Lecture 5: Algae Flashcards

1
Q

Where is photosynthesis widespread?

A

Photosynthesis is widespread (polyphyletic) in Eukaryotes

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2
Q

What are algae?

A

Algae are photosynthetic eukaryotes other than land plants

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3
Q

Describe most algae

A
  1. Most algae are aquatic (both freshwater and marine)

2. Many are unicellular

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4
Q

Describe most multicellular species

A

Most multicellular species produce bodies in which all cells are in contact with the environment (simple multicellularity)

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5
Q

What two things are closely related? What is the group they form called?

A

Plants and green algae are closely related and together form a monophyletic group.

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6
Q

What features of land plants are present in some green algae?

A

Many of the…
1) key physiological
2) structural features
of land plants are present in some green algae

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7
Q

The ____________, ______________, and _________ are the green algae most closely related to land plants.

A

1) Charales
2) Coleochaetales
3) Zygnematales

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8
Q

What do the Charles, coleochaetales, and zygnematales all have?

A

1) All occur in freshwater
2) All have a haplontic life cycle
3) All produce sporopollenin in the cell walls of the zygote

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9
Q

What are the six features found in the green algae and in plants that are thought to have played a role in the transition to land?

A

Great POMPS

1) The use of the enzyme Glycolate oxidase in photoresipiration
2) Phragmoplast
3) Oogamy
4) Matrotrophy
5) Plasmodesmata
6) Sporopollenin

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10
Q

What is oogamy?

A

Oogamy is a mode of fertilization where a nonflagellated gamete (the egg) is fertilized by a flagellated gamete, as in humans

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11
Q

What is matrotrophy?

A

Matrotrophy is the retention of the fertilized egg (the zygote) and supply of “maternal” care to it

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12
Q

What is sporopollenin?

A

Sporopollenin is a complex polymer hat serves a protective function

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13
Q

What is the phragmoplast?

A

The phragmoplast is the cytoskeletal structure responsible for the deposition of the cell plate

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14
Q

What are plasmodesmata?

A

Plasmodesmata are microscopic channels that allow communication between cells

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15
Q

What is glycolate oxidase?

A

Glycolate oxidase increases the efficiency with which 2-Carbon molecules produced during photorespiration are recycled

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16
Q

What is a phylogeny?

A

A phylogeny is a starting point of the evolutionary diversification of plants and a way to organize information about the past

A hypothesis of the evolutionary relationships among species or other entities

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17
Q

What does a node indicate?

A

A node indicates the last common ancestor

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18
Q

What does monophyletic mean?

A

A group consisting of all the descendants of a common ancestor
- MUST all have the SAME last common ancestor

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19
Q

What is a paraphyletic group?

A

A paraphyletic group includes some, but NOT all, descendants

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20
Q

When are paraphyletic groups useful?

A

Paraphyletic groups can be useful when they refer to organisms that are functionally similar
- For example, Turtles, Lizards, and Crocodiles are not all descendants but are functionally similar

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21
Q

Within a Eukaryotic tree, which relationships are unresolved?

A

the deepest relationships are unresolved (polygamy)

- It’s therefore harder to know who’s related to who

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22
Q

What is polygamy?

A

a flat line indicating we don’t know the relationship

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23
Q

What are algae?

A

Algae is an informal term for photosynthetic eukaryotes that are not “land plans” and are typically aquatic
- polyphyletic

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24
Q

What is polyphyletic?

A

when you group an organism by characteristics

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25
Q

Describe rhodophyta

A
  • Red Algae
  • Mostly multicellular
  • Chlorophyll (a & c) and phycobilins (red pigment)
  • Some crustose red algae grow at a depth of 250 meters
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26
Q

What are two traits of algae that are of interest

A

1) Cellulose in cell walls (occurs in all of these groups)

2) Sporopollenin (found in cell walls of some chlorophytes and in land plants and close green algal relatives)

27
Q

Describe green algae

A
  • Chlorophyll a and b
  • starch stored in chloroplasts
  • 2-7 thylakoids stacked in grana
  • stellate flagella
28
Q

State 3 types of green algae

A

1) Chlorophyta
2) Volvox
3) Dasycladales
4) Ulva (sea lettuce)

29
Q

What is chlamydomonas?

