2.1 - Structure of eukaryotic and prokaryotics

Question 1

1) List three ways eukaryotic cells differ from prokaryotic cells.

Answer 1

● membrane bound organelles
● DNA is enclosed in a nucleus
● Have larger ribosomes (80S) than prokaryotic cells (70S)

Question 2

2) Prokaryotic cells include bacterial cells. List the differences between Prokaryotic and Eukaryotic cells.

Answer 2

● No membrane bound organelles (e.g. mitochondria, endoplasmic reticulum, golgi)
● No nucleus - instead they have a single circular DNA molecule that is free in the cytoplasm and is not associated with proteins
● Smaller ribosomes 70S
● Has a murein cell wall, a capsule and plasmids

Question 3

Structure and function of nucleus

Answer 3

containing chromosomes, consisting of protein-bound, linear DNA within the nucleoplasm. Contains one (nucleolus) or more nucleoli
Found in animal and plant cell.

Question 4

Structure and function of nuclear envelope

Answer 4

Double membrane surrounding the nucleus with nuclear pores to let molecules in and out

Found in animal and plant cell.

Question 5

Structure and function of plasma membrane

Answer 5

Description of structure: A phospholipid bilayer with hydrophilic phosphate heads facing outwards and hydrophobic fatty acid tails facing inwards.
Function: Involved in the transport of substances via diffusion or facilitated diffusion, active transport (with the aid of proteins)

Found in eukaryotes and prokaryotes

Question 6

Function of cytoplasms

Answer 6

Where chemical reactions take place

Found in animal, plant and prokaryotes

Question 7

Structure and function of ribosome

Answer 7

Where amino acids are joined together to make proteins (i.e. protein synthesis)
They have no membrane
● EA, EP = have 80s ribosomes
● P = have 70s ribosomes

Question 8

Structure and function of mitochondria

Answer 8

Site of AEROBIC respiration
Produces ATP (releases energy)
Contains short, circular DNA (not associated with proteins)
Has a double membrane. The inner membrane is folded forming cristae.
Contains smaller (70S) ribosomes (thought to have evolved from prokaryotic cells.)

Found in animal and plant cells

Question 9

Structure and function of rough endoplasmic reticulum

Answer 9

Has ribosomes on their surface which are involved in protein synthesis
Proteins are also folded up inside the RER
Found in eukaryotes

Question 10

Structure and function of smooth endoplasmic reticulum

Answer 10

Synthesis and storage of molecules such as lipids, steroids and sterols
Found in eukaryotes

Question 11

Structure and function of Golgi apparatus

Answer 11

Modifies proteins (e.g. by adding carbohydrate groups to form a glycoprotein or lipid groups to make a lipoprotein)
Stores proteins
Packages proteins into vesicles
Transport vesicles to cell surface
Found in eukaryotes

Question 12

Structure and function of lysosomes

Answer 12

A vesicle that contains hydrolytic enzymes (lysozymes) which are used to digest molecules
Found in eukaryotes

Question 13

Structure and function of chloroplasts

Answer 13

Chlorophyll absorb light for photosynthesis to produce carbohydrates
Has a double membrane. Inside there are thylakoid membranes which can form a stack called a granum (pl. grana). The grana are linked by lamellae.
Contain starch grains
Found in plant cells and algae

Question 14

Structure and function of cell walls

Answer 14

For strength and support
Found in plant cells and algae and prokaryotes and fungi

Question 15

Structure and function of a permanent vacuole

Answer 15

Tonoplast – a membrane surrounding the vacuole
When the vacuole is full of fluid the cell becomes turgid.
Temporary food store containing sugars and amino acids
Contains pigments (colour petals)

Question 16

Structure and function of flagellum

Answer 16

For movement.

Question 17

Structure and function of slime capsule

Answer 17

A ‘slime’ layer on the outside of the cell, made of polysaccharides
It provides protection for the cell and might help cells stick together
Found in prokaryotes

Question 18

Structure and function of circular dna

Answer 18

Genetic material in a prokaryote (not enclosed in a nucleus)
Found in prokaryotes

Question 19

What is plant cell wall made of?

Answer 19

Cellulose

Question 20

What is algae cell wall made of?

Answer 20

Cellulose

Question 21

What is fungi cell wall made of?

Answer 21

Chitin

Question 22

What is prokaryote cell wall made of ?

Answer 22

Murein

Question 23

4. Describe the replication process of bacterial cells (6 marks)

Answer 23

● Binary Fission
● Circular DNA and plasmids replicate
● Circular DNA attaches to opposite ends of cell membrane
● Bacterial cell grows
● The cell membrane pinches inwards in the middle of the cell
● cytoplasm divides to form two daughter cells (each has a variable number of plasmids)
● A cell wall is formed around each daughter cell.

Question 24

Draw and label the structure of a virus

Answer 24

Check notes

Question 25

6. How does a Virus Replicate?

Answer 25

1. Virus attaches to a host cell 2. Virus injects its genetic material into the host cell 3. The host cell transcribes and translates the viral genes 4. These proteins form new virus particles 5. The virus particles burst out of the host cell, so the host cell is destroyed

Question 26

Why is mitochondria being present in a cell proof that a cell is a eukaryote

Answer 26

Mitochondria are membrane bound organelles