Test: Organisms and cells - Class 7 MCQ

The nucleus contains DNA (deoxyribonucleic acid), which stores genetic information. During cell division, the nucleus ensures that genetic material is replicated and passed on to new cells, allowing them to inherit the instructions for their structure and function.

Chloroplasts contain chlorophyll, a pigment that absorbs sunlight and converts it into chemical energy during photosynthesis. This process allows plants to produce their own food using solar energy.

Plants absorb carbon dioxide from the air through tiny pores called stomata, located on the underside of their leaves. These pores are regulated by guard cells. Carbon dioxide is used in photosynthesis to produce glucose and oxygen.

Mature red blood cells in mammals do not contain a nucleus, allowing more space for hemoglobin, a protein that carries oxygen and gives them their red color. Neuron cells, root hair cells, and sperm cells all contain a nucleus to support their functions.

Sperm cells are specialized for reproduction. They have a tail (flagellum) that allows them to swim toward an ovum (egg) for fertilization. Neuron cells, red blood cells, and root hair cells have other functions unrelated to reproduction.

Sensitivity refers to the ability of living organisms to detect and respond to changes in their internal or external environment. This is different from movement, respiration, and excretion, which are also vital characteristics but involve different processes.

Neuron cells, or neurons, are specialized cells in the nervous system that receive, carry, and pass on electrical impulses to coordinate body functions, such as movement and sensation. Muscle cells respond to impulses, while red and white blood cells have other roles.

Viruses do not meet several criteria of the MRS GREN framework. They do not grow, respire, or move independently. They also do not excrete waste or perform other metabolic activities that characterize living organisms.

Root hair cells in plants absorb water and nutrients from the soil, which are essential for the plant’s nutrition. Neuron cells transmit signals, red blood cells transport oxygen, and sperm cells are involved in reproduction, not nutrition.

Excretion is the process by which living organisms remove waste products of metabolism and substances that are in excess. Growth, respiration, and nutrition involve other vital processes, such as increasing in size, releasing energy, and intake of materials, respectively.