General Biology and Zoology Test

Placenta in mammalian embryo is formed by chorion. 

The respiratory quotient (RQ or respiratory coefficient) is a dimensionless number used in calculations of basal metabolic rate (BMR), when estimated from carbon dioxide production. It is 1 for carbohydrates as numbers of oxygen and carbon dioxide molecules are equal.

Hair on the skin, are derived from epidermis and are made up of cornified cells.

The quadratojugal is a small jaw bone that is present in most amphibians, reptiles and birds, but has been lost in mammals. It is connected to the jugal as well as other bones, though these may vary with species.

Centrolecithal describes the placement of the yolk in the centre of the cytoplasm of ovums. Many arthropod eggs are centrolecithal.

r-strategists species are those that place emphasis on a high growth rate and typically exploit less-crowded ecological niches and produce many offspring, each of which has a relatively low probability of surviving to adulthood.

Vitamin K is required for blood clotting. It is also required for the production of prothrombin (Factor II).

Tubular secretion is the transfer of materials from peritubular capillaries to renal tubular lumen and occurs mainly by active transport.

The Hering-Breuer inflation reflex, named for Josef Breuer and Ewald Hering, is a reflex triggered to prevent over-inflation of the lung. Pulmonary stretch receptors, present in the smooth muscle of the airways, respond to excessive stretching of the lung during large inspirations.

Euchromatin is a lightly packed form of chromatin (DNA, RNA and protein) that is enriched in genes and is often (but not always) under active transcription. Euchromatin comprises the most active portion of the genome within the cell nucleus. 92% of the human genome is euchromatic.

The amniotic cavity is the closed sac between the embryo and the amnion, containing the amniotic fluid. The amniotic cavity is formed by the fusion of the parts of the amniotic fold, which first makes its appearance at the cephalic extremity and subsequently at the caudal end and sides of the embryo.

The mammalian liver, in its histological structure, is characterized by the presence of Glisson's capsules and Kupffer cells.

Descent from common ancestors with modifications is the main basis of evolution.

Ecdysone is a steroidal prohormone of the major insect molting hormone 20-hydroxyecdysone, which is secreted from the prothoracic glands. Insect molting hormones are generally called ecdysteroids

Mitral valve is the valve between the left atrium and the left ventricle of the heart, which has two tapered cusps.

With regard to transfusions of packed red blood cells, individuals with type O Rh D negative blood are often called universal donors and those with type AB Rh D positive blood are called universal recipients

The difference between different amino acids is because of their R side chains.

Cobra venom is neurotoxic.

The saltwater crocodile, also known as the estuarine crocodile, Indo-Pacific crocodile, marine crocodile, sea-going crocodile or informally as saltie, is the largest of all living reptiles.

The fluid mosaic model suggests that the cell membrane is lipid bi-layer. It contains both extrinsic and intrinsic proteins.

Oxidative phosphorylation (OXPHOS) is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing energy, which is used to reform ATP. In most eukaryotes, this takes place inside mitochondria.

Benthos is the community of organisms that live on, in or near the seabed, also known as the benthic zone. This community lives in or near marine sedimentary environments, from tidal pools along the foreshore, out to the continental shelf, and then down to the abyssal depths.

Lethal alleles (also referred to as lethal genes or lethals) are alleles that cause the death of the organism that carry them. They are usually a result of mutations in genes that are essential for growth or development. Lethal alleles may be recessive, dominant or conditional, depending on the gene or genes involved.

Digestion of fats, proteins and carbohydrates is completed in the small intestine.