University:
Acadia University
Course:
BIOL-2013 | Cell and Molecular Biology
Academic year:

2024
Views:

34

Pages:

2
Author:

Nabila n.

Cell Specialisation & Differentiation Cell Specialisation: Cells may be specialised to carry out a specific function. Animal Cells Sperm Cells The acrosome contains enzymes to help break down the egg membrane. Mitochondria provide energy to power the tail. The haploid nucleus contains half the number of chromosomes of a normal cell. The long tail and streamlined shape enable the sperm to swim to the egg. Nerve Cells Nerve cells (neurons) are highly specialised for transmitting impulses around the body. They are long and have branched connections to join to other neurons and form networks. Muscle Cells Muscle cells contain lots of mitochondria to provide energy. These cells can contract and relax, and they can also store glucose as glycogen. Plant Cells Xylem Cells Xylem vessels transport water and strengthen plant structures. They are made of dead cells that have lost their end walls and cytoplasm to become hollow tubes for transporting water. Their walls are thickened with lignin to provide strength. Root Hair Cells Root hair cells are found in the roots of plants and are specialised for absorbing water and mineral ions. They have hair-like projections that provide a large surface area for water absorption. Phloem Cells Phloem vessels transport sugars (sucrose) in plants. Phloem cells have perforated end walls and a very thin layer of cytoplasm to aid transport. Each cell has an attached companion cell, which supplies materials the cytoplasm normally makes. Cell Differentiation When new cells are formed in organisms, they are simple in form. However, over time, they differentiate (become specialised) to form different types of cells. Most types of animal cell differentiate early in life – many in the embryo – whereas many types of plant cell retain the ability to differentiate throughout their life. In mature animals, new cells are still formed by cell division to replace old cells and to repair tissues. As the cell differentiates into a specialised cell, it adopts different subcellular structures. For example, cells in the bone marrow differentiate into new red blood cells. The cells lose their nucleus, change shape and become filled with the red, oxygen-carrying pigment, haemoglobin.