INC CET / BSc Nursing Entrance Biology - Zoology Syllabus

What activates trypsinogen to trypsin in the small intestine?

The enzyme enterokinase (enteropeptidase), secreted by the intestinal mucosa.

What is the function of bile in digestion?

Bile (from the liver, stored in the gall bladder) emulsifies fats into small droplets and provides an alkaline medium; it contains no digestive enzymes.

Where is most of the absorption of digested food completed in the human alimentary canal?

In the small intestine, mainly through villi and microvilli that increase the surface area.

What is the difference between breathing and respiration?

Breathing (ventilation) is the physical exchange of air between lungs and atmosphere; respiration is the biochemical process of oxidising glucose to release energy (ATP) in cells.

How is most oxygen transported in the blood?

About 97% is transported bound to haemoglobin as oxyhaemoglobin in red blood cells; about 3% is dissolved in plasma.

How is the majority of carbon dioxide transported in blood?

About 70% as bicarbonate ions (HCO3-) in plasma, about 20-25% as carbaminohaemoglobin, and about 7% dissolved in plasma.

Trace the path of blood through the four chambers of the human heart.

Deoxygenated blood: right atrium → right ventricle → lungs; oxygenated blood: left atrium → left ventricle → aorta → body.

What is the normal human blood pressure value and what do the two numbers represent?

120/80 mm Hg; 120 is systolic pressure (ventricular contraction) and 80 is diastolic pressure (ventricular relaxation).

Which node is called the pacemaker of the heart and why?

The sinoatrial (SA) node, because it generates the impulses (action potentials) that initiate and set the rhythm of each heartbeat.

What is the functional unit of the kidney called?

The nephron (each kidney has about one million nephrons).

What are the three main processes of urine formation?

Glomerular filtration, tubular reabsorption, and tubular secretion.

Which nitrogenous waste is excreted by humans, and what are the categories based on excretory products?

Humans are ureotelic (excrete urea); categories are ammonotelic (ammonia), ureotelic (urea), and uricotelic (uric acid).

What proteins are responsible for muscle contraction and what theory explains it?

Actin (thin) and myosin (thick) filaments; contraction is explained by the sliding filament theory, where actin slides over myosin.

What ion is essential for muscle contraction and triggers it?

Calcium ions (Ca2+), released from the sarcoplasmic reticulum, bind troponin to expose myosin-binding sites on actin.

What are the three parts of a neuron?

The cell body (cyton/soma), dendrites (receive impulses), and axon (conducts impulses away).

What is a synapse and how is the impulse transmitted across it?

A synapse is the junction between two neurons; the impulse is transmitted chemically via neurotransmitters (e.g., acetylcholine) released across the synaptic cleft.

Which gland is called the master gland of the body and why?

The pituitary gland, because it secretes hormones that regulate other endocrine glands.

Which hormone regulates blood glucose by lowering it, and which raises it?

Insulin lowers blood glucose; glucagon raises it. Both are secreted by the pancreas (islets of Langerhans).

What hormone does the thyroid gland secrete and what element is essential for it?

Thyroxine (T4) and triiodothyronine (T3); iodine is essential for their synthesis. Deficiency causes goitre.

Where are sperm produced and where do they mature in the human male?

Sperm are produced in the seminiferous tubules of the testes and mature/are stored in the epididymis.

Name the parts of the female reproductive system where fertilisation and implantation occur.

Fertilisation occurs in the fallopian tube (ampulla region); implantation occurs in the uterus (endometrium).

What are the four phases of the human menstrual cycle?

Menstrual phase, follicular (proliferative) phase, ovulatory phase, and luteal (secretory) phase.

Which hormone surge triggers ovulation, and on roughly which day of a 28-day cycle does ovulation occur?

A surge of luteinising hormone (LH); ovulation occurs around day 14.

What does ART stand for, and give two examples of assisted reproductive technologies.

Assisted Reproductive Technology; examples include IVF (in vitro fertilisation), ZIFT, GIFT, and ICSI.

What is the full form of STDs and name two examples.

Sexually Transmitted Diseases; examples include AIDS (HIV), syphilis, gonorrhoea, and genital herpes.

Distinguish between active and passive immunity.

Active immunity is produced by the body's own cells after exposure to antigen (long-lasting); passive immunity is the transfer of ready-made antibodies (e.g., mother to fetus, antiserum), which is short-lasting.

Which microorganism causes malaria and which mosquito transmits it?

Plasmodium (a protozoan); transmitted by the female Anopheles mosquito.

Name two microbes used in industry: one for fermenting bread/alcohol and one for producing curd.

Saccharomyces cerevisiae (yeast) for bread and alcohol; Lactobacillus (lactic acid bacteria, LAB) for converting milk to curd.

What are the two core techniques (tools) of genetic engineering used in biotechnology?

Restriction enzymes (molecular scissors that cut DNA at specific sites) and vectors/plasmids (DNA carriers), along with ligase to join DNA fragments.

What is the role of restriction endonucleases and what are 'sticky ends'?

Restriction endonucleases cut DNA at specific recognition sequences; sticky ends are short single-stranded overhangs left after cutting that allow complementary DNA fragments to join.

Define an ecosystem and name its two main components.

An ecosystem is a functional unit of nature where living organisms interact with each other and their physical environment; its components are biotic (living) and abiotic (non-living).

What is the 10 percent law of energy flow in an ecosystem?

Only about 10% of the energy at one trophic level is transferred to the next higher trophic level; the rest is lost mainly as heat (Lindeman's law).