Organelles

Question 1

role of nucleus

Answer 1

double membrane bound structure containing nuclear chromatin (genetic info) that controls cell growth + reproduction

Question 2

role of nucleolus

Answer 2

prominent structure in nucleus

produces ribosomes that move out of nucleus and take positions on rough endoplasmic reticulum

Question 3

role of cystol/cytoplasm

Answer 3

where other cell organelles reside

where most cellular metabolism occurs

Question 4

role of centrosome

or microtubule organising center (MTOC)

Answer 4

produce microtubules
e.g. spindle fibres
plant cell centrosome is simpler + has no centrioles

Question 5

role of centriole

Answer 5

small hollow cylinders made of ring of 9 fused microtubules
involved in development of spindle fibres
ONLY IN ANIMAL CELLS

Question 6

role of golgi apparatus

Answer 6

stack of membrane bound vesicles that package macromolecules for transport in cell
single membrane

Question 7

role of lysosome

Answer 7

round organelle surrounded by membrane
contain hydrolytic enzymes to digest invading cells
more common in animal cells
found near vacuole in plant cells

Question 8

role of peroxisome

Answer 8

membrane bound packets of oxidative enzymes
contains reducing enzyme catalase
plant cells -> turn fatty acids to sugars
animal cells -> protect cell from its ken production of toxic hydrogen peroxide

Question 9

role of secretory vesicle

Answer 9

cell secretions (e.g. hormones, neurotransmitters) are packaged into it at golgi apparatus, then it’s transported to cell surface to release them

Question 10

role of cell membrane

Answer 10

double layer of phospholipids
exposed heads = hydrophilic
tails = hydrophobic
so acts as a protective barrier to uncontrolled water flow
also made of proteins
controls movement of substances in and out of the cell

Question 11

role of mitochondria

Answer 11

oval shaped + double membrane
site of aerobic respiration on cristae
provide cell with energy need to move, divide, produce secretory product is + survive
power house of cell

Question 12

role of vacuole

Answer 12

membrane bound sac of cell sap
regulates turgor or pressure in plant cell
involved intracellular digestion + release of cellular waste products
animal cell -> small
plant cell -> store nutrients + waste, help cell increase in size during growth

Question 13

role of cell wall

Answer 13

rigid + made of polysaccharides (cellulose)
provides + maintains shape and gives protective barrier
fluid in vacuole pushes out against cell wall
PLANT CELLS ONLY

Question 14

role of chloroplasts

Answer 14

site of photosynthesis
contain chlorophyll -> gives green colour and ability to absorb energy from sunlight
have double outer membrane
PLANT CELLS ONLY

Question 15

role of smooth endoplasmic reticulum (ER)

Answer 15

network of membrane bound vesicles + tubules
has diff. functions depending on cell type
lipid/steroid hormone synthesis, breakdown of lipid-solvable toxins in liver cells, controls calcium release in muscle cell contraction
involved in formation + transport of proteins

Question 16

role of rough endoplasmic reticulum

Answer 16

“pebbled” surface -> ribosomes

proteins synthesised by the ribosomes collect in it for transport

Question 17

role of ribosomes

Answer 17

small organelle attached to RER
site of protein synthesis
packets of RNA + protein
made of 2 parts -> large + small subunit

Question 18

role of cytoskeleton

Answer 18

helps maintain cell shape
involved in cell motility (ability of cell to move using metabolic energy)
network of: microtubules, actin filaments, intermediate fibers

Question 19

define prokaryotes

Answer 19

small simple cells
lack membrane bound organelles 
no true nucleus 
genetic material not enclosed -> in cytoplasm 
DNA is circular -> plasmids 
no ER, golgi or mitochondrion

Question 20

define eukaryotes

Answer 20

larger more complex cells
have membrane bound organelles
have a true nucleus -> DNA enclosed (packed into chromosomes)