2.1.1 - Cell Structure (set B - Organelle Working Together)

Question 1

Explain the first stage of protein production involving the copying of DNA?

Answer 1

Chromosome in the nucleus contains gene for specific amino acid, mRNA copies the code from gene and travels through nuclear pores to rough endoplasmic reticulum where it attaches to a ribosome

Question 2

Explain the second stage of protein production involving the reading of code?

Answer 2

The ribosome reads the mRNA sequence and translates that genetic code into a specified string of amino acids, which grow into long chains that fold to form proteins.

Question 3

Explain the third stage of protein production involving the movement of proteins from the RER?

Answer 3

Protein passes into cisternae of rough endoplasmic reticulum where it is packaged into a vesicle, vesicle travels along microtubules to Golgi apparatus where it fuses with the membrane of the Golgi and enters

Question 4

Explain the fourth stage of protein production involving the movement of proteins through the Golgi?

Answer 4

Protein moves through cisternae of Golgi where it is modified and processed, may have other substances added like carbohydrates and is re-folded

Question 5

Explain the fifth stage of protein production involving the movement of proteins from the Golgi?

Answer 5

Protein is repackaged into a secretory Golgi vesicle and exits the Golgi where it travels along microtubules to cell surface membrane

Question 6

Explain the final stage of protein production involving the protein being released from the cell, exocytosis?

Answer 6

Secretory Golgi Vesicle carrying the protein fuses with cell surface membrane and protein is released from cell - in process called exocytosis (movement of material in the cell into extra cellular fluid)

Question 7

Explain what the cytoskeleton is in cells?

Answer 7

a network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence, in eukaryotic cells they are arranged as microfilaments and microtubules

Question 8

Explain how the cytoskeleton is important for support and strength within the cell?

Answer 8

Microtubules and microfilaments support the cells organelles keeping them in position and also help to strengthen the cell and maintain is shape

Question 9

Explain how the cytoskeleton is important for movement of materials in cells?

Answer 9

Involved with the movement of chromosomes when they separate during cell division - which depends on the contraction of microtubules in the spindle

Question 10

Explain why the cytoskeleton is important for movement of cilia and flagella?

Answer 10

The movement of the cilia and flagella is caused by the cytoskeleton protein filaments that run through them

Question 11

What are microtubules?

Answer 11

Microtubules are made of tubulin - they extend throughout the cell providing it with proper shape and keeping the organelles in place.

• They are the largest structures in the cytoskeleton

Question 12

Importance of microtubules in cells?

Answer 12

• Involved in movement of organelles inside the cytoplasm of cells and allows areas of the cell to communicate with each other
• form a structural network - offering mechanical support

Question 13

Explain what microfilaments are?

Answer 13

Microfilaments or actin filaments consist of two intertwined strands of the protein, actin - they have a vital role in cell movement, cell division and muscle contraction

• smallest filament of the cytoskeleton

Question 14

Explain the function of microfilaments?

Answer 14

Present in the cytoplasm of eukaryotic cells, they are flexible but very strong offering support to the cell - flexible nature allows them to aid in cell movement

Question 15

Explain how microfilaments flexibility enhances its function?

Answer 15

• enables it to help in cell movement
• means they can disassemble and re uniform rapidly which allows a cell to modify its shape and move - used by white blood cells to reach the site of an infection and submerge the pathogen

Question 16

Explain the role of the smooth endoplasmic reticulum?

Answer 16

Is responsible for lipid and carbohydrate synthesis and storage

• no ribosomes

Question 17

Explain the role of the rough endoplasmic reticulum?

Answer 17

Has ribosomes bound to the surface and is responsible for the synthesis and transport of proteins

• more common in secretory cells which release hormones or enzymes

Question 18

Explain the function and structure of ribosomes?

Answer 18

Found free-floating in the cytoplasms or attached to the RER, they are not membrane bound and are constructed of RNA molecules (made in the nucleolus)

• site of protein synthesis

Question 19

What is the function of the Golgi apparatus?

Answer 19

A compact structure formed of cisternae (no ribosomes) it modifies proteins and repackages them into lysosomes (proteins that will remain in the cell) or secretory proteins that will leave the cell

Question 20

What are intermediate fibres?

Answer 20

Fibres which give mechanical strength to cells, helping maintain their integrity

• makes up the cytoskeleton

Question 21

Explain what centrioles are?

Answer 21

Components of the cytoskeleton, composed of microtubules - two associated centrioles form the centrosome

• involved in cell division

Question 22

What is the function of the centrosome?

Answer 22

Involved in the assembled and organisation of spindle fibres during cell divisions

• spindle fibre are a network of filament that help move chromosomes in cell division

Question 23

Give the three components that make up the cytoskeleton?

Answer 23

• microfilaments
• microtubules
• intermediate fibre