Untitled Quiz

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What characteristic distinguishes Charophytes from other green algae?

They consist of unicellular organisms only.

They gave rise to land plants. (correct)

They lack photosynthetic pigments.

They are exclusively marine species.

Which of the following statements about Volvox is true?

Volvox has a greater number of cells than Ulva.

Volvox forms a solid multicellular structure.

Volvox is a unicellular organism.

Volvox demonstrates cellular specialization. (correct)

What is a common use of agarose derived from Rhodophyta?

To enhance flavor in food products.

As an energy source in cellular respiration.

As a solidifier in nutrient culture media. (correct)

To replace dairy products in ice cream.

What type of lifecycle do some colonial chlorophytes like Volvox exhibit?

Both asexual and sexual reproduction. Signup and view all the answers

Which of the following groups includes multicellular organisms specifically among green algae?

Both Chlorophyta and Charophytes. Signup and view all the answers

What is a key difference between eukaryotic cells and prokaryotic cells?

Eukaryotic cells possess a more complex cytoskeleton. Signup and view all the answers

The theory of endosymbiosis explains the origin of which cellular structures?

Chloroplasts and mitochondria Signup and view all the answers

Which group is not classified under the Domain Eukarya?

Bacteria Signup and view all the answers

What characterizes the cells found in early eukaryotic microfossils?

Presence of a nuclear envelope Signup and view all the answers

Which of the following is part of the SAR supergroup under Protista?

Dinoflagellates Signup and view all the answers

What process describes the living together in close association of two different organisms where one lives inside the other?

Endosymbiosis Signup and view all the answers

Which of the following groups includes organisms like Euglena and Trypanosoma?

Kinetoplastids Signup and view all the answers

What significant feature developed from infolding of the plasma membrane in ancestral eukaryotic cells?

Nuclear envelope Signup and view all the answers

Which kingdom under Domain Eukarya is primarily responsible for photosynthesis?

Plantae Signup and view all the answers

Which type of organism might be studied in a course on botany?

Land plants Signup and view all the answers

Which process led to the formation of red algae from cyanobacteria?

Endosymbiosis Signup and view all the answers

What characterizes the reproduction process in Euglenids?

Mitosis with intact nuclear membrane Signup and view all the answers

In what way do chloroplasts and mitochondria replicate?

By binary fission Signup and view all the answers

Which of the following best describes the protist group?

Polyphyletic with high diversity Signup and view all the answers

Which feature distinguishes Euglenozoans within Excavata?

Unique feeding groove Signup and view all the answers

What distinguishes flagella from cilia in protists?

Length and number Signup and view all the answers

Which of the following is true about mixotrophs?

They utilize both phototrophic and heterotrophic nutrition. Signup and view all the answers

Which of the following organisms is an example of a parasitic kinetoplastid?

Trypanosome Signup and view all the answers

What is a prominent component of the cell wall in red algae?

Cellulose Signup and view all the answers

What type of locomotion is primarily seen in amoebas?

Pseudopods Signup and view all the answers

How do protists typically exhibit diversity?

Morphological variations and modes of nutrition Signup and view all the answers

What is the advantage of sexual reproduction in protists?

Allows for frequent genetic recombination Signup and view all the answers

What is the primary function of cilia in protists?

Feeding and locomotion Signup and view all the answers

What characterizes the supergroup SAR?

Comprises three branches: Stramenopila, Alveolata, and Rhizaria Signup and view all the answers

What is the primary use of algin produced by giant kelps and other brown algae?

Stabilizer in food products Signup and view all the answers

Which component is NOT a characteristic of diatoms?

Presence of cilia for movement Signup and view all the answers

What environmental condition can lead to red tide blooms caused by dinoflagellates?

Nutrient runoff Signup and view all the answers

How do ciliates, such as Paramecium, accomplish movement?

Through cilia Signup and view all the answers

Which statement about apicomplexans is true?

They are spore-forming animal parasites. Signup and view all the answers

What is the function of the apical complex in Apicomplexans?

To invade host cells Signup and view all the answers

Which group does the term 'Stramenopila' belong to?

Supergroup: SAR Signup and view all the answers

Which of the following best describes the locomotion of Rhizaria?

Flowing cytoplasmic projections Signup and view all the answers

What is a major ecological role of diatoms?

They serve as food for fish. Signup and view all the answers

Which statement is false regarding the classification of green algae?

All green algae are freshwater organisms. Signup and view all the answers

What is the primary composition of the shells formed by foraminifera?

Calcium carbonate Signup and view all the answers

What characteristic is shared by all members of the Supergroup SAR?

They include both autotrophs and heterotrophs. Signup and view all the answers

In which environment do dinoflagellates typically thrive?

Aquatic environments Signup and view all the answers

What is the significance of diatomaceous earth?

It's used for industrial filtration. Signup and view all the answers

What is considered the most promising long-term solution for managing diseases caused by parasites?

