Water and its importance Flashcards

1
Q

Structure of water

A

-polar molecule
-hydrogen bonds between water molecules as a result of dipoles formed by electronegativity
-individually weak, collectively strong

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2
Q

High specific heat capacity

A
  • Important in stabilising internal body temp as the environment changes
  • Keeping aquatic env. stable.

…to raise by 1 degree 1g of water

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3
Q

High latent heat of evaporation

A

-important in thermoregulation of mammals eg sweat

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4
Q

High cohesion between molcules

A

-important in transpiration stream and long continuous columns of H20 form in the xylem vessel
-Provides supportive role
-Mobility of aquatic animals

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5
Q

universal solvent

A

-important for polar molecules, ion transport, removing waste
-allowing chemical reactions to take place

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6
Q

Biofluids

A

-Intracellular eg. cytosol
-Extracellular eg fluid between cells

plasma, TF, lymph, serum, urine

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7
Q

Formation of lymph

A

excess tissue fluid drains back into the blood circulatory system via a network of lymph vessels

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8
Q

Composition of lymph

A

lymphocytes, small proteins, lipids, glucose (lower levels than plasma and TF), CO2 (higher levels than plasma and TF)

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9
Q

Role of lymph

A

-Important in immune response. Lymph nodes are where pathogens and foreign pathogens are filtered from lymph fluid and engulfed and destroyed

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10
Q

Urine

A

-Formed by kidney
-Ultrafiltration of blood followed by selective reabsorption
-Breakdown of excess amino acids and proteins, forms ammonia (highly toxic), then converts to urea which dissolves in water to form urine
-Urine removes urea, soluble waste products, excess water and ions

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11
Q

Serum

A

-Plasma with CF removed
-Contains antibodies, antigens, hormones, soluble proteins

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12
Q

Plasma

A

-straw-coloured mammalian biofluid
-Non cellular component of blood

-Water: transports dissolved substances, thermoregulation, regulation of blood pressure and volume

-Mineral ions: Osmotic balance, Ph buffering, regulation of membrane fluidity, eg calcium important in the clotting

-Plasma proteins (fibrinogen)

-Non cellular substances (digestion products, excretory products, hormones)

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13
Q

Functions of carbohydrates

A

SCEEM

Structural eg celulose
Cell markers eg receptors, antigens
Energy source eg glucose
Energy store eg. glycogen, starch
Macromolecules

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14
Q

Monosaccharides

A

-small soluble molecules
-eg. glucose, fructose, galactose
-glucose exists as linear and non linear
-Alpha glucose, beta glucose
-Difference, right-hand side. ABBA. OH group
-Glucose, fructose, galactose (identical to B glucose but left side=right side)

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15
Q

IMPORTANT

Structure of Monosaccharides

A

PAGE 47 BIBLE

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16
Q

Forming disaccharides

A

Joining 2 monosaccharides:
Condensation reactions makes glycosidic bond (1-4), and produces H20

Splitting a disaccharide
Hydrolysis, breaks glycosidic bond, addition of h20

glycosidic bond= type of covalent bond

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17
Q

Different disaccharides

A

alpha glucose + alpha glucose-> maltose + H20
alpha glucose + fructose -> sucrose + h20
alpha glucose + galactose-> lactose + h20

18
Q

Polysaccharide: glycogen

PAGE 49!!

A

-Liver and skeletal muscles
-Formed by many condensation reactions between many a.glucose

FUNCTION= Storage of Glucose and Energy

  • 1.4 glycosidic bond between adjacent a.glucose and at branching points, glycosidic bond formed at 1-6
19
Q

Properties of Glycogen:

A

-Insoluble= doesn’t affect water potential
-Compact= can store large quantities of glc in 1 location
-Chemically inactive= does not take part in cell metabolism

20
Q

Advantages of highly branched molecule:

A

-Many terminals ends for enzyme attachment for QUICK AND EASY addition or removal of glc

-Glc can be stored quickly
-More compact= takes up less space in cell

21
Q

Polysaccharide: starch

PAGE 50!!

A
  • Starch grains inside plant cells, seeds, storage organs.
  • Also acts as a temporary energy store in leaves when glc made faster than it can be stored or moved

-amylose and amylopectin
(both made of many a.glc joined by many condensation reactions= glycosidic bonds)

Amylose- linear, smaller, less easily digested, more compact. 30% of starch, insoluble
Amylopectin- highly branched, larger, easily digested, less compact. 70% of starch, soluble

22
Q

Reducing sugars

A

Sugars with ability to donate an e to another molecule. can reduce Cu2+ to Cu+

(glc, galactose, fructose, ribose)

23
Q

How to test for reducing sugar (glc)

A

-Add Benedict’s reagent
-Place the boiling tube in 90 degrees water bath for 10 mins
-Observe colour of ppt form and estimate quantity of reducing sugar present
-Blue, green, yellow, red, brown (most)

Reducing sugar (reduced) + Cu2+ (blue) > Reducing sugar (oxidised) + Cu+

ppt= CuO

24
Q

Benedicts reagent

A

Does not differentiate between reducing and non reducing sugars

Therefore, negative result initially only = no REDUCING SUGARS present

25
Making it more quantitive, filtration method
-React with excess Benedict's solution -filter to remove ppt -Air dry ppt -Weigh to constant mass -Amount of ppt is proportional to amount of reducing sugar present
26
Making it more quantitive, Colorimeter method
-Select the appropriate filter -zero colorimeter between readings -stir solution between readings -Filter and centrifuge to remove suspended material -put sample into cuvette and take transmission and absorbance value -Repeat and take colorimeter readings with known conc -Plot calibration curve
27
what is a biosensor
an analytical device that uses biological molecule to detect presence of a specific chemical molecule
28
Different types of biosensors for glc
-Clinistrips (Clinistix for glc in urine) Colour on test strip compared to colour charts -Glucometers (presence of glucose in blood
29
Testing for non-reducing sugars (sucrose)
If the benedicts test shows a negative result, should not assume no sugars are present (only means there are no RS present, but could still be NRS) -Add **HCl** -place in **100 degrees water bath for 5 mins** (Hcl hydrolyses glycosidic bond within disaccharide)... scr(NRS)-> glc + frc (both RS) -+ **sodium hydrogen carbonate** to neutralise -+ **Benedicts reagent** -If NRS present= brick red cloudy ppt -If it turns bright blue & clear= NO SUGARS PRESENT.
30
Testing for starch
**KI-I solution** Yellow-brown -> blue-black
31
Testing for proteins
-Biuret solution -Blue -> lilac
32
Testing for lipids
-Add Sudan III solution -If lipids present, top layer will will be bright red
33
Osmosis
Movement of water molecules from an area of higher water potential to an area of lower water potential down a water potential gradient across a partially permeable membrane Pure water= 0 kPa
34
Hypertonic solution
-higher number of solute molecules, so low water potential
35
Hypotonic
-lower number of solute molecules, so high water potential
36
Osmosis in erythrocytes
Rupture- cytolysed Shrink- crenated | -Pressure exerted on csm when water moves in-
37
Osmosis in plant cells
Cell wall, protoplast and central vacuole Same water potential- **incipient plasmolysis**>> protoplast isn't applying any pressure on the cell wall. Lower water potential- **flaccid**, protoplasm shrinks and pulls away from cell wall Higher water potential- **TURGID**= protoplasm exerts a force on cell wall as it inc in volume, cell wall does not rupture as cellulose is tough and inelastic. Prevents further h20 molecules from entering
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