Worksheet 2, ProtistsSupplemental InstructionIowa State University

Leader: Delaney R.Course: Biol 211

Instructor: Dr. StewartDate: 9-7-2017

1. True or False? Protists are eukaryotes.

True

2. Malaria is one of the most dangerous infectious diseases on a global scale. What is it caused by?

Parasitic protists Plasmodium – blood flow is restricted and RBC’s cannot get oxygen to every organ

3. What is the mechanism of infection for malaria?

Anopheles mosquito bite -

4. Can you think of a few factors that contribute to the presence of malaria?

High human population densities (more hosts = more parasites), poorer nations not having access to antimalarial drugs or other preventative measures (mosquito nets), and increasing drug-resistance in Plasmodium, insecticide – resistance in mosquitoes (an example of evolution by natural selection.)

5. What was the Irish Potato Famine caused by? a. Virus b. Prion c. Prokaryoted. Protist

6. Can you think of a few factors that contributed to the Irish Potato Famine?

Overreliance on one crop, low genetic diversity in potato population, and social causes.

7. Why must the diatom in this diagram switch from asexual reproduction (mitosis) to

sexual reproduction (meiosis?)

The smaller diatoms cannot divide anymore, so then carry on to produce sperm and egg, fertilize, develop zygote, and grow a mature cell.

8. Does mitosis occur in asexual or sexual reproduction? What about meiosis?

Mitosis – asexual Meiosis – sexual

9. Which of the following statements is true about a protist’s life cycle? a. Their life cycle can include both asexual and sexual reproductionb. Only sexual reproduction is used by a protist c. Protists only use meiosis d. Protists can only perform mitosis

10. Why are protists so important?

Ancestors of plants, fungi, and animals. They are abundant in aquatic ecosystems, autotrophic protists (algae) produce oxygen by photosynthesis, provides habitat for small fish, some protists are decomposers that are important in energy and nutrient flow pathways as well as being consumers (also important in energy and nutrient flow.)

11. There are different feeding strategies of predacious protists. Can you name them and how they work?

Pseudopodia engulf food and cilia sweep food into mouth.

12. Protists are motile which enables them to seek out food and other resources. What are 3 mechanisms they use to move?

Flagella, cilia, and pseudopodia

13. Why would a protist need to utilize both asexual reproduction and sexual reproduction within their life cycle?

To cope with environmental stress or low population numbers.

14. What trophic level do autotrophic protists (algae) belong to?

Primary producers

15. What are some characteristics of protists?

- Eukaryotic - Occur as unicellular or colonies - Simple body plan - Can be heterotrophic or autotrophic (algae) - Autotrophic protists have chloroplasts (unlike autotrophic prokaryotes that

have only chlorophyll.) - They are motile – flagella, cilia, and pseudopodia - Aerobic cellular respiration produces ATP - Reproduce asexually by mitosis and sexually by meiosis..