Zoology Test

Vestigial organs are remnants of structures that had functions in ancestors but are now reduced/unused. Wisdom teeth are human third molars that often don't emerge properly - they're evolutionary leftovers from larger-jawed ancestors. The intestine and hair are functional; muscle of glottis has a purpose.

Neo-Lamarckism extends Lamarck's theory with modern genetics. It emphasizes that mutations, variations, and environmental factors together drive evolution. Unlike Darwinism (natural selection + variation), Neo-Lamarckism gives environmental influences a more direct role. 'Enormous fertility' and 'variation' alone are incomplete.

Fossils are preserved remains/traces of organisms that show evolutionary changes over time. They provide direct physical evidence of species that lived in different eras. Embryos show developmental similarities, mountains are geological, and vestigial organs (like wisdom teeth) are evidence but less direct/evident than fossils.

Viruses have either DNA or RNA as genetic material, never both. This is a fundamental viral characteristic. Option B is wrong because viruses replicate in various cells (plant, animal, bacterial), not just animal cells. Option C is wrong because viruses are not considered fully living (they need host cells). Option D is wrong because viruses are much smaller than bacteria.

Blood group O individuals have both anti-A and anti-B antibodies in their plasma because they lack both A and B antigens on their red blood cells. This is why O is the universal donor but can only receive O blood. AB has neither antibody, A has anti-B, and B has anti-A.

Miller and Urey conducted their famous 1953 experiment simulating early Earth conditions (water, methane, ammonia, hydrogen, electrical sparks) and successfully produced amino acids - the building blocks of life. Oparin had earlier proposed the theoretical primordial soup concept, but Miller-Urey provided the experimental evidence. Lamarck and De Vries worked on different evolutionary mechanisms.

Darwin's theory centers on natural selection - organisms with favorable variations are more likely to survive and reproduce, passing those traits to offspring. While variation provides the raw material, natural selection is the driving force. Mutation is the source of variation, and inheritance of acquired characters is Lamarck's incorrect theory.

The sperm's middle piece contains the centriole (which forms the basal body of the flagellum) and mitochondria spirally wrapped around it, providing energy for motility. The nucleus is in the head, and while proteins are components of all cell parts, centriole is the specific organelle located in the middle piece that anchors the flagellum.

Color blindness is a classic X-linked recessive trait - the gene is located on the X chromosome, making it sex-linked. Males (XY) express it with one affected X, while females (XX) need two affected X chromosomes. Baldness is sex-influenced (hormone-modified) rather than sex-linked. Diabetes is polygenic/multifactorial and polio is an infectious disease, neither being sex-linked genetic conditions.

The Mesozoic Era (Triassic, Jurassic, Cretaceous periods) is famously called the 'Age of Reptiles' when dinosaurs dominated terrestrial ecosystems. While birds evolved from theropod dinosaurs during this era and plants continued to diversify, reptiles (particularly dinosaurs) were the dominant vertebrates. Fishes were most prominent in earlier periods.

Java man (Homo erectus erectus) had an average cranial capacity of approximately 900 cc, fitting squarely in the 800-1000 cc range. Homo erectus generally ranged 850-1250 cc. Neanderthals had larger capacities (1450-1600 cc), and modern humans average 1300-1400 cc, placing both outside the specified range.

Ammonia is highly toxic and requires large amounts of water for dilution and excretion. Urea is less toxic and can be concentrated. CO2 is eliminated through lungs and amino acids are building blocks, not excretory products. Aquatic organisms excrete ammonia directly, while terrestrial organisms convert it to less toxic urea or uric acid to conserve water.

Transamination is the process where an amino group is transferred from an amino acid to a keto acid, forming a new amino acid. This is a key step in amino acid metabolism where nitrogen is ultimately converted to urea in the liver. Option B correctly identifies conversion of ammonia to urea (urea cycle), while C describes deamination (removal, not transfer). Option A is the reverse of what actually happens.

Frogs are carnivorous and require protein-digesting enzymes. Trypsin and pepsin are proteases that break down proteins, while erepsin (peptidase) further breaks down peptides. Option A lists three protein-digesting enzymes. Option C contains carbohydrate enzymes (amylopsin, ptyalin) and lipase (fat), option B has incorrect combinations, and option D includes enzymes not typically found in frogs.

Mother A (genotype I^A I^A or I^A i) × Father B (genotype I^B I^B or I^B i) can produce children with genotypes I^A I^B (AB), I^A i (A), I^B i (B), or ii (O). The Punnett square shows a 1:1:1:1 ratio, giving 25% probability for each blood type including O. The phrasing '1 out of 4' represents this probability per child, not a guarantee across 4 children.

Glycogen is the storage form of glucose in animals. It is primarily stored in the liver and muscle tissues, where it can be quickly mobilized when blood glucose levels drop.

Enzymes are biological catalysts that speed up chemical reactions without being consumed. While most enzymes are proteins (option A), they are fundamentally defined by their catalytic function, not their chemical composition.

Mammary glands are the defining characteristic of all mammals, giving the class its name. While some mammals like whales have lost hair (option B) and there are other exceptions to features like the diaphragm or teeth, mammary glands are universal in mammals.

Calcium ions (Ca++) are essential for the blood clotting cascade. Factor IV in the coagulation pathway is actually calcium ions, which are required cofactors for multiple steps in the clotting process.

Each haemoglobin molecule contains four iron-containing heme groups, and each heme can bind one oxygen molecule. Therefore, one haemoglobin molecule carries four oxygen molecules.

Crows and other birds have a beak made of keratin (a chitin-like protein), which is hard and lacks teeth. This adaptation is characteristic of birds, unlike mammals (bats), reptiles (lizards), or reptiles (snakes) which have teeth or jaws.

Carbon monoxide (CO) binds to haemoglobin with approximately 200-250 times greater affinity than oxygen, forming carboxyhaemoglobin. This stable complex is the strongest bond among the options, which is why CO is so toxic.

During anaerobic respiration in muscles, pyruvate is converted to lactic acid. When lactic acid accumulates faster than it can be cleared, it causes muscle fatigue and burning sensation.