Eukaryotic cell structure

Question 1

What is a plasma membrane ( cell surface membrane), what is its function?

Answer 1

• A boundary between a cell and its environment

- Controls what passes in and out of the cell

Question 2

What is the nucleus what is its function?

Answer 2

• 10nm in diameter it contains the DNA.

- important in replication, cell division and protein synthesis

Question 3

What is a mitochondrion, why is it important?

Answer 3

• 1-10nm
• site of aerobic respiration and where most of the cells ATP is made
• contains folds called cristae

Question 4

What is the Rough Endoplasmic Reticulum why is it important?

Answer 4

• a membrane system connected to the nucleus with many folds, has ribosomes on surface
• it collects, stores and transports proteins made in the ribosomes

Question 5

what is the smooth endoplasmic reticulum and why is it important?

Answer 5

• membrane system with no ribosomes, found in small patches in the cytoplasm
• important for the synthesis of lipids and some steroids - additionally detoxification eg alcohol

Question 6

what is the Golgi apparatus and why is it important?

Answer 6

• stack of flattened membrane disks free in the cytoplasm

- receives packages (vesicles) from the rough ER and synthesises and modifies chemicals before secretion from the cell

Question 7

what is a ribosome and why is it important?

Answer 7

• 20nm attached to ER or free in cytoplasm

- the site of translation where genetic code is used to build proteins

Question 8

what is a lysosome and why is it important?

Answer 8

• a small vesicle containing digestive enzymes
• breaks down substances organelles or whole cells
• eg in phagocytosis lysosomes are used by white blood cells to destroy bacteria