single cell and muticellular organisms Flashcards
(18 cards)
explain scale of cells
porkaryotic cells are usually smaller but not always. I 1cm long is the biggest prokaryote. it underwent many modifications. one is having a big vacuole. the DNA and ribosome is in a Pepin.
explain autotrophs
self feeding there are two types. photoautotrophs: uses light energy like plants and chemoautotrophs: uses inorganic compounds and like bacteria and archaea.
what are the types of heterotrophs
feed on other organisms
photoheterotrph: uses plants and organic compounds like bacteria
chemoheteretorphs: organic compounds like animals
animal cells vs plant cells
animals have no cell wall, cholorplasts and have no vacuole
how do we have prokaryotic cells to go to eukaryotic cells
prokaryotes developed a nucleus. a aerobic prokaryote was engulfed in the eukaryote and instead to being eaten, they formed a symbiosis relationship with each other. (this is the mitochondria). after, it picked up photoautotrophic prokaryote that can take in light energy for energy- ancestor of chloroplasts for plants. those that did not go under that is the animal cells.
how do cells become multicellular
cells join together to become specialised. this allows for more complexity and a larger size.
why are multicellular organisms larger than prokaryotic organism
internal specialisation or internal organs. they can be autotrophs, hetetrophs or both. eg. choanoflagellete- closest relative to animals. can be unicellular or colonial. it has a solar and flagellum structure to help them capture food.
explain Porifera (sponges)
they have no nerves, no symmetry. they do not move around. water flows int through small holes through chimneys. there are feeding cells that collect food.
explain clonal organisms
one way of evolving is to take a simple organism and repeat it many many times. its a lot of asexually produce individuals that live in close proximity. they have lost physiolocial connection to one another.
explain colonial organism
asexually produced organisms that are connected and are interdependent.- you can get specialised ones in here. because tis part of a colony, those that don’t reproduce can still survive. there are different environments that allow hormones to develop ad some not to.
what are the requirements for multicellular organisms
- cell adhere
- communicate
- cooperate
-specialise
this allows for greater size and complexity and allow new ways of living, doesn’t mean better but just different.
example could be:
ingestion, internal, structural
how do cells adhere
desmosomes that are on the cell membrane. the desmosomes of two wells are bolted together. they provide a structure. plants have an advantage because of the cell wall
how do cells communicate
communications need molecules to move from interior of one cell to another. for cells, they can do this is through gap junctions. they sit on the membrane of cells and opens and close to let molecule s in. plants have plasmodemata - a bit more tricky because either cell wall
how does gas exchange occur in animals
single cells just diffuse but in multicellular has a gas exchange system. some multicellular organisms that are very thin can just diffuse as well.
explain the concept of surface are to volume ratio.
the bigger the surface area, the more you need a specialised transport system.
insects: white tubes (tracheal network) delivery of gas directly to the cells which relies on diffusion. this is why insects cant get larger because this system cant get larger. if oxygen content of environment is higher, then insects can get larger.
gills:
lungs:
explain the internal transport system of plants and animals
circulatory system. can be open or closed. fishes have one single closed hoop and mammals have a double loop.
plants have xylem and phloem
explain digestion
development of gut. some are simple in flatworms where ingestion and secretion occurs in the same place. its not as efficient because the system can only do one thing at a time. this is why we develop alimentary canal
structural support
resist gravity and allow the organism to move around. simplest form are known as hydrostatic skeletons. they are bags of fluid under pressure. no hard body parts but can push against the fluid filled structures. there are also hard external and internal skeletons.
