Cells

Cells Components – organelles Nucleus Nucleolus Nuclear membrane Cytoplasm Cell membrane Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum Mitochondria Ribosomes Lysosomes Vacuole Centrosome Centrioles Golgi Complex

these functions include: Organelles Organelles are: ↙ ↓ ↘ Specialised Structures have certain shapes perform specific functions these functions include: ↙ ↙ ↓ ↘ ↘ Growth Metabolism Reproduction Respiration Excretion ↙ ↓ ↘ Movement Irritability Maintenance O²

Functions Respiration Controlled absorption of oxygen combines with nutrients and produces energy and ATP. The waste product is carbon dioxide. Excretion Any harmful waste is removed e.g. Uric acid and Carbon Dioxide Growth Cells grow and repair by producing protein. Movement Some cells such as blood cells can move, parts of cells move but usually in one direction Reproduction All cells grow and then most reproduce themselves either by mitosis (simple cell division) or meiosis (sexual reproduction) Metabolism Chemical reactions: Anabolism – a chemical reaction for growth and repair by producing proteins Catabolism - a chemical reaction for the breakdown of substances for energy and waste Sensitivity Cells respond to external stimuli

Cell Structure

Task Write down 5 organelles in a cell and see if you can remember their specific functions

Organelles and their functions Nucleus The ‘BRAIN’ of the cell Contains DNA – this is our genetic information, a segment of DNA located in a set position on a chromosome is a gene these contain hereditary information and control most cellular structure and function. Chromosomes are thread like structures contained within the cell nucleus. 46 chromosomes normally make up somatic (body)cells, these cells divide by mitosis. The nuclear membrane allows the passage of substances in and out of the nucleus.

Organelles and their functions Cytoplasm The fluid part of the cell, a jelly like substances with organelles embedded within. Found inside the cell but outside the nucleus. Cell membrane The cell membrane surrounds the cell keeping everything inside, but letting other substances out such as waste Known as a semi-permeable membrane meaning it has pores to allow movement. It allows the passage of substances in and out of the cell. It is made up of proteins and lipids (fat)

Organelles and their functions Nucleolus Important in the production of ribosomes. Situated inside the nucleus. Nuclear Membrane Surrounds the outside of the nucleus. Allows passage of substances in and out.

Organelles and their functions Smooth + Rough Endoplasmic Reticulum A network of canals through the cytoplasm to allow substances to move around ‘The circulation of the cell’ Mitochondria It is known as the powerhouse of the cell as it supplies the cell with its energy A chemical reaction that takes place here results in the release of ATP – Adenosine Triphosphate. ATP transports energy around the body.

Organelles and their functions Ribosomes Known as the protein factories of the cell Produce enzymes for growth and repair Lysosomes Destroys worn out parts of the cell and bacteria Breaks down food for energy Vacuoles Empty spaces in the cytoplasm

Organelles and their functions Centrosomes Dense area of cytoplasm that contains the Centrioles Centrioles Paired cylindrical structures at right angles to each other inside the centrosomes Play an important part in Mitosis Golgi complex Creates the communication network in the cell, consisting of flattened channels stacked on one and other Packages secreted proteins Lipid secretion and carbohydrate synthesis

How cells function Watch the following short video on the functions of cells. Make notes if you would like to. http://www.youtube.com/watch?v=NiiLS_ovLwM&feature=related

Draw and colour your own picture of a cell. Task Draw and colour your own picture of a cell. Remember use individual flare and pictures to help you remember the functions.

Cell Division It takes approximately two hours to take pace and happens in five phases: Prophase - The production phase Centrosome divides Centioles rearrange themselves at either end of the cell DNA shortens and thickens Chromosomes begin forming Nucleoli disappear Metaphase - The meeting phase Nuclear membranes disappear Energy is provided by the mitochondria Chromosomes align themselves in the centre of the cell in pairs

Anaphase - The away phase Spindle fibres begin to disintegrate Chromosomes are pulled towards the Centrioles Telophase - Fibres spindles completely disintegrate Nuclear membrane surrounds the nuclear matter Interphase – The resting phase Cells increase in size DNA is being reproduced