MCB L1

Question 1

Describe the structure of prokaryotes

Answer 1

Simple structure - no nucleus
DNA not localised, “free”, attached to cell wall, cell membrane (plasma membrane)
Outer cell wall - protection (prokaryotes live in hostile environments)
Variable shapes + sizes (rods, spheres, spirals)

Question 2

State the 3 different shapes of prokaryotes

Answer 2

Spherical cells
Rod shaped cells
Spiral cells

Question 3

State an example of a prokaryote

Answer 3

Bacteria:
Archae
Eubacteria - ecoli (model organism for eubacteria)

Question 4

Diagram of prokaryote

Answer 4

Prokaryotic DNA
Ribosomes
Cell Membrane
Cell Wall
Flagellum

Question 5

How do prokaryotes become resistant to antibioitics

Answer 5

Rapid growth due to frequent divisions
Leads to rapid evolving
-change in genetics (genetic replication)
-Exchange of DNA between cells
-Mutations

Leads to antibiotic resistance

Question 6

State a common type of antibiotic resistanct prokaryote

Answer 6

MRSA - post surgery infection
people get infected with MRSA (antibiotic resistant bacteria, post surgery)

Question 7

What are the components of the plasma membrane?

Answer 7

DNA
RNA
Proteins

Question 8

State the 3 divisions of organisms

Answer 8

Bacteria (eubacteria)
Archae (Archaebacteria)
Eukaroytes

Question 9

How do we classify the different divisions of organisms?

Answer 9

We cannot do this based on how they look, they all have similar shapes and sizes

We can only do this based on DNA sequence

Question 10

What are the two divisions of prokaryotes?

Answer 10

Prokaryotes diverged early in evolution into 2 distinct groups:

Eubacteria
Archae

Question 11

State 2 examples of eukaryotes

Answer 11

Humans
Maize

Question 12

State an example of archaebacteria

Answer 12

Sulfolobus

Question 13

State an example of eubacteria

Answer 13

E-coli

Question 14

State the compartments of the eukaryotic cell

Answer 14

RECOGNISE ON DIAGRAM

1. Plasma membrane
2. Nucleus
3. Ribosomes in cytosol
4. Mitochondrion
5. Lysosomes
6. Golgi apparatus
7. ER
8. Vesicles
9. Peroxisomes
10. Centrosome with pair of centrioles
11. ECM
12. Actin Filaments
13. Intermediate filaments
14. Microtubules

Question 15

State the function of the nucleus

Answer 15

Contains genome
DNA + RNA synthesis

Question 16

State the function of lysosomes

Answer 16

Intracellular digestion / degradation

Question 17

State the function of ER

Answer 17

Synthesis of proteins + lipids

(where cell membrane components are made, the above)

(materials for export)

Question 18

State the function of golgi apparatus

Answer 18

Modifications, sorting, packaging of proteins + lipids (of materials produced in ER)

Transports materials outside cell using vesicles

Question 19

State the function of endosomes

Answer 19

Sorting of molecules entering cell via membranes

Question 20

State the function of mitochondria

Answer 20

ATP synthesis
Cellular respiration

Question 21

State the function of peroxisomes

Answer 21

Oxidation of toxic molecules

Question 22

State the function of chloroplasts

Answer 22

Traps sunlight energy - converts into large molecules

“large molecules” = food, used for ATP synthesis in mitochondira

Question 23

Why do eukaryotyes have membrane-bound organelles

Answer 23

Organelles in eukaryotes are in membrane-bound compartments

Because each organelle undergoes seperate reactions which are NOT COMPATIBLE with each other - therefore, organelles need to be in seperate comparments

Question 24

Describe the structure of the golgi apparatus

Answer 24

Flattened stacks of membrane enclosed sacs

Question 25

State the function of the plasma membrane

Answer 25

Allow materials to be imported and exported from the cell via endocytosis and exocytosis

Question 26

What is the cytoplasm ?

Answer 26

All aqeous material in plasma membrane

Question 27

What is the cytosol ?

Answer 27

All cytoplasm not enclosed in membrane bound organelles

Question 28

What is the role of the cytosol ?

Answer 28

• Many chemical reactions take place in cytosol
• e.g. initial breakdown of nutrients

Question 29

What are diverse cell types ?

Answer 29

Specialised cells.
Certain cells are specialised for certain functions and therefore, have different quantities of certain components

Question 30

Give examples of diverse cell types

Answer 30

1. Oxyntic cells (stomach)
2. Astrocytes (brain)
3. Cardiac muscle cells (heart)
4. Egg cells / Sperm cells (sex cells)
5. Hair cells (inner ear)

Question 31

State the function of oxyntic cells, where they are found and how they are specialised to this function

Answer 31

Found in stomach
Produce gastric juice which produces HCl
Have lots of mitochondria