2 The substances formed by specific chemical bond between fatty acids and alcohol are called lipids. Digestion of lipids consumed by us is nothing but their conversion into fatty acids and alcohol. Fatty acids are absorbed and distributed everywhere within the body. From those fatty acids, different cells produce various substances necessary to themselves. Ex. the molecules called phospholipids which are essential for producing plasma membrane are formed from fatty acids. Besides, fatty acids are used for producing hormones like progesterone, estrogen, testosterone, aldosterone, etc. and the covering around the axons of nerve cells. We get 9 Kcal of energy per gram of lipids. Excess of lipids are stored in adipose connective tissue in the body.
Questions and Answers:
(1) Define lipids.
(2) What happens to fats that are eaten in excess?
(3) Which hormones regulating reproductive functions are produced from fatty acids?
(4) How is plasma membrane of the cells formed?
(5) What happens to lipids when their digestion is completed? How much energy do they provide?

ATP: Energy Currency

With the help of suitable diagrams, explain the five stages of prophase-I of meiosis.

Mitochondria and Krebs cycle:

(a) Which co-enzymes are shown in the diagram?
(b) Which chemical reaction takes place in the mitochondria? Which molecules are produced in this reaction?

 

How energy is formed from oxidation of carbohydrates, fats and proteins?
Correct the dagram below.


 

Observe the diagrams and answer the following questions.



(a) Which peculiarity do you observe in the figure of Metaphase-I of meiosis ?
(b) What is the important difference between Telophase-I and Telophase-II of meiosis?
(c) Which figure shows phenomena of crossing over?

With the help of suitable diagrams, explain the mitosis in detail.

How do all the life processes contribute to the growth and development of the body?

1 Dietary fibre — found mainly in fruits, vegetables, whole grains and legumes — is probably best known for its ability to prevent or relieve constipation. But foods containing fibre can provide other health benefits as well, such as helping to maintain a healthy weight and lowering your risk of diabetes, heart disease and some types of cancer. Dietary fibre, also known as roughage or bulk, includes the parts of plant foods your body can’t digest or absorb. Unlike other food components, such as fats, proteins or carbohydrates — which your body breaks down and absorbs — fibre isn’t digested by your body. Instead, it passes relatively intact through your stomach, small intestine and colon and out of your body.
Questions and Answers :
(1) Which food items provide rich fibre content?
(2) Enlist the advantages of fibres in diet.
(3) Are fibres digested in the body?
(4) Which is the path through which fibres pass in the digestive tract?
(5) What is a roughage?

 Explain the Krebs cycle with reaction.