Organelles

Question 1

Role of nucleus?

Answer 1

o Contains the DNA

Question 2

how many nucleoli in a cell?

Answer 2

atleast one

Question 3

are nucleoli membrane bound?

Answer 3

no

Question 4

describe function of nucleolus

Answer 4

contain active dna (chromatin pulled away); produces rRNA

Question 5

how many bilayers does the nuclear membrane contain?

Answer 5

2

Question 6

inner membrane of nuclear envelope is supported by

Answer 6

nuclear lamina (intermediate filaments; they are crosshhatched)

Question 7

the outer membrane of the nuclear envelope is supported by the

Answer 7

cytoskeleton

Question 8

what is embedded into nuclear envelope’s bilayers?

Answer 8

nuclear pore complexes

Question 9

The nuclear membrane is continuous with the

Answer 9

endoplasmic reticulum

Question 10

describe ribosome structure

Answer 10

made of rRNA and proteins; contain a large and small subunit

Question 11

role of ribosomes?

Answer 11

translate proteins

Question 12

where are ribosomes found?

Answer 12

free in cytoplasm, or bound to rough ER

Question 13

what does and doesnt the endomembrane system have?

Answer 13

Includes plasma membrane; nuclear envelope  endoplasmic reticulum  vesicles  golgi apparatuslysosome/vacuoles

Does NOT contain mitochondria, chlrorplasts, peroxisomes

Question 14

difference in structure between rough and smooth er?

Answer 14

rough has ribosomes attached. Smooth doesn’t.

Question 15

describe role of rough ER in protein

Answer 15

proteins passed into lumen of ER

carbs can be added to proteins to form glycoproteins

Question 16

synthesis role of rough ER?

Answer 16

makes proteins (due to ribosomes) and phospholipids

Question 17

roles of smooth ER?

Answer 17

Metabolises carbs
Makes lipids, phospholipids, steroid hormones
Detoxifies drugs and poisons
Stores calcium

Question 18

general role of golgi apparatus?

Answer 18

receives, sorts, ships and manufactures stuff

Question 19

describe how golgi apparatus enables transport of vesicles

Answer 19

o Transport vesicle containing proteins breaks off of ER
o Vesicle sent to cis golgi (means golgi is on the same side as ER), and fuses with cis-golgi to form cisternae (long vesicles)
o cisternae “mature”
o vesicles bud off the trans-golgi
o transported to places within the cell (or outside); messenger proteins and cytoskeleton ensure the transport is regulated.

Question 20

lysosomes contain

Answer 20

digestive (hydrolytic) enzymes; v acidic

Question 21

roles of lysosomes:

Answer 21

phagocytosis and autophagy (of damaged organelles)

Question 22

role of vacuole in single celled organisms? eg amoeba

Answer 22

expels water or lets it in to maintain osmotic pressure

Question 23

structure of peroxisomes?

Answer 23

contain lipid bilayer and crystalline core.

Question 24

role of peroxisomes?

Answer 24

transfer hydrogen from various compounds to oxygen, forming H2O2 (detoxifies alcohol in liver_

Question 25

glyoxysomes are

Answer 25

specialised peroxisomes in plant tissue

Question 26

role of glyoxysomes?

Answer 26

Break down fat reserves in seeds to produce sugars for the growing seedling

Question 27

describe how mitochondria/chloroplasts were formed.

Answer 27

aerobic/photosynthetic prokaryote was engulfed by ancient eukaryote - forming first aerobic/photosynthetic eukaryotes.
Endosymbiosis as engulfed cell gained protection, whereas other cell gained glucose/ATP

Question 28

evidence for endosymbiotic origin of chloroplast/mitochondria?

Answer 28

similar size to prokaryotes
both have double membrane
divide by binary fission, like bacteria
DNA is circular

Question 29

structure of mitocondria

Answer 29

o Has an enclosing outer membrane and an internal highly folded membrane (cristae) and inside a matrix (fluid)

Question 30

structure of chloroplast?

Answer 30

o Double-membrane bound
o Thylakoids: membranous, fluid filled flattened disks.
 Grana (sing. granum): stacks of thylakoids (g is for group)
• Stacks of thylakoids ensure that photons are captured by atleast one
 Chlorophyll is embedded into thylakoid membranes, as are some enzymes in the first stage.
o Stroma: fluid in chloroplasts, which bathes the grana.
 Contains some enzymes involved in the second stage, and ribosomes and DNA