Development of a vaccine Signup and view all the answers

Why is eradicating all mosquito vectors considered challenging?

Many eradication methods can harm the environment Signup and view all the answers

What is a potential drawback of using treatments to kill parasites?

The parasite can become resistant to new poisons or drugs Signup and view all the answers

What characteristic of a vaccine makes it preferable over drugs and pesticides in the long run?

It reduces the need for ongoing treatments Signup and view all the answers

In the context of biological classification, which of the following groups includes Euglena?

Excavata Signup and view all the answers

Which of the following statements about drug resistance in parasites is accurate?

Drug resistance can develop over time with repeated treatments. Signup and view all the answers

Which group in the Protista cladogram is known for containing several types of algae?

Stramenopila Signup and view all the answers

Which of the following is a feature of the Protista Supergroup Excavata?

It includes organisms with flagella for movement. Signup and view all the answers

Study Notes

Protist

Protists are classified as eukaryotes, which are organisms with a nucleus and other membrane-bound organelles.
Protists are grouped together because they are not fungi, plants, or animals, rather they are a diverse group and have no unifying characteristics.
Protists vary widely in size, shape, and mode of nutrition, ranging from single-celled organisms to multicellular forms.
Protists can have different types of symmetries, and exhibit a range of nutritional strategies, including photosynthesis, heterotrophy, and mixotrophy.

Five Supergroups of Protists

Protists are polyphyletic, meaning they do not include the most recent common ancestor and all its descendants.
There are five supergroups of protists: Excavata, SAR (Stramenopila, Alveolata, Rhizaria), Amoebozoa, Opisthokonta, and Archaeplastida.

Early Eukaryotic Origins

Eukaryotic cells differ from prokaryotes in two significant ways: the presence of a more complex cytoskeleton and compartmentalization (nucleus & organelles).
The earliest eukaryotic fossils date back about 1.5 billion years ago (BYA).

The Origin of the Nucleus and ER

The nuclear envelope and endoplasmic reticulum (ER) originated from infoldings of the plasma membrane.
The nuclear envelope eventually enclosed DNA to form the nucleus.

The Endosymbiotic Theory

The mitochondria and chloroplasts of eukaryotic cells likely originated from engulfed prokaryotic cells.
Aerobic bacteria were engulfed by ancestral eukaryotic cells, which then evolved into mitochondria.
Photosynthetic bacteria were engulfed by other ancestral eukaryotic cells, which then evolved into chloroplasts.
- This process is called endosymbiosis, which is an intimate, long-term association between two different species.

The Evolution of Brown and Red Algae

Red algae likely originated from a eukaryotic cell engulfing cyanobacteria.
Brown Algae likely originated from a eukaryotic cell engulfing red algae.
It is possible that all chloroplasts derived from a single line of cyanobacteria.

Evidence for Endosymbiosis

Many symbiotic relationships exist in nature.
Mitochondria and chloroplasts have their own circular DNA, similar to bacterial DNA in size and organization.
Ribosomes inside mitochondria are similar to bacterial ribosomes.
Chloroplasts and mitochondria replicate through binary fission, not mitosis, which is a process that evolved in eukaryotes.

Cell Surface Variation in Protists

Some protists lack a cell wall, such as Amoeba and Euglena.
- Euglena has protein strips that surround its plasma membrane.
Other protists have cell walls, such as red algae (cellulose cell walls) and diatoms (silica cell walls).

Locomotion in Protists

Protists use a variety of methods to move.
** Flagella** are long, whip-like structures that propel cells through water.
Cilia are short, numerous hairs that are used for movement and feeding.
Pseudopods are temporary projections of cytoplasm that allow protists to move and engulf food.

Nutrition in Protists

Autotrophs produce their own food through photosynthesis.
Heterotrophs obtain energy from organic material created by other organisms.
- Phagotrophs engulf particles of food into food vacuoles.
- Mixotrophs can both produce food through photosynthesis and obtain it from external sources.

Reproduction in Protists

Asexual Reproduction is the primary mode of reproduction in protists.
- It involves a single parent cell that divides to produce genetically identical offspring.
Sexual Reproduction also occurs in protists, which includes:
- The fusion of haploid gametes produced by meiosis.
- Genetic recombination, which increases diversity.

Multicellularity in Protists

Multicellularity originated in protists.
Multicellularity can lead to specialization.
- A thallus is a well-formed multicellular structure.

Supergroup: Excavata

Excavata is characterized by a feeding groove that looks like it was excavated from the side of the cell body.
Excavata includes Euglenids (Euglena) and Kinetoplastids (Trypanosoma).

Supergroup: Excavata: Group: Euglenozoa

Euglenids are a diverse group that includes both free-living and parasitic forms.
- Euglena.
Kinetoplastids are parasitic protists that have a unique, single mitochondrion.
- Trypanosoma.
- Trypanosoma causes diseases such as Leishmaniasis, African sleeping sickness, and Chagas disease.

