CBSE Class X – Science Biology Exam ( Full Syllabus)

Hormones and enzymes are proteins, and the formation of any specific protein is controlled by a particular gene. Fat biosynthesis occurs through metabolic reaction.

The maleness of a child is determined by the presence of the Y chromo-some in the zygote inherited from the father.

The character of the cross will be cross fertilization, which is the transfer of pollen from one plant to the stigma of fower; borne on a distinct plant of the same species.

If we dig into the earth and start fnding fossils, the fossils we fnd closer to the surface are more contemporary than the fossils we fnd in deeper layers.

The sex of the children will be determined by what they inherit from their father. A child who inherits an X chromosome from her father will be a girl and the one who inherits a Y chromosome from him will be a boy

The tendril of a pea plant and the phylloclade of Opuntia are homologous structures, as they are modifed stems but serve diferent functions in diferent plants.

similarities due to sharing of chromosomes from both the parents variation due to mutuation ,genetic recombination

A nephron is a fltering unit present in kidney. It has diferent parts like Bowman’s capsule, glomerulus and tubular region (Renal tubule). Glucose, amino acids and salts are selectively reabsorbed in tubular region.

The lime water turns milky on passing carbon dioxide gas into it due to formation of insoluble calcium carbonate. When the exhaled air rich in carbon dioxide is blown from mouth into test tube, it reacts with lime water (calcium hydroxide) to produce calcium carbonate and water

Small intestine receives Juices from liver, pancreas and walls of small intestine. Bile Juice from liver emulsifes the fats and makes the medium alkaline. Pancreas and small intestine Juices contain amylase, lipase and tryspin

Digestion of food starts in mouth by salivary amylase. From here it enters into the stomach via oesophagus The simpler substances formed by chemical digestion are then absorbed by small intestinal villi.

During inhalation, the air is drawn through the nostrils into the nasal passage. From there, air enters into pharynx, larynx, trachea (windpipe), bronchi, lungs and fnally to the alveoli.

Amylase is the enzyme which helps in primary digestion of starch only.Digestion of starch by salivary amylase into maltose starts in mouth. Oesophagus then pushes the food into stomach.

They convert carbon dioxide and water into carbohydrates in the absence of sunlight Explanation: Autotrophs obtain the required carbon and energy requirements from carbon dioxide and Sunlight. They combine carbon dioxide and water to form carbohydrates

Living organisms are well organised structures; they can have tissues, tissues have cells, cells have smaller components in them, and so on. Living creatures keep repairing and maintaining their structures