Biology Questions

The red blood corpuscles  or erythrocytes usually carry antigens and there are two types of antigens. The A group persons have antigen A in their red corpuscles and the B group have antigen B in their red corpuscles. The AB group person have both antigen A and antigen B in their erythrocytes. The 'O' group persons have no antigens in their red corpuscles.

a -  at the peak of changes in blood pressure indicates the systiolic pressure.

An organelle called Eyespot allows some protists to detect light. It allows the cells to sense light direction and intensity and respond to it by swimming either towards the light (positive phototaxis) or away from the light (negative phototaxis).

Eyespot is a photoreceptive organelle found in the flagellate or (motile) cells of green algae and other unicellular photosynthetic organisms such as euglenids.

Eyespot-mediated light perception helps the cells in finding an environment with optimal light conditions for photosynthesis. Eyespots are the simplest and most common "eyes" found in nature, composed of photoreceptors and areas of bright orange-red pigment granules.

The hormone adrenaline also called epinephrine is known as a stress harmone. In emotional upset (like fear, anger etc.) this harmone is poured into the blood and it accelerates heart beat. The hormone acetylcholine decelerates heartbeat rate.

Outward extension of the shoulder bone is called as the acromion.

There are about 1,000,000 nephrons in each human kidney.

Nephron, functional unit of the kidney, the structure that actually produces urine in the process of removing waste and excess substances from the blood.