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Biology sem. 2 final EDDY
Terms in this set (63)
What is DNA?
Your genetic code that serves as the primary material that causes recognizable, inheritable characteristics in related groups of organisms?
Who founded DNA?
James Watson and Francis Crick and Rosalind F.
What are the parts of DNA
Nucleotides, backbone, and the nitrogenous bases.
Why is DNA important?
it serves as the blueprint for traits of all living things. It is what makes us unique.
Steps of DNA replication
1. Double helix unwinds at replication origin(s)
2. At the replication fork, new nucleotides are added to each side and new base pairs are formed according to the base pairing rules, the two original strands act as templates for the two new strands
3. Results in two identical DNA molecules
What is RNA?
It is transcribed by DNA and is used to make proteins, single-stranded nucleic acid that contains the sugar ribose
Compare and contrast DNA and RNA
Both are nucleic acids and house information crucial to the cell. However, they are very different. DNA is a doubles stranded helix with deoxyribose for its sugar. It has the base thymine. RNA is single stranded and has uracil in place of thymine. Its sugar is ribose.
Three main types of RNA
Messenger RNA (mRNA)- first form of RNA after DNA transcription, this form carries instructions for making proteins from a gene
Transfer RNA (tRNA)- translates the mRNA sequence and carries a particular aminoacid that is associated with that code
Ribosomal RNA (rRNA)- make up part of a ribosome
What is transcription?
The making of RNA from the information in DNA. During transcription, the information on a gene is copied into mRNA. It is stage 1 of gene expression
What is translation?
The 2nd stage of gene expression. The genetic code carried by mRNA is decoded to produce the specific sequence
Describe gene expression
Gene expression is the manifestation of genes into specific traits, taking DNA, making RNA, and using the RNA to make specific proteins
What is mutation? What causes it? What does it effect?
Mutation is a change in the structure or amount of genetic material of an organism, resulting in a mutant; an individual whose DNA or chromosomes differ from some previous or normal state. It usually occurs naturally as accidental changes to DNA during the cell cycle. It can also be caused when DNA polymerase fails to correct its mistake. It can be influenced by the environment. It may only affect one amino acid in the protein, may have no ill effects
a change of a single nucleotide in a sequence from one base to another
insertion or deletion mutation
occur when a base is inserted into or deleted from a DNA sequence
A mutation that has no effect on a genes function
When a codon is changed in such a way that a different amino acid is coded for
Remaining sequence is misread due to a shift in the codon translation
When a codon is changed to a stop signal and the polypeptide is cut short
What is a genetic switch?
A genetic switch is a molecular system that controls the expression of a specific gene
How do cells try and regulate mutations?
Chemical changes alter the form and consequently the function of proteins. Before and after transcription, RNA polymerase binds to the start/promoter region of DNA
What are introns and exons?
introns are junk DNA- noncoding sequences. Exons are functional mRNA coding regions.
What is a genome and genome mapping?
A genome is all of the genetic material in an organism, population, or species. Genome mapping determines the relative position of all of the genes in chromosomes in an organisms genome.
What is a clone?
A clone is a member of a population of genetically identical cells produced from a single cell. It is genetically identical to a pre-existing organism
What are stems cells?
A stem cell is a cell that can continuously divide and differentiate into various tissues.
What are some tools of cloning?
Some tools of cloning are DNA sequencing and Polymerase chain reaction
What is evolution? Who discovered it? When and how was it discovered?
Evolution is the process by which a species changes overtime. It was discovered by Charles Darwin in 1858. His theory was based on his experiences, advanced through his travels, and concluded after years of study
What is a theory and how is it different from a law?
A theory is a broad explanation that has been scientifically tested and supported. A law is a statement about an observed phenomenon. It is just a description.
What else contributed to Darwin's theory?
Thomas Malthus influenced Darwin's theories. Birds (finches) also helped his theory.
What is natural selection?
The idea that the fittest survive and pass along their traits to their offspring.
What are the steps of evolution?
Overproduction- every population is capable of producing more offspring than can possibly survive
Variation - genetic variation exists within every population
Selection - certain traits can make individuals more or less likely to survive and have offspring
Adaptation - over time, those traits that improve the chances of survival and reproduction become more common
What is adaptation?
An adaptation is an inherited trait that is present in a population. The trait helps individuals survive and produce
How do finches play a role in development of the theory of evolution?
14 finch species have evolved very different behaviors and different anatomy to accommodate their roles on the island. Finch species adapted for different diets and this helped with Darwin's theory.
What are fossils and what role do they play in evolution?
Fossils are traces of organisms that lived in the past. Sometimes comparing fossils and living beings reveals a pattern of gradual change from the past to the present.
What 5 factors affect evolution?
Natural selection - better traits are more selected over worse traits
Gene flow- genes are added and removed from population
Mate choice - limited choices of mates = limited traits
Mutation - random alteration of genetic material
Genetic drift - cause rare alleles to be lost from one generation to the next
What is microevolution?
The study of inherited traits in a population over time that leads to gradual change
What are population genetics? What are gene pools?
