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Flashcards in Cell Basics Deck (31)
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1
Q

How heavy is the average human?

A

70Kg

2
Q

How much of us is water?

A

60%

3
Q

How much of the water in our body is extracellular?

A

1/3

4
Q

How many litres of interstitial water are there in an average human?

A

11l

5
Q

How many litres of blood does the average human have?

A

3l plasma +2 l blood cells=5l

6
Q

What is the resting heart rate?

A

70bpm

7
Q

What is the cardiac output at rest?

A

70ml

8
Q

How much blood passes through the heart in 1 min?

A

70ml/beat * 70 bpm = 4900ml/min = 5l

Therefore the total blood volume circulates once per minute

9
Q

What does haematoxylin do?

A

Stains nuclei

10
Q

What does eosin do?

A

Stains cytoplasm and extracellular matrix

11
Q

How does autoradiography work?

A

Molecules are labelled with a radioactive marker eg.monoclonal antibodies. These are then injected into the patient and wherever the molecules bind onto cells or are taken up will be shown on x-ray.

12
Q

What is the relationship between wavelength, frequency, energy and penetration and hence resolution in ultrasound?

A

Shorter wavelength means higher frequency so more energy and good resolution .

13
Q

How does transmission electron microscopy work?

A

Uses an electron beam generated in a vacuum
Shorter wavelength than light so higher resolution
Electron beam passes through the tissue - the portions which the beam have passed through appear bright, those which the tissue has absorbed or scattered appear dark.

14
Q

How are samples prepared for TEM?

A

Fix with glutaraldehyde
Embed in epoxy resin
Stain (osmium tetroxide)
Use microtome with diamond knives

15
Q

What needs to stay constant in the internal environment?

A
O2, CO2, Na+, K+, Cl-, Ca2+
Glucose, urea
 PH
Temp
Volume and pressure
16
Q

What is the difference between necrosis and apoptosis?

A

Necrosis- death of cells due to trauma- cell membrane ruptures and cell bursts as water rushes in

Apoptosis- programmed cell death due to DNA damage or other- initiated by kinases

17
Q

What is osmolality?

A

Moles/l-
Write as Osm/L
If sodium chloride - two ions present so double final answer

18
Q

What is normal plasma osmolality?

A

290mOsmol/Kg

19
Q

What is the most common protein found in the blood ?

A

Albumin

20
Q

Why don’t cells burst due to their intracellular proteins?

A

Sodium/potassium ATPase pumps 3 sodium out and 2 potassium in leading to a net loss of osmotically active ions so balances out effect of proteins.
This causes cells to have a membrane potential of -70mV

21
Q

When can intracellular potassium become life threatening?

A

More potassium present in ECF
Therefore lesser diffusion gradient for potassium out of cell so more remains inside cell making it more positive
This raises the membrane potential- voltage gated sodium channels activate and cannot reprime as not negative enough- this causes reduced opening of channels during action potential so membrane potential rises less- may not reach threshold
=no action potential- in heart this causes MI

22
Q

What is physiological pH?

A

7.4

23
Q

How are cells attached to each other?

A

Desmosomes, adherens junctions, occluding junctions

24
Q

How are cells attached to the basement membrane?

A

Focal adhesions, hemidesmosomes

25
Q

What makes up a hemidesmosome?

A

Integrins attach to basement membrane

26
Q

What are focal adhesions?

A

They have actin filaments and integrins which anchor the cell to the extracellular matrix and allow cell migration

27
Q

What is the function of integrins?

A

Attachment of cell to ECM

Signal transduction from ECM to the cell

28
Q

What chemical is used to separate cells?

A

Collagenase

29
Q

How do cultured cells behave differently to those in the body?

A

Stop growing, senescence

30
Q

What are the different ways cells can communicate with one another?

A
Autocrine-to self
Paracrine- to others
Endocrine-secrete into blood
Neurocrine-synapse secretes into blood
Synaptic transmission
31
Q

How are prokaryotic cells different?

A
Pili
Plasmids
No membrane bound organelles
Capsule
Nuceloid circular DNA