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102, theme 3 > Molecular Cell Biology > Flashcards

Molecular Cell Biology Flashcards

1
Q

Biomarkers

A

A naturally occurring molecule, gene, or characteristic by which a particular pathological or physiological process or disease, can be identified

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2
Q

C-Reactive Protein (CRP)

A
  • Measure of inflammation

- CRP is a general marker so isn’t useful for precise diagnosis

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3
Q

Anti Citrillunated Peptide Antibody

A
  • Used to help diagnose rheumatoid arthritis

- ACPA is more definitive 95% of people who have it also have RA

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4
Q

Disease Specific Biomarker

- Uses

A
  • Diagnose disease
  • Monitor disease progression
  • Predict response of treatment
  • Prognostic - E.g. breast cancer and BRCA1 gene mutation
    • Low risk
    • High risk
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5
Q

Define Translational Research w Example

A

Translational medicine is an effort to build on basic scientific research to create new therapies, medical procedures, or diagnostics.
*Example: Ab block of TNF was thought to treat rheumatoid arthritis.

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6
Q

Define Stratified Medicine. 4 categories, explain use in practice.

A

Making sure you’re treating the patient with the correct medicines. based on genetic and epigenetic makeup.

Benefit + No Toxicity
Benefit + Toxicity
No Benefit + No Toxicity
No Benefit + Toxicity

  • Depends on severity of disease and if benefits outweigh the risks, e.g. if indigestion tablets work but causes adverse reaction then it isn’t feasible.
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7
Q

Example of Stratified Medicine in Practice.

A

Breast cancer has many different biomarkers which can affect treatment.

  • Estrogen receptor ER+ patients are treated with Tamoxifen
  • HER2+ patients can be given herceptin
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8
Q

Cetuximab and K-RAS mutation

A

Cetuximab inhibits K-RAS which stops enzyme cascade leading to proliferation. A mutation in K-RAS allows it to evade the effects of the drug. Drug only works if the K-RAS gene is normal.

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9
Q

Personalised Medicine

A

Medical care in which the treatment is customised for an individual patient

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10
Q

CAR T-cell therapy mechanism

A

T-cells isolated via leukophoresis from patient with cancer. Introduce a gene into a lentivirus which causes it to present the antigen which is present on the cancer. they then expand T-cells up which respond to the cancer then it is administered to the patient. the T-cells go round and fight the cancer in the body

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11
Q

Gene Therapy: SCID.

  • What is SCID?
  • Why would it work?
  • Treatment (Old and New)
A

Severe combined immunodeficiency.
-Rare inherited diseases where children are born with defective immune systems due to a gene mutation.
-It would work because it is a monogenetic defect so it is easier to correct.
-Old: Bone marrow transplants from donor, risk of rejection and latent viruses
New: take stem cells from Bone marrow and GM them using a virus then reimplant them

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12
Q

Differences between eukaryotic & prokaryotic cells

A 
Euk/Prok
size - 5microm/1-5microm
nucleus - Yes/No
Organelles - Yes/No
Chromatin - Yes/No
Cell wall - No(except plants)/ Yes
Chloroplasts - Plants/ Some
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13
Q

Features of an animal cell with function

A

Nucleus - contains DNA in the form of chromatin.
Nucleolus - makes rRNA within the nucleus.
Mitochondria - makes energy
Endoplasmic reticulum - RER has ribosomes for protein synthesis
Golgi - involved in secretion
Intermediate Filament - involved in structure
Microtubule - Structure of the cell, part of cytoskeleton originate from centrosomes which are involved in cell division

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14
Q

Cell Membrane features

A
  • Phospholipids
  • Cholesterol
  • Membrane Proteins
  • Glycolipids (binding sites and cell specificity)
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15
Q

Functions of the membrane

A
  • Define the boundary of the cell
  • Regulate transport of solutes
  • Mediate cell communication
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16
Q

What are Phospholipids made of

A
  • Polar head
  • Non polar hydrophobic tail
    -Phosphate forms the head which can be attached to an R group.
    the bend in the tail is important for its function in the membrane.
17
Q

What affects the fluidity of the membrane?

