(a) To explain the function of the internal system unit components and how they communicate.

Internal Component
Function
Connected to other components
Processor

The processor controls the functions of electronic products. Processor receives input data, processes information and sends it back to it to whatever component it came from. It is called heart of the computer.
A processor is connected to many components like speakers, keyboard, motherboard etc. but mainly processor is connected to motherboard.
Motherboard

A motherboard is knows as logic board, system board and main board as well. It acts a connection point where almost all components are connected to. It holds important components like the memory, processor etc.
Almost every like keyboard, printer, hard drives, monitor etc. and connected to the motherboard.
BIOS

BIOS (Basic Input/output System) is a chip situated on all motherboard. It contains information and setups that how system is boot and how is operates. It is mainly used for settings of the system.
It is connected to motherboard.
Power Supply

Power supply unit is the component that stores power to the computers. It pulls the required amount of electricity and converts the AC current to DC current. It depend on the computer how powerful it is.
It is located in back of the computer. it is also connected to the motherboard.
Fan and heat sink

Heat sink is the component who drops the temperature of the electronic devices by scattering heat into surrounding air.
Fan and heat sink is connected to motherboard.
Hard Drive (SATA and IDE)
[Master and slave settings]

It is mechanisms that control the positioning, reading, and writing of the hard disk, which furnishes the largest amount of data storage for the PC. They are used to store files, documents and almost anything on the computer.
It is connected to motherboard.
Hard Drive controller

The hard drive controller is the interface that enables the computer to read and write information to the hard drive. It is a circuit which enable the CPU to connect with the hard drive or other kinds of disk drives.

RAM

RAM(Random Access Memory) is a type of computer memory. It is the most common type of memory found in the computers and other devices like printers. It is a form of computer data storage. It is unstable.
RAM is connected to motherboard.
ROM

In ROM (Read Only Memory) computer memory in which data is pre-recorded. Once data has been written in ROM, it cannot be deleted and can only be read. ROM is non-volatile. They are used broadly used in calculator and minor devices.
ROM is connected to motherboard.
CACHE

It is a component that clearly stores data so that in future data can be served faster.
It is next to the CPU chip in motherboard.
Expansion cards (network & Graphic)

Expansion card is electronic board added into an expansion slot of a desktop computer such as network card and graphic card. Network card is an expansion card which helps computer to connect to network such as home network using a cable. Graphic card is an internal circuit board which allows a display device such as monitor to display from the computer.

It is connected to motherboard.
Ports – USB and Serial

USB ports are normal cable joiningboundary on personal computer. Serial ports are used to connect a serial device to a computer. They usually found in IBM computers.
USB and serial ports are connected to motherboards.

(b) A schematic connection diagram showing how the components are connected to each other

(c) To explain PC peripherals

Peripheral
Function
How connected

Monitor

The monitor is a visual display unit. It is a piece of electrical equipment which display images produced from video output devices such as computer. Monitor does not produce any permanent record.
Monitor is connected to CPU with VGA(video graphic array) and DIV(digital video interface) ports.
Printer