1.2(a) The Proteome & (b) Synthesis of Proteins

Question 1

What is the genome

Answer 1

The entire hereditary information encoded in an organism’s DNA

Question 2

What is the preteome

Answer 2

The entire set of proteins expressed by a genome

Question 3

Why is the proteome larger than the genome

Answer 3

Due to alternative RNA splicing

Question 4

What are genes that do not code for proteins called

Answer 4

Non-coding RNA genes

Question 5

Give example of non-coding RNA genes

Answer 5

Genes that are transcribed to produce tRNA, rRNA and RNA molecules that control expression of other genes

Question 6

What are the factors that affect the set of proteins expressed by a given cell type

Answer 6

Metabolic activity of the cell
Cellular stress
Diseased versus healthy cells
The response to signalling molecule

Question 7

What is the role of the endoplasmic reticulum

Answer 7

It forms a network of membrane tubules continuous with the nuclear membrane. It is also involved in the synthesis of lipids and proteins.

Question 8

What does the smooth endoplasmic reticulum synthesise

Answer 8

Lipids

Question 9

What does the rough endoplasmic reticulum synthesise

Answer 9

Proteins

Question 10

What is the Golgi apparatus

Answer 10

A series of flattened membrane discs, this is where post translational modifications happen here.

Question 11

What does the Golgi apparatus do

Answer 11

Packages proteins into membrane bound vesicles inside the cell before they are sent to their destination.

Question 12

What are lysosomes

Answer 12

Membrane bound organelles containing a variety of hydrolases (enzymes) that digest proteins, lipids, nucleic acids and carbohydrates.

Question 13

What is a vesicle

Answer 13

A structure within or outside a cell, consisting of a cytoplasm enclosed by a bilipid layer

Question 14

What do vesicles do

Answer 14

Transport materials between membrane compartments

Question 15

What are lipids

Answer 15

The building blocks of cells e.g., fats, oils and hormones

Question 16

What are the 2 parts of the cytoplasm

Answer 16

Cytosol - the liquid of the cytoplasm
Ribosomes and the membrane bound organelles

Question 17

Where does the synthesis of all proteins begin

Answer 17

cytosolic ribosomes

Question 18

Where are cytosolic proteins found

Answer 18

The cytosol

Question 19

Where are cytosolic proteins synthesised

Answer 19

The cytosolic ribosomes only (ribosomes NOT attached to the ER)

Question 20

What are transmembrane proteins

Answer 20

Those that span the membrane

Question 21

Where does the synthesis of cytosolic ribosomes start

Answer 21

The cytosolic ribosomes

Question 22

Transmembrane proteins carry a signal sequence, what does this do,

Answer 22

They halt translation and directs the ribosome synthesising the protein to dock with the ER, forming the RER

Question 23

What is a signal sequence

Answer 23

A short stretch of amino acids at one end of the polypeptide that determines the eventual location of a protein in a cell

Question 24

What happens as proteins move through the Golgi Apparatus

Answer 24

They undergo post-translational modifications

Question 25

What happens once proteins are in the ER

Answer 25

Transported by vesicles that bud off from the ER and fuse with the Golgi apparatus

Question 26

What is the most common post translational modification

Answer 26

The addition of a carbohydrate group

Question 27

What are secretory proteins

Answer 27

proteins which leave the cell

Question 28

What is proteolytic cleavage

Answer 28

another type of post translational modification and is the process of breaking bonds between amino acids in proteins

Question 29

What does proteolytic cleavage prevent

Answer 29

Digestive enzymes becoming active in an inappropriate locations