3.2.1.1 EUKARYOTIC CELL ORGANELLES STRUCTURE + FUNCTION

Question 1

Structure of nucleus:

Answer 1

• large organelle enclosed by a double membrane (an envelope) perforated by pores
• contains chromosomes and one or more nuclei

Question 2

Function of nucleus:

Answer 2

• chromosomes contain DNA which controls synthesis of proteins
• ribosomes formed in the nucleolus
• contains DNA of the cell

Question 3

Structure of mitochondria:

Answer 3

• has an outer and inner membrane which forms a cristae (folded)
• inside the inner membrane is the matrix containing enzymes, a circular DNA, ribosomes and starch grains

Question 4

Function of mitochondria:

Answer 4

• the site of AEROBIC RESPIRATION and responsible for producing ATP

Question 5

Structure of chloroplasts:

Answer 5

• has a chloroplast envelope- double membrane which controls what enters + exits the cell
• contains a matrix called the stroma which are stacked in places to form grana containing chlorophyll- contains circular DNA, ribosomes and starch grains

Question 6

Function of chloroplasts:

Answer 6

Photosynthesis due to chlorophyll being present

Question 7

Structure of endoplasmic reticulum:

Answer 7

3D system of sheet like membranes, spreading throughout cytoplasm of cells

Question 8

Structure of rough endoplasmic reticulum:

Answer 8

• ribosomes present on outer surface of membranes

Question 9

Function of rough endoplasmic reticulum:

Answer 9

• ribosomes provide a large surface area for the synthesis of proteins and glycoproteins
• provides a pathway for the transport of materials, especially proteins throughout the cell

Question 10

Structure of the smooth endoplasmic reticulum:

Answer 10

• lacks ribosomes on its surface and is often more tubular in appearance

Question 11

Function of the smooth endoplasmic reticulum:

Answer 11

• synthesises, stores and transports lipids and carbs

Question 12

Structure of the Golgi apparatus:

Answer 12

• similar to the SER but more compact- like a pile of pitta break
• consists of a stack of membranes which make up flattened sacs (cisternae), with small, rounded, hallow structures called vesicles

Question 13

Function of the Golgi apparatus:

Answer 13

• relieves proteins synthesised on the ER and prepares them for excretion from the cell
• adds carbs and proteins to make glycoproteins
• forms lysosomes
• produces secretary enzymes
• transports, modifies and stores lipids

Question 14

Structure of lysosomes:

Answer 14

• formed when vesicles produced by the Golgi apparatus contain enzymes such as proteases and lipases
• a vesicle containing digestive enzymes

Question 15

Function of lysosomes:

Answer 15

• hydrolyse material ingested by phagocytic cells- such as white blood cells + bacteria
• release enzymes to the outside of the cell (exocytosis) in order to destroy material around the cell
• digest worn out organelles
• completely breakdown cells after they have died

Question 16

Structure of ribosomes:

Answer 16

• 80s- found in eukaryotes, 70s- found in prokaryotes
• small cytoplasmic granule found in all cells on/ in RER or cytoplasm
• made of protein + RNA

Question 17

Function of ribosomes:

Answer 17

• site of protein synthesis

Question 18

Structure of cell wall:

Answer 18

Consists of cellulose micro fibrils and other polysaccharides

Question 19

Function of cell wall:

Answer 19

Provides mechanical strength to the cell in order to prevent it from bursting

Question 20

Structure of vacuole:

Answer 20

• fluid filled sac bounded by a single membrane called the tonoplast

Question 21

Function of vacuole:

Answer 21

• support herbaceous plants and parts of woody plants by making cells turgid
• sugars + AAs may act as a temporary food store

Question 22

Function of vacuole:

Answer 22

• support herbaceous plants and parts of woody plants by making cells turgid
• sugars + AAs may act as a temporary food store