Lecture 1 Flashcards
(57 cards)
1
Q
What makes eukarya unique to the other domains of life?
A
- they have membrane bound organelles
2
Q
What are two things seen in eukarya today that derived from bacteria?
A
- chloroplasts
- mitochondria
3
Q
T/F: 3 independent events have led to multi-cellular life in fungi
A
- false
- only 2 independent events have occurred
4
Q
T/F: there’s lots of things that have become multi-cellular
A
- true
5
Q
What does the large amount of multicellular life suggest about the process of multicellularity?
A
- it’s fairly easy to do so
6
Q
What are the 5 kingdoms/ phyla that have complex multicellularity?
A
- animals
- fungi
- red algae
- green algae (aka land plants)
- brown algae
7
Q
What are 2 characteristics that were important for becoming multicellular?
A
- plastids
- mitochondria
8
Q
What are 7 characteristics that almost all eukaryotes have? (not just plants and animals)
A
- cytoskeleton
- endomembrane system
- primary genome of multiple, linear chromosomes
- 80s ribosomes
- mitochondria
- plastids (mostly in algae and plants)
- sexual reproductions
9
Q
What does an agile cytoskeleton allow eukaryotes to do?
A
- move
- structure
- internal transport (phagocytosis)
10
Q
What is an endomembrane system?
A
- series of compartmentalizing membranes
11
Q
What’s the difference between eukaryotic and prokaryotic DNA?
A
- eukaryotic = linear
- prokaryotic = circular
12
Q
What are the pros of having linear DNA?
A
- select expression
- it’s easier to show just parts of chromosomes
- more control
13
Q
What are the pros and cons of having circular DNA?
A
- pro - good for replicating the whole things at once
- con - hard to select stuff
14
Q
What are 80s ribosomes?
A
- translational machinery
15
Q
Prokaryotes and eukaryotes both have ribosomes, what is the difference between the 2 types?
A
- eukaryotes = 80s
- prokaryotes = 70s
16
Q
T/F: all eukaryotes have mitochondria
A
- true
- it makes ATP
17
Q
How are prokaryotes similar to eukaryotes in the way it makes ATP? What makes it different?
A
- prokaryotes make ATP similarly to eukaryotes, through oxygenated phosphorylation
- prokaryotes don’t have mitochondira
18
Q
What is sexual reproduction?
A
- when a sperm and egg combine to make a new offspring different from either of the parents
19
Q
What are 2 ways sexual reproduction provides diversity?
A
- diversity through gametes
- diversity through fusion of gametes (random combination)
20
Q
T/F: all eukaryotes produce offspring sexually
A
- false
- most, but not all
21
Q
Define microtubules
A
- a hollow tube formed from tubulin dimers
- used in the cytoskeleton
- in animals
- used in mitosis and meiosis
22
Q
Define microfilaments
A
- a double helix of actin monomers
- used in internal transport movement in animals
23
Q
Define intermediate filaments
A
- a strong fiber composed of intermediate filament proteins
- in between microtubules and microfilaments
- not found in plants
24
Q
What is the arrangement of the microtubules in cilia/flagella?
A
- 9 + 2 arrangement
- 9 on the outside, 2 on the inside
25
What's the structure of cilia/ flagella from the inside to the outside?
- central microtubules
- cross-linking proteins
- microtuble doublets/ dynein arms
- plasma membrane
26
What are the dynein arms?
- the proteins that link the microtubules together
| - act like little legs between the microtubules to move them
27
What's the difference between prokaryotic and eukaryotic nuclei?
- euk - membrane bound nucleus
| - pro - no membrane around the nucleus
28
What are 2 functions for all the organelles in a cell?
- greatly increases the surface area of the cell so more processes can occur
- different parts of the cell doing different things is more efficient (compartmentalization)
29
What does the vacuole do in an animal cell?
- it releases shit (toxins) from the cell
30
What does endo mean? Symbiotic?
