Cell ultrastructure

Question 1

Nucleus Structure

Answer 1

Large organelle enclosed by a double membrane perforated by pores. Contains chromosomes and one or more nucleoli

Question 2

Ribosome Structure

Answer 2

Very small organelle not bound by a membrane. Consists of a large and small subunit. Made of protein and RNA

Question 3

golgi apparatus structure

Answer 3

stack of membrane bounded, flattened sacs in the cytoplasm, looking like a pile of pitta bread

Question 4

centriole function

Answer 4

form a spindle shaped structure of protein fibres on which the chromosomes move during nuclear division

Question 5

cell surface membrane function

Answer 5

a partially permeable barrier which controls the passage of substances into and out of the cell

Question 6

nucleus function

Answer 6

chromosomes contain DNA which controls the synthesis of proteins. ribosomes formed in the nucleolus

Question 7

cell wall function

Answer 7

provides mechanical support and protection. prevents cell from bursting

Question 8

centrioles structure

Answer 8

a pair of short cylinders. each cylinder is made up of nine fibres.

Question 9

mitochondria function

Answer 9

the site of aerobic respiration and responsible for producing most of the ATP in a cell

Question 10

permanent vacuole structure

Answer 10

a sac bounded by a single membrane. contains cell sap which is a solution of mineral salts, pigments, organic acids and other substances.

Question 11

endoplasmic reticulum function

Answer 11

forms a system of channels for transporting the minerals through the cytoplasm. one type has ribosomes on its surface and is the site of protein synthesis. the other type has no ribosomes and is where steroids and other lipids are synthesised.

Question 12

golgi apparatus function

Answer 12

receives proteins synthesised on the ER and prepares them for secretion from the cell. this often involves adding carbohydrate to the protein to make them into glycoproteins

Question 13

lysosomes function

Answer 13

responsible for destroying worn out organelles and for digesting the contents of the vacuole formed by phagocytosis

Question 14

mitochondria structure

Answer 14

had an outer membrane and an inner one which is folded to form christae. inside the inner membrane is the matrix containing enzymes, a circular DNA molecule and ribosomes

Question 15

cell surface membrane structure

Answer 15

a phospholipid bilayer with intrinsic and extrinsic molecules

Question 16

cell wall structure

Answer 16

consists of cellulose microfibrils and other polysaccharides

Question 17

chloroplast structure

Answer 17

surrounded by two membranes. contains a matrix fluid called stroma which has a system of membranes running through it. these are stacked in places to form grana containing chlorophyll. stroma contains circular DNA, ribosomes and starch grains

Question 18

lysosomes structure

Answer 18

a vesicle containing digestive enzymes

Question 19

rough endoplasmic reticulum

Answer 19

a complex network of flattened membrane bounded sacs called cisternae. often has ribosomes on the cytoplasmic side

Question 20

chloroplast function

Answer 20

the organelle in which photosynthesis takes place. pigments capture the energy of sunlight and transfer it to chemical bonds

Question 21

permanent vacuole

Answer 21

stores of waste products and other substances. changes in volume affect the turgidity of the cell

Question 22

ribosome function

Answer 22

uses the information in nucleus acid to synthesise proteins