Being Multicellular Chapter 28

Question 1

__ multicellularity is widespread amongeukaryotes

Answer 1

simple

Question 2

simple multicellular organisms have __ but most importantly __

Answer 2

full range of functions; always in direct contact w/ cell environment

Question 3

advantages to multicellularity

Answer 3

avoid getting eaten, maintain position better, feeding, float better

Question 4

disadvantages to multicellularity

Answer 4

cheating–using nutrients for own good aka cancer

Question 5

complex multicellularity evolved

Answer 5

at least 6 times

Question 6

complex multicellular organisms share 3 features

Answer 6

mechanisms for adhesion between cells
specialized structure for communication
complex patterns of cellular & tissue differentiation (can be deadly for organism)

Question 7

only some of the cells in multicellular organisms are in..

Answer 7

direct contact with environment

Question 8

most prokaryotic organisms are ____ and some live in___

Answer 8

single celled; colonies

Question 9

diffusion is effective only over __ and is __

Answer 9

short distances; slow

Question 10

how do we get around diffusion?

Answer 10

by pumping blood

Question 11

why did many aquatic organisms increase their surface area?

Answer 11

to increase drag

-reduces their rate of sinking and allows them to float w/o expending more energy

Question 12

what is bulk flow?

Answer 12

means by which molecules move through organisms at rates beyond those possible by diffusion across concentration gradient
-distributes nutrients
also carries developmental signals

Question 13

how do plants manage bulk flow?

Answer 13

through system of tissues powered by evaporation of water from leaf surfaces

Question 14

how do fungi use bulk flow?

Answer 14

use filaments to transport using osmosis

Question 15

complex multicellularity requires __ between cells. how is this accomplished?

Answer 15

adhesion; transmembrane proteins: cadherins, integrins

in plants, pectins

Question 16

why did adhesion come about?

Answer 16

maybe to stick to rock/sediment/capture bacteria

aids in predation (choanoflagellates)

Question 17

complex multicellularity requires ___ via molecular signals

Answer 17

communication

Question 18

complex multicellular organisms have ___ that allow for targeted communication in animals

Answer 18

gap junctions

Question 19

how do plants communicate?

Answer 19

plasmodesmata

allows for targeting as well as opening in cell walls

Question 20

complex multicellularity requires a ___ for coordinated growth and cell differentiation

Answer 20

genetic program

Question 21

development in cells is a results of

Answer 21

molecular communication, 2 cells in the same organism can be exposed to different environments

Question 22

the innovation of complex multicellularity was to differentiate cells in ___ instead of ___

Answer 22

space; time

Question 23

plants have patches of tissues on ___ whereas animals have it on __

Answer 23

outside; inside

Question 24

___ shape patterns of growth and development in plants

Answer 24

cell walls

Question 25

plants can’t move, so what happens?

Answer 25

they have meristem tissue that acts as embryonic tissue as long as the plant is alive

Question 26

how are plants and animals different?

Answer 26

• animals’ cell division & tissue diff. occurs throughout their developing bodies
• animals can move their muscles

Question 27

do plants and animals have a common ancestor?

Answer 27

no

Question 28

when did we first find evidence of complex multicellular organisms?

Answer 28

579-555 mya

Question 29

what is absolutely necessary for complex multicellular life?

Answer 29

oxygen

Question 30

when did oxygen first accumulate?

Answer 30

2400 mya, levels remained low abundant around 580-560 mya

Question 31

land plants evolved from

Answer 31

green algae that could carry out photosynthesis on land

Question 32

complex land plants first came about when?

Answer 32

465 mya