Biology (CDS-Solved Paper)

Both the statements are individually true and statement II is the correct explanation of statement I. A person may suffer from tuberculosis if she /he frequently visits crowded place because the bacteria of tuberculosis (Mycobacterium tuberculosis) spreads through the droplets by sneezing or coughing by diseased/ affected person.

Both the statements are individually true, but statement II is not the correct explanation of statement I. ‘Bioaccumulation  is the accumulation of substances, such as metals and pesticides in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost by catabolism and excretion. Fishes have higher bioaccumulation than planktons due to their larger size and food requirement along with their large adipose tissues which deposit and accumulate metals and pesticides.

Flying fish is a true fish as per the biological system of classification. It is a marine fish, which belongs to order– Beloniformes and class–Pisces. Other fishes are not true fishes. Silver fish is an arthropod, jellyfish and cuttle fish are the animals, which belong to class–Cnidaria.

The excess fat in the body gets stored in the adipocytes of the body tissue named adipose. It is found under the skin. This is made up of fat cells.

The miss matched pair is Nereis–pseudopodia as, it does not have pseudopodia. It has lateral appandages for its movements. Other pairs are correctly matched.

The lysosomes take their origin from Golgi bodies. These contain hydrolytic enzymes which digest and clean cellular debris.

The protein molecules synthesised on ribosomes get processed inside the endoplasmic reticulum which is a double membrane structure.
It reaches to thylakoid by crossing the double membranes of chloroplast. So, it crosses four membranes in total to reach thylakoid structure.

Statement (a) about lymph is correct. Other statements can be corrected as lymph is a colourless fluid containing specialised lymphocytes, not RBCs. It circulates throughout the lymphatic system. Lymph is also an important carrier for nutrients, hormones, etc.

All amphibians and few reptiles have three-chambered heart. They have two auricles and one ventricle and only mixed blood flows through the heart. Whereas, Pisces have two-chambered heart.

Accumulation of lactic acid in the muscle of sprinters leads to cramp. This occurs under conditions of high energy demand, rapid fluctuations of the energy requirement and insufficient supply of O2 . This leads to cramps or muscle fatigue due to the accumulation of lactic acid during anaerobic respiration.