AS Biology Unit 2 - Organelles

What is it?

• A series of curved sacs enclosed by a membrane, each sac smaller than the last.

Where is it:

• Found In the cytoplasm of most eukaryotic cells

Recognising an Electron Microscope:

• Stacks of  curved and flattened Cisternae present, each one smaller than the previous 
• Smooth membrane with no ribosomes
• Vesicles Present

Role:

• Vesicles formed in the rER fuse to the Golgi Apparatus
• It modifies protein by adding carbohydrates
• Removes water from concentrated proteins
• Produces lysosomes/secretory vesicles

Where is it?

• Found in the cytoplasm of most eukaryotic cells

What does one look like?

• Shaped like a peanut
• Surrounded by a double membrane
• Inner membrane folded into finger like projections called CRISTAE
• Central area contains a jelly called the MATRIX
• Floating in the matrix are: Ribosomes and Circular DNA 

Role:

• To create ATP energy from a series of complicated biochemical reactions
• The energy created is used to drive other functions of the cell
• They are the site of the later stages of aerobic respiration

What is it?

• A small organelle made of RNA and protein

Where is it?

• It is found in the cytoplasm or atached to endoplasmic reticulum

Role:

• They are the site of protein systhesis

What is it?

• It is a organelle encolsed by a double membrane perforated by pores

Where is it?

• It is found in the cytoplasm of eukaryotic cells 

Role:

• Contains chromosomes
• Contains the nucleolus 
• The DNA in the chromosomes contain genes that control the synthesis of proteins

What is it?

• It is a dense body

Where is it?

• It is found within the nucleus 

Role:

• It is where ribosome are made

Under an Electron Microscope:

• It shows up as a dark staining area.

What is it?

• It is a series of single flattened sacs enclosed by a membrane
• Ribosomes are found on the surface

Where is it?

• It spreads throughout the ctyoplasm stretching from the cell membrane forming continious connections with the nuclear envelope.  

Roles:

• It makes up a large part of the transport system
• It is the site of synthesis for many important chemical reactions
• Proteins are produced by the ribosomes attached to the rER
• The proteins are them stored and transported within the rER
• Proteins are folded in the lumen of the rER into 3D Tertiary strucutres
• The rER produce vesicles and package the proteins

What is it?

• A series of single tubular sacs made of membrane
• Does not have any attached ribosomes

Where is it?

• It is found in the cytoplasm of many animal and plant cells

Role:

• Makes lipids and steroids
• e.g. Reproducive Hormone

What is it?

• Two hollow cylinders made up of a ring of nine protein microtubles.
• They are arranged at right angles to eachother

Where is it?

• They are found in the cytoplam near the nucleus

Roles:

• They are involved in the formation of spindle during nuclear division.
  • When the cell divides they pull apart and produce a spindle of microtubles which are involved in the movement of chromosomes.
• They are involved in transport within the cell cytoplasm.

What is it?

• Spherical Sacs containing digestive enzymes bound by a single membrane.

Where is it?

• Found in the cytoplasm of eukaryotic cells

Role:

• Involved in the break down of unwanted strucutres within the cell.
• Involved in the destruction of whole cells when old cells are replaced or during development.
• The acrosome is a specalised lysosome

What is it?

• A phospholipid bilayer containing proteins and other molecules forming a partially permeable barrier. 

Where is it?

• It is surrounds animal and plant cells

Role:

• It gives the cell shape and protection
• It regulates the movements of substances into and out of the cell

What is it?

• An organelle found in plant cells with a double outer memberane
• Within the stroma there are other membrane structures e.g. thylakoids

Where is it?

• Found in green parts of the plant

Roles:

• They contain chlorophyll which is responsible for the plants green colour and ability to absorb energy from the sunlight.
• They create sugars which they use for food.