POI (Bio Midterms IB 1, Oct 2023) Flashcards
Why does cyanobacteria (a prokaryote) have no chloroplasts
Prokaryotes do not have membrane-bound organelles
What are prokaryote cell walls made out of?
peptidoglycan
Define holozoic
eat other organisms with internal digestion of nutrients
Why are feces not considered “waste material” of metabolism?
Reason: They do not undergo metabolism.
- Thus, they undergo “ingestion” instead of excretion
Define saphotrophs
secrete digestive enzymes to the env. and then absorb the nutrients into their body has there been external digestion.
Why are fungi called decomposers?
they break down the dead and decaying organic matter into a simpler substance.
It provides the nutrients back to the soil.
If venus flytraps are plants, why do they eat insects
They’re mixotrophs.
- they eat insects in order to get e.g. extra nitrogen
Give another function of vacuoles asides from packaging for protein transport in animal cells [3]
As small, temporary structures,
Functions::
- expel excess water
- expel other waste products
-> Thus: they function to maintain homeostasis (and the above functions are how)
Why is the morphological similarities between organisms in the hydrothermal vents not an evidence for LUCA
Similarities can be caused by environment, not necessarily common ancestor (LUCA)
Why don’t fungi need centrioles for cell division? (HW)
Although centrioles, like those found in centrosomes, are found throughout all kingdoms of life, including fungi, most fungi evolved a centriole-less MTOC known as the spindle pole body (SPB) [1]. While SPBs and centrosomes are morphologically distinct, both organelles share components and regulators
Why are cells small?
For efficiency.
- Need sufficient amount of workers for specialization
Why is the aseptate fungal hyphae considered as one cell?
No clear division of cells — meaning they share one cytoplasm
Why controls the sieve tube mvmt if they have no nucleus?
Because of a companion cell that controls their movement (elevator lol)
How does the genetic code provide evidence of universal common ancestry?
Genetic code is universal aka same across all domains and kingdoms with only a few exceptions
- same gene code = same ancestor (implications)
Explain the Louis Pasteur experiment
Pasteur’s experiment consisted of boiled broth in flasks with S-shaped necks. The broth was boiled after being poured into the flasks to destroy any living microorganisms that may have been present in the broth. The S-shaped necks prevented microorganisms from entering and contaminating the broth after boiling.
He, then, broke the necks off of some of his flasks. The broth in the flasks with the S-shaped necks stayed clear indefinitely, but the broth in the flasks with the broken necks quickly became cloudy. Pasteur took his experiment one step further. He believed that living microorganisms in the air were caught in the curve of the S-shaped flasks. He tilted these flasks so that microbes present in the neck could enter the clear broth. The broth in the tilted flasks began to grow cloudy. This experiment disproved spontaneous generation. Science could now solidly say that flies come from flies, and germs come from germs.
ALSO: he used s-shaped/swanshaped necks of flasks because of vitalism
