Multicellular Life

Question 1

what is a multicellular organism

Answer 1

organism containing more than 1 cell

Question 2

how do multicellular organisms contrast with unicellular organisms

Answer 2

unicellular organisms formed from single cell that performs many different functions like respiration, motility, prey capture, metabolism

Question 3

WHat does multicellularity allow in animals

Answer 3

generation of a vast array of diff cell types

Question 4

How are cells in multicellular organisms specialized

Answer 4

Different cell types are specialized for specific functions

Question 5

What is required for successful multicellular development

Answer 5

Coordinated development and cooperation of potentially thousands of billions of cells

Question 6

what are prokaryotes def

Answer 6

enclosed by a single outer membrane
lack nucleus and membrane bound cytoplasmi organelles

Question 7

what are the two main groups of prokaryotes

Answer 7

archaea
bacteria

Question 8

Why is multicellularity thought to be advantageous

Answer 8

animals more closely related to unicellular organisms than other multicellular
selective advantages of being multicellular

Question 9

desribe unicellular organisms

Answer 9

-single cell
-single cell carries out all life processes
-damage can cause serious injury or death
-whole cell body exposed to environment
-short lifespan

Question 10

Describe multicellular organisms

Answer 10

-more than one cell
-complex organisation
-Division of labour (multiple cells perform different functions)
-only outer cells exposed to envir
-damaged cells may be replaced
-complex behaviours

Question 11

what is simple multiellularity def

Answer 11

organisms that consist of multiple cells that adhere to each other with limited coordination and differentiation

Question 12

Can organisms with simple multicellularity exist in unicellular forms

Answer 12

yes they may exist as either unicellular or multicellular forms

Question 13

what are complex obligate multicellularity

Answer 13

organisms comprise several distinct differentiated cell types
multicellularity needed for survival

Question 14

how is complex multicellularity generated

Answer 14

Cell-tye-specific genes and intricate coordination of developmental processes

Question 15

what are the two forms of choanoflagellate S. rosetta

Answer 15

Single celled and colonial forms, with multiple cells linked by an extracellular matrix

Question 16

How does the presence of prey bacteria affect colony formation?

Answer 16

It increases colony formation and helps capture prey

Question 17

How does the presence of predators affect colony formation

Answer 17

It increases colony formation and protects from being eaten

Question 18

What happens when food is in short supply in a colony

Answer 18

cells can feed off each other to ensure survival of the colony

Question 19

What is the origin of programmed cell death in colonies?

Answer 19

Not all cells need to be identical, which can limit cooperation.

Question 20

What can “cheater” cells do in a colony

Answer 20

They can exploit the altruism of other cells.

Question 21

What happens when the unequal passing on of genetic information in a colony

Answer 21

limits cooperation between cells

Question 22

Where is complex multicellularity found and how did it evolve?

Answer 22

found in animals, land plants, brown algae, fungi, and red algae, and evolved independently in each.

Question 23

How does complex multicellularity begin?

Answer 23

from a single cell with all cells in the organism having the same genome

Question 24

why is cell communication important in complex multicellularity

Answer 24

developing complex patterns and body plans

Question 25

when is cell-cell communication reliable

Answer 25

when cells follow same rules and share same genome

Question 26

what percentage of 1.8mill names species are animals

Answer 26

80%

Question 27

have simple multicellular organisms evolved many complex forms

Answer 27

no simple multicellular have not evolved

Question 28

what are the two paths to multicellularity

Answer 28

Aggregative clonal

Question 29

what does aggregative multicellularity do

Answer 29

separate cells converge and adhere to each other

Question 30

how many times to aggregative multicellular cells evolve

Answer 30

evolved minimum 7 times in eukaryotes

Question 31

when does aggregative multicellularity occur

Answer 31

in response to harsh conditions

Question 32

what is aggregate formed of

Answer 32

quiescent cells that neither feed or divide

Question 33

is aggregative multicellularity simple or complex multicellularity

Answer 33

simple

Question 34

do aggregative multicells move

Answer 34

motility is step towards formation of aggregate can disperse if separated cells can divide

Question 35

what is clonal multicellularity

Answer 35

Serial cell division without dispersion of sister cells

Question 36

what is the result of clonal multicellularity

Answer 36

changes in cell cycle and ECM genes

Question 37

whats more diverse than aggregative forms

Answer 37

clonal multicellularity more widespread phylogenetically and more diverse morphologically

Question 38

is clonal multicellularity simple of omplex

Answer 38

underlies all forms complex multicellularity sometimes underlies simple multicellularity

Question 39

How is a multicellular organism established?

