Animal Cell Structure

what is a plasma membrane (cell surface membrane) composed of and what is its function?

It is composed of a phospholipid bilayer with embedded proteins, its function is controlling the movement of substances in and out of the cell via diffusion, osmosis, active transport and facilitated diffusion.

What is the nucleus composed of and what is its function?

It is enclosed by a nuclear envelope (double membrane) with nuclear pores. It contains chromatin (DNA and proteins) and a nucleolus which synthesises ribosomes. The function is controlling cell activity by storing genetic material ,the DNA codes for polypeptides.

What is the mitochondria composed of and what is its role?

It has a double membrane, the inner membrane is folded into Christa’s to increase the surface area for ATP production. The matrix contains enzymes for aerobic respiration. Mitochondria have their own circular DnA and their own 70s ribosomes. It produces ATP via aerobic respiration.

What are the ribosomes composed of and what is there function?

It is composed of RNA and protein, found either free-floating in the cytoplasm or attached to the rough endoplasmic reticulum, the function is the site of protein synthesis.

Tell me about the the rough endoplasmic reticulum vs the smooth endoplasmic reticulum?

. Both are a 3D system of sheet-like membranes spreading through the cell

. Both membranes form a series of flattened sacs called cisternae

. The rough ER has ribosomes attached to its surface, involved in protein synthesis, the SER is similar but has no ribosomes attached

. The RER provides a large surface area to synthesise proteins.

. The RER also transports proteins and packages them into vesicles before they move to the Golgi body.

.The SER synthesises, stores and transports lipids and carbohydrates.

What is the Golgi apparatus composed of and what’s its function?

It’s a series of flattened sacs, similar to the endoplasmic reticulum but more compact, that modify, sort, and package proteins and lipids into vesicles for secretion. Its function is to modify and process proteins and lipids.

What are lysosomes composed of and what is their function?

They are small vesicles containing digestive/ hydrolytic enzymes. Their function is to breakdown waste materials and cellular debris.

What are centrioles composed of and what’s their function?

They are found in pairs near the nucleus. They are involved in cell division helping to organise the mitotic spindle.

What are the cytoskeletons made up of and what’s their function?

They are a network of protein microtubules and and microfilaments, their function is to provide mechanical strength to the cell, support organelles and enable vesicle movement within the cell.