Module 2. Cell structure (set 1)

Question 1

What are the distinguishing features of eukaryotic cells
(2 marks)

Answer 1

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

Question 2

What are the distinguishing features of prokaryotic cells
(2 marks)

Answer 2

• Cytoplasm lacking membrane-bound organelles
• So genetic information **not ** enclosed in a nucleus

Question 3

Explain the role of the membrane in the rough endoplasmic reticulum. (2)

Answer 3

• compartmentalisation
• separate proteins from cytoplasm

Question 4

Outline the role of organelles in the production, transport and release of proteins from eukaryotic cells.
Do not include details of transcription and translation in your answer.
[4 marks]
[4.1 - JUN20] [AS]

Answer 4

1. DNA in nucleus is code (for protein);
2. Ribosomes/rough endoplasmic reticulum produce (protein);
3. Mitochondria produce ATP (for protein synthesis);
4. Golgi apparatus package/modify;
   OR
   Carbohydrate added/glycoprotein produced by Golgi apparatus; Accept body for ‘apparatus’
5. Vesicles transport
   OR
   Rough endoplasmic reticulum transports;
6. (Vesicles) fuse with cell(-surface) membrane; Accept exocytosis at cell membrane

Question 5

Outline the similarities in, and the differences between, the structures of **chloroplasts **and mitochondria.

Answer 5

Similarities
1. Double membrane;
2. Both contain (circular) DNA;
3. Both contain ribosomes;
Ignore numbers in front of ribosomes

Differences
4. Thylakoids/lamellae/grana v cristae;
5. Stroma v matrix;
6. Pigments v no pigments;

Question 6

U. marinum cells ingest bacteria and digest them in the cytoplasm. Describe the role of one named organelle in digesting these bacteria.
[3 marks]
[3.2 - JUN21] [AS]

Answer 6

1. Lysosomes;
2. Fuse with vesicle;
   Accept phagosome for vesicle
3. (Releases) hydrolytic enzymes;
   Accept lysozymes for “hydrolytic enzymes”

Question 7

The figure below shows transmission electron micrographs of two cells, one **animal **cell [A] and one prokaryotic cell [B].
Contrast the structure of the two cells.
[5 marks]
[4c PMT]

Answer 7

1. Magnification (figures) show A (eukaryotic) is bigger than B (prokaryotic)
2. A has a nucleus whereas B has free DNA;
3. A has mitochondria whereas B does not;
4. A has Golgi body/endoplasmic reticulum whereas B does not;
5. A has no cell wall whereas B has a murein/glycoprotein cell wall;
   Accept peptidoglycan
6. A has no capsule whereas B has a capsule;
7. A has DNA is bound to histones/proteins whereas B has DNA not associated with histones/proteins
   OR
   A has **linear DNA **whereas B has circular DNA;
8. A has larger ribosomes;

Question 8

Contrast the structure of a bacterial cell and the structure of a human cell
(5 marks)

Answer 8

1. Bacterial cell is much smaller than a human cell;
2. Bacterial cell has a cell wall but human cell does not;
3. Bacterial cell lacks a nucleus but human cell has a nucleus;
4. Bacterial cell lacks membrane-bound organelles but human cell has membrane-bound organelles;
   Accept any named membrane-bound organelle
5. Bacterial ribosomes smaller than human ribosomes / bacteria have 70S ribosomes whereas humans have 80S ribosomes;
6. Bacterial DNA is circular but human DNA is linear;
7. Bacterial DNA is ‘naked’ whereas human DNA is bound to histones / proteins

Question 9

Describe how eukaryotic cells are organised in complex multicellular organisms

Answer 9

Eukaryotic cells become specialised for specific functions

Question 10

Tissue

Answer 10

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

Question 11

Organ

Answer 11

Aggregations of tissues performing specific functions

Question 12

Organ system

Answer 12

Group of organs working together to perform specific functions