Cell Theory

•  The cell is the basic unti of life
• All living organismsare composed of cells 
• Cells arise from pre-existing cells

When do cells divide?

• Cells divide when they are too large
• Unable to distribute nutrients and water throughout the cell
•  

• Interphase
• Prophase
• Metaphase
• Anaphase
• Telephase
• Cytokinesis

Interphase

Cell grows larger, copies organelles and makes the molecular building blocks it will need in later steps

Cell synthesize a copy of the dna in its nucleus

The chromosomes condense (making them easier to pull apart later on)

Part of the nucleus where ribosomes are made disappear

Nuclear envelope breaks down releasing the chromosomes

Telophase (First part of cytokinesis)

Miotonic spindle is broken down into its building blocks

Two new nuclei form from each set of chromosomes

Nuclear membranes and nucleoli reappear

The chromosomes begin to expand and return to their regular form

Organelles

OrganelleDescriptionFunction

Cytoplasm:Mostly water and contains  cellsAllows organelles to move and stores cells for when needed

Cell membrane:Double layed cell wall called a semi-permeable membraneSupports the cell, and allows certain substances to enter

NucleusRoughly SphericalContains genetic information that controls all cell activity

Mitochondria: Called power plantsMakes energy for the cell and contains enzymes that help convert stored energy to usable forms

• Endoplasmic Reticulum:3d network of branching tubes and pockets. Continuous from the cell membrane to the nucleus membraneTransports materials such as protein. In the brain it assists with the production and release of hormon

Golgi Bodies:Collects and processes materials to be removed from the cell.

Makes and secretes mucus

Vacuoles:Containing some substances, removes unwanted substances from the cell and maintains fluid pressure

RibosomesMakes protein, and essential for life

Centrioles:Found in animal cellsUsed in cell division to separate chromosomes so that each new cell has a copy of DNA

Cell wall(Plant)Protects the cell from physical injury and supports its structure

Vacuole(plant):Large and takes up most of the space in the cellKeeps the cell plump if full of water, which keeps plants alive

Chloroplasts:Gives leaves their green colour and converts light into energy.

Chromatid

• Each of the two strands into which a chromosome divides into during cell division
• Each contain a double helix of DNA

-Benign:

oNon-cancerous

oDoes not affect other cells except by crowding

oOnly dangerous if they push or limit organs, blood vessels

-Malignant:

oCancerous

oSpread and invade other cells

Specialized Cells

Cells that are specialized for specific parts of an organism. These do not replicate and simply die after their life cycle

-Stem Cells:

A cell that has the potential to become any kind of other cell

-Red blood cells:

oContain haemoglobin, that carries oxygen in blood. 

oCells are smooth so that can easier pass through the blood vessels

-White blood cells:

oCan move like an amoeba to engulf bacteria and fight infection

-Bone Cells:

oCollects calcium from food

oAllows for the repair and growth of bones

-Mouth:

oMechanical/physical  to break food down

oChemical enzymes in saliva with water breaks molecules into smaller ones

-Esophagus:

oTransports food to the stomach via peristalsis

-Stomach: 

oMuscular organ that continues mechanical and chemical breakdown of food

oReleases enzymes and stomach acid

-Small Intestine

o6 metres in length

oAbsorbs nutrients that pass directly into the blood stream

oContains folds called vili, that increase surface area for absorption of nutrients

-Large Intestine

o1.5 metres in length

oAlso called the colon

oAbsorbs water and materials

oStores solid waste matter for egestion

oContains ecoli bacteria that live in symbiosis

Digests and makes vitamins

Accessory organs helps digestion, but food never passes through these organs

-LIVER:

oCreates a chemical called bile that breaks down fats

oBile is stored in the gallbladder

-

Pancreas

oCreates other digestive enzymes

Pulmonary Circuit

-Path of blood in the lungs

-Carries deoxygenated blood away from the heart, and returns oxygenated blood back to the heart

-Path of the blood:

1.Deoxygenated blood leaves through the right ventricle, through the pulmonary artery

2.From the right atrium, the blood is pumped to the right ventricle

3.Blood is then pumped from the right ventricle through the pulmonary valve and into the pulmonary trunk of the pulmonary artery 

-Short band of tough, flexible fibrous connective tissue that connects two bones or 

Cartilages or holds together a joint

-Smooth Muscles:

oFound in the digestive system, blood vessels etc.

oHas the ability to stretch and maintain tension for long periods of time

oContracts involuntarily because your nervous system controls it

-Cardiac Muscles(Only found in heart):

oSpecialized for endurance and consistency 

oInvoluntarily controlled

-Origin

oWhere the muscles are anchored to by tendons(Tissue that attaches muscle to bones

Colitis

oEpithelial tissue lining becomes inflamed and stops working properly