Genetic information, Variation And Relationship Between Organisms Flashcards
(28 cards)
Phylogenic Classification
- Based upon evolutionary relationships
- Classifies species using shared features derived from their ancestors
- Arranges the groups into a hierarchy
Artificial Classification
Divides organisms by characteristics, such as size or number of legs
Species
-A group of organisms which have similar characteristics and are able to breed to produce fertile offspring
Courtship behaviour includes …
- Species recognition
- Identifying a mate that is capable of breeding
- Pair bond formation
- Synchronisation of mating
- Initiating breeding by bringing a member of the opposite sex into a physiological state that allows breeding to occur
Stabilising selection
- Selection that favours individuals close to the mean, maintains the traits of the population
Directional Selection
-A type of selection that favours individuals that differ in one direction (fall to the left or right) from the population mean. This changes the traits of the population
The reproductive success of individuals affects allele frequency in populations. This happens when:
- Random gene mutations lead to new alleles in a gene pool - the variety of alleles in reproduction
- This nee allele allows individuals to survive and reproduce
- Their offspring inherit the new alleles
- Over many generations, the new advantageous allele will increase at the expense of the less advantageous allele
- The frequency of the new allele increases
What is natural selection?
DARWINISM
- ‘Survival of the fittest’
- Advantageous mutations
- Better adapted to the environment
- Reproductively successful
- Inherit desired alleles
Genetic Diversity is
-The total number of different alleles in a population
Polyploidy
-Changes in the whole sets of chromosomes e.g when organisms have 3 or more sets of chromosomes rather than 2
Non-Disjunction
-When individual homologous pairs of chromosomes Gail to separate during meiosis. The resultant offspring have more or fewer chromosomes in their body cells
Substitution is
-One base is substituted with another
Deletion
-One bad is deleted
Insertion
-One base is added
Gene Mutation is
-Permanent alteration in the DNA base sequence that makes up a gene
Translation
- Is the process of making proteins by forming a specific sequence of amino acids based on coded instructions in mRNA
- RNA polymerase catalysed phosphodiester bonds between adjacent RNA nucleotides and the mRNA strand detached allowing the DNA helix to reform
Transcription
- Section of DNA unwinds
- 1 strand of DNA acts as a template
- Free RNA nucleotides match up with complementary base pairs from the promoter region
- RNA polymerase catalysed reactions to link nucleotides by forming phosphodiester bonds
- At the terminator region,the RNA polymerase detaches
- Pre-mRNA formed
What is splicing?
Where does it take place?
- Splicing is the removal of introns from pre-mRNA to produce mRNA
- Splicing takes place in the nucleus before the mRNA passes into the cytoplasms via a nuclear pore
Introns
-Much of the DNA in eukaryotes does not code for polypeptides. Within genes there are portions of non-coding sequences called INTRONS
Exons
-These sequences within genes which code for amino acids are called EXONS
What is the process of splicing?
-Because the pre-mRNA molecule has been produced using a complete template strand. It still contains INTRONS sequencing which must be removed via SPLICING
Why Doesn’t splicing take place in Prokaryotes?
-In prokaryotes, transcription results directly in the production of mRNA from DNA, this is because the DNA does NOT contain INTRONS
Stabilising selection
-A type of selection that favours individuals close to the mean, maintain the traits of the population
Directional Selection
-A type of selection that favours individuals that differs in one dissection (fall to the left or right) from the population mean. This changes the traits of the population
