The given question says that a student has constructed a model of cellular transport using fences and several gates.
This model can be used to demonstrate the cellular transport.
The gates of the fences can be supposed as the protein pumps and the other fence demonstrates the lipid bilayer.
Let’s suppose in the fence, there are many cattles, and outside, there are less cattles, but the student open the gate and bring more cattles inside the fence. In this case, the transport of the cattles is similar to the active transport of the molecules using protein pumps. At cellular level, the energy for the active transport is provided by ATP molecules.
Now, let’s say, the student wants to feed the cattles with some nutrition rich food, which can help in maintaining the health of the cattles. The student fills his car with the cattle food and he enters inside the fence through gates. In this case, the food was not present in the fence, but was abundant in the outside environment, so, the diffusion would occur. But food cannot come self, without help of others, so, the movement is facilitated by the car, as it is done by the carrier proteins. Hence, it is an example of facilitated diffusion.
Simple. Air has mass. And if air has mass it also has weight. You can feel air when the wind blows. Or do an experiment. Weigh an empty container. Then pump it to a vacuum. Weigh it again. The difference is the weight of the air inside.
Answer:
The answer is letter B
Explanation:
A cell contains thousands of different kinds of enzymes, each promoting a different chemical reaction.
Answer:
The main function of the virion is to deliver its DNA or RNA genome into the host cell so that the genome can be expressed (transcribed and translated) by the host cell. The viral genome, often with associated basic proteins, is packaged inside a symmetric protein capsid.
Explanation:
what is a virus A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology.
