Biology Test 280

Pineapple fruit develops from a cluster of compactly borne flowers on a common axis. It develops from spike, spadix, or catkin. In such cases, the flowers remain with their succulent petals, the axis bearing them grows and becomes fleshy or woody.

The aleurone layer of maize grain is especially rich in proteins. Aleurone is a protein found in protein granules of mature seeds and tubers. The aleurone layer is the outermost layer is the outermost layer of the endosperm.

he number of chromosomes in the diploid cell of the root tip as given is 42, which means one set is of 21 chromosomes. So the cells of the aleurone layer of the given plant will have 63 chromosomes.

Phylloclade is a modification of stem because the stem modifies into a green fleshy leaf life structure having distinct nodes and internodes.

A typical flower with superior ovary and other floral parts inferior is. A typical flower that has an ovary placed superior along with the other floral organs is known as hypogynous. The other floral organs are also attached under the ovary to the receptacle.

Angiogram is an X-ray diagnostic procedure used to visualize the blood vessels following injection of a contrast 16 substance into an artery. Coronary angiography is used to detect obstruction in the coronary arteries, due to presence of atherosclerotic plaques which can lead to heart attack, To clear the passage, a very small balloon tipped catheter is inserted into the coronary artery under X-ray observation, Then the balloon is inflated with air to destroy the plaques, thereby clearing the lumen of the blood vessel for blood flow, This procedure is known as coronary artery angioplasty.

SAN (sino-atrial node) is located in the right upper y corner of right atrium. AV bundle continues from AVN (Atrio-ventricular node). Purkinje fibres are modified cardiac muscle fibres that originate from AV node and spread into two ventricles. The nodal musculature has the ability to generate action potential without any external stimuli i.e. it is autoexcitable. AVN is located in the lower left corner of the right atrium close to the atrio-ventricular septum.

Coronary arteries supply blood to the heart muscle. Like all other tissues in the body, the heart muscle needs oxygen-rich blood to function.

In the given diagram 'D' represent the vena cava. Vena cava is either of two large veins that carry deoxygenated blood into the right atrium.

The cardiac impulse originates from SA node. This impulse is of highest rhythmicity. By determining the rate of discharge of the cardiac impulse the SA node determines the rate of heart beat.