LEC 2: ALGAE AND ALGAL SYMBIOSIS

Question 1

Are protists considered plants, animals or fungi?

Answer 1

Neither, they are the progenitor of all Eukaryotes

Question 2

Why are protists that share similar characteristics with plants, like photosynthesis, not considered plants?

Answer 2

Because protist photosynthesizers have a different chloroplast endosymbiosis event

Question 3

Explain why Algae are considered a polyphyletic group

Answer 3

Because although different species of algae share similar characteristics, they do not get those characteristic similarities from a common ancestor.

Question 4

True or False; red algae must be red (color)

Answer 4

False, they do not always have to be red

Question 5

What pigment causes a red color in Red Algae

Answer 5

Phycobiliprotein

Question 6

What function(s) does phycobiliprotein serve in Red Algae

Answer 6

Helps with light capturing during photosynthesis and protects the algae from harmful UV rays

Question 7

Do red algae harvest light directly? Why or why not?

Answer 7

Red algae only have phycobiliprotein and chlorophyll a pigments. They photosynthesize using these pigments but do not harvest light directly because they are missing chlorophyll b pigment.

Question 8

What feature excludes red algae from the Viridiplantae class?

Answer 8

Red algae do not have Chlorophyll B pigment and are therefore not considered green/land plants

Question 9

What is a Glaucophyte and what feature differentiates it from others of its kind?

Answer 9

• Glaucophytes are unicellular progenitors of green/red algae
• The membrane of its chloroplasts still have remnants of bacterial residue (peptidoglycan) which is typically degenerated by eukaryotic cells that have undergone endosymbiosis.

Question 10

What two features are shared among all green algae?

Answer 10

1. They all have Chlorophyll A and Chlorophyll B (light-harvesting) pigments
2. They all store their starches in plastids.

Question 11

What are three factors that make Chlamydomonas an valuable candidate of research?

Answer 11

1. They have red eye spots on their chloroplasts that guide them towards light to help photosynthesis.
2. They still have flagella that are used for motility and during the reproductive cycle.
3. They have pyrenoids which are CCMs (carbon concentrating mechanisms) which are used when Oxygen levels are low.

Question 12

True or False; all green plants must have a cell wall

Answer 12

False - some green plants do not

Question 13

What is a zoospore?

Answer 13

Also known as a gamete, it is a halpoid cell

Question 14

What are the chromosome counts for gametophyte cells and sporophyte cells?

Answer 14

Gametophytes are haploid and have a single set of chromosomes. Sporophytes are diploid and have two sets of chromosomes.

Question 15

I am a composite organism made mostly of green algae as well as fungi and cyanobacteria. I live in a mutualistic symbiosis and you can find me in nearly all ecosystems. Who am I?

Answer 15

Lichen

Question 16

What are a coupe of carotenoids functions?

Answer 16

It protects the cell from UV rays and helps obtain the energy from the sunlight.

Question 17

What environmental shift causes the shift from asexual to sexual stage in Chlamydomonas?

Answer 17

Nitrogen starvation

Question 18

What is a zygote?

Answer 18

A cell that is participating in the reproductive stage of a plant’s life cycle.

Question 19

What is a Mycobiont?

Answer 19

The fungal part of Lichen that provides minerals and protection.

Question 20

What is a Photobiont?

Answer 20

The photosynthesizing/green algae partner in Lichen that harvest light for energy in the form of carbohydrates.

Question 21

What is a protoplasmic thread/conjugation tube? When is it formed?

Answer 21

Early in the reproductive stage, Chlamydomonas zygotes clump together close enough to which their flagella attach.

It is the attachment of flagella to create a tube by which cytoplasmic material is shared.

Question 22

What are the five layers of lichen in order of closest to the surface to the farthest?

Answer 22

Cortex, photobiont layer, loosely packed hyphae, tightly woven lower cortex and anchoring hyphae called rhizines which attach to the substrate and helped in the terrestrialization of plants.

Question 23

The process of exchanging cytoplasmic material is called what?

Answer 23

Plasmogamy

Question 24

What stage of the life cycle are plasmogamy and karyogamy? (diploid/haploid)

Answer 24

Diploid (2n)

Question 25

What process transitions a zygote from a zygospore?

Answer 25

The thickening of the cell wall

Question 26

Can gametes divide by meiosis?

Answer 26

No

Question 27

What is algal symbioses?

Answer 27

The mutualistic partnership between an algal partner and another organism

Question 28

What two organisms have undergone algal symbioses?

Answer 28

Lichen and sea sponges

Question 29

What are a coupe of carotenoids functions?

Answer 29

It protects the cell from UV rays and helps obtain the energy from the sunlight.