Structure of Eukaryotic cells

Question 1

What is the structure and function of the cell surface membrane?

Answer 1

• phospholipid bilayer with embedded proteins
• selectively permeable - enables control of substances passing in and out of the cell
• barrier between internal and external environment of cell

Question 2

What is the structure and function of the Nucleus?

Answer 2

• Nuclear envelope, nuclear pores, nucleolus, DNA/chromatin
• Controls cell activity through transcription on mRNA
• Nuclear pores allow substances like mRNA to move between the nucleus and cytoplasm
• Nucleolus makes ribosomes which are made up of proteins and ribosomal RNA.

Question 3

What is the structure and function of the Mitochondria?

Answer 3

• double membrane - inner membrane folded to form cristae
• matrix containing small 70s ribosomes small circular DNA and enzymes involved in aerobic respiration producing ATP for energy release

Question 4

What is the structure and function of Lysosomes

Answer 4

• An organelle that contains digestive (hydrolytic) enzymes
• Releases lysozymes to break down/hydrolyse pathogens or worn out cell components

Question 4

What is the structure and function of the Golgi Apparatus?

Answer 4

• 3 or more fluid filled membrane bound sacs with vesicles at the edge
• recieves proteins from RER
• modifies / processes protein e.g. adds carbohydrates/sugars
• packages into vesicles e.g. for transport to cell surface membrane for exocytosis
• also makes lysosomes

Question 5

What is the structure and function of Ribosomes

Answer 5

• Float free in cytoplasm or bound to RER, not membrane bound. Made from 1 large and 1 small subunit
• Site of protein synthesis, specifically translation

Question 6

What is the structure and function of the Rough Endoplasmic Reticulum?

Answer 6

• Ribosomes bound by a system of membranes
• folds polypeptides to secondary/teriary structure
• packages to vesicles, transport to the golgi apparatus