Cell structure - 2

Question 1

Describe the structure and roles of the Cell wall

Answer 1

• Gives Plants strength, support and structure
• Made of cellulose
• can Function as a carbohydrate store

Question 2

Describe the structure and roles of the Nucleus

Answer 2

• Largest organelle
• Controls the cell
• Contains the genetic
  information

Question 3

Describe the structure and roles of the Nuclear envelope

Answer 3

• A double membrane that surrounds the nucleus
• Contains pores that allow larger substances to enter/exit the nucleus

Question 4

Describe the structure and roles of the Nucleolus

Answer 4

• Densely stained region where ribosomal RNA is produced

Question 5

Describe the structure and roles of the Mitochondria

Answer 5

• Energy-generating organelle
• Surrounded by two membranes that fold to form cristae
• Cristae project into a liquid called the matrix
• 2-5um long

Question 6

Describe the structure and roles of the Chloroplast

Answer 6

• Surrounded by a double membrane.
• Filled with a liquid called stroma
• Contains sacks of thylakoid membranes called grana
• 6-10um long

Question 7

Describe the structure and roles of the Vacuoles

Answer 7

• Membrane is called the tonoplast
• Filled with a cell sap
• Important in keeping the cell firm

Question 8

Describe the structure and roles of the RER

Answer 8

• Forms flattened sacs called cisternae which are double membraned
• Is the site of protein synthesis due to the presence of ribosomes

Question 9

Describe the structure and roles of the SER

Answer 9

• site of lipids, steroids and cholesterol production
• Contains enzymes

Question 10

Describe the structure and roles of the Ribosomes

Answer 10

• Made in the nucleus
• Two separate units
• Some remain free while others attach to ER
• Site of protein production
• 20nm

Question 11

Describe the structure and roles of the Golgi Apparatus

Answer 11

• Stack of flattened double membrane cisternae
• Modifies, sorts and packages molecules ready for transport
• Opposite ends the sacs give off vesicles

Question 12

Describe the structure and roles of the lysosomes

Answer 12

• Responsible for breaking down unwanted organelles and foreign matter
• Sacs surrounded by a single membrane
• Low pH
• Contain digestive enzymes

Question 12

Describe the structure and roles of the Centrioles

Answer 12

• Produce mitotic spindle for cell division
• Involved in formation of cilia and undulipodia
• Made of tubulin forming bundles of microtubules
• 0.4um long

Question 13

Describe the structure and roles of the Cytoskeleton

Answer 13

• Maintains shape and stability
• Allows substances and organelles to move within the cell and the cells itself to move
• Two types: actin filament (7nm) and microtubules (20 - 30nm)

Question 13

Describe the structure and roles of the Cilia and undulipodia

Answer 13

• Arranged in the 9 + 2 formation
• Cilia are short and abundant on cells
  They beat rhythmically
• < 10um
• Undulipodia are long and singular
• Cause the cell to move

Question 14

Describe the features of Eukaryotes

Answer 14

• DNA is always membrane-bound
• Include: animals, plants and fungi
• 10-100um

Question 15

Describe the structure of Prokaryotes

Answer 15

• DNA is suspended freely in the cytoplasm
• 1-5um

Question 16

What is the difference between cilia and undulipodium

Answer 16

Cilia are short and abundant where as undulipodia are long and singular

Question 17

State 3 differences between prokaryotic and eukaryotic cells

Answer 17

-Eukaryotic cells have membrane bound organelles where as prokaryotes don’t
- Eukaryotes are much larger than prokaryotes
- Eukaryotes have their DNA in a nucleus where as prokaryotes DNA is freely suspended