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Biology 1407 - 02M > Chapter 28 > Flashcards

Chapter 28 Flashcards

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1
Q

Are protists paraphyletic or monophyletic?

A

paraphyletic

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2
Q

What were the first eukaryotes?

A

Protists

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3
Q

Eukaryotic differences from Prokaryotes

A

Presence of a complex skeleton

Compartmentalization (nucleus and organelles).

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4
Q

Appearance of eukaryotes in microfossils occurred about what time?

A

1.5 BYA

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5
Q

The word Eukaryote derived from Greek words means what?

A

True nucleus

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6
Q

Which ways did Eukaryotic cells evolve?

A

Horizontal Gene Transfer

Infoldings of membranes

engulfing other cells

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7
Q

Out of the three ways that Eukaryotic cells evolved to what they are today, which method is the way that the nuclear envelope and endoplasmic reticulum arose?

A

Membrane Infoldings

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8
Q

Bacteria that live within other cells and provide some benefit for their host cells are called?

A

endosymbiotic bacteria (endosymbiosis means “living together in close association”)

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9
Q

How to we know the mitochondria came first when Eukaryotes were first evolving?

A

It is the most widespread common trait in Eukaryotes

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10
Q

Who championed the Theory of Endosymbiosis in 1970?

A

Lynn Margulis

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11
Q

Who first proposed the theory of endosymbiosis in 1905?

A

Konstantin Mereschkowsky

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12
Q

What facts serve as evidence to support the theory of endosymbiosis?

A

DNA inside mitochondria and chloroplasts. (Circular DNA, similar to bacteria DNA in size and character.)

the MRNAs produced from the genes of the mitochondrial genome are translated using ribosomes that are very much like bacterial ribosomes in size and structure

Many antibiotics that inhibit protein synthesis in bacteria also inhibit protein synthesis in mitochondria and chloroplasts

Chloroplasts and mitochondria replicate by binary fission – not mitosis.

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13
Q

How does the theory of endosymbiosis believe the mitochondria became a part of the Eukaryotic cell?

A

Energy producing bacteria may have to come to reside within larger bacteria or archaebacteria, eventually evolving into what we now know as mitochondria

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14
Q

How does the theory of endosymbiosis believe the chloroplast became a part of the Eukaryotic cell?

A

Photosynthetic bacteria were likely engulfed by other, larger bacteria leading to the evolution of chloroplasts. All chloroplasts are likely derived from a single line of cyanobacteria.

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15
Q

How is it assumed Brown algae obtained their chloroplasts?

A

by engulfing one or more red algae, a process called secondary endosymbiosis. this why chloroplasts in brown algae have four membranes

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16
Q

How do prokaryotes carry genes?

A

on a single DNA molecule

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17
Q

How do eukaryotes carry genes?

A

On multiple chromosomes, which are usually present in pairs

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18
Q

Mitosis in Eukaryotes

A

Mitosis is the separation of chromosomes while cytokinesis is the division of the cytoplasm

In fungi and some protist groups the nuclear envelope does not dissolve so mitosis occurs in the nucleus rather than the cytoplasm like in most eukaryotes. Then two daughter nuclei form and then the cell will split.

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19
Q

How could you distinguish the difference between primary and secondary symbiosis by looking at micrographs of cells with chloroplasts?

A

Counting the number of cell membranes of chloroplasts indicates primary or secondary endosymbiosis

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20
Q

Protist Overview

A

Most diverse of the four eukaryotic kingdoms and are united on the basis that they are not fungi, plants, or animals (classified by exclusion)

Unicellular, colonial, and multicellular groups.
Most are microscopic but some are huge.
Many forms and symmetries.
All types of nutrition.

They are not monophyletic, they are paraphyletic

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21
Q

Are protists present in all 5 eukaryotic supergroups? What are they?

A

Yes,

Excavata
S A R
Archaeplastida
Amoebozoa
Ophisthokonta

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22
Q

What is being used to test different hypothesis regarding evolutionary relationship controversies in protist phylogeny?

A

DNA sequence data

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23
Q

Do protists have a varied array of cell surfaces?

A

Yes (Plasma Membrane and/or extracellular matrix (ECM))

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24
Q

Some protists, such as amoebas are surrounded by only what cell surface?

