Lecture 1 - Principles of cell function Flashcards

1
Q

2 types of cells

A

Prokaryotic (Bacterial)
Eukaryotic (Animal)

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2
Q

5 unique features of a prokaryotic cell

A

Flagella
Pili
Cell Wall
Capsule
Endospores

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3
Q

What is the flagella?

A

Antennae of bacterial cell - tries to gauge external environment (is there something near that is important for nutrition purposes)

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4
Q

What is the pili?

A

The “hairs” that allow bacterial cells to attach to membranes to cause infection

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5
Q

Cell wall

A

Very thick

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6
Q

Role of Capsule

A

Prevents cell from drying out

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7
Q

Endospores are where, what, for? resistant to?

A

Within the cell wall
Walls very thick
For survival under harsh conditions
Resistant to various degrees to heat, desiccation (removal of moisture), freezing, toxic chemicals

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8
Q

Eukaryotic cells have no…

A

Pili, capsule

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9
Q

Eukaryotic cells have a

A

Well defined nucleus - contains nucleolus
Cytoplasm - number of organelles

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10
Q

DORA: Prokaryotes

A

D (DNA): DNA is naked, circular
O (Organelles): No nucleus, no membrane-bound
R (reproduction): Binary fission, single chromosome (haploid)
A (Average size): Smaller

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11
Q

What is binary fission?

A

Asexual reproduction where 1organism becomes 2, 2 becomes 4 and so forth

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12
Q

DORA Eukaryotes

A

D (DNA): DNA is bound to protein, linear
O (Organelles): Has a nucleus, membrane-bound, 80s ribosomes
R (Reproduction): Mitosis and meiosis, chromosomes paired (diploid or more)
A (Average size): Larger

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13
Q

In mitosis, daughter cells have … number of chromosomes as parent

A

Same

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14
Q

In meiosis, what happens with the cell?

A

Divides cell in 2 - 23 chromosomes each

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15
Q

DIfferent names for a membrane

A

Cell membrane, cytoplasmic membrane, plasmalemma, phospholipid bilayer, lipid bilayer

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16
Q

Cells are …permeable

A

semipermeable
if it wasn’t, anything could come in or out. only certain molecules are allowed in

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17
Q

Cells have the ability to…

A

Engulf

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18
Q

Another word for when a cell uses its plasma membrane to engulf a large particle

A

Phagocytosis

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19
Q

Interface of cells is between what kind of environments

A

Internal and external

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20
Q

3 Functions of the boundary in a membrane

A
  1. keeps nutrients in the cell,
  2. helps retain transported substances - useful substances are kept within the cell for use
  3. Excretion of unwanted substances
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21
Q

Interface between the environments

A

Cells respond to changes in the environment
Receptors help identify substances needed by the cell
Then, secretion of hormones or neurotransmitters

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22
Q

2 Major plasma membrane functions

A
  1. Receptors that have specific domains on it means only a certain molecule can attach on it e.g. if a mutation on the insulin receptors occur, the receptor may not be able to detect the insulin
  2. Anchors - hold certain proteins e.g. can trap mitochondria to cell membrane for energy purposes.
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23
Q

The cell membrane contains … that has a hydrophilic and hydrophobic part

A

Phospholipid bilayer

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24
Q

The reason why phospholipids have a hydrophilic and hydrophobic part to it is because…

A

Phospholipids

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25
Q

What is the protoplasm?

A

The cytoplasm and nucleus

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26
Q

The 2 faces/surfaces of the membrane

A

Protoplasm surface, face (P-face)
External surface, face (E-face)

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27
Q

The p-face and e-face contain what?

A

The intra-membranous particles that are proteins

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28
Q

Differences between the e-face or p-face and the e-surface or p-surface

A

The outside part of the cell membrane is the e-surface. It is hydrophilic
The inner part of a cell membrane when “unzipped” is the e-face. It is hydrophobic
P-face and e-face contain intramembraneous particles that are proteins

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29
Q

The cell membrane has 2 specific features - 2 dark lines and then a transparent zone in between them. What are these called?

A

The 2 dark lines are called the electron dense.
The transparent zone is called the electron lucid gap

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30
Q

Since the outsides of the cell membrane are hydrophilic, does a molecule that is soluble in water easily in water move freely into the cell?

A

Yes but since the e-face and p-face are hydrophobic, they will determine whether the entered molecule is important. If so, it will let it through. If not, it will repel it away.

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31
Q

Fluid mosaic model

A

States that membrane proteins are highly mobile - wherever the need for protein is, it can move there in 3 dimensions.

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32
Q

Many proteins are:

A

Glycoproteins (a component of glucose and protein)

33
Q

What are amphipathic molecules

A

Those that are both hydrophilic and hydrophobic

34
Q

A typical cell membrane is composed of:

A

Lipids and proteins in equal amounts

35
Q

3 major types of lipids/proteins that you find in the cell membrane

A
  1. Phospholipids,
  2. Cholesterol
  3. Glycolipids
36
Q

Phospholipids, Cholesterol and Glycolipids are

A

Amphipathic

37
Q

Do red blood cells have high or low glycolipids

A

Low

38
Q

Do myelin sheath cells have high or low glycolipids

A

High

39
Q

Why do RBC’s have low glycolipids

A

Their function is to carry a lot of oxygen so if theres a lot of glycolipids it will take more effort to move and will be slower. Also, you want to have more hydrophilic molecules in the membrane as it easier for diffusion into cell.

