The Rise of Eukarya

Question 1

What is the advantage of organisms being ‘wall-less mutants’?

Answer 1

taking advantage of one of the most abundant food sources – other cells. Internal digestion is possible now. But now it is important to have lysosomes and nuclear membrane

Question 2

why is an envelope necessary for wall-less mutants

Answer 2

DNA is at risk of enzyme degradation when food is taken in

Question 3

how did mitochondria arise in eukaryotic cells?

Answer 3

By an engulfment process, where aerobic bacteria were enslaved to produce more energy using oxygen (Endosymbiosis theory)

Question 4

what evidence is there for the arising of mitochondria in cells?

Answer 4

Double membrane
Own DNA (bacteria type DNA-plasmid)
Divide by what seems to be binary fission (bacterial asexual reproduction)
Pelomyxa contains no mitochondria, but instead has symbiotic bacteria inside

Question 5

6 most important changes in evolution of eukaryote

Answer 5

• mitochondria
• motor proteins
• mitosis
• chloroplasts
• sexual reproduction
• multicellularity

Question 6

mitochondria

Answer 6

• endosymbiosis theory

Question 7

motor proteins

Answer 7

molecules that move material around the cell
provide movement for the cells
cytoplasmic streaming
thought to be a symbiotic relationship with bacteria (cilia and flagella)
allowed for behaviour to develop

Question 8

mitosis (and chromosomes)

Answer 8

copying of genetic material to allow for the distribution of a copy to each cell
growth, repair or replace cells, asexual reproduction unicellular organisms
much more efficient than relying on the random distribution

Question 9

chloroplasts (and photosynthesis)

Answer 9

evolved from green symbionts that live inside cells for protection, while providing the cell with food by photosynthesis
chloroplasts contain DNA, replicate like bacteria, have bacterial ribosomes, antibiotics kill them – this indicates that they likely began as a symbiotic relationship
chlorophyll molecules are found in different combinations in eukaryotic photosynthesizers
symbiotic relationships still exist (sea squirts, hydra etc)

Question 10

sexual reproduction

Answer 10

more complexity and diversity
fusing together to exchange genes
produces genetic variety for natural selection to act on
diploid haploid cycle for new variety

Question 11

multicellularity

Answer 11

colonies help to avoid predation

division of labour