Answer 39

Through serial division of a single founding cell

Question 40

what controls the development of multicellular organisms

Answer 40

genomes and environment

Question 41

do all cells in multicellular organisms have same genome

Answer 41

yes

Question 42

whats a genome

Answer 42

complete set of dna

Question 43

What does having the same genome in all cells enable?

Answer 43

efficient: cell-cell communication development of complex morphologies and behaviours

Question 44

WHat ability to proliferating cells have

Answer 44

switch between unicellular and multicellular forms

Question 45

What happens if division of labour occurs

Answer 45

cells specialised for specific functions locks cells into multicellular condition

Question 46

what does specialisation of cell types lead to

Answer 46

development of organs

Question 47

What requirements are needed for embryonic development

Answer 47

-regulated cell cycle -regulated programmes of gene activity -cell differentiation -signal transduction -cell motility and cohesion

Question 48

What do single cell organisms ancestral to animals possessed

Answer 48

-characteristic eukaryotic cell cycle -undergoes cell differentiation -cell signalling molecules -cadherin-mediated cell adhesion (basis of embryonic development)

Question 49

What is clonal multicellularity in animals marked by

Answer 49

diversification of transcription factor families and signalling molecules -expansion of existing gene families -emergence of new gene families

Question 50

What does the phylogenetic tree show

Answer 50

how species are related through evolution

Question 51

what is the closet living thing to animals that are unicellular

Answer 51

choanoflagellates

Question 52

Are sponges a type of animal

Answer 52

yes

Question 53

How do unicellular eukaryotes exist

Answer 53

single cells or colonies of cells connected by an ECM and attached to a stalk

Question 54

What do unicellular eukaryotes contain

Answer 54

cell body collar of actin-filles tentacles that capture bacteria flagellum: enables movement

Question 55

WHat are sponges composed of

Answer 55

spicules chonaocytes (have fagellum and villi)

Question 56

what division of labour does a sponge have

Answer 56

one cell type fo sructure one for movement and prey captured

Question 57

what two phases to chlamydomonas have

Answer 57

swimming (flagella) non swimming (flagella resorbed and undergoes cell division, reproduction)

Question 58

whats a volvox

Answer 58

green algae that forms spherical colonies

Question 59

What did the cell wall evolve into in Volvocine algae

Answer 59

extracellular matrix (ECM)

Question 60

what does graded complexity in volvocine algae allow for

Answer 60

enables exploration of mechanisms underlying the evolution of multicellularity

Question 61

how does gonium (simple form) exhibit multicellularity

Answer 61

cells attached to neighbouring walls by ECM structures

Question 62

what happens if cytokinesis fails in simple forms like gonium

Answer 62

organism cant complete cytokinesis limited morphologies

Question 63

how is pandorina different from gonium

Answer 63

outer cell wall surrounds entire colony and ells embedded in ECM

Question 64

How did ECM change in volvox

Answer 64

ECM further expanded and adapted cytokinesis and cell wall

Question 65

how are new colonies formed in volvocine algae

Answer 65

form from clusters of cells single cell detached from colony divide and form new colony

Question 66

how is volvox different from simpler volvocine algae

Answer 66

only a few internal cells can reproduce, most surface celsl cannot divide

Question 67

what roles do surface cells in volvox perform

Answer 67

surface cells have flagella an dbeat them to induce a rolling motion but they cannot reproduce

Question 68

what does multicellularity require

Answer 68

cooperation, altrium and prioritising the needs of the organism over individual cells

Question 69

how does cancer relate to multicellularity

Answer 69

cancer results from loss of cooperation cells act independently like unicellular

Question 70

how are hallmarks of cancer related to multicellularity

Answer 70

cancer results from defects in mechanisms that organise, function and stabilise complex multicellular organisms

Question 71

what happens to cells during cancer in terms of behaviour

Answer 71

cells revert to unicellular behaviours, reactivating ancestral traits and showing selfish survival behaviours