- endo= inside
| - symbiotic = beneficial
31
What is an ability that bacteria had that would help multicellular organisms?
- oxidative phosphorylation
32
What is one piece of evidence that verifies multicellularity arose from bacteria?
- mothers contribute the mitochondria during reproduction because mitochondria makes its own DNA
- it has its own DNA that is similar to bacteria
33
What are the 7 main pieces if evidence for endosymbiotic origins?
- circular DNA
- independent fission
- size
- double membrane
- certain proteins specific to bacteria cell membrane are also in mitochondria/chloroplast membranes
- 70s ribosomes
- prokaryote DNA in eukaryote genome
34
T/F: most eukaryotes aren't multicellular
- true
35
What was the great oxygenation event?
- there used to be lots of iron and heavy metals in the Earth
- took a long time for the iron deposits to be saturated
- once saturated, oxygen was released into the air
36
What 2 things contributed enough energy to become multicellular?
- cyanobacteria
| - mitochondria and aerobic respiration
37
What are the 3 ideas for the origins of the endosymbiotic theory?
- symbiotic theory
- syncytial theory
- colonial theory
38
What is the symbiotic theory?
- mutually beneficial relationship between species
- collectively really good at everything
- suggests they became so dependent on each other that they formed a species
39
What's the part of the symbiotic theory that doesn't make sense?
- every single part has its own genome
| - how do you go from individual genomes to one?
40
What's the syncytial theory?
a single cell grew and gained more nuclei, which specialized to do specialized things and compartmentalizes
41
What is the colonial theory?
- a colony of cells from the same species specialize and compartmentalizes to become multicellular
42
Which theory is most likely and why?
- colonial theory
| - easy to see how the genome would work since it's from the same species, used to work together
43
What's a disadvantage does the colonial theory have?
- the cells still started out as individual so the genomes could be slightly different
44
What are the selective advantages to multicellularity?
- division of labour and economy of scale
- increased size
- complexity (most of the time at least)
- surface area/ volume relationship
45
T/F: a few specialized cells is less efficient than having lots of cells that aren't specialized
- false, much more efficient to have a few cells that are very specialized than lots that multitask
46
What are the 9 advantages to being bigger?
- avoid predation/ eat larger things
- exploit new environments, reach upwards
- storage (fat cells)
- increased feeding mechanisms/ opportunities
- protected internal environment (against cold, chemicals)
- new metabolic functions (maintain body temperature)
- enhanced motility
- increased traction in current/wind
- share information with other cells
47
What are 2 parts included in the complexity of multicellular organisms?
- predator/prey and host/parasite interactions
| - increased opportunity for diversity in form/function and niches
48
What's an example of a complex trait?
- light sensing
- can be an advantage if the organisms needs to see brightness, direction, shape, colour, movement
- unnecessary if at the bottom of the ocean
49
What are the advantages of surface area/ volume relationships?
- as an organisms gets larger the SA/V decreases
- eukaryotes with mitochondria and endomembranous system can support much higher rates of supply and production
- prokaryotes are limited in size if they rely on cell membrane transport alone
50
What is metabolism supported by?
- things moving across the cell membrane
- the surface area is limiting how much can move in or out of the cell
- as a cell gets bigger the ability to provide things to the cell gets worse
51
What are the challenges of being multicellular and large?
- intercellular communication
- cell adhesion
- homeostasis
- reproduction and growth
52
What is a gap junction?
- a physical connection between 2 adjacent cells
| - like pores
53
What is the plasmodesmata?
- a gap junction but for plants
| - a different structure than a gap junction, but functionally is doing the same thing
54
What is bulk flow?
- the mass movement of solutes and solvents across the body (like blood)
- moves a large quantity over a long distance
55
What is electrical communication?
- rapid movement of signals between cells
- in animals it's the nervous system
- plants use this too but it's not a nervous system
56
Why is cell adhesion necessary?
- need something to have cells hold onto each other
57
When does multicellularity arise?
- after a rise in atmospheric oxygen
