provide haploid cells?
copies once and divides twice
how does sexual reproduction increase genetic variation?
millions of options for each gamete to combine with creates genetic variation through reproduction
What are the disadvantages of asexual reproduction?
no genetic variation
What are the advantages of asexual reproduction?
"Cheap" and valuable in a stable environment
what are advantages of sexual reproduction?
genetic variation, works well in a dynamic environment
what are disadvantages of sexual reproduction?
takes a lot of time and energy
What did Mendel study?
what is the law of segregation?
during the production of gametes the two copies of each hereditary factor segregate so that offspring acquire one factor from each parent
What is hybridization?
mating of two true-breeding varieties
What does P generation stand for?
What does F1 generation mean?
first generation after p
What does F2 generation mean?
offspring of F1
what are alleles?
alternate versions of genes
what do genes contribute to the phenotype and genotype?
they hold heritable factors on chromosomes
What is a genotype?
genetic makeup of an organism
What is a phenotype?
What is complete dominance?
either dominant or recessive
What is incomplete dominance?
A blending of traits. Red+White=Pink.
What is codominance?
when both alleles contribute to the phenotype
What is pleiotropy?
genes have multiple phenotypic effects
what is epistatis?
genes at one location effect expression of genes at other location
What is polygenic inheritance?
two or more genes are on a single phenotype
What is a phenotype made up of?
environment and genotype
what are chromosomal behaviors during meiosis?
homologous pairs join together to become tetrads. crossing over and recombination occur
What did Morgan do?
first to associate a specific gene with a specific chromosome (fruit flies)
what is the difference between linked and sex linked?
linkage occurs when genes are close together on a chromosome. sex linkage means they are both on the sex chromosome. they can be both but they aren't usually.
do all eukaryotes have the sex chromosomes XX or XY?
No, but all humans do
name three examples of sex chromosomes eakaryotes have that humans don't
XO, ZW, halpo-diploid
name the four main types of chromosomal error and explain each
translocation (segment is moved), Inversion (reversed), duplication (repeated), deletion (deleted, this is the most lethal)
What is nondisjunction?
Failure for chromosomes to separate properly.
what is important to remember about the DNA process?
it is repeatedly proofread and repaired
Which nitrogen bases pair together?
Adenine to Thymine and Guanine to Cytosine
Where does the copying of DNA occur and what helps it happen?
in the nucleus; DNA polymerase
Where does transcription occur? what makes it happen?
in the nucleus; RNA polymerase
Where does translation occur? what makes it happen?
in the cytoplasm; ribosomes
how does DNA get turned into protein?
DNA becomes RNA which turns into proteins
What did Watson and Crick do?
They "figured out" the structure of DNA
What did Rosalind Franklin do?
Took the first picture of DNA (also actually was the first to know the structure of DNA)
what did avery, mcCarty, and macLeod discover?
DNA was a substance of inheritance
What did Hershey and Chase do?
Determined that DNA was the genetic material.
What did Chargaff do?
Discovered that A=T and C=G
What did Stahl and Meselson discover?
discovered semi-conservative process of copying DNA
what is evolution?
the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth.
what is natural selection?
The idea that the fittest survive and pass along their traits to their offspring.
What is descent with modification?
The passing of traits from parent to offspring
What is convergent evolution?
evolution from different ancestors of similar but spatially separated habitats
What is divergent evolution?
accumulation of differences between groups which leads to new species
what is adaptive evolution?
evolutionary changes that are adaptive to the given environment
What is adaptive radiation?
process by which organisms diversify rapidly from ancestral species into a multitude of new forms
What did Linnaeus do?
developed the scientific naming system still used today
What did Cuvier do?
What did Hutton and Lyell's work suggest?
The Earth was millions of years old.
How did Lamarck propose that species evolve?
through use and disuse and inheritance of acquired taste
what is evidence of Darwin's theory?
fossil record, artificial selection, and natural selection
What is microevolution?
change in genetic makeup of a population or species
what is a species?
a group of organisms whose individuals have the ability to breed and produce offspring.
what is a population?
a localized group of interbreeding individuals of the same species
what is a gene pool?
the total of all genes in the population at one time
what is evolutionary fitness?
what is absolute fitness?
number of offspring
What is Darwinian fitness?
contribution to the gene pool
how does the population evolve?
the individuals that survive have their traits passed on to the next generation
what is geographic variation?
differences between gene pools due to environmental factors or to chance
What is a cline?
a type of geographic variation; individuals correspond to gradual changes in the environment
how does being diploidy help variation be more prominent?
being diploidy hides genetic variation via recessive alleles
What is heterozygote advantage?
it is an example of polymorphism where the heterozygote has greater survival and reproductive success than either homozygote
what is frequency-dependent selection?
survival of our phenotype declines if that form becomes common
how do variations normally occur?
they occur as quantitative variations
What is polymorphism?
the existence of two or more forms of a character, in high frequencies, within a population. Applies to only discrete characters. (can happen geographically between isolated populations)
What is natural selection?
differential success in reproduction due to variation in heritable traits. Individuals don't evolve.
What is the Hardy-Weinberg principle?
p2 + 2pq + q2
what are the four main mechanisms of microevolution?
genetic drift, gene flow, mutation, and natural selection
Explain genetic drift
change caused by chance
Explain gene flow
migrations of fertile individual gametes between populations
changes in genes; can be good or bad
what are the three modes of selection?
directional, disruptive, stabilizing
Explain directional selection
population leans strongly towards one phenotype or another because of an outside force
explain diversifying selection
splits population to the extreme phenotypes on both sides
Explain stabilizing selection
population squeezes to the centered phenotype
What is sexual selection?
the ability of an organism to attract or choose their mate
how are sexual selection and sexual di-morphism different?
sexual dimorphism is difference in appearance between males and females in a species while sexual selection is the ability to use those differences to find a mate
What is intrasexual selection?
competition among males
What is intersexual selection?
what can natural selection not do?
it cannot make any perfect organisms
Why can't natural selection fashion perfect organisms?
not all variations of traits are heritable, evolution is limited by historical constraints, adaptations are compromises, selection edits existing variations, new alleles cannot arise as needed, chance plays a role, and not all evolution is adaptive
What is macroevolution?
evolution of new species or groups
What is the biological species concept?
being re-productively compatible, at least potentially, but choosing not to interbreed with other species
explain the types of reproductive isolation
Pre-zygotic: temporal (seasonal), behavioral (actions), mechanical (doesn't fit), gametic (leggo my eggo). Post-zygotic: reduced hybrid viability (offspring does not survive), reduced hybrid fertility (offspring survives but cannot reproduce.
What is allopatric speciation?
when gene flow is interrupted or reduced when a population is divided into geographically isolated subpopulations
What is sympatric speciation?
speciation takes place in geographically overlapping populations
what are the main drivers of sympatric species?
polyploidy and hybridization
what is an allopolyploid?
a species with multiple sets of chromosomes derived from different species
What is punctuated equilibrium?
the theory that evolution happened in spurts
what is gradual evolution?
the theory that everything transitions continually overtime
What is paedomorphosis?
the rate of reproductive development accelerates compared with somatic developers
What is heterochrony?
an evolutionary change in the rate or timing of developmental events
What is allometric growth?
proportioning that helps give a body its specific form
how long before Wallace did Darwin find his discoveries?
Where was Darwin when he found fossils of a giant armadillo and a ground sloth?
Argentina. He ate armadillo, thought it tasted like chicken, and found the fossils.
what is a question that darwin asked that helped him find evidence of the fossil record?
why do fossils turn up where similar species now live?