2.1.1 Structure of eukaryotic cells

Question 1

What are the distinguishing features of eukaryotic cells?

Answer 1

● Cytoplasm containing membrane-bound organelles
● So DNA enclosed in a nucleus

Question 2

Describe the general structure of eukaryotic cells

Answer 2

Question 3

Describe the structure of the cell-surface membrane

Answer 3

Question 4

Describe the function of the cell-surface membrane

Answer 4

● Selectively permeable → enables control of passage of substances in / out of cell

● Molecules / receptors / antigens on surface → allow cell recognition / signalling

Question 5

Describe the structure of the nucleus

Answer 5

Question 6

Describe the function of the nucleus

Answer 6

● Holds / stores genetic information which codes for polypeptides (proteins)

● Site of DNA replication

● Site of transcription (part of protein synthesis), producing mRNA

● Nucleolus makes ribosomes / rRNA

Question 7

Describe the structure of a ribosome

Answer 7

● Made of ribosomal RNA and protein (two subunits)
● Not a membrane-bound organelle

Question 8

Describe the function of a ribosome

Answer 8

Site of protein synthesis (translation)

Question 9

Describe the structure of rough (rER) & smooth endoplasmic reticulum (sER)

Answer 9

Question 10

Describe the function of rER

Answer 10

● Ribosomes on surface synthesise proteins

● Proteins processed / folded / transported inside rER

● Proteins packaged into vesicles for transport eg. to Golgi apparatus

Question 11

Describe the function of sER

Answer 11

● Synthesises and processes lipids

● Eg. cholesterol and steroid hormones

Question 12

Describe the structure of Golgi apparatus and Golgi vesicles

Answer 12

Question 13

Describe the function of Golgi apparatus

Answer 13

● Modifies protein, eg. adds carbohydrates to produce glycoproteins

● Modifies lipids, eg. adds carbohydrates to make glycolipids

● Packages proteins / lipids into Golgi vesicles

● Produces lysosomes (a type of Golgi vesicle)

Question 14

Describe the function of Golgi vesicles

Answer 14

● Transports proteins / lipids to their required destination

● Eg. moves to and fuses with cell-surface membrane

Question 15

Describe the structure of lysosomes

Answer 15

Question 16

Describe the function of lysosomes

Answer 16

● Release hydrolytic enzymes (lysozymes)

● To break down / hydrolyse pathogens or worn-out cell components

Question 17

Describe the structure of mitochondria

Answer 17

Question 18

Describe the function of mitochondria

Answer 18

● Site of aerobic respiration

● To produce ATP for energy release

● Eg. for protein synthesis / vesicle movement / active transport

Question 19

Describe the structure of chloroplasts in plants and algae

Answer 19

Question 20

Describe the function of chloroplasts in plants and algae

Answer 20

● Absorbs light energy for photosynthesis

● To produce organic substances eg. carbohydrates / lipids

Question 21

Describe the structure of the cell wall in plants, algae and fungi

Answer 21

● Provides mechanical strength to cell

● So prevents cell changing shape or bursting under pressure due to osmosis

Question 22

Describe the structure of the cell vacuole in plants

Answer 22

Question 23

Describe the function of the cell vacuole in plants

Answer 23

● Maintains turgor pressure in cell (stopping plant wilting)

● Contains cell sap → stores sugars, amino acids, pigments and any waste chemicals

Question 24

What is a tissue?

Answer 24

Group of specialised cells with a similar structure working together to perform a specific function, often with the same origin

Question 25

What is an organ?

Answer 25

Aggregations of tissues performing specific functions

Question 26

What is an organ system?

Answer 26

Group of organs working together to perform specific functions

Question 27

Suggest how you can apply your knowledge of cell features / organelles to explain adaptations of eukaryotic cells

Answer 27

General answer format: ● [Named cell] has many [named organelle, eg. ribosomes] ● To [link organelle function to cell function eg. increase rate of protein synthesis, making many antibodies]