2.1 Cell structure

Question 1

The function of the nucleus

Answer 1

• Act as the control centre of the cell through the production of mRNA and tRNA and hence protein synthesis
• Retain the genetic material of the cell in the form of DNA and chromosomes
• Manufacture ribosomal RNA and ribosomes

Question 2

The structural features of a nucleus

Answer 2

• Nuclear envelope
• Nuclear pores - allows large molecules out
• Nucleoplasm
• Chromosomes- consist of protein-bound, linear DNA
• Nucleolus - manufactures ribosomal RNA and assembles ribosomes

Question 3

The function of a mitochondrion

Answer 3

Site of aerobic respiration and produces ATP

Question 4

The structural features of a mitochondrion

Answer 4

• Double membrane
• Cristae
• Matrix

Question 5

The function of chloroplasts

Answer 5

Carry out photosynthesis

Question 6

Structural features of a chloroplast

Answer 6

• Chloroplast envelope
• Grana (stacks of thylakoids)
• Stroma
  -Starch grains

Question 7

Function of RER

Answer 7

• Provide a large SA for the synthesis of proteins and glycoproteins
• Provides a pathway for the transport of materials throughout the cell

Question 8

Function of SER

Answer 8

• Synthesise, store and transport lipids and carbohydrates

Question 9

Function of Golgi body (5 things)

Answer 9

• Add carbohydrate to protein to form glycoproteins
• Produce secretory enzymes
• Secrete carbohydrates
• Transport, modify and store lipids
• Form lysosomes

Question 10

Function of lysosomes

Answer 10

• Hydrolyse material ingested by phagocytic cells
• Release enzymes to the outside of the cell (exocytosis)
• Digest worn out organelles (autophagy)
• Autolysis (completely break down cells )

Question 11

Function of ribosomes

Answer 11

Protein synthesis

Question 12

What ribosomes are found in animal cells

Answer 12

80S

Question 13

Where are 70S ribosomes found

Answer 13

Prokaryotic cells, mitochondria and chloroplasts

Question 14

Function of a cell wall

Answer 14

• Provide mechanical support from osmotic entry
• To provide mechanical support as a whole
• To allow water to pass along it

Question 15

What are cell walls of plants and algae made of

Answer 15

Cellulose

Question 16

What are cell walls of fungi made of

Answer 16

Chitin

Question 17

What is the boundary between 2 adjacent cell walls called

Answer 17

Middle lamella

Question 18

Function of plant vacuoles

Answer 18

• Make a cell turgid
• Sugars and amino acids may act as a temporary food store
• Pigment may attract pollinators

Question 19

What is the cell wall of a bacteria made of

Answer 19

Murein

Question 20

How do bacteria store food

Answer 20

As glycogen granules and oil droplets

Question 21

What form is the genetic material of bacteria

Answer 21

Circular strands of DNA

Question 22

Role of a capsule

Answer 22

Protects bacterium from other cells and helps groups of bacteria to stick together for further protection

Question 23

Describe 2 functions of the golgi apparatus in a eukaryotic cell (2 marks)

Answer 23

• Modify/ package/ transport proteins
• Modify/ package/ transport lipids
• Forms vesicles

Question 24

Describe the structure and function of the nucleus (4 marks)

Answer 24

Structure
1. Nuclear envelope and pores
OR
Double membrane and pores;
2. Chromosomes/chromatin
OR
DNA with histones;
3. Nucleolus/nucleoli;
Function
4. (Holds/stores) genetic information/material
for polypeptides (production)
OR
(Is) code for polypeptides;
5. DNA replication (occurs);
6. Production of mRNA/tRNA
OR
Transcription (occurs);
7. Production of rRNA/ribosomes;

Question 25

Give 2 features of all prokaryotic cells that are not features of eukaryotic cells (1 mark)

Answer 25

No membrane-bound organelles/correct
example
OR
(Single,) circular/loop DNA (in cytoplasm)
OR
DNA free in cytoplasm
OR
DNA not associated with proteins/histones
OR
Murein/peptidoglycan (in) cell wall;

Question 26

Describe how a sample of chloroplasts could be isolated from leaves (4 marks)

Answer 26

1. Break open cells/tissue and filter
   OR
   Grind/blend cells/tissue/leaves and filter;
2. In cold, same water potential/concentration, pH
   controlled solution;
3. Centrifuge/spin and remove nuclei/cell debris;
4. (Centrifuge/spin) at high(er) speed, chloroplasts
   settle out;