A
  • % of cholesterol

- How many bends in the hydrophobic tails

18
Q

Permeability of the membrane

  • Permeable
  • Impermeable
  • Semi-permeable
A

Permeable
- Gases
- Small uncharged polar molecules (Ethanol)
Semi-permeable
- Water
- Urea
Impermeable
- Large uncharged polar molecules (glucose)
- Ions
- Charged polar molecules (protein, aa, ATP)

19
Q

Types of integral membrane proteins

A
  • Transporters
  • Anchors
  • Receptors
  • Enzyme
20
Q

Types of Transporters and functions

A

Channel proteins - passive diffusion down conc gradient
Transporter mediated - for larger molecules
Active transport - uses energy to pump against conc gradient

21
Q

Mitochondria - function and structure

A
  • Function
    to produce energy for the cell via ATP generation.
  • Structure
    Permeable outer membrane
    Less permeable inner membrane folded into cristae
    Inside the inner membrane is the Matrix
22
Q

How does the mitochondria make ATP?

A
  • Pump is driving H+ into the intermembrane space forming a strong proton motive force which then drive the ATP synthase which is the turbine generating ATP from ADP and Phosphate
23
Q

Golgi Apparatus function

A

modification, packaging and sorting proteins ready for secretion or for another organelle.

24
Q

Lysosomes and peroxisomes

what are they and what’s their function?

A

Lysosomes
-Small irregular cytoplasmic vesicles
-Packed with degradative enzymes
-Principal sites of intracellular digestion
=
Peroxisomes
-Small cytoplasmic vesicles
-Contained environment for reactive H2O2 generation
-The main function of the oxidation reactions is the breakdown of fatty acids
-Detoxify toxic substances such as ethanol (via catalase)

25
Q

Cytoskeleton- functions

A

-Pulls the chromosomes apart during mitosis
-Drives and guides the intracellular traffic of organelles, proteins and RNA
-Supports the plasma membrane
-Enables some cells to move
controls cell shape

26
Q

Three major components of the cytoskeleton

A

Microtubules -
20 nm diameter
Polymers of tubulin dimers
Organised from structures such as the centrosome
Form the spindle in mitosis
Important in cell shape and movement
Carry cargo-bearing motor proteins
=
Intermediate filaments -
10 nm diameter filaments
Made of a family of fibrous proteins;
keratin filaments in epithelial cells,
vimentin in many other cells,
neurofilament proteins in neurones,
lamins within the nucleus.
Twisted into ropes and provide tensile strength
Needed to maintain cell shape
=
Actin filaments - 7nm small, essential for movement, involved in moving proteins.
Can form contractile bundles and microvilli
May associate with myosin to form powerful contractile structures
Carry cargo-bearing motor proteins (e.g. myosin)

27
Q

Which proteins are responsible for the movement of cargo across the microtubule tracts

A

Dyneins towards minus end (nucleus)

Kinesins towards + end (cell membrane)

28
Q

Stem cells - characteristics

A
  • Not terminally differentiated cells
  • immortal cells
  • Daughter cells have choice to remain stem or to differentiate
  • Found where there is high turnover of cells
  • Commonly occur at stem cell niches, this is important as the further the cell from the niche the more differentiated it is.
29
Q

Embryonic stem cells - totipotent and pluripotent

Adult stem cells

A

Totipotent cells- can differentiate into any type of cell of the body plus the placenta and form an organism.
pluripotent can form any cell in the body
=
Multipotent cells - can differentiate into different types of cell but of one cell lineage/ tissue type

30
Q

Gut adult stem cells

A
  • epithelial cells must be replaced frequently
  • the pit of the crypt has stem cells that are constantly generating more cells
  • replenishes the gut epithelium
31
Q

other examples of stem cells

A

Skin and Haematopoetic.

32
Q

Induced Pluripotent stem cells.

Adv vs Dis

A

Despecialise skin cells to make them pluripotent then specialise them

Advantages
-Cells taken from patient should not elicit immune response
-Fewer ethical issues
-Theoretically, any cell type could be replaced
=
Disadvantages
-More basic research needs to be done on developmental pathways
-Transplanted stem cells could develop into cancer cells

33
Q

Necrosis vs Apoptosis

A

Apoptosis (or programmed cell death) is the normal pathway. Signalling processes within the cell activate intracellular suicide proteases. These:
- Degrade intracellular structures and organelles
- Collapse the cytoskeleton
- Fragment the cell into mini-cells, which are engulfed by phagocytes for degradation.
** Apoptosis is neat and doesnt affect surrounding cells
=
Necrosis
this is uncontrolled cell death which results in lysis of the cell releasing toxic enzymes to neighbouring cells.

102, theme 3 (13 decks)

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