Unit 1 Key Area 2

Question 1

What is the proteome

Answer 1

The entire set of genes expressed by the genome

Question 2

Why is the proteome larger than the genes

Answer 2

Because more than one protein can be produced from one single gene as a result of the alternative rna splicing

Question 3

What are genes called that do not code for proteins

Answer 3

Non coding RNA genes

Question 4

What do non coding rna genes include

Answer 4

Those that are transcribed to produce tRNA, rRNA & RNA molecules that control the expression of other genes

Question 5

The set of proteins can vary over time and under different conditions. What are these conditions

Answer 5

Metabolic activity of the cell
Diseased vs healthy cells
Cellular stress
The response to signalling molecules

Question 6

What in eukaryotic cells increases the total area of membrane

Answer 6

System of internal membrane

Question 7

do eukaryotes have a small or large SA:Volume ratio

Answer 7

RELATIVELY SMALL

Question 8

What is a con of having a small plasma membrane

Answer 8

it hs too small for carrying out vital functions carried out by membranes

Question 9

What is the endoplasmic recticulum

Answer 9

a network of membrane tubules continuous with the nuclear membrane

Question 10

what is the golgi apparatus

Answer 10

a series of flattened membrane discs

Question 11

what is a lysosome

Answer 11

membrane bound organelles cintaining a variety of hydrolases

Question 12

what do hydrolases digest

Answer 12

Lipids, nucleic acids and carbs

Question 13

what is a vesicle

Answer 13

it transports materials between membrane compartments

Question 14

where are lipids and proteins synthesised

Answer 14

the endoplasmic reticulum

Question 15

what is the Rough Endoplasmic reticulum

Answer 15

has ribosomes on its cytosolic face while smooth er lacks ribosomes

Question 16

what happens with the lipids in the SER

Answer 16

inserted into its membrane

Question 17

where does the synthesis of all proteins begin

Answer 17

the cytosolic ribosomes

Question 18

where is the synthesis of proteins completed

Answer 18

the cytosolic ribosomes

Question 19

where do the proteins remain after completion of synthesis

Answer 19

in the cytosol

Question 20

what do transmembrane proteins carry

Answer 20

a signal sequence

Question 21

what does a signal sequence do

Answer 21

halts translation and directs the ribosome synthesising the protein to dock with the ER

Question 22

what does the docking of ribsomes form

Answer 22

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

when does translation occur

Answer 24

continues after docking and the protein is inserted into the membrane of the ER

Question 25

What happens when the proteins are in the ER

Answer 25

they are transported by vesicles that bud off from the ER and fuse the golgi apparatus

Question 26

what happens in the golgi apparatus

Answer 26

the proteins move through the GA and they undergo Post translational modification

Question 27

what is the process for going through the golgi apparatus

Answer 27

molecules move through the golgi disc in vesicles that bud off from one disc and fuse to the next one in the stack.

Question 28

what do enzymes do in the golgi

Answer 28

catalyse the addition of various sugars in multiple steps to form the carbohydrates

Question 29

what is a MAJOR modification

Answer 29

the addition of carbohydrate groups

Question 30

what happens after the post translational modifications

Answer 30

the vesicles leave the golgi apparatus and take proteins to the plasma membrane and lysosomes

Question 31

where do vesicles also move to

Answer 31

move along microtubules to other membranes and fuse with them within the cell

Question 32

What is are examples of secreted proteins

Answer 32

peptide hormones and digestive enzymes

Question 33

where do secreted proteins begin translation

Answer 33

in ribosomes on the rer by entering its lumen

Question 34

what is the process of the secratory pathway

Answer 34

enter the rer lumen then move through the golgi apparatus (the normal protein synthesis occurs) the PTM occurs they are then packaged into secretory vesicles and the vesicles move to and fuse with the plasma membrane releasing the proteins out of the cell or move along microtubules

Question 35

what are many secreted proteins synthesised as?

Answer 35

inactive presursors

Question 36

what do inactive precursors require

Answer 36

proteolytic cleavage to produce active proteins

Question 37

what is proteolytic cleavage

Answer 37

another type of PTM

Question 38

why are digestive enzymes secreted proteins

Answer 38

if they were active within the cell it would be lethal for the cell and they require proteolytic cleavage to become active and carry out its function

Question 39

What do amino acids differ in

Answer 39

the R group present

Question 40

What do R groups vary in

Answer 40

size, shape, charge, hydrogen bonding capacity and chemical reactivity

Question 41

what are the r group classified as?

Answer 41

basic (+) acidic (-) polar and hydrophobic

Question 42

what does a diversity allow proteins to do

Answer 42

carry out a range of functionsw

Question 43

what is the primary function

Answer 43

the sequence in which the amino acids are synthesised into the polypeptide

Question 44

WHat does the secondary structure involve

Answer 44

hydrogen bonding along the backbone allowing the alpha helices, parallel or anti- parallell beta pleated sheets or turns to form

Question 45

what does folding of the polypeptide form

Answer 45

the tertiary structure

Question 46

how is the tertiary strucure stablised

Answer 46

with interactions between the r groups

Question 47

what is the quaternary structure

Answer 47

exists in proteins with twoor more connected polypeptide subunits

Question 47

what does the QS describe

Answer 47

the spatial arrangement of subunits

Question 47

what are disulfide bridges

Answer 47

covalent bonds between r groups containing sulfur

Question 47

# ilhhd what are examples of the interactions between the r groups

Answer 47

Ionic bonds London Dispersion forces Hydrogen bonds hydrophobic interactions Disulfide bridges

Question 47

what does a decrease in pH or increase in temperature do to the affinity of haemoglobin to oxygen

Answer 47

decrease affinity of haemoglobin for oxygen ∴ a reduced binding and this then causes the promotion of increases oxygen delivery to tissue

Question 47

what is a prosthetic group

Answer 47

a non-protein unit tightly bound to a protein essential for its function

Question 48

what is the ability of haemoglobin binding to O2 dependent on

Answer 48

the non-protein haem group