DPT Admission Test Biology Syllabus

What is the general molecular formula for carbohydrates?

(CH2O)n, meaning carbohydrates contain carbon, hydrogen, and oxygen, with hydrogen and oxygen typically in a 2:1 ratio.

Classify carbohydrates into their three main groups with one example of each.

Monosaccharides (e.g. glucose), disaccharides (e.g. sucrose), and polysaccharides (e.g. starch).

Which monosaccharides combine to form sucrose, lactose, and maltose?

Sucrose = glucose + fructose; Lactose = glucose + galactose; Maltose = glucose + glucose.

Name three important storage and structural polysaccharides and their roles.

Starch (plant energy storage), glycogen (animal energy storage), and cellulose (plant cell wall structure).

What type of bond joins monosaccharides together, and what reaction forms it?

A glycosidic bond, formed by a condensation (dehydration) reaction that releases a water molecule.

What is the general structure of an amino acid?

A central (alpha) carbon bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a variable R (side) group.

How many amino acids commonly occur in proteins, and how are they linked?

There are 20 standard amino acids, linked by peptide bonds formed through condensation reactions.

Describe the four levels of protein structure.

Primary (amino acid sequence), Secondary (alpha-helices and beta-pleated sheets from hydrogen bonding), Tertiary (overall 3D folding), and Quaternary (assembly of multiple polypeptide subunits).

What is denaturation of a protein?

Denaturation is the loss of a protein's native 3D structure (secondary, tertiary, quaternary) due to heat, pH change, or chemicals, causing loss of function; the primary structure remains intact.

What is a peptide bond and between which groups does it form?

A peptide bond is a covalent bond formed between the carboxyl group (-COOH) of one amino acid and the amino group (-NH2) of another, with the loss of water.

What are the building blocks (monomers) of a triglyceride (fat)?

One molecule of glycerol and three fatty acid molecules, joined by ester bonds via condensation.

Differentiate between saturated and unsaturated fatty acids.

Saturated fatty acids have no carbon-carbon double bonds (single bonds only) and are usually solid at room temperature. Unsaturated fatty acids have one or more double bonds and are usually liquid (oils).

What is the structure of a phospholipid and why is it important in membranes?

A phospholipid has a glycerol backbone with two fatty acid tails and a phosphate-containing head. The hydrophilic head and hydrophobic tails make it amphipathic, allowing it to form the bilayer of cell membranes.

Name three biological functions of lipids.

Long-term energy storage, thermal insulation and protection, and forming components of cell membranes; they also serve as precursors for steroid hormones.

What are the three components of a single nucleotide?

A pentose sugar, a phosphate group, and a nitrogenous base.

Name the nitrogenous bases found in DNA and RNA and the base-pairing rules.

DNA: adenine (A), thymine (T), guanine (G), cytosine (C); RNA replaces thymine with uracil (U). Pairing: A-T (A-U in RNA) and G-C.

List three key structural differences between DNA and RNA.

DNA has deoxyribose sugar, the base thymine, and is double-stranded; RNA has ribose sugar, the base uracil, and is usually single-stranded.

What type of bond holds the two strands of DNA together, and how many bonds for each base pair?

Hydrogen bonds; A-T pairs have 2 hydrogen bonds and G-C pairs have 3 hydrogen bonds.

Name the three types of RNA and their functions.

mRNA (messenger RNA) carries the genetic code from DNA; tRNA (transfer RNA) brings amino acids to the ribosome; rRNA (ribosomal RNA) forms part of the ribosome.

List four properties of water that make it biologically important.

High specific heat capacity (temperature regulation), excellent solvent (transport medium), high cohesion and surface tension, and it acts as a reactant/medium for metabolic reactions like hydrolysis.

Why is water described as a 'universal solvent'?

Water is polar, so it readily dissolves polar and ionic substances by forming hydration shells around them, making it the medium for most biochemical reactions and transport.

According to the induced-fit model, how does an enzyme bind its substrate?

The active site is not rigid; when the substrate approaches, the active site changes shape slightly to fit snugly around the substrate, optimizing catalysis.

How do enzymes speed up reactions?

Enzymes lower the activation energy of a reaction by binding substrates at the active site to form an enzyme-substrate complex, without being consumed themselves.

How do temperature and pH affect enzyme activity?

Activity increases with temperature up to an optimum, then falls as the enzyme denatures. Each enzyme has an optimum pH; deviation reduces activity and extremes cause denaturation.

What is the effect of substrate concentration on enzyme reaction rate?

Rate increases with substrate concentration until all active sites are saturated, after which the rate plateaus at Vmax (maximum velocity).

Differentiate between competitive and non-competitive enzyme inhibition.

A competitive inhibitor resembles the substrate and binds the active site (can be overcome by more substrate). A non-competitive inhibitor binds a site other than the active site, changing the enzyme's shape (not overcome by more substrate).

Write the overall balanced equation for photosynthesis.

6CO2 + 6H2O --(light, chlorophyll)--> C6H12O6 + 6O2.

Write the overall balanced equation for aerobic respiration and state the net ATP yield.

C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy; complete aerobic respiration of one glucose yields about 36-38 ATP.

Name the four stages of aerobic respiration and where each occurs.

Glycolysis (cytoplasm), link reaction and Krebs cycle (mitochondrial matrix), and the electron transport chain/oxidative phosphorylation (inner mitochondrial membrane).

What are the functions of the stomach, small intestine, and pancreas in digestion?

The stomach secretes acid and pepsin to begin protein digestion; the small intestine is the main site of digestion and absorption; the pancreas secretes digestive enzymes and bicarbonate into the small intestine.

Trace the path of blood through the human heart starting from the body.

Body -> superior/inferior vena cava -> right atrium -> right ventricle -> pulmonary artery -> lungs -> pulmonary veins -> left atrium -> left ventricle -> aorta -> body.

How does gas exchange occur in the alveoli of the lungs?

Oxygen diffuses from the alveolar air (high O2) into the blood capillaries, while carbon dioxide diffuses from the blood into the alveoli to be exhaled, across the thin moist alveolar walls.

What are the three main parts of a neuron and the function of each?

Dendrites receive impulses, the cell body (soma) integrates them, and the axon transmits impulses away to other cells (often insulated by a myelin sheath).

What are the two divisions of the human nervous system, and what does each include?

The central nervous system (brain and spinal cord) and the peripheral nervous system (all nerves outside the CNS, including the somatic and autonomic systems).

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

A synapse is the junction between two neurons. The impulse is carried across the synaptic cleft by neurotransmitters released from the presynaptic neuron, which bind receptors on the postsynaptic neuron.