Supergroup: SAR

SAR is composed of three groups: Stramenopila, Alveolata, and Rhizaria.

Supergroup: SAR: Group: Stramenopila

Stramenopila includes brown algae and diatoms.

Supergroup: SAR: Group: Stramenopila: Subgroup: Brown Algae

Brown algae are a prominent group of seaweeds.
- They contain the pigment fucoxanthin, which gives them their characteristic brown colour.
- Giant kelp is a large and important species of brown algae.
- Brown algae produce algin, a substance used as a thickener and emulsifier in various products.

Supergroup: SAR: Group: Stramenopila: Subgroup: Diatoms

Diatoms are photosynthetic, single-celled organisms with unique double shells made of silica.
Diatoms are an important food source for marine organisms.
Diatomaceous earth is a product made from the fossilized shells of diatoms, which has various industrial uses.

Supergroup: SAR: Group: Alveolata

Alveolates are characterized by flattened sacs called alveoli stacked in layers below their plasma membrane.
Alveolates include dinoflagellates, apicomplexans, and ciliates.

Supergroup: SAR: Group: Alveolata: Subgroup: Dinoflagellates

Dinoflagellates are photosynthetic, unicellular organisms with two distinct flagella.
Some dinoflagellates are luminescent, producing twinkling or flashing effects in the sea at night.
Dinoflagellate blooms, also known as red tides, are caused by an excessive increase in dinoflagellate populations, which can release toxins that cause harmful effects to various organisms, including humans.

Supergroup: SAR: Group: Alveolata: Subgroup: Apicomplexans

Apicomplexans are parasitic protists characterized by an apical complex, an organellar arrangement that allows them to invade host cells.
Plasmodium is an apicomplexan that causes malaria, a disease transmitted by mosquitoes.

Supergroup: SAR: Group: Alveolata: Subgroup: Ciliates

Ciliates are protists with large numbers of cilia arranged in longitudinal rows or spirals around the cell.
Ciliates are characterized by having two nuclei:
- A micronucleus used for sexual reproduction.
- A macronucleus essential for daily functions.
Paramecium is a well-known and often-studied example of a ciliate.

Supergroup: SAR: Group: Rhizaria

Rhizaria are heterotrophic protists that use pseudopods to move.
Rhizaria includes:
- Radiolaria (marine).
- Foraminifera (marine).
- Cercozoa (soil).

Supergroup: SAR: Group: Rhizaria: Subgroup: Foraminifera

Foraminifera are marine protists that have shells made of calcium carbonate.
Foraminifera play a role in the formation of limestone.

Supergroup: Archaeplastida

Archaeplastida includes red algae, green algae, and land plants.
Green algae are divided into two lineages:
- Chlorophyta.
- Charophyta, which are the closest relatives to land plants.

Supergroup: Archaeplastida: Group: Rhodophyta (Red Algae)

Red algae are multicellular, marine protists.
They contain phycobilins, accessory photosynthetic pigments that give them their characteristic red color.
Agarose, a substance derived from red algae, is used in various applications.

Supergroup: Archaeplastida: Group: Chlorophyta (Green Algae)

Chlorophyta is a diverse group of green algae that include:
- Unicellular forms, such as Chlamydomonas.
- Colonial forms, such as Volvox.
- Multicellular forms, such as Ulva.

Supergroup: Archaeplastida: Group: Charophyta (Green Algae)

Charophyta are the closest relatives to land plants.
- They share many similarities with land plants in terms of their biochemistry and structural features.

Cellular Specialization in Colonial Chlorophyta

Cellular specialization is a defining feature of multicellularity.
Volvox is a colonial green algae with a hollow sphere made of a single layer of cells.
- Some cells reproduce asexually, while others reproduce sexually.
Ulva is a multicellular green algae that forms a complex thallus.

Vaccine Development

Vaccine development is the most promising way to combat the spread of parasitic diseases in the long run.
Vaccines provide long-term protection against parasites.
Vaccines eliminate the need for harmful pesticides or drugs, which can lead to drug resistance.

Challenges of Eradication

Eradicating mosquito vectors is difficult.
Eradication methods can be harmful to the environment.
Parasite resistance is a real concern with drug treatments.

Protist Cladogram

Protists are a diverse group of eukaryotic organisms.
The Protist cladogram shows the evolutionary relationships between different protist groups.
Protists are classified into supergroups, groups, and subgroups.

Supergroup Amoebozoa

Amoeba proteus is an example of a protist found in the Amoebozoa supergroup.

Supergroup Excavata

Euglena is an example of a protist found in the Excavata supergroup. This group includes Euglenozoa and Parabasalids.
Termite flagellates are parabasalids.
Leishmania donovani is a parabasalid which causes Leishmaniasis.
The Excavata group includes organisms with flagella.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.