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BS1040: Microbiology and Cell Biology > MC2: The eukaryotes > Flashcards

Flashcards in MC2: The eukaryotes Deck (40)
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What are the two key differences between a prokaryote and a eukaryote?

Prokaryotes have a nuceloid and no organelles

Eukaryotes have a nucleus and membrane-bounds organelles


How do unicellular eukaryotes reproduce?

Asexually by mitosis when in favourable conditions

Sexually by meiosis and syngamy under stressful conditions (e.g. nutrient limitations and DNA damage)


Who invented the first microscope? Why?

Antonie van Leeuwenhoek whilst trying to look at the quality of thread


What discoveries did Antonie van Leeuwenhoek make? When?

  • 1674: protists (known as infusoria) in lakes
  • 1676: the vacuole of the cell
  • 1677: spermatozoa
  • 1682: the banded pattern of muscular fibres
  • 1683: bacteria such as Selenomonads from the human mouth


What were protista?

The ancestor of plants, fungi and animals


What is a monophyletic group?

A group containing a common ancestor and all of its descendents


What is a paraphyletic group?

A group that contains its most recent common ancestor, but does not contain all the descendents of that ancestor


What is a polyphletic group?

A group that does not contain the most recent common ancester of all its members


What defines a protist?

  • "A eukaryotic microbe that is not an animal, plant, or (true) fungus"
  • Simple and primitive organisms
  • Unicellular
  • Motile and lack cell walls
  • Taxonomy still changing


What are the three major types of protist?

  1. Fungus-like slime/water moulds, e.g. slime mould
  2. Animal-like protozoa, e.g. amoeba
  3. Plant-like algae, e.g. Euglena


How do protists differ from:

  1. prokaryotes
  2. animals
  3. fungi?

  1. The cells have features of eukaryotes and cells are bigger
  2. They are always unicellular
  3. They are motile and lack cell walls


Where do all free-living protists live?

In water


What type of symmetry do protists display?

Asymmetry or radial/bilateral symmetry


What are the different types of protist locomotion?

  • Finger-like pseudopodia, e.g. amoeba
  • Whip-like flagella, e.g. Euglena
  • Hairy cilia (used to direct food into mouth), e.g. Paramoecium
  • By contraction
  • No motion


Define 'holozoic'.

A form of nutrition where a whole particle is taken in via the vacuole


Define 'mixotrophic'.

A form of nutrition where particles are taken in and photosynthesised


Define 'parasitic' in terms of nutrition

A form of nutrition involving feeding off the host organism


Define 'saprozoic'

A form of nutrition where protists live on decaying matter


What are the four main types of nutrition of protists?

  1. Holozoic
  2. Mixotrophic
  3. Parasitic
  4. Saprozoic


Is digestion in protists intra- or extracellular?

Intracellular, occuring in the food vacuole


How do respiration and excretion take place in protists?

By the exchange of gases through the body surface

Some excretion occurs through contractile vacuole


What is a protist's nitrogenous waste and how is it excreted?

Ammonia, excreted through urea


How do some fresh-water protozoa get rid of excess water?

Through contractile vacuoles


What caused the Irish potato famine?

Phytophthora infestans came to Europe in the 1800s and caused the potato famine of 1845

It is an oomycete and is very flexible and adaptable, and finds ways to escape plant resistance

Researchers and plant-breeders are developing a resistance involving multiple genes to slow the spread of the fungus


Why has Dictyostelium discoideum been studied lots?

It is a cellular slime mould that has been used as a model for studying intercellular communication and cooperation amongst microbes

It is used as a model to understand human muscle


How many species of Plasmodium parasite cause malaria in humans? Name these species.


  1. P. falciparum
  2. P. vivax
  3. P. ovale
  4. P. malariae
  5. P. knowlesi


How can free-living aquatic amoeba cause disease in humans?

They can either eat bacteria or other amoeba and can farm or house bacterial pathogens which cause disease


Which type of protist fixes up to half the CO2 in the oceans? How?

Plant-like protists

They photosynthesise using chlorophyll and other pigments


What are diatoms and what is their structure?

  • Producers in the food chain that are structured like a petri dish
  • They have walls made of silica and pectin


What is the role of diatoms in the oceans?

They fix carbon and monitor water status