Biology
The diagram given below represents a section of the human heart. Answer the questions that follow:
(i) Which parts of heart are in the diastolic phase? Give a reason to support your answer.
(ii) Label the parts numbered 1 and 2 in the diagram. What type of blood flows through them?
(iii) What causes the heart sounds 'LUBB' and 'DUP'?
(iv) Name the blood vessels that supply oxygenated blood to the heart muscles.
(v) Draw neat labelled diagrams of a cross section of an artery and a vein.
Answer
(i) In the diagram, ventricles are in the diastolic phase. The reason is that the arrows are shown from atria to the ventricles. It indicates that tricuspid and bicuspid valves are open and the blood is flowing from the atria to the ventricles. During this, the pressure in the ventricles falls and hence they are in the diastolic phase.
(ii) The parts numbered 1 and 2 are:
- 1 → Pulmonary artery, Deoxygenated blood.
- 2 →Pulmonary veins, Oxygenated blood.
(iii) The first sound "LUBB" is produced when the atrio-ventricular (tricuspid and bicuspid) valves get closed sharply at the start of ventricular systole. The second sound "DUP" is produced when at the beginning of ventricular diastole, the semilunar valves at the roots of aorta and pulmonary artery get closed.
(iv) Coronary arteries supply oxygenated blood to the heart muscles.
(v) Below diagrams show the cross section of an artery and a vein:
Related Questions
Give biological reasons for the following statements:
(i) Some women have facial hair like beard and moustache.
(ii) Cutting of trees should be discouraged.
(iii) In some xerophytes leaves are modified into spines.
(iv) There is frequent urination in winter than in summer.
(v) The left ventricle of the heart has a thicker wall than the right ventricle.
Give appropriate biological / technical terms for the following:
(i) The type of immunity that exists in our body due to our genetic makeup.
(ii) The suppressed allele of a gene.
(iii) The accessory gland in human males whose secretion activates the sperms.
(iv) An apparatus that measures the rate of water uptake in a cut shoot due to transpiration.
(v) The kind of twins formed from two fertilised eggs.
(vi) A pair of corresponding chromosomes of the same size and shape, one from each parent.
(vii) The mild chemical substance which when applied on the body kills germs.
(viii) The type of waste generated in hospitals and pathological laboratories.
(ix) The antiseptic substance in tears.
(x) Cellular components of blood containing haemoglobin.
The diagram shown below is the longitudinal section of a testis of man. Study it carefully and answer the questions that follow:
(i) Label the parts numbered 1 to 3 in the diagram.
(ii) In which part of the testis are the sperms produced?
(iii) State the functions of the parts labelled 1 and 3 in the diagram.
(iv) Name the cells that secrete Testosterone.
(v) Draw a neat, labelled diagram of a sperm.
In a homozygous pea plant, axial flowers (A) are dominant over terminal flowers (a).
(i) What is the phenotype and genotype of the F1 generation if a plant bearing pure axial flowers is crossed with a plant bearing pure terminal flowers?
(ii) Draw a Punnett square board to show the gametes and offsprings when both the parent plants are heterozygous for axial flowers.
(iii) What is the phenotypic ratio and genotypic ratio of the above cross shown in (ii).
(iv) State Mendel's Law of Dominance.
(v) Name two genetic disorders commonly seen in human males.