A

Plasma Membrane

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25
Q

All other protists have what along with a plasma membrane?

A

Extracellular Matrix

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26
Q

What do some ECM form?

A

strong cell walls

ex. diatoms and foraminifera secrete glassy shells of silica

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27
Q

How to some protists survive and reproduce asexually in harsh conditions?

A

By forming cysts

these cysts are a dormant form of a cell with a resistant outer covering and inside the cell metabolic activity is reduced to pretty much zero

HOWEVER not all cysts are resistant to all environments. Ex. some amoebas can form cysts resistant to gastric acid but not to desiccation or high temperatures.

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28
Q

Protists movement is typically what methods?

A

flagellar rotation

pseudopods

cilia

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29
Q

How many flagella to protists typically have and how do they use them?

A

wave one or more flagella to propel themselves though the water

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30
Q

Some protists have cilia, what are cilia?

A

banks of short, flagella-like structures that create water currents for their feeding or propulsion.

can act like oars to move the protist through fluid

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31
Q

Other protists (typically amoebas) use something called pseudopods for movement. What are they?

A

Pseudopods means false feet in Greek

REMEBER THIS IS TYPICALLY AMOEBAS

other protists also have long, thin pseudopods that can be extended or retracted. Since the tips can adhere to surfaces, the cell moves through a rolling motion, shortening the front pseudopods and extending the ones in the back

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32
Q

Are protists heterotrophic or autotrophic?

A

both (HEHEHEHE)

33
Q

Autotrophic protists

A

Some are photosynthetic while other are chemoautotrophic

34
Q

heterotrophic protists

A

some of them are phagotrophs (ingest particles of food into vesicles called food vacuoles or phagosomes)

35
Q

What are Mixotrophs?

A

protists that are both phototrophic and heterotrophic

36
Q

How do protists typically reproduce?

A

asexually

some reproduce regularly, whereas some reproduce at times of stress such as food shortages

37
Q

What is asexual reproduction?

A

involves mitosis but differs from multicellular organism mitosis

nuclear membrane persists throughout mitosis so the mitotic spindles form in the nucleus

some species the cell splits in equal halfs but some species divide by budding and some divide by schizogony

38
Q

What is budding?

A

the daughter cell is considerably smaller than its parent and then grows to adult size

39
Q

What is schizogony?

A

cell division preceded by several nuclear divisions; allows cytokinesis to produce several individuals almost simultaneously

40
Q

Most eukaryotic cells have the ability to reproduce sexually, can protists do this?

A

No

41
Q

What is meiosis and what organism did it arise from?

A

it is a major evolutionary innovation that arose in ancestral protists

allows for the production of haploid cells from diploid cells and the generation of genetic diversity

42
Q

What is sexual reproduction??

A

process of producing offspring by fertilization, the union of two haploid cells, which were generated by meiosis.

the advantage of it is that it allows for frequent genetic recombination, which contributes to the variation required for evolution by natural selection

43
Q

What contributed to the tremendous explosion of diversity among the eukaryotes?

A

the evolution of meiosis and sexual reproduction

44
Q

diversity in eukaryotes was promoted by the development of what?

A

multicellularity

45
Q

Multicellularity has arisen multiple times among eukaryotes. (True or False)

A

True

46
Q

How did multicellularity come to be?

A

Some single celled eukaryotes began living in association with others, in colonies. Then the individual members of the colony began to take on the characteristics of a single individual (true multicellularity)

47
Q

What is an advantage of multicellularity?

A

it fosters specialization

few innovations have had as great an influence on the history of life

48
Q

What is the supergroup Excavata composed of?

A

the two monophyletic clades, diplomonads and the Parabasalids, and the Euglenozoa

They share similarities in cytoskeletal features and D N A sequences

49
Q

What does the name Excavata refer to?

A

a groove down one side of the cell body in some groups

50
Q

What are diplomonads

A

unicellular

lack a functional mitochondria

multiple posterior flagella

2 haploid nuclei per cell

Ex. Giardia intestinalis (a parasite) pass from human to human via water and causes diarrhea

51
Q

What are Parabasalids?

A

Undulating membrane for locomotion

multiple flagella

semi functional mitochondria

one nucleus per cell

Some live in termite guts and have symbiotic relationship with cellulose-degrading bacteria.

