Science M.C.Q. [I MARKS]

Amoeba, yeast and rhizobium are examples of unicellular organisms while Yak is an example of multicellular organisms.

Nucleus contains thread-like structures called chromosomes. These carry genes and help in inheritance or transfer of characters from the parents to the offspring.

Nucleus contains thread-like structures called chromatins. Chromosomes are condensed form of chromatin. During cell division, these chromosomes carry genes and help in transfer of characters from parents to offspring.

The group of similar cells which work together to perform a particular function is called tissue.

Chloroplasts are found only in those plant cells which carry out photosynthesis like the cells in green leaves. So, chloroplasts are not found in the root cells of a plant.

The cell wall is made up of cellulose.

Unicellular organisms are those organisms that have single cell. Euglena, Chlorella and Escherichia are unicellular organisms.

Centrosome is an organelle present near the nucleus of an animal cell. It initiates the process of cell division. In plant cells, centrioles appear only at the time of cell division.

Genes are the unit of inheritance located in the chromosomes. The other statements are incorrect and their correct form are as:
Nucleus is located in the cell Chromosomes are located in the nucleus.
Cell membrane surrounds the cell and nuclear membrane surrounds the nucleus.

Chloroplasts are found only in those plant cells which carry out photosynthesis like the cells in green leaves. So, chloroplasts are not found in the root cells of a plant.

Golgi bodies are usually called dictyosomes in plants. The main function of golgi body is to secrete digestive enzymes through membrane-bound vesicles.

Plastids are of three types, i.e. chloroplasts, leucoplasts and chromoplasts. Leucoplasts are colourless plastids which are capable of storing food materials.

Nerve cells (neurons) are long, branched and have thread-like projections so that they can connect other nerves cells and transmit messages over long distance.

The nucleus consists of genetic material in the form of a dense mass. It is surrounded by double membrane called nuclear envelope. It is the controlling centre of the cell.

Mitochondria - provides energy, chloroplast - helps in synthesis of food, nucleus - controls all the activities of the cell and cell wall, gives shape to the cell.

A nerve cell is the longest cell in the human body.

Cell wall is the non-living part of the cell. It allows all the substances to pass through it. They only have structural function and determines shape of cells. On the contrary, cell membrane which is living, is active and has molecules present in it that are always dynamic.

Germinating seeds contain more mitochondria.

Chromosome and genes are related to inheritance of characters. Chromosomes are present in nucleus. They contain genes, which are unit of inheritance.