3. 1. 5 - Domains, kingdoms or both? Flashcards
what is molecular phylogeny?
the analysis of genetic material of organisms to establish their evolutionary relationships
why is molecular phylogeny important?
- it supports and clarifies the relationships based on morphology
- it allows scientists to analyse the structures of chemicals / DNA to identify inter-relationships between groups of organisms
what is gel electrophoresis?
a method of separating fragments of proteins or nucleic acids based on their electrical charge and size
- improving species identification and the development of evolutionary models
explain the process of gel electrophoresis.
- DNA cut into fragments using restriction endonuclease enzyme
- wells filled with solutions containing DNA fragments are placed into an agarose plate with a buffer (used to keep a constant pH) at the opposite end (with a positive charge - DNA has a negative phosphate group)
- an electrical current is passed through the apparatus and the DNA fragments move towards the positive anode
- as the fragments move towards the positive electrode, shorter (+ more negative) fragments move faster (and therefore further)
- once the electrophoresis is complete, the plate is placed under UV light so the bands can be identified
what dye is added and when?
- dyes are not added to the gel/ mixture
Ninhydrin is added to the gel after electrophoresis
- used to identify and compare the amino acids in particular protein
it reacts with amino acids so they show up as purple patches and can be compared with known amino acids
what are some examples of two organisms with a biochemical relationship?
- Vertebrates and echinoderms
- blood pigments: any one group contains only one type of blood pigment
- analysis of amino acids
- a combination of DNA analysis, protein analysis and anatomical observations
what is an endosymbiont?
an organism that lives inside the cells or the body of another organism
how could eukaryotes have evolved from prokaryotes?
- eukaryotic cell engulfs aerobic prokaryote as food
- in some cells, the aerobic prokaryote is not digested
- it uses oxygen for cellular respiration
- aerobic prokaryotes become permanent feature as mitochondria
- passed on to daughter cells during reproduction
after looking at how eukaryotes may have developed from prokaryotes, what theory developed?
- 3 domain theory: Archaea Bacteria Eukaryota (research shows they all probably had a common ancestor around 3 billion years ago)
in the modern classification system, what are the 6 kingdoms?
Eubacteria Archaea bacteria Protoctista Fungi Plantae Animalia
what is the Archaea bacteria kingdom?
- prokaryotic cells
- ancient bacteria
- include extremophiles
- normally reproduce asexually
what is the eubacteria kingdom?
- prokaryotic cells
- true bacteria
- cyanobacteria
- normally reproduce asexually
what is the protoctista kingdom?
- eukaryotic cells
- includes all single-celled organisms
- catch-all for the other organisms that don’t fit other kingdoms
- mainly reproduce asexually
what is the fungi kingdom?
- eukaryotic cells
- unicellular organisms and multicellular organisms
- all heterotrophs
- can reproduce both asexually and sexually
what is the plantae kingdom?
- eukaryotic cells
- all multicellular
- almost all autotrophs
- reproduce both asexually and sexually