Trichomonas vaginalis causes trichomoniasis, a common STD

52
Q

What are Euglenozoa?

A

Bodies change shape when swimming – alternate between being stretched out and rounded up

Can change shape because they lack cell walls. Instead strips of protein encircle the cell making up the pellicle. These strips provide flexibility.

Among the earliest eukaryotes to possess mitochondria since they diverged early

Include free-living euglenids and parasitic kinetoplastids

53
Q

What are Euglenids? (PROTIST)

A

1/3 of euglenids have chloroplasts and are autotrophic; the others lack chloroplasts, ingest their food, and are heterotrophic (in the dark the ones with chloroplasts may become heterotrophic, and will become autotrophic again once put in the light)

Reproduction is asexual; occurs via mitosis (NO SEXUAL REPRODUCTION)

Euglena have two anterior (and unequal) flagella attached at reservoir. One is long and project along one side the other does not emerge.

Contractile vacuoles – collect excess water and empty it into the reservoir

Stigma – helps photosynthetic euglenids move towards light

Numerous small chloroplasts; Likely evolved from symbiotic relationship through ingestion of green algae.

54
Q

What are Parasitic kinetoplastids?

A

2nd major group in Euglenozoa

the name kinetoplastid refers to a unique, single mitochondrion

have DNA maxicircles and minicircles that are linked together – responsible for rapid glycolysis and unusual RNA editing.

Parasitism has evolved many times within kinetoplastids

Trypanosomes cause human diseases
(African sleeping sickness – tsetse fly.
Leishmaniasis – sand fly.
Chagas disease – skin contact with urine or blood of infected wild animal.)

Difficult to control because organisms repeatedly change their protective coat
(Elaborate genetic mechanism for changing antigen on coat.
Difficult to make a vaccine; other methods used to control flies.
Sequencing of genomes revealed core of common genes in all 3 – hope for single drug target.)

55
Q

What supergroup is Stramenopila part of?

A

SAR supergroup

56
Q

What do Stramenopiles consist of?

A

Brown Algae, diatoms, & oomycetes

they have very fine hair on their flagella (some lost this in evolution)

57
Q

What is Brown Algae

A

Conspicuous seaweeds of northern regions

Haplodiplontic life cycle involves alternation of generations

Sporophyte – multicellular and diploid.

Gametophyte – multicellular and haploid.

Not plant

58
Q

What are Diatoms?

A

Phylum Chrysophyta

Photosynthetic, unicellular organisms

Unique double shells made of silica

Some move using raphes
(Two long grooves lined with vibrating fibrils.)

59
Q

What are Oomycetes

A

NOT TRUE FUNGI EVEN THOUGH THEY USED TO BE CONSIDERED

“Water molds”

Either parasites or saprobes

Motile zoospores with two unequal flagella
(Produced asexually)

Undergo sexual reproduction

Found in water or on land

Phytophthora infestans
(Irish potato famine (1845 to1849). 400,000 people died.)

60
Q

What makes up Alveolata?

A

Consist of Dinoflagellates, Apicomplexans (kind of like a drill mechanisms that allows it to drill into cells), & Ciliates

Flattened vesicles called alveoli

Common lineage despite diverse modes of locomotion

61
Q

What are dinoflagellates?

A

Photosynthetic, unicellular with flagella

Live in aquatic environments

Some are luminescent

Do not appear to be directly related to any other phylum

DNA not complexed with histones

Noctiluca is responsible for the glowing waves

Primarily asexual; sexual reproduction under starvation conditions

“Red tide” are population explosions of dinoflagellates (Fish, birds, and marine mammals may die from neurotoxins produced by dinoflagellates)

62
Q

What are Apicomplexans?

A

Spore-forming animal parasites

Apical complex is a unique arrangement of organelles at one end of the cell
(Enables the cell to invade its host.)

Plasmodium causes MALARIA
Complex life cycle – sexual, asexual, different hosts.
Eradication focused on eliminating mosquito vector, drug development, vaccines.
DDT (SUCKS FOR ENVIRONMENT) resistant mosquitoes.

malaria reproduces sexually in the vector (mosquito) and asexually in the host

63
Q

What are Gregarines?

