1. Cells and Cell theory

What are cells

The smallest basic unit of life with its own structures and functions

Cell theory

1. All living organisms are made up of one or more cells

2. Cells are the simplest unit that can carry out all life processes

3. All cells come from pre-existing cells

Prokaryotes

• Smaller, unicellular organisms with NO membrane bound organelles

• Found within bacteria and archaea domains

• DNA floats in cytoplasm

Eukaryotes

• Larger, mostly multicellular organisms with membrane bound organelles

• Found within the eukarya domain

• DNA in nucleus

Cytoplasm

• Plants and animals

• composed of water and other dissolved substances

• all internal organelles are suspended in it and can move around

• Chemical reactions take place here

Cell membrane

• Plants and animals

• Double layer (phospholipid bilayer)

• regulates what enters and leaves the cell

• Semi-permeable (water and oxygen can easily pass, larger molecules cannot)

• Similar membranes are found around other organelles in eukaryotes

nucleus

• plants and animals

• organelle that contains genetic information controlling cell activities

• surrounded by a porous nuclear envelope

• chromosomes store DNA

• nucleolus as its core that produces ribosomes

Mitochondria

• plants and animals

• powerhouse of the cell

• coverts glucose into energy through cellular respiration

• muscles cells will have more mitochondria than fat cells

endoplasmic reticulum

• plants and animals

• transportation system within the cell

• extends from nucleus to cell membrane

• assists in the production and transportation of proteins and hormones

• can be smooth or rough depending on whether it is coated in ribosomes

golgi apparatus

• plants and animals

• packaging centre of the cell

• processes and packages proteins and fats to be exported from the cell

• also creates and secretes mucus

• cells, such as intestine cells, that secrete mucus has many golgi bodies

vacuole

• plants and animals

• fluid or solid filled sacs surrounded by a membrane

• many functions including maintaining pressure within the cell (plants), isolating wastes, etc.

• in animals, many vacuoles can be found in a cell

• in plants, one large central vacuole dominates the cell

ribosome

• plants and animals

• composed of proteins and RNAs

• main function is to help with building proteins in cells

cytoskeleton

• plants and animals

• structure that provides shape and organization to the cell

• helps with cell division and movement

lysosome

• animal only

• membrane-bound organelle that contains enzymes

• they destroy things that do not belong to the cell or thing that need to be removed

• acts like the digestive system of the cell

centrosome

• animals only

• organelle that contains a pair of centrioles arranged at right angles

• critical structure during cell division

chloroplast

• membrane bound organelle that contains a green pigment known as chlorophyll

• helps plants with photosynthesis

cell wall

• plants only

• located outside the cell membrane

• porous, but rigid, structure that supports and protects plant cells

• made of cellulose