Eukaryotes and Prokaryotes

Question 1

How do you know if something is living?

Answer 1

MRSGREN

Movement, Respiration, Sensory, Growth, Reproduction, Excretion, Nutrition

Question 2

What is the cell theory?

Answer 2

All living things are made of cells, all cells come from pre-existing cells

Question 3

What are the 3 domains of life?

Answer 3

Archaea (extreme env), Bacteria (E.Coli), Eukarya

Question 4

What is the endosymbiotic theory?

Answer 4

Evolution of eukaryotes through many types of free-living prokaryotes which were engulfed by larger PK cells and turned into mitochondria/chloroplast

Question 5

How does mitochondria and chloroplast relate to the evolution theory?

Answer 5

They have their own DNA so closely related to PK DNA

Question 6

What are the advantages of PK?

Answer 6

Provide vitamins, Prevent pathogen colonies, Stimulate immune system, Help decomposition

Question 7

What are the disadvantages of PK?

Answer 7

Food poisoning, Dental disease

Question 8

Describe the different types of structures of PK

Answer 8

Rods, balls, helices

Question 9

What indicates a cell is prokaryotic?

Answer 9

Lack of nucleus, organelles, organisation in multicellular complex

Question 10

How do you differentiate 2 groups of bacteria?

Answer 10

Using gram stain technique analysing their cell wall differences

Question 11

What does a gram stain test show?

Answer 11

Gram-negative - Stains pink

Gram positive - Stains purple

Question 12

What causes the difference in colour stain?

Answer 12

GP - Thick layer of peptidoglycan so keeps the crystal violet during decolourisation stage.
GN - Thin pep wall so loses crystal violet stain, instead stained by safranin

Question 13

Describe the process of gram staining

Answer 13

Cells stained with crystal violet dye
Iodine solution (I+KI) added - Forms complex btw crystal violet & iodine - Large complex so insoluble
Decolouriser alcohol (ethyl alcohol/acetone) added - Dehydrates pep layer hence shrinks BUT complex cant penetrate pep layer so stays in cell of GP
Counterstain (Safranin - weakly water soluble) added, staining sample pink in GN BUT as its lighter than crystal violet, doesn't interfere with purple colour of GP cells

Question 14

Describe the binding of B-lactam to transpeptidase

Answer 14

Penicillin has B-lactam ring which interferes with bacterial cell wall synthesis by inhibiting crosslink of peptide chains of bacterial cell wall

Question 15

Describe the differences between prokaryotes and eukaryotes

Answer 15

Loss of cell wall, gains nuclear membrane, gains internal membranes/digestive vesicles, evolved mitotic spindle/centromere