b2.2- organelles and compartmentalisation

Question 1

not organelles [3]

Answer 1

1. cell wall
2. cytoplasm
3. cytoskeleton

Question 2

organelles [4]

Answer 2

1. nuclei
2. vesicles
3. ribosomes
4. plasma membrane

Question 3

study of individual organelles became possible when… [2]

Answer 3

1. ultracentrifuges was invented
2. methods of using them for cell fractionation was developed

Question 4

adaptations of the mitochondrion for production of ATP by aerobic cell respiration [4]

Answer 4

1. double membrane with a small volume of intermembrane space
2. large surface area of cristae
3. compartmentalisation of enzymes
4. substrates of the Calvin cycle in the matrix

Question 5

adaptations of the chloroplast for photosynthesis [4]

Answer 5

1. large surface area of thykaloid membranes with photosystems
2. small volumes of liquid inside thylakoids
3. compartmentalisation of enzymes
4. substrates of the Calvin cycle in the stroma

Question 6

functional benefits of the double membrane of the nucleus [2]

Answer 6

1. need for pores in the nuclear membrane
2. for the nuclear membrane to break into vesicles during mitosis and meiosis

Question 7

function of free ribosomes

Answer 7

site for translation to make intracellular protein in the cytoplasm
eg. cytoplasm, lysosomes, mitochondria, chloroplasts and nucleus

Question 8

function of rough ER

Answer 8

proteins exported for use outside of cell

Question 9

structure and function of vesicles in cells

Answer 9

• small, membrane-bound cell structures
• transport and storage of materials

Question 10

structure of Golgi apparatus

Answer 10

stack of flattened, membrane-bound sacs
electron micrograph:
- stack of sacs with no interconnection
- budding off vesicles often see

Question 11

function of Golgi apparatus in processing and secretion of protein

Answer 11

modify and package protein into vesicles

Question 12

role of clathrin in the formation of vesicles

Answer 12

1. forms cage like structure through polymerisation of multiple clathrin molecules around the area of a membrane
2. membrane starts to invaginate-> clathrin surround invagination and forms a clathrin coated pit
   - acts as a scaffold for the formation
   - brings together necessary molecules needed to shape and pinch off a piece of the membrane to form a vesicle
3. breaks down through hydrolysis back to individual pieces

Question 13

clathrin

Answer 13

• small, membrane-bound cell structures
• transport and storage of materials
  electron micrograph: made of phospholipid layer

Question 14

types of vesicles [4]

Answer 14

1. transport
2. secretory
3. lysosomes
4. peroxisomes

Question 15

function of ribosomes

Answer 15

translate mRNA from the nucleus into proteins

Question 16

advantages of compartmentalisation to eukaryotes [4]

Answer 16

1. provides optimum local conditions and enzymes for metabolic reactions
2. shorter particles movement needed
3. concentration gradient can be generated more easily
4. more specialisation within the cell- allows more complex + defined cell functions to take place

Question 17

function of outer membrane

Answer 17

separate the content of mitochondrion from the rest of the cell

Question 18

function of inner membrane + cristae

Answer 18

• electron transport chain reaction for respiration
• contians enzyme
  eg. ATP synthease (to make ATP)

Question 19

inner membrane + cristae increases efficiency by

Answer 19

increase surface area for oxidative phosphorylation

Question 20

function of matrix

Answer 20

contain enzymes for Kreb cycle and link reaction

Question 21

matrix increases efficiency by

Answer 21

presence of respiratory enzymes

Question 22

function of mitochondrial DNA and ribosomes

Answer 22

• expression of mitochondrial genes
• can grow and reproduce

Question 23

mitochondrial DNA and ribosomes increases efficiency by

Answer 23

• contains mitochondrion DNA
• shows maternal ancestor lineage

Question 24

function of inter-membrane space [3]

Answer 24

1. protons are pumped into the spaces by electron transport chain
2. acts as a buffer between cytoplasm + matrix
3. allows for regulation of exchange of material between the two compartments

Question 25

inter-membrane space increases efficiency by

Answer 25

• space is small: can build up proton concentration quickly

Question 26

structures that indicate the probable origin of a chloroplast [2]

Answer 26

• naked DNA
• 70S ribosomes

Question 27

advantages of having a double membrane in the nucleus [2]

Answer 27

1. allow nuclear pores formation
   - nuclear pore bigger than channels protein, allows larger molecules to pass through nuclear pores
2. keep optimum conditions in the nucleus for metabolic reactions

Question 28

why is it important that a nucleus have pores in its nuclear membrane

Answer 28

allow molecules to pass through nucleus

Question 29

function of the photosystems I and II in the thylakoid membranes of the chloroplast

Answer 29

• to produce glucose
• Photosystem I and II absorbs sunlight
• energy form sunlight is used to power the transfer of electrons from water to carbon dioxide
• electron transfer ultimately generates glucose

Question 30

benefit of the double membrane of the nucleus in maintaining the stability of genetic information

Answer 30

prevents the loss of DNA to cytoplasm

Question 31

non-membrane organelles [5]

Answer 31

1. centrioles
2. cilia
3. flagella
4. microvilli
5. ribosomes

Question 32

function of cilia

Answer 32

locomotion

Question 33

function of contractile vacuole

Answer 33

homeostasis

Question 34

where could genes be located in a prokaryotic cell

Answer 34

nucleoid
plasmids