A

a unicellular chlorophyte with a haplontic life cycle (vegetative - doing photosynthesis and metabolic activity)

30
Q

Describe gametes

A

gametes can’t live very long - if they don’t fuse then they die
- spores can survive much longer

31
Q

What is ulva?

A

Sea lettuce

- a multicellular chlorophyte with alternation of generations

32
Q

All plants have ______________ and are distinguished by __________

A

All plants have alternation of generations and are distinguished by ploidy

33
Q

All _____________ have a haplontic life cycle

A

All streptophyte algae have a haplontic life cycle

34
Q

Features found in all streptophyte algae

A
  • fresh water
  • haplontic
  • sporopollenin (zygote)
  • phragmoplast
  • plasmodesmata
  • open mitosis
  • glycolate oxidase
35
Q

What feature did all 3 candidates of the closest alga relative to plants share?

A

the presence of sporopollenin in the wall of the zygote

36
Q

What is sporopollenin?

A

Sporopollenin is the most degradation resistant polymer known
- protection from UV radiation, desiccation, damage

37
Q

Where do green algae grow?

A

green algae grow in freshwater habitats where water levels fluctuate

38
Q

Filaments type of cell division

A

filaments, single plane of cell division

39
Q

Sheets type of cell division

A

Sheets, two planes of cell division

40
Q

Parenchymatous type of cell division

A

Parenchymatous, three planes of cell division

41
Q

_________ and ________ allow for complex multicellular development

A

phragmoplast and cell plate allow for complex multicellular development

42
Q

What are plasmodesmata?

A

span two cell walls and their connections together - control what moves between them

43
Q

All cells have _____________-

A

intercellular connections

44
Q

What moves between cells?

A

There are intercellular movements of proteins, mRNA, small molecules, and virus particles

45
Q

What happens in “open” mitosis?

A

In “open” mitosis, the nuclear envelope breaks down before the chromosomes separate (and then reforms around the two sets of chromosomes)
- fungi and animals

46
Q

What happens in “closed” mitosis?

A

In “closed” mitosis, the nuclear envelope remains intact (later pinches to form two nuclei)

47
Q

What is rubisco?

A

rubisco is the enzyme that catalyzes the entry of CO2 into the Calvin cycle

48
Q

What can rubisco also catalyze?

A

Rubisco can also catalyze a reaction with O2 (instead of CO2) which leads to a loss of carbon and energy

  • this is because rubisco has trouble distinguishing O2 and CO2
  • higher rates at higher temperatures
49
Q

What is glycolate oxidase?

A

an enzyme that helps mitigate against the losses in carbon and energy that occur when rubisco reacts with oxygen

  • deals with temperature fluctuations
  • selectivity comes with speed –> if very selective also very slow
50
Q

What are oogamous and what does it mean?

A

Choleochaete and Chara/Nitella are oogamous meaning they make eggs and swimming sperm

51
Q

What are conjugating algae and what does it mean?

A

Zygnematales are conjugating algae - fertilization involves cytoplasmic bridges between cells
- eggs don’t move and sperm/male component moves

52
Q

Where are gametes produced?

A

gametes produced in gametangia

53
Q

Where are sperm produced?

A

sperm produced in the antheridium

54
Q

Where are eggs retained?

A

eggs retained in the oogonium

55
Q

All green algae have _________ via ________

A

all green algae have haplontic life cycles via mitosis

56
Q

What are chara lifecycles triggered by?

A

chara lifecycle triggered by stress

form a diploid

57
Q

What is matrotrophy?

A

wall ingrowths indicate nutrient transfer to zygote

58
Q

What do zygotes undergo and what does this produce?

A

zygotes undergo meiosis which produce four haploid daughter cells that undergo 2 to 3 mitotic divisions which produce haploid “meiospores” that then disperse

59
Q

How can haploid alga also reproduce?

A

can also reproduce asexually (mitotically produced zoospores)

60
Q

What are zygnematales?

A

1) no swimming sperm

2) dismiss floating around and have to come into contact with a spirogyra

61
Q

What is desiccation tolerance?

A

the ability to survive drying and go back to metabolic processes when rehydrated

62
Q

What is photorespiration?

A

when rubisco acts on oxygen with an acceptor carbohydrate molecule

63
Q

Gamete vs. spore

A

Gamete: always fuse
- no independent existence

Spore - grow up on its own
- persists

64
Q

What is alternation of generations?

A

genetically distinct in policy