A

Use their apical complex to attach themselves in the intestines of arthropods, annelids, and mollusks

64
Q

What is Toxoplasma gondii?

A

Using apical complex, invades epithelial cells of human gut

Causes infections in humans with immunosuppression

Can cross placental barrier to harm fetus

65
Q

What are Ciliates

A

Pellicle – tough but flexible outer covering

Feature large numbers of cilia arranged in longitudinal rows or spirals around the cell (Beat in a coordinated fashion.)

2 types of nuclei
- Micronucleus – used only as germ line for sexual reproduction; D N A not transcribed.
- Macronucleus – essential for function.

Have two types of vacuoles
- Food vacuoles – digestion of food.
- Contractile vacuoles – regulation of water balance

PARAMECIUM CAUDATUMMMMMMMM

66
Q

What are Rhizaria

A

Rhizaria use pseudopods for locomotion

Three distinct monophyletic groups: Radiolaria, Foraminifera, and Cercozoa

67
Q

What are Radiolarians

A

Phylum Actinopoda

Glassy exoskeletons made of silica

Needlelike pseudopods

68
Q

What are Foraminifera?

A

Heterotrophic marine protists

Pore-studded shells called tests, through which thin podia emerge

Use podia for swimming and feeding

Complex life cycles with haploid and diploid generations

Limestones are rich in forams
White Cliffs of Dover (FOUND ON MASSIVE CLIFFS AND HE RLLY LIKES THIS FOR NO GOOD REASON)

69
Q

What are Cercozoa?

A

Morphologically diverse group of primarily soil protists
- Locomotion with flagella or pseudopods.
- Some have silica-based shells made of scales or plates.

70
Q

What does the Group Archaeplastida consist of?

A

This group consists of Rhodophyta, Chlorophyta, Charophytes, and land plants

THEY ARE ALLLLLL PHOTOSYNTHETIC
These photosynthetic organisms acquired their chloroplast through primary endosymbiosis

71
Q

What is Rhodophyta?

A

Red algae range from microscopic to very large

Lack flagella and centrioles

Have accessory photosynthetic pigments which are often red

Have both haploid and diploid phases

72
Q

What are Green Algae?

A

Green algae consist of 2 lineages
- Chlorophyta.
- Unusual diversity and lines of specialization.
- Charophytes.
- Gave rise to the land plants.

73
Q

What was Cell specialization in colonial chlorophytes?

A

Multicellularity arose many times in the eukaryotes

CELL SPECIALIZATION STARTED WITH Colonial chlorophytes

different cells doing different in jobs even though they have the same DNA

Volvox - hollow sphere made up of a single layer of 500 to 60,000 individual cells each with 2 flagella.

74
Q

What are Charophytes?

A

Also green algae; distinguished from chlorophytes by phylogenetic relationship to land plants

Both charophyte clades form green mats around the edges of freshwater ponds and marshes

One species must have successfully inched its way onto land through adaptations to drying

75
Q

What are Amoebozoa

A

Amoebas move by means of pseudopods
- Pseudopods are flowing projections of cytoplasm.
- Extend and pull the amoeba forward.
Engulf food particles.
- An amoeba puts a pseudopod forward and then flows into it.
- Microfilaments of actin and myosin are associated with these movements.

Most amoeba are free living

Found in the soil as well as freshwater.

Some are parasitic.

76
Q

What is the Acanthamoeba?

A

enters the body through a wound and crosses the blood-brain barrier into the brain; causes inflammation and death.

77
Q

What are Plasmodial slime molds?

A

Stream along as a plasmodium
- Nonwalled, multinucleate mass of cytoplasm. (ONE MASS)
- Form called feeding phase.

Ingests bacteria and other organic material

When food or moisture is scarce, organism forms sporangia, where spores are produced

78
Q

What are Opisthokonta?

A

Choanoflagellates
- Unicellular organisms.
- Fungi and animal common ancestor.
- Most like the common ancestor of sponges.
- Have a single emergent flagellum surrounded by a funnel-shaped, contractile collar; structure is exactly matched in sponges, which are animals.

Colonial choanoflagellates
resemble their close animal relatives, the sponges. Sponges are multicellular even though they don’t have tissues.

Biology 1407 - 02M (8 decks)

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