Cell Ultrastructure, Polarity, & Acidity

Question 1

What is the equation used to calculate the pH of a solution?

Answer 1

pH = pK + log(base/acid) - (the Henderson-Hasselbalch Equation)

Question 2

What is meant by the term ampipathic?

Answer 2

A molecule contains both hydrophilic and hydrophobic components

Question 3

Describe the role of the Golgi apparatus.

Answer 3

The Golgi apparatus processes proteins from the smooth ER, further glycosylating them, and tagging them for transportation into vesicles towards their appropriate destination

Question 4

What makes a molecule hydrophilic?

Answer 4

A bond within the molecule may have a dipole, meaning an uneven share of electrons between the 2 molecules forming a bond - this forms an unequal distribution of charge, making a molecule hydrophilic

Question 5

Why do metabolically active tissues cause a localised decrease in pH?

Answer 5

Greater respiration rates produce more CO2 - when taken up by red blood cells, CO2 is converted to carbonic acid (by carbonic anhydrase)

Question 6

What 2 structures to lipids form in solution?

Answer 6

Lipid bilayer

Micelle

Question 7

Where are lysosomes generated?

Answer 7

The Golgi apparatus

Question 8

Which face of the Golgi apparatus receives vesicles from the Endoplasmic reticulum?

Answer 8

The cis face

Question 9

In which 2 ways can you differentiate the rough Endoplasmic reticulum from the smooth Endoplasmic reticulum?

Answer 9

Firstly, the rough Endoplasmic reticulum is associated with ribosomes while the smooth endoplasmic reticulum is not
Secondly, the rough Endoplasmic reticulum tends to be flat, while the smooth Endoplasmic reticulum tends to be tubular

Question 10

What 3 groups make up the hydrophilic head of a lipid? What bond joins them all?

Answer 10

A glycerol, phosphate, and choline group, held together by ester bonds

Question 11

List 2 functions of the plasma membrane.

Answer 11

• to transport molecules in and out of the cell

- for cell morphology (the cells form and structure)

Question 12

What prevents lysosomes from digesting themselves?

Answer 12

A specialised glycocalyx on the inner surface of their membrane

Question 13

What is the role of a peroxisome? Where are they abundant?

Answer 13

Peroxisomes oxidise unwanted molecules and hence detoxify certain areas of the body, notably the liver

Question 14

Do mitochondria contain their own genetic information?

Answer 14

Yes

Question 15

Are mitochondria inherited maternally or paternally?

Answer 15

They are maternally inherited

Question 16

How can you tell if a molecule is hydrophobic or hydrophilic?

Answer 16

A molecule will be hydrophilic is it has a lot of charged residues (through a dipole) while a hydrophobic molecule will have little/no hydrop-

Question 17

Are the genes in euchromatin expressed? How about the genes in heterochromatin?

Answer 17

The genes in euchromatin are expressed, while the genes in heterochromatin are not expressed

Question 18

What is the limit of resolution? What is it reversely proportional to?

Answer 18

The limit of resolution is the minimum distance at which 2 objects can be distinguished - it is inversely proportional to wavelength

Question 19

What does it mean if an image is unresolved? What does it mean if it is resolved?

Answer 19

If an image is resolved it can be seen as a distinct structure, while if it unresolved it will appear blurry and merge into the surrounding structures (it will not be distinct)

Question 20

Resolution is inversely proportional to wavelength. What does this mean?

Answer 20

As resolution increases, wavelength decreases

Question 21

When might there be no nuclear envelope surrounding the nucleus?

Answer 21

When a cell is dividing