revision exam bio

which three components make up a nucleotide

nitrogenous base, phosphate group and sugar

explain why species should have multiple defintions

living, extinct, sexually reproducing and asexually reproducing organisms must be classified differently.

define competitive exclusion principle

two species competing for same limited resources that cannot occupy the same ecological niche at the same time.

define symbiotic relationship

a close, long-term association between two different species where at least one species benefits,

mutualism (both benefit),

commensalism (one benefits, the other is unaffected),

parasitism (one benefits at the expense of the other)

what are the common assumptions of cladistics  

common ancestry, bifurcation, and physical change

what is the process that tranfers carbon from living organisms to the atmosphere

respiration

what is a point mutation

a genetic alteration in which a single nucleotide in a DNA or RNA sequence is changed, inserted, or deleted.

what is a frameshift mutation

a type of gene mutation that results from the insertion or deletion of nucleotides in a DNA sequence

what is gene expression

genetic information synthesised into a functional product.

what do telomeres do

protect the ends of chromosomes from damage.

what is the primary purpose of polymerase chain reaction (PCR)

amplify specific DNA sequences to produce many copies for anaylsis.

what are histones

proteins essential for packaging DNA into nucleosomes and chromosomes, which forms the basis of chromatin

how does natural selection affect allele frequencies in a population

increasing or decreasing the frequency of alleles to increase survival and reproduction rates.

why are pioneer species effective colonisers in new environments 

they can fix nitrogen and photosynthesise

natural selection

process where organisms with traits better suited to their environment are more likely to survive and reproduce, passing those advantageous traits to their offspring

microevolution and example

are the small scale changes in genetic material. an example is the change in coloration of peppered moths in a industrial poullution.

exons

are the coding regions of a gene sequence, meaning they are transcribed into mRNA and translated into proteins.

introns

are the non-coding intervening sequences that are removed from the RNA transcript before translation.

macroevolution and example

are the large scale changes in the whole taxonomic group. an example is the evolution of whales from land-dwelling ancestors.

clade

a group of organism that includes a common ancestor with all its descendants.

pioneer species

an organism that is first to colonise a disturbed environment.

k-selected speices

• organisms that produce a small number of offspring

• invest heavily in parental care

• high survival rates

• live in stable environments.

r-selected spieces

• organisms with high growth rates that produce many offspring

• low chance of survival

• live in unstable environments

• little parental care

allopatric

requires the physical separation of populations

DNA profiling

used to identify unique genetic information.

Gel electrophoresis

used to separate and analyse macromolecules.

DNA sequencing

used to map genomes.

Polymerase chain

used to amplify a region of DNA.

The steps involved in the production of recombinant DNA are:

• isolation using restriction enzymes

• insertion of DNA fragments into a plasmid vector

• joining of DNA using DNA ligase

• amplification of recombinant DNA

primary succession

in barren areas when organism colonise a habitat for the first time.

secondary succession

occurs after areas that already contain soil and other biotic components have been disturbed and re-colonised.