The study of microevolution through observing changes in the number and types of alleles in populations is called population genetics. The combination of alleles in a population at any moment in time makes up that populations genes pool
Describe genotype and allele frequencies
Genotype frequencies - population is the number of individuals with a given genotype divided by the total number of individuals in the population
Allele frequencies - the percentage of specific alleles within a sample of a population, always equal to 1
What is the Hardy-Weinberg principle?
When allele frequencies in a population are not changing/remain constant (therefore the population is NOT evolving). This principle predicts that a population will not change unless at least one of the five forces acts upon it. The sum of all of the frequencies is 1.
What is convergent evolution and how does it lead to homologous and analogous traits?
Convergent evolution is when similar adaptations are seen in different yet similar geographical locations. Similar environments lead to similar adaptations.
What is stabilizing, disruptive, and directional selection?
Directional selection acts to eliminate one extreme from a range if phenotypes. Stabilization selection eliminates individuals with alleles for any extreme type. Disruptive selection results in the increasing of 2 distinct phenotypes in a population.
What are vestigial organs?
Vestigial organs are remnants of structures that served important functions in the organisms ancestors, but lost all or most of its original function.
Difference between punctuated equilibrium and gradualism?
Gradualism is a slow gradual change that consists of many small changes to a species over a long period of time. Punctuated equilibrium is the opposite. It is a sudden change.
What is an ecosystem?
Includes a community of organisms and their physical environment
Difference between biotic and abiotic factors
Biotic factors are living and abiotic factors are nonliving
What is a habitat and how does is support biodiversity?
A habitat is a place where an organism lives. Rainforests supports more of a variety of organisms because there are more resources and habitats
Describe succession and the ways in which it takes place.
Primary succession is new growth on virgin soil. Secondary succession is the replacement growth arising from downfall of a pre existing community. Pioneer species are the first species to appear in a newly made habitat. They often change the habitat to make it more hospitable for other organisms.
All of the biomes
Tundra - coolest, treeless Plain
Tropical rainforest - no dry season
Grassland - open area covered with grass
Temperate forest - widest seasonal changes
Taiga - largest land biome, coniferous
Desert - dry, low level of rainfall
Freshwater - made up of any body of water that is made of freshwater
Marine - all of the oceans, coral reefs, there is about one cup of salt for every gallon
Freshwater, wetlands, estuaries, and marine
What are trophic levels? What are producers, consumers, and decomposers?
In an ecosystem energy flows from the sun to producers to consumers to decomposers. Each step in the transfer of energy is called a tropic level. Producers are photosynthetic organsisms that serve as the basic food source for an organism. Consumers are organisms that eat other organisms instead of producing their own food. Decomposers break down the remains of animals.
Describe food webs and food chains
A food chain is a representation of the flow of energy. When energy flows from one trophic level to the next, a food chain is formed. A food web shows energy flow as a more complicated interconnected groups rather than a simple source.
Why are keystone species important?
Their presence and role within an ecosystem has a disproportionate effect on other organisms within the system. It is often a dominant predator whose removal allows a prey population to explode and often decreases overall diversity.
Describe all of the types of ecological interactions
Predation- the act of one organism killing another for food
Parasitism- one organism feeds off another organism without killing it
Symbiosis - a relationship between two species in which both species benefit
commensalism- two species have a relationship in which one species benefits and the other is neither harmed nor helped
What factors influence population growth?
Population growth is based on birth rate, death rate, immigration, and emigration
What is the difference between exponential and logistic growth?
Exponential growth occurs when resources are plentiful whereas logistic growth occurs when the resources are limited
What is carrying capacity? Describe how density-dependent and density independent factors affect it
It is an average population density or population size of a species below which it's numbers tend to increase and above when it's numbers tend to decrease because of shortages of resources. Maximum number of individuals that an areas resources can sustain indefinitely. Density independent factors are variables that affect a population regardless of the populations density. Density - dependent factors are affected by the number of organisms present in a given area.
What is a niche? Describe fundamental and realized niche.
A niche is the role or function of an organism or species in an ecosystem. Fundamental niche is the entire set of conditions under which an animal can survive and reproduce itself. Realized niche is the set of conditions actually used by given animals after interactions with other species have been taken into account.
What are invasive species?
An invasive species is a species that is not native to a specific location, has a tendency to a degree believed to cause damage to the environment, human economy, or human health
Describe how a pond is it's own aquatic system
An aquatic system contains living things that depend on the water for survival, such as plants and plants. Therefore a pond is an aquatic ecosystem because it does just that.
During meiosis, one cell divides twice to form four daughter cells. These four daughter cells only have half the number of chromosomes of a parent cell- they are haploid. Meiosis produces our sex cells or gametes (eggs in females and sperm In males)
Who is Gregor Mendel?
- Austrian monk
- on his garden plot in the monastery, Mendel noted how characteristics in plants were passed on from one generation to the next
- known as father of genetics
Differences between genotypes and phenotypes
A genotype is a set of genes in our DNA which is responsible for a particular trait. The phenotype is the physical characteristic of that trait
What is heredity?
The passing on of genetic traits (coded for in DNA) from parents to offspring
Describe Mendel's experiment
Mendel studied pea plants. He crossed purebred parent generations and followed the traits of the offspring through the F1 (recessive traits "disappear")and F2 generations (recessive trait reappears) He noticed the dominant always won over the recessive. He just kept crossing the plants.
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