Final Flashcards
What is the purpose of replication?
the process by which genetic information is duplicated. This occurs to ensure that each cell in an organism has a complete and correct copy of the genome
What is the purpose of transcriptions?
DNA is transcribing into mRNA
What is the translation?
mRNA is translated into a polypeptide chain with the aid of rRNA.
How does the DNA Polymerase complex work to replicate DNA?
By adding nucleotides one at a time to the 3’ end of a new strand, directed by the old template strand
A and G pairs with…
T and C
What is the difference between leading and lagging strands?
The leading strand is replicated continuously while the lagging strand is replicated discontinuously as Okazaki Fragments
What is the job of DNA Ligase?
It is and enzyme that can use ATP-Hydrolysis to link together breaks in the sugar-phosphate backbone
Where can DNA Polymerase add deoxynucleotides?
To the 3’ end and only if there is a sequence of nucleic acids to be copied on the 5’ side
Primase
synthesizes a new RNA primer
DNA Helicase
Unwinds the double helix
What is a gene?
Has 3 regions - Promoter region, Transcribed region and the terminator region
Promoter Region
1) Contains binding sites for transcription factors. 2) Contains binding sites for other factors that can un-pack or un-wind the chromatin. 3) Specifies where RNA Polymerase should begin transcription
Transcribed Region
1) The template strand of DNA (3’-5’) serves as a template to make an RNA copy of the non-template (5’-3’). 2) The RNA copy specifies where translation should start and end, also the amino acid sequence of the encoded protein.
Terminator Region
1) Contains binding sites for other factors that cause RNA Polymerase to stop transcription and leave the DNA. 2) Specifies the end of the RNA and how it should process the end
Introns
the non-coding part of the DNA that gets removed during the processing mRNA
Exons
The coding part of the DNA
mRNA
Encodes proteins and are translated by ribosomes
rRNA
Make up the majority of ribosomes, including most of the enzymatic functions
tRNA
Essential for translation of proteins
Eukaryotes
Multicellular organism (US!)
Caps and tails are added to…?
Eukaryotic RNA’s. Cap to 5’ and tail to 3’
How is the central dogma infiltrated?
DNA–transcription–>RNA–translation–>Polypeptide
How does the mRNA nucleotide sequence code for a protein amino acid sequence?
To code for 20 amino acids, need at least 3 nucleotides (4x4x4) = 64 codons. Thus a triplet code (3 nucleotides code one amino acid) seemed likely.
What are the stop codons for mRNA?
UAA, UAG, UGA
Point mutations
Caused by base-pair substitution, insertion, or deletion of nucleotides
Base -pair substituions are caused by
replication errors
Insertion or Deletion
Mutations caused by mistakes in repair or replication
Silent Mutation
don’t cause any changes in the encoded protein
Non-silent Mutation
Cause changes in coding. 3 types
mis-sense mutation
codon changed to a different amino acid
non-sense mutation
codon changed to stop
frame-shift mutation
insertion/deletion causes a change in codon reading frame
Darwin’s observation that fossil animals shared features with modern organism led to the conclusion that
Species change over time
Ecological niche
How an organism or population responds to the distribution of resources and competition. Unrelated organisms in similar environments look the same.
Convergent Evolution
Process by which unrelated organisms acquire very similar adaptations because of similar environments.
Adaptive Radiation
Rapid phenotypic adaptation of species to a range of environments resulting in physiological adaptations
The target of natural selection is?
the Individual
Heritable variation
Trait to pass on
3 conditions for natural selection
1: Heritable variation 2: Organisms struggle to survive 3: Organisms differ in fitness
Fitness
The relative reproductive success of an individual
Sickle cell anemia phenotypes
SS = Normal red blood cells Ss = Some red blood cells are misshapen and deflated, but not sickled ss = red blood cells are sickled, leads to anemia
Why are malaria and Sickle cell anemia found in the same regions of the world?
SS = More likely to die from malaria Ss = Cells are less likely to be infected by malaria ss = Die of anemia
Gene pool
Total of all the alleles of gene that occur in a population. All members of a single species have the same genes but different alleles. EX: Dogs (different breed)
Hardy- Weinberg equation
1=p^2 + 2pq + q^2 p^2 = frequency of homozygous (BB) 2pq = frequency for heterozygous (Bb) q^2 = Frequency of homozygous (bb)
H-W only holds if?
No evolution (No mutation, nor migration, no genetic drift, no natural selection, random mating)
Mutation
Spontaneous change of DNA
Gene Flow
Brings new alleles into the population (Have to contribute to the gene pool)
Genetic Drift
Genetic change by chance alone. (Strongest in small populations)
Natural selection
Results in the survival and reproductive success of individuals best adapted to their environment. Not random
Non-random mating
Individuals select mates based on phenotypes (EX: Giraffes). Includes inbreeding
Endemic
Only found in particular area and nowhere else
Peter and Rosemary Grant
Study finches on the Galapagos islands.
Directional Selection
Favors individuals at one end of the phenotypic range
Stabilizing selection
Favors intermediate individuals (Pressure against the extremes)
Disruptive selection
Favors individuals at BOTH extremes (Pressure against the intermediate)
Frequency-Dependent Selection
If a rare phonetype is more fit it will spread throughout th population therefore it is no longer rare. Sometimes it is only fit if it IS rare
Taxon
Group at end of Phylogenic tree
Phylogenic tree
Shows relationships between different individuals or groups
Sister Taxa
Most recent, common ancestor
Trees can rotate around?
Node
Speciation
Through generations, genes of an individual are passes from generation to generation. Do not extend much between species.
Taxonomy
Science of distinguishing species
Biological Species Concept
Groups of actual or potential breeding groups which are reproductively separated
Phylogenetic Species Concept
Group of organisms that share an ancestor and are distinct from other lineages
Allopatric Speciation
two geographically isolated populations that become separate over time.
Sympatric Speciation
Changes in genome/polity. Can’t interbreed, different chromosomes. No geographic seperation
Prezygotic barriers
Block the formation of a zygote from occurring by preventing the successful completion of mating, and hindering fertilization if mating is successful. Geographical isolation, Mechanical isolation, behavioral isolation
Postzygoti barriers
Sterile hybrids, genes of the different parent species may impair hybrid’s development
Tundra
- Found further north
- Not a lot of rain
- Pretty cold
- Boggy
- Layer of permafrost that never melts
Boreal Forest
- Largest biome
- Still north
- Conifers (Pine trees)
- Canada
Temperate Forest
- Very seasonal
- Canopy and shrub layers
*
Temperate Grassland
- No trees, lots of shrubs
- Capable of supporting large herbivores
- Seasonal Variation
- Colorado
Desert
- Capable of storing water
- Sporadic rainfall
- Nocternal mammals
- Variable tempertures
Tropical Forest
- Lots of rain
- Little plants
- No severe seasonal change
- Brazil
