<span>The key points about cell theory are as follows:
1. All living organisms are made up of cells; the organisms may be unicellular or multi cellular.
2. The cell is the basic unit of life.
3. New cells are derived from pre-existing cells.
4. All cells maintain homeostasis.
Some new facts have been added to these basic facts; the new facts added include the following:
(A). Energy flow occur withing all living cells.
(B). Hereditary information derived from DNA is passed from cell to cell.
(C). All living cells are made up of the same basic chemical compositions.</span>
Answer: c. proteasome
Explanation:
Proteasomes are extremely important multi-catalytic proteases and are involved in various cellular functions. The proteasome is an essential component of eukaryotic cells and is responsible for the ATP-dependent proteolytic degradation of most cellular proteins. They are present in the nucleus and cytosol and can represent up to 1% of total cell proteins. Proteasomes generally degrade proteins to small peptides, most of which are rapidly hydrolyzed by cytoplasmic exopeptidases. It catalyzes the rapid degradation of many enzymes, regulatory proteins, and eliminates abnormal proteins resulting from mutation or damaged proteins. The inability of this cellular organelle can lead to neurodegenerative diseases, such as Parkinson´s disease.
Before assessing the two given cases, an assumption needs to be made about the digestion of the two types of food items, corn and beef. Let us assume that both get digested by expending same amount of energy by the human body. Let the amount of energy at producer level be an arbitrary X.
Case 1: Corn to human:
Since corn is at the producer level, it will have X amount of energy. The transfer of energy from corn to human will take place with a loss of 90% energy at the producer level. Hence the humans will receive 10% of X amount of energy.
Case 2: Corn to cow to human:
Since corn has X amount of energy, only 10% will pass to the next level, i.e. cow. So cow has 10% of X. Cow transfers only 10% of the energy that it has. Hence humans receive only 10% of 10% of X amount of energy.
It can be seen that humans receive more energy in case 1 than case 2. Hence we can say that it is more efficient for humans to feed on corn.
Answer:
The loss of phytoplankton is a huge problem for marine food chains, says Worm, because every creature in the ocean either eats phytoplankton or eats other organisms that depend on it.
Hope this helps!
Answer:
Genetic variation is caused by:
mutation
random mating between organisms
random fertilization
crossing over (or recombination) between
chromatids of homologous chromosomes during
meiosis
