U4 AO2 Flashcards
Name these deffinitions:
-Gene pool
-Gene frequency
-Gene pool: Collection of all the alleles (alternate forms of genes) within a population (group of individuals living in the same place at the same time).bigger gene pools equate to higher gene frequencies and an increased number of phenotypes and genotypes within the population.
-Gene frequency; how often an allele is present within a population
What are mutations
Random and rare permanent changes to an organisms DNA sequence sparked by either mutagens or environmental factors.These changes to the nucleotide sequnce alter the folding and therefore functioning of proteins meaning these mutations can either be Advantageous,neutral or deleterious.Mutations have the ability to introduce new alleles into a new population however for this to happen mutations must occur in the gamete cells (Teste and ovum) of an organism,ensuring its heritability.
Explain all the forms of point mutations (Mutations only affecting a single nucleotide)
Silent:Due to the degenerate (Redundant) nature of nucleotides, changing 1 nucleotide can still code for the same amino acid and therefore protein.
Misense:Mutations of nucleotides causing a different amino acid and protein to be formed
Nonsense:Mutations causing a stop codon to prematurly occur,causing a shorter and perhaps non functioning protein to be formed.
Frameshift :Adding or deleting a nucleotide changing the way in which amino acids are read.
Name the types of block mutations (Changes to longer sections of DNA,causing significiant change in the sequence,involves the altercation of chromosome structure)
Anaploidy:the addition or deletion of a chromosome
Polyploidy:Instead of sets of 2, there is 3 chromosomes in each pair
What are environmental selection pressures?
Factors in the environment affecting an organisms ability to survive and reproduce.Its because of this that natural selection is able to occur.organisms with selective advantage for the selection pressure are considered to be “fitter”and are favoured to survive passing on the advantageous allele.
What are the 4 conditions of Natural selection
-Variability;there is a range of alleles within a population
-Selection pressure:Environmental acts on the population
-Selection advantage:Organisms with selective advantage are more likely to surive
-Heritability:Organisms with selective advantage that survive produce fertile and viable offspring passing on the adavnatagous allele
How does natural selection effect a populations genetic diversity?
As advantagous traits become more frequent within a polpulation due to natural selection the populations genetic diversity (The range of alleles within population) decreases.This is negative since the survivability of an organsim depends on its genetic diversity and its ability to adapt to new selection pressures.
Name these deffinitions
-Genetic drift
-Bottleneck effect
-Founder effect
genetic drift is a random event such as a natural disaster reducing a populations genetic diversity.
Bottleneck effect:Random event such as a natural disaster reducing populations genetic diversity
Founder effect:When small part of a population goes to a different area starting there own population which is unrepresentative of the original Population
Both the bottleneck effect and founder effect reduce genetic diversity.
Why is genetic diveristy disadvantagous?
Populations with low genetic diiversity have low adaptive potential to new selection pressures, and there are higher chances of inbreeding (breeding between the same species) to occur causing a higher chance of harmful alleles within the gene pool.
name these deffinitions?
-Gene flow
-immigration
-Emigration
-Interbreeding
Geneflow:The flow of different alleles through a population via migration or interbreeding
Immigration:The movement of new alleles into a population, which increases their genetic diversity and therefore the populations survival
Emigration:The removal of new alleles into a population which decreases the genetic diversity and therefore decreases the organisms survivability
Interbreeding:breeding between 2 different species causing populations too share alleles.Interbreeding increases a populations genetic diversity and therefore increases their survival rates.
What is allopetric speciation.
Speciation that occurs due to a geographical barrier.It occurs via a geographical barrier that seperates the population causing different selection pressures and the process of natural selection to favour different selective advantagous to occur.Eventually genetic differences are formed leading to speciation.A famous example of allopetric speciation are gallopagous finches.
what does a species refer too
group of individuals that can breed together to form viable and fertile offspring.
What is Sympotratic speciation
Speciation that occurs without a geographical barrier.It can also form from abnormalities in gamete production causing polyploidy. A famous example of sympotratic speciation is howea plants.
What is selective breeding?
Occurs when humans add or remove alleles from a population via controlling breeding processes.Meaning the humans are acting as the selection pressure.Selective breeding can limit genetic diversity and lead to an overexpression of deleterious alleles,causing lower adaptive potentials and inbreeding.
name these deffinitions
-Antimicrobial agent
-Antimicrobal resistance
-Antibiotic resistance
-Antimicrobial agent:An agent that slows or kills bacteria growth (Disinfectants,antisepetics,antivirals)
-Antimicrobal resistance:Ability of a microorganism to survive against a antimicrobal agent
-Antibiotic resistance:Resistance to antbiotics that has occured due to natural selection, with antibiotics acting as a selection pressure.
How does antibiotic resistance occur
Variability:There is a variety of both resistant (due to mutations) and non resistance antibiotics bacteria
Selection pressure: Antibiotics is introduced acting as a selection pressure killing all non resistance antibiotic resistant bacteria
Selection advantage:Only resistant bacteria survive
heritability:Surviving bacteria are able to grow and reproduce
What kind of modifications make a cell antibiotic resistant?
-Imperiability of cell wall
-Inactivation via addition of a phosphate group
-Pumping out
-Modification (Changing the protein shape)
name some factors leading to antibiotic resistance?
-Not following/Finnishing an antibiotics plan, allowing any bacteri with resistance to replicate
-Antibiotics is prescribed when not needed,exposing it to natural flora
-A widespreas use of antibiotics
Name these deffinitions
-Antigenic drift
-Antigenic shift
Antigenic drift:Small and gradual changes changes to surface antigens that eventually cause a virus to become unrecognisable
Antigenic shift:Sudden and significant changes, mutating too form new virus.Antigenic shift commonly occurs when 2 viruses effect the same host cell causing a viral recombination process to occur forming a new virus subtype.