40
Q

Why is cholesterol important

A

It increases stability and prevents loss of membrane liquidity at a low degree.
It is less likely to be affected by significant changes in temperature. This is important since a change of 1 or 2 degrees can be very dangerous

41
Q

50% of the plasma membrane is:

A

non-aqueous - used for transport receptors and anchoring sites
Hence, it is easier to move through here since it is ampipathic

42
Q

Another name for RBC

A

Erythrocyte

43
Q

2 main membrane transport mechanisms of Band 3 protein

A

Ion transport
Maintenance of protein to protein interactions

44
Q

Under normal circumstances, sodium is… whereas potassium is…

A

Sodium is outside, potassium is inside

45
Q

During action potential, Na moves… and K moves…

A

Na moves inside, K moves outside

46
Q

Protein inside cell membrane does what during action potential

A

The protein inside the membrane pulls sodium in and pushes potassium out. This protein has electrochemical difference that allows it to do this.

47
Q

What is the role of glycolipids?

A

They identify cells

48
Q

Role of Band 3 protein

A

Ensuring that chloride goes into the cell, bicarbonate goes out (ANTIPORTER)

49
Q

3 methods of transporting large substances

A
  1. Exocytosis - exits e.g. adrenaline around the body
  2. Endocytosis - inside of us
  3. Phagocytosis - bacteria engulfing
50
Q

Fluid ingestion is called?

A

Pinocytosis

51
Q

When a cell secretes something and it only affects itself, the form of chemical signalling is called?

A

Autocrine response

52
Q

When a cell secretes something and activates another cell in the vicinity, it is called a

A

Paracrine response

53
Q

When a cell secretes something and affects another cell far and wide within the body, it is called a

A

Endocrine response

54
Q

Process of getting insulin into cell

A

The insulin receptors activates the GLUT-4 receptor which leads to the absorption of glucose into the cell

55
Q

An absence of the GLUT-4 receptor leads to what disease?

A

Diabetes

56
Q

5 types of transports of substances across cell membranes

A
  1. Passive diffusion - e.g. water
  2. Facilitated diffusion e.g. GLUT-4
  3. Selective facilitated diffusion e..g GLUT-4 only allow glucose to move through them
  4. Primary active transport - Sodium and potassium causing ATP (energy)
  5. Secondary active transport - Antiporter transport e.g. Band 3 protein
57
Q

Movement of substance through diffusion is done by what

A

down concentration gradient (from a high concentration of a substance to low)

58
Q

Does diffusion occur across cell plasma membranes?

A

Not necessarily

59
Q

Does diffusion require energy?

A

No (passive transport)

60
Q

Examples of diffusion

A

Diffusion of oxygen from the alveolus into blood capillaries

61
Q

Movement of substance through osmosis

A

Down concentration gradient

62
Q

Does osmosis occur across cell plasma membrane

A

Yes

63
Q

Does osmosis require energy

A

No (passive transport)

64
Q

Example of osmosis

A

Uptake of water by the root hair from the soil

65
Q

Examples of substances used in active transport

A

Mineral ions, glucose, amino acids

66
Q

Movement of substance through active transport

A

Against concentration gradient (low concentration to high concentration)

67
Q

Does active transport occur across cell plasma membrane

A

Yes

68
Q

Does active transport require energy

A

Yes

69
Q

Example of active transport

A

Reabsorption of glucose into the kidney

70
Q

What is osmolarity

A

Total solute concentration within a specific volume of a solvent.
Number of osmoles of solute per litre
Measured in osmoles per litre (Osm/L)

71
Q

Osmolality

A

Number of osmoles of solute per kilogram of solvent

72
Q

What’s an osmole

A

number of moles of a solute that contributes to the osmotic pressure of a solution

73
Q

What are osmotically active substances

A

Substances that cause the movement of water across a membrane

74
Q

Examples of osmotically active particles in biological systems

A

Ions e.g. Na - wherever sodium goes, water follows
Small molecules - glucose
Proteins - Albumin
Other organic molecules

75
Q

Examples of osmotically active particles in clinical solutions

A

Saline solution (NaCl)
Dextrose solution (Glucose)
Ringer’s lactate (various electrolytes including lactate)

76
Q

If osmolarity is equal to the molarity of glucose into a solution, glucose does not…

A

dissociate in a solution. hence, in a solution of 100mM of glucose, its osmolarity is 100mOsm/L

77
Q

NaCl dissociates into:

A

Na+ and Cl-. Because of this, in a solution of 150mM of NaCl, its osmolarity increases to 300 mOsm/L since both sodium and chloride have 150mM each. THIS IS AN ISOTONIC SOLUTION - NO WATER
This is why energy drinks with NaCl in them will hydrate you more since the body’s natural osmolarity is 275- 295 mOsm/L

78
Q

3 types of solution

A

Isotonic: no net movement of water
Hypotonic: water enters cell
Hypertonic: water leaves cell - leaves spikes leading to cells getting caught and causing a clot.