b2.2 - organelles and compartmentalisation

Question 1

compartmentalisation

Answer 1

• organisation of different functions/ processes within specific areas/ structures within the cell
• separated by plasma membranes

Question 2

advantages of compartmentalisation

Answer 2

• allows for development of specialised structures (lysosomes, mitochondria, chloroplast…)
• separates chemical reactions/ cellular processes in the cell
• faster rate of chemical rxn (more efficient)

Question 3

organelles that aren’t organelles and why

Answer 3

• cytoskeleton: not membrane bounded, not involved in metabolic processes
• cell wall
• cytoplasm: no specific function

Question 4

to be considered an organelle…

Answer 4

• have specific metabolic function
• membrane bounded

(except ribosomes!!— not membrane bounded but have specific function)

Question 5

post transcriptional modification

Answer 5

changes to mRNA after transcription (removal of pieces)

Question 6

compartmentalising nucleus and cytoplasm

Answer 6

• allows post transcriptional modification
• extracellular signals (hormone/growth factor—-> passed to nucleus to change gene expression)

Question 7

why are nucleus and cytoplasm separated by compartmentalisation

Answer 7

prevent protein synthesis before post transcriptional modification of mRNA

Question 8

disadvantage of compartmentalisation in cells?

Answer 8

It can delay a cell’s ability to respond to the environment.

Question 9

thylakoid membranes main function in photosynthesis

Answer 9

• increase surface area

Question 10

what does the inside of thylakoid membrane do (lumen)

Answer 10

• contains substrates, enzymes, pigments used for photosynthesis

Question 11

role of cristae in cellular respiration

Answer 11

• increase surface area of inner membrane

Question 12

mitochondria membranes

Answer 12

• 2 (inner and outer)

Question 13

purpose of matrix

Answer 13

contains high concentrations of enzymes for cell respiration

Question 14

chloroplast membranes

Answer 14

3 - inner, outer, thylakoid

Question 15

thylakoid

Answer 15

membrane bounded sacs of photosynthetic pigments & proteins

• forms stalks of granum
• absorbs light energy
• granum joined by lamellae
• disc shape maximises surface area

Question 16

nuclear membranes

Answer 16

2 - inner, outer

outer: ribosomes attached
inner: controls entry/exit of signaling molecules

Question 17

double membrane function of nucleus

Answer 17

• protects genetic material

Question 18

ribosomes

Answer 18

• translate mRNA from nucleus into proteins
• bound or free

Question 19

bound ribosomes

Answer 19

• joined to the cytosolic of RER
• proteins produced ends up inside the RER
• used to make proteins for outside the cell

Question 20

free ribosomes

Answer 20

• in cytoplasm
• used to make proteins used inside the cell

Question 21

types of vesicles (4)

Answer 21

• transport vesicles
• secretory enzymes: store and transport molecules to be secreted outside the cell, such as hormones, neurotransmitters and digestive enzymes
• lysosomes
• peroxisomes (similar to lysosomes, different enzymes—> for detoxification)