Biology Test - 18

Diffusion is faster in substances with molecules having hydrophobic moiety. Among the following, lipids have hydrophobic moiety whereas carbohydrates, proteins and vitamins have hydrophilic moiety.

A microspore is a first cell of male gametophyte.

After meiosis, the haploid microspores undergo several changes to give rise to pollen grains which later produce the sperm cells or male gametes. In this process, the microscope is the first haploid cell produced and hence, is considered as the first cell of the male gametophyte.

Ependyma is the thin epithelium lining in the ventricles of the brain and the central canal of the spinal cord. These are ciliated simple columnar epithelium cells. These are involved in the production of cerebrospinal fluid (CSF).

Myoglobin is found to be highly abundant in the muscles of whales and seals. Myoglobin is oxygen and iron-binding protein allowing organisms to hold their breath longer underwater. Myoglobin is a protein found in the muscles of almost all mammals that binds to both iron and oxygen. It is also made up of heme and globin protein. The main function of myoglobin is binding to oxygen and carrying it to different muscle tissues.

Stored blood becomes brown due to the formation of methemoglobin.

When the blood is stored for a long time period, the heme group of haemoglobin \(\left(\mathrm{fe}^{2+}\right)\) gets oxidised to ferric state \(\left(\mathrm{fe}^{3+}\right)\), and the haemoglobin gets converted into methemoglobin which is a brown colour pigment (this gives blood the brown colour). Methemoglobin is also incapable to transport \(\mathrm{O}_{2}\) molecules.

A Southern blot is a method used in molecular biology for the detection of a specific DNA sequence in DNA samples. Southern blotting combines the transfer of electrophoresis-separated DNA fragments to a filter membrane and subsequent fragment detection by probe hybridization.

The correct sequence will be- ii, vi, v, iii, i, and iv

The correct match is: 1 - c, 2 - a, 3 - d, 4 - b

• An earthworm moves by using two different sets of muscles (muscle fibres). Circular muscles loop around each segment, and longitudinal muscles run along the length of the body. When the circular muscles contract, the earthworm stretches, becoming longer and thinner.
• Echinoderms possess a unique ambulacral or water vascular system, consisting of a central ring canal and radial canals that extend along each arm.
• Skeletal muscle is a specialized contractile tissue found in animals that functions to move an organism's body. Skeletal muscle is comprised from a series of bundles of muscle fibers, surrounded by protective membranes.
• Locomotion in Hydra is carried out by two types of contractile cells.

Half haemophilic and half carriers.

Chymotrypsin is an enzyme that digests food proteins within the small intestine. The active site of this enzyme contains partial positive and partial negative charges.

The process of taking oxygen rich air in the body is called Inhalation.

Breathing is the process of transfer of air into and out of the lungs to perform gas exchange. The breathing cycle consists of two processes namely inhalation and exhalation. The process of taking oxygen-rich air in the body is called inhalation.