Cell - The Unit of Life Test 11

Active transport is the movement of molecules or ions from a region of their lower concentration to a region of their higher concentration, against the concentration gradient. It requires energy in the form of ATP.

The cell membrane is a phospholipid bilayer which is semi – permeable. Water moves across this membrane by the process of diffusion. The diffusion of water across a semi – permeable membrane is known as osmosis.

Fluidity of the cell membrane is the measure of the ability to move within the membrane. This movement is allowed due to the quasi-fluid nature of lipid present in the cell membrane.

Eukaryotic cells possess a true nucleus. Plants, fungi and protists are eukaryotic organisms as they have a well – defined nucleus. However, monerans do not possess a well – defined nucleus and are thus, prokaryotes.

Plants cells are differentiated from animal cells on the basis of the presence of certain organelles such as plastids, cell wall and a large central vacuole. Only animal cells possess centrioles in their cytoplasm.

The structure of the cell membrane was studied in detail in the 1950s after the advent of the electron microscope. The cell membrane is a phospholipid bilayer containing various proteins in its structure.

The cell wall covering the cell of fungi and plants is a non-living structure. The cell membrane covering the cell and the various organelles of the cell such as the nucleus and the lysosomes are living.

The cell wall is a non-living rigid structure that covers the cells of fungi and plants. It also provides functions like protection from infection and mechanical stresses, and cell to cell interactions.

The algal cell wall contains cellulose, galactans, mannans and minerals like calcium carbonate. However, the plant cell wall contains cellulose, hemicellulose, pectins and proteins.

The algal cell wall contains cellulose, galactans, mannans and minerals like calcium carbonate. The plant cell wall contains cellulose, hemicellulose, pectins and proteins. Hence, cellulose is the common component.

The middle lamella is a layer present between two plant cells which joins the cell walls of both the cells. It is the first layer which is formed and deposited during cytokinesis. It mainly contains calcium pectate.

The middle lamella is a layer present between two plant cells which joins the cell walls of both the cells. It mainly contains calcium pectate. It is the first layer which is formed and deposited during cytokinesis.

Adjacent plant cells adhere to each other due to the presence of the middle lamella. However, the plasmodesmata pass through the middle lamella and connect the cytoplasm of the two cells.

The functions of the endoplasmic reticulum (ER), Golgi bodies, vacuoles and lysosomes are coordinated. Hence, they form an endomembrane system. Peroxisomes are not a part of the endomembrane system.

The functions of the endoplasmic reticulum (ER), Golgi bodies, vacuoles and lysosomes are coordinated. Hence, they form an endomembrane system. Peroxisomes are not a part of the endomembrane system.