2.1.4 - The Ultrasound of Eukaryotic cells: Membrane-bound organelles

Question 1

Name the structures found in eukaryotic cells

Answer 1

nucleus 
nuclear envelope
nucleolus 
cytoplasm
plasma membrane
mitochondrion
Golgi apparatus
Smooth Endoplasmic Reticulum
Rough Endoplasmic Reticulum
Vesicles
Ribosomes
Lysosomes
(plant only)
chloroplast
vacuole
amyloplast

Question 2

Describe the structure and function of the nucleus

Answer 2

Function
stores organisms genome and transmits genetic information
- provides instructions for protein synthesis

Structure
- surrounded by double membrane called nuclear envelope
- pores in the nuclear envelope
this allows molecules through

Question 3

Describe the structure and function of the Rough Endoplasmic Reticulum (RER)

Answer 3

Function
intracellular transport system
- cisternae form channels for transporting substances from one area of a cell to another
- large surface area for ribosomes to assemble proteins - then transported to Golgi Apparatus

Structure

• system of membranes containing fluid-filled cavities (cisternae) that are continuous with the nuclear membrane
• coated with ribosomes

Question 4

Describe the structure and function of the Smooth Endoplasmic Reticulum (SER)

Answer 4

Function
contains enzymes that catalyse reactions involved in lipid metabolism
- involved with absorption, synthesis and transport of lipids (from the gut)

Structure
- system of membranes containing fluid-filled cavities (cisternae) that are continuous with the nuclear membrane

Question 5

Describe the structure and function of the Golgi Apparatus

Answer 5

Function
modify proteins
- proteins are packaged into vesicles which are pinched off and then:
- stored in the cell or
- moved to the plasma membrane to be incorporated or transported outside of cell

Structure

• stack of membrane bound flattened sacs
• secretory vesicles bring materials to and from the Golgi apparatus

Question 6

Describe the structure and function of the Mitochondria

Answer 6

Function
site of ATP production during aerobic respiration

Structure

• spherical, rod shaped or branched
• surrounded by 2 membranes with a fluid-filled space between them
• inner membrane tightly folded into cristae
• inner section fluid filled ‘matrix’

Question 7

Describe the structure and function of the Lysosome

Answer 7

Function
engulf, digest old cell organelles and foreign matter and return digested components for reuse
-keep powerful hydrolytic enzymes away from rest of cells

Structure

• small bags formed from Golgi apparatus
• surrounded by single membrane
• contain powerful hydrolytic enzymes
• abundant in phagocytic cells to ingest/digest pathogens

Question 8

Describe the structure and function of Cilia and Undulipodia (longer cilium)

Answer 8

Function
epithelial cells lining airways have hundreds of cilia that beat and move bands of mucus
- act as receptor to detect signals from immediate environment

Structure

• protrusions from cell surrounded by plasma membrane
• each contains microtubules
• formed in centrioles