1.2 cell structure and organisation

Question 1

what is a eukaryotic cell?

Answer 1

a cell that contains membrane-bound organelles.

Question 2

what is a prokaryotic cell?

Answer 2

a cell that does not contain any membrane-bound organelles.

Question 3

what is the nuclear membrane?

Answer 3

a double membrane surrounding the nucleus.

Question 4

what is the job of the nuclear pores?

Answer 4

to allow the passage of some molecules, such as mRNA, between the nucleus and cytoplasm.

Question 5

what is the job of the nucleolus?

Answer 5

synthesises components of ribosomes and makes rRNA.

Question 6

what is the nucleoplasm?

Answer 6

a granular material containing chromatin.

Question 7

what is chromatin made up of?

Answer 7

DNA molecules bound with proteins called histones.

Question 8

what is the job of the nucleus?

Answer 8

it contains DNA which codes for protein synthesis.

Question 8

what is the cristae?

Answer 8

the inner membrane of the mitochondria that increases its surface area.

Question 9

what is the matrix?

Answer 9

similar to the cytoplasm, it contains enzymes involved in the Krebs cycle.

Question 10

why do the mitochondria and chloroplasts have 70s ribosomes and small circles of DNA?

Answer 10

so the mitochondria can self replicate and synthesise their own proteins.

Question 11

what is the job of the mitochondria?

Answer 11

ATP synthesis by aerobic respiration.

Question 12

what is the stroma?

Answer 12

the fluid found between the double membrane containing ribosomes, circular DNA, and lipids.

Question 13

what is a thylakoid?

Answer 13

a flattened sac within the stroma containing chlorophyll.

Question 14

what is a benefit of the granum?

Answer 14

the stack of thylakoids means a bigger surface area for trapping light energy.

Question 15

what is the job of the chloroplast?

Answer 15

it traps light energy, which is used to synthesis carbohydrates and also in photosynthesis.

Question 16

what is the endoplasmic reticulum?

Answer 16

a membrane system found throughout the cytoplasm of eukaryotic cells.

Question 17

what is on the surface of the rough ER?

Answer 17

it has ribosomes on its surface.

Question 18

what is the job of the rough ER?

Answer 18

manufactures and transports proteins.

Question 19

what does the smooth ER lack?

Answer 19

it has no ribosomes on its surface.

Question 20

what is the job of the smooth ER?

Answer 20

it manufactures and transports lipids.

Question 21

where is the ER found on the electron microgram?

Answer 21

next to the nucleus.

Question 22

what is the job of the ER?

Answer 22

it is found in large amounts in cells that make enzymes that may be secreted out of the cell?

Question 23

what is the golgi body?

Answer 23

it consists of a number of flattened sacs in which proteins and other molecules are modified.

Question 24

what are the jobs of the golgi body?

Answer 24

produces secretory enzymes; secreting carbohydrates; producing glycoprotein; transporting and storing lipids; forming lysosomes containing digestive enzymes.

Question 25

where are ribosomes found?

Answer 25

free within the cytoplasm or attached to the rough endoplasmic reticulum.

Question 26

what are ribosomal subunits?

Answer 26

a large and a small subunit made from ribosomal RNA and protein.

Question 27

where are the subunits manufactured?

Answer 27

the nucleolus.

Question 28

what size ribosomes do prokaryotic cells have?

Answer 28

70s (smaller)

Question 29

what size ribosomes do eukaryotic cells have?

Answer 29

80s (bigger)

Question 30

what is the job of the ribosomes?

Answer 30

they are the sites of protein synthesis. they synthesise proteins at their primary structure.

Question 31

what kind of membrane surrounds the lysosomes?

Answer 31

a single membrane.

Question 32

where are lysosomes formed?

Answer 32

in the golgi body.

Question 33

what is the job of the lysosomes?

Answer 33

they contain digestive enzymes that break down cellular waste and debris.