Science M.C.Q. [I MARKS]

A cell wall is the distinguishing feature between a plant cell and animal cell. It is thick wall made up of cellulose around cell membrane that exclusively present only in plant cell.

Cell membrane is the common part of every cell. It encloses the protoplasm, protects the cell, gives the cell its shape and control the entry and exit of substances.

The organisms which are made of single cell are called unicellular organisms. The single cell behaves as a complete organism performing basic functions such as respiration, reproduction, nutrition, movement, etc.

Rbosome is not a part of nucleus. They are found floating in the cytosol or attached to the endoplasmic reticulum. Nucleus is the largest organelle in cell that contains thread-like structure is called chromosomes on which genes are present. Nucleolus is the round irregular structures present inside nucleus.

The pigment chlorophyll present in the chloroplasts, which is responsible for green colour of leaves. It can absorb solar energy for photosynthesis.

In a cell the following organelles perform the following functions. Intracellular digestion - lysosome, intracellular respiration mitochondira, intracellular movement - microtubules, cell secretion - golgi complex.

Mitochondria is the site of cellular respiration or oxidation of food in a cell. It uses glucose and oxygen to produce energy. Hence, it is knowns as “Powerhouse of the cell”.

Chromosomes are the thread-like structures present in the nucleus. They contain genes that function to transfer the characteristics from the parents to the offsprings.

Onion peel cells are plant cells.

The green plastids present in plant cells are chloroplasts. Chloroplasts contain green colored pigment called chlorophyll.

The blood is a liquid connective tissue.

Organisms which do not have true nucleus are called prokaryotes. Bacteria and blue green algae are examples of prokaryotes.

Cell wall is the non - living part of the plant cell.

Lysosomes break down and digest food particles in a cell. They also help the cell to protect itself from pathogens, by forming a complex along with the pathogen, called phagosome. They also aid in recycling proteins and digest worn-out cells. Hence, they are known as the 'suicidal bags'. But they do not aid in photosynthesis.

A cell wall and vacuole are absent in animal cells.

Lysosomes are called "suicide bags" of the cell because they have hydrolytic enzymes stored in them. These enzymes are used to digest complex molecules in a cell. When released into the cytoplasm, these enzymes can "digest" or destroy the cell itself. Therefore, they are called "suicide bags".

Chromatin material is a tangled fibrous mass. The chromatin material condenses to form chromosomes during cell division.

Amoeba have pseudopodia, which are projections of varying lengths protruding out of its body. Amoeba does not have a regular shape and uses pseudopodia for locomotion and digestion.

A cell wall is the distinguishing feature between a plant cell and animal cell. It is thick wall made up of cellulose around cell membrane that exclusively present only in plant cell.

The cell membrane controls the entry (movement into the cell) and exit (movement out of the cell) of materials. It also protects and gives shape to the cell.