Chapter 2: 2.4

Question 1

Difference between prokaryotic and eukaryotic cell in terms of it’s structure?

Answer 1

Prokaryotic:
- Complex single-celled organisms with divided internal area of cytoplasm

Eukaryotic:

• make up multi cellular organisms (animals, plants)
• Complicated internal structure which is made up of nucleoplasm and cytoplasm

Question 2

What is metabolism?

Answer 2

The synthesis (catabolism) and decomposition (anabolism) of molecules. There are different sets of reactions take place in different region

simplified: is the synthesis (building up) and breaking down of molecules

Question 3

What do membranes do?

Answer 3

Regulates the movement of substances into and out of the cell

Act as an effective barrier in controlling which substance enter and exit cells

Question 4

What are the common organelles/features that can be found on the eukaryotic cell?

Answer 4

• Microtubule network
• Vesicles
• Nucleus / nucleolus
• Golgi apparatus
• Cytosol
• Ribosome
• Centriole
• Cell-surface membrane
• RER (rough endoplasmic reticulum)
• SER (smooth endoplasmic reticulum)
• Cytoskeleton
• Mitochondria
• Secretory vesicles

Question 5

What does the nucleus contain?

Answer 5

It contains coded genetic information in the form of DNA (deoxyribonucleic acid) molecules

Question 6

How are chromosomes formed?

Answer 6

DNA associated with proteins called histones to form chromatin. Chromatin coils and condenses during cell division to form chromosomes.

Question 7

What is a nucleolus? What is it composed of?

Answer 7

Is an area within nucleus responsible for producing ribosomes. Made up of proteins and RNA.

Question 8

How are ribosomes formed?

Answer 8

RNA is used to produce ribosomal RNA (rRNA) which is then combined with proteins to form ribosomes which are necessary for protein synthesis.

Question 9

What is the function of mitochondria?

Answer 9

To produce their own enzymes and to reproduce themselves

A site for final stage of cellular respiration, where ATP is then produced

Question 10

What are vesicles? What is their structure like?

Answer 10

Membranous sacs with storage and transport roles.

Consist of a single membrane containing fluid. Used to transport materials inside the cell.

Question 11

What are lysosomes? What is the function of lysosomes?

Answer 11

They are specialised vesicles that contain hydrolytic enzymes

Responsible for the break down waste material in cells including organelles

Play a role in the breaking down of pathogens ingested by phagocyte cells

Play role in programmed cell death

Question 12

What are the 4 main functions of the cytoskeleton?

Answer 12

• Has microtubules and microfilaments that support the cell’s organelles, keeping them in position
• They help to strengthen the cell and ensure it maintains its shape
• They are responsible for the movement of materials within the cell (For example,
• They have proteins that cause the cell to move (e.g. in single cell have flagellum - that propels the cell in a direction)

Question 13

What are centrioles?

Answer 13

These are components of the cytoskeleton present in most eukaryotic cells.

Question 14

What are flagella?

Answer 14

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Question 15

What is the cillia? Describe it’s structure?

Answer 15

Is small hair like structures that are found on the surface of the membrane of some animal cell

Have an outer membrane and ring of nine pairs of protein microtubules inside with two microtubles in the middle

Question 16

What is the smooth endoplasmic reticulum (RER)?

Answer 16

It is responsible for lipid

Carbohydrate synthesis and storage

Question 17

What is the rough endoplasmic reticulum (RER)

Answer 17

Responsible for the synthesis and transport of proteins

Question 18

What are ribosomes?

Answer 18

Constructed of RNA molecules made in the nucleolus - the site of protein synthesis. Can be found free-floating in cytoplasm or attached to ER, forming RER.

Question 19

What is the Golgi apparatus?

Answer 19

Similar to smooth endoplasmic reticulum - compact structure formed of cisternae, does not contain ribosomes. Modifies proteins and packages them into vesicles.

Question 20

What happens during protein production?

Answer 20

1) Proteins are synthesised on the the ribosomes bound to the endoplasmic reticulum
2) They then pass into the cisternae and are packaged into transport vesicles
3) Vesicles containing the newly synthesised proteins move towards the Golgi Apparatus via transport function of the cytoskeleton
4) The vesicles fuse with the cis face of the Golgi Apparatus and proteins enter. The proteins are structurally modified before leaving the Golgi apparatus in vesicles from its trans face
5) Secretory vesicles that carry protein that are released from the cell. They move towards and fuse with cell-surface membrane, releasing the contents by exocytosis
[some vesicles then form lysosomes - which contain enzymes for the use in the cell]

Question 21

What is the function of spindle fibres?

Answer 21

Have the role in the physical segregation of chromosomes in cell division.

Question 22

What is the structure of Centrioles?

Answer 22

Composed of micro-tubules

2 centrioles form the centrosome (involved in assembly/organisation of spindle fibres in cell division).

Question 23

What is the function Lysosomes?

Answer 23

Responsible for breaking down waste materials in cells including old organelles

Have an important role in the immune system as they are responsible for breaking down pathogens ingested by phagocytic cells

Responsible in playing a role in programmed cell death

Question 24

What is endoplasmic reticulum?

Answer 24

Is the network of membranes enclosing flattened sacs called cisternae

Question 25

What is the nucleolus?

Answer 25

Is an area within the nucleus and responsible for producing ribosomes.

Question 26

What is the nucleolus composed of?

Answer 26

Protein and RNA

Question 27

What is the function of RNA?

Answer 27

Used to produce ribosomal RNA which is then combined with proteins to form ribosomes necessary for protein synthesis

Question 28

What is the cytoplasm composed of?

Answer 28

composed of cytostol: which is made up of salts, water and organic molecules

Question 29

What is the function of DNA in the nucleus?

Answer 29

To direct the creation of all proteins needed by the cell (however ribosomes conduct protein synthesis outside of the nucleus) Controls metabolic activities in the cell

Question 30

What is the structure of the nucleus like?

Answer 30

DNA is contained in a double membrane called a nuclear envelope to prevent damage in cytoplasm Has a nuclear envelope contains nuclear pores that allow for the exchange of molecules in/out of nucleus.

Question 31

What is cytokineses?

Answer 31

process where cytoplasm of a single eukaryotic cell is divided into two daughter cell

Question 32

What are lysosomes?

Answer 32

They are specialised forms of vesicles that contain hydrolytic enzymes

Question 33

What is the cytoplasm composed of?

Answer 33

composed of cytosol (water, salts and organic molecules)

Question 34

What does the number of mitochondria in the cell tell you?

Answer 34

It tells you about the amount of energy the cell uses (i..e. so more mitochondria means very active)

Question 35

What does the structure of the mitochondria look like?

Answer 35

Has double membrane - with inner membrane consisting of highly folded structures called cristae and a fluid interior matrix Cristae also contains enzymes for aerobic respiration Have mitochondrial (mt)DNA

Question 36

What are the 3 components of the cytoskeleton?

Answer 36

Microfilaments - contrile fibres formed from proteins of actin Microtubules - globular tubulin proteins polymerase to form tubes that are used to form a scaffold-like structure Intermediate fibres - fibres that give mechanical strength