Cells

Question 1

What is cell membrane made up of?

LPS

Answer 1

• Lipids
• Proteins
• Sugars

Question 2

What is the purpose of the cell membrane?

Answer 2

• It provides a boundary between the living cell and the external world.
• It has a hydrophobic layer which prevents polar and large molecules from passing through.
• Provides a method for things to be communicated on the outside.

Question 3

What can pass through the membrane?

Answer 3

• Moderately non-polar molecules can pass through.
• Highly hydrophobic molecules will enter and not leave.

Question 4

How can you break the lipid bilayer barrier?

Tunnel

Answer 4

By adding molecules which tunnel and disrupt the membrane or by adding specific carriers which will bring another molecule across the membrane (Ion carriers)

Question 5

What does Amphotericin B do?

Polar channel, leaky

Answer 5

• It has a big hydrophilic line and a big hydrophobic line - one part will want to sit in the membrane and one part is polar so it doesn’t want to sit in the membrane.
• It is organised to be a rod-shaped molecule.
• The non-polar part will be in contact with the lipid tails and the polar part will gather together and create a polar channel going through the membrane and stops the membrane from doing what it normally does (stops it separating the inside and outside).
• By inserting into the membrane it makes them leaky which Can be used to treat fungal infections.
• This is an example of disrupting the membrane.

Question 6

What does Valinmycin do?

Peptide, electron density

Answer 6

• It is an ion carrier which breaks down the lipid bilayer.
• It is partly peptide with lots of esters, and it has side chains that are greasy and hydrophobic so they’ll want to sit in the membrane.
• The middle section has a lot of electron density from all the carbonyl groups and the partial negative charge is good for binding potassium ions.
• The negative charge on all the oxygens creates a perfect hole for the potassium to sit in the middle.
• The potassium is surrounded by hydrophobic parts so the molecule can slide into the membrane and pass through because it has a hydrophobic exterior and that will in general disrupt the ion balances in the cells and result in their death.
• This method works against human and bacterial cells.

Question 7

What is the nucleus composed of?

LPD

Answer 7

• DNA
• Proteins
• LIpid membrane

Question 8

What is the nucleus for and what is stored there?

Answer 8

It is where genetic information is stored and used as DNA.

Question 9

What are nucleosomes composed of?

Answer 9

DNA wrapped around histone proteins.

Question 10

Where does transcription of DNA and RNA occur?

Answer 10

Nucleus

Question 11

What is the function of DNA?

Answer 11

To encode proteins made in the cytoplasm.

Question 12

What is the cytoplasm made up of?

WSP

Answer 12

• Water
• Small molecules
• Proteins

Question 13

What happens in the cytoplasm?

Answer 13

It is where most metabolism (processing of small molecules) happens.

Question 14

What is cytoplasm a medium for?

Answer 14

Signal transduction

Question 15

What are the mitochondria composed of?

LPDRS

Answer 15

• Lipids
• Proteins
• DNA
• RNA
• Small molecules

Question 16

What happens in the mitochondria?

Answer 16

• The production of ATP by ATP synthase which sits on the inner membrane.
• They also have their own DNA, transcription & translation machinery

Question 17

What is the endoplasmic reticulum composed of?

LPR

Answer 17

• Lipids (phospholipids)
• Proteins
• RNA

Question 18

What are the two types of endoplasmic reticulum?

Answer 18

• Smooth
• Rough

Question 19

Where is the endoplasmic reticulum found?

Answer 19

It surrounds the nucleus.

Question 20

Where does the rough character on the endoplasmic reticulum come from?

Answer 20

The presence of ribosomes.

Question 21

What does the endoplasmic reticulum act as?

Answer 21

Intracellular transport system

Question 22

What do the ribosomes on the endoplasmic reticulum do?

Answer 22

They produce proteins which get exported outside the cell.

Question 23

What is the smooth endoplasmic reticulum involved in? Give an example.

Synthesis

Answer 23

• Involved in lipid biosynthesis - enzymes
• Lovastatin is an example of this which reduces cholesterol by inhibiting an enzyme.

Question 24

What is the golgi apparatus composed of?

Answer 24

• Lipids (phospholipids)
• Proteins

Question 25

What is the Golgi apparatus responsible for?

Vesicles

Answer 25

It receives proteins from the endoplasmic reticulum in vesicles and applies post-translational modifications to them to give them more chemistry.

Question 26

Give examples of types of post-translational modifications.

Answer 26

• Phosphorylation
• Glycosylation
• Sulfation

Question 27

Where is the Golgi apparatus found?

Answer 27

Near the endoplasmic reticulum.

Question 28

What happens in the ribosome?

tRNAs

Answer 28

It is where mRNA is translated into proteins via tRNAS.

Question 29

Where are ribosomes found?

Answer 29

• Cytoplasm
• Mitochondria
• Rough endoplasmic reticulum

Question 30

What are endosomes?

Compartments

Answer 30

Lipid-bilayer bounded compartments within the cell.

Question 31

What do endosomes do?

Bud off

Answer 31

• The bud off from the Er and Golgi to transport or excrete proteins.
• They allow the cell to uptake materials
• They can evolve into lysosomes.

Question 32

Why is lysosomal escape important?

Nucleic acid

Answer 32

Lysosomal escape is critical for nucleic acid therapeutics and other nanoparticle therapies since large molecules cannot diffuse through the membrane

Question 33

How are bacteria different from other cells?

Answer 33

• They are smaller than animal cells
• They have a cell wall & membrane
• DNA is freely floating