Cellular activities

Cellular Respiration

Cellular respiration is the process by which cells convert nutrients into energy in the form of adenosine triphosphate (ATP).
The process begins in the cytoplasm with glycolysis, where glucose is broken down into two molecules of pyruvate, producing a small amount of ATP and reducing power in the form of NADH.
Following glycolysis, the pyruvate molecules enter the mitochondria where they are fully oxidised to water and carbon dioxide in the Krebs cycle and electron transport chain, yielding a large amount of ATP.

Protein Synthesis

Protein synthesis is the process by which cells use genetic information to build proteins. It happens in two key stages: transcription and translation.
During transcription in the nucleus, the DNA code for a protein is copied into a molecule of messenger RNA (mRNA).
The mRNA molecule then moves out of the nucleus and attaches to a ribosome, where translation takes place. The ribosome reads the sequence of codons in the mRNA and synthesizes the protein according to this code.

Cell Division

-Cell division is the process by which a cell reproduces itself. It is a critical part of the lifecycle of a cell, allowing for growth, repair and reproduction of organisms.

In mitosis, the cell’s nucleus divides in a way that each of the two new cells created have the same number and type of chromosomes as the parent nucleus.
In meiosis, the cell divides twice to produce four new cells, each with half the number of chromosomes of the parent cell. This type of cell division is crucial in sexual reproduction.

Protein Processing and Transport

Newly synthesised proteins are often processed in the endoplasmic reticulum (ER) and Golgi apparatus before they reach their final destination.
In the ER, proteins can be modified by having sugar chains added to them. The ER also aids in the folding of proteins into the correct shape. Proteins made in the ER are packed into transport vesicles.
The Golgi apparatus further modifies proteins and lipids from the ER and sorts them for transport to their final destinations inside or outside the cell.

Digestion and Waste Removal

-Lysosomes are involved in digestion and waste removal within the cell. They contain digestive enzymes that break down waste materials, including complex molecules and unwanted parts of the cell.

Waste material can be expelled from the cell via exocytosis, where a vesicle inside the cell fuses with the cell membrane and releases its contents outside of the cell.