Answer:
Watson and Crick proposed the double helical model of DNA.
Explanation:
- This model says that DNA exist as double helix. It has two polynucelotide strands running in opposite direction i.e the strands are anti-parallel.
- Each polynucleotide strand is made up of several nucleotide liknked together by phophodiester bonds.
- The two strands are not coiled upon each other but the double strand is coiled upon itself around a common axis like the spiral stair case. Here base pairs forms the stairs and backbone of two strands form railing. Back bone contains sugar and phosphate.
- The base pairing is specific, adenine always pairs with thymine and guanine always pairs with cytosine. Thus if we see any base pair, it consists of one purine and one pyrimidine.
- The two strands of DNA thus show complementary base pairing.
- The strands are held together because of hydrogen bonding between the bases in opposite strand.
- One full helical turn involves ten base pairs and the base pairs are stacked 3.4 A apart.
- This form is called as B-form of DNA.
Answer:
1) Hunger, savor, appetite. Three main biological reasons why we eat. Also, the economic ability to pay for the food. And the fisical capability to go and buy food, to cook.
2) Our physiological needs are the main reason why we choose food. People need energy to survive.
Everyone would like to have the possibility to eat what he wants. But food choices depend on the financial situation, social class, and preferences.
That is why poor people or people who have less money to spend on food, often eat food that can feed more people but it doesn’t have nutritional values. When people have money, they immediately have a wider spectrum of groceries that can choose from.
Explanation:
Savour is equal to enjoying. When people are not hungry they are happier. We choose what to eat depending on the look, taste, smell, texture. As sweets smell good, people consider them the most attractive food. Food is not just the source of nutrition, it is also the source of satisfaction.
It can cause bacteria in bacteria can cause diseases
