Molecules

3 different groups:

1. Carboxylic acid group

2. Amino group

3. R Group/side chain 

'where two molecules are joined together by removing a H atom and a OH atom. These atoms then form a water molecule'                    ANABOLIC REACTION!

Condensation reactions --> creation of dipeptide:

amino acid + amino acid = dipeptide

Hydrogen atom from amino group of one amino acid is removed.

One hydrogen and one oxygen atom is removed from the carboxylic acid group of another amino acid.

H + O + H = H20

BONDS FORMED = PEPTIDE BONDS

MANY AMINO ACIDS = POLYPEPTIDE

GLOBULAR:

• Roughly spherical/globular in shape
• soluble in water
• biochemical functions

EXAMPLE: enzymes, haemoglobin

These are folded so that the R group is on the outside. R group = hydrophilic SO globular proteins = soluble in water based products (plasma,cytoplasm)

FIBROUS:

• polypeptide chains form long fibres or sheets
• insoluble in water
• structural functions

EXAMPLE: keratin, collagen

 1. Temperature

temperature increase = vibrations

large vibrations = breaking of weak bonds (hydrogen etc.)

this causes denaturation: the conformation of the protein is changed

OCCURS AT AROUND 45 DEGREES

2. pH value
pH concentration = concentration of the hydrogen atoms

hydrogen bonds depend on the attraction of H+ and O-

change in pH = change in attraction = hydrogen bonds break

HAEMOGLOBIN:

• 4 polypepetide chains
• each chain has a haem group attatched - a prosthetic group
• each heme group has iron ion in the middle
• iron ion binds with 1 oxygen molecule
• 4 IRON IONS = 4 OXYGEN MOLECULES ON EACH HAEMOGLOBIN MOLECULE

haem group receives oxygen atom --> haemoglobin molecule changes --> exposes next haem group to the oxygen

This makes it easier for oxygen to be picked up.

3 CONDITIONS:

1. Beta thalassaemia

• common in Greeks/Italians
• beta chains in haemoglobin shorter than normal = less oxygen carriage than normal

2. Diabetes

• blood glucose levels high as cannot be regulated normally
• glucose attatches to RBCs = glycosylated haemoglobin
• picks up oxygen well but does not let go easily
• organs and tissues receive less oxygen = damage
• EXAMPLE: diabetic retinopathy - blindness - blood vessels in eye lack oxygen and become damaged

3. Sickle cell anaemia

• valine instead of glutamic acid in haemoglobin
• haemoglobin chains are long and stiff = RBCs change shape
• RBCs become 'sickle' shaped and get stuck in capillaries
  

• Attracted to other water molecules

the negative charges of oxygen atoms attract the positive charges of hydrogen atoms; force of attraction between water molecules known as HYGROGEN BONDS

• Attracted to other polar molecules/molecules with a slight charge on the surface

the negative charge of oxygen molecules or positive charge of hydrogen molecules can attract to charges on other molecules

• Universal solvent and excellent transport medium 

many substances can dissolve in it; forms a shell around molecules, causing them to dissolve

• Polar molecule

areas of positive and negative charge

8 COMPONENTS:

1. water

2. proteins (firbinogen - blood clotting & antibodies - immune response)

3. ions (sodium, potassium etc.)

4. hormones (insulin, oestrogen etc.)

5. oxygen

6. dissolved food substances (amino acids, glucose etc.)

7. heat (carried in blood plasma)

8. waste products (urea, CO2 etc.)

SERUM = blood plasma - fibrinogen

This is used to treat patients in hospitals

TISSUE FLUID  = blood that has passed through capillaries

Capillaries are not permeable to most blood cells and large plasma proteins = don't pass thru

High blood pressure at arterial end of capillaries = small components in plasma are squeezed out

LYMPH =  tissue fluid that does not return to capillaries at venule end; must reach the lymphatic capillaries to be called lymph

lymph capillaries --> lymph vessels

contraction of muscles = fluid moves through lymph vessels

TRAVELS THROUGH, WITH VALVES TO PREVENT BACKFLOW, UNTIL IT REACHES THE BLOODSTREAM, WHERE IT IS RETURNED TO A VEIN IN THE NECK REGION.

'Movement of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient'

• PASSIVE - no extra energy required
• occurs until there is an even distribution
  

molecules can diffuse across plasma membrane through phospholipid bilayer

WHEN IS IT NEEDED?

• when molecules are soluble in water
• when molecules are charged (ions etc.)

this means they cannot diffuse through phospholipid bilayer

SO FACILITATED DIFFUSION IS USED...   'diffusion helped by proteins'

USING

• Protein channels 

some are lined with hydrophilic amino acids and water; some permanently open

• carrier proteins

molecules bind to --> protein changes shape, releasing molecule on other side

• no additional energy - PASSIVE PROCESS

'the movement of water molecules from a region of high water potential to a region of lower water potential across a semi-permeable membrane'

Water potential = tendancy of a solution to gain or lose water (PURE WATER = 0)

water + solute = water potential decrease

THIS OCCURS UNTIL EQUILIBRIUM IS REACHED (EVEN DISTRIBUTION)

THE 'TONICS

1. Isotonic - solution and cell have equal water potential

2. Hypertonic- cell has higher water potential than solution

3. Hypotonic - cell has lower water potential than solution

water is small = fits through the phosholipids in the phospholipid bilayer =  all membranes permeable to water to a degree

electrolyte = ions with + or - charge

+ charge = cations

- charge = anions

electrolytes are responsible for maintaining water potential

BUT SOLUTES - LIKE GLUCOSE - CAN DISSOLVE IN BLOOD PLASMA AND LOWER W.P

When testing electrolytes, measure:

sodium, potassium, chloride, bicarbonate, calcium, magnesium, phosphate ions

ENDOCYTOSIS:

taking molecules in

EXOCYTOSIS:

releasing molecules

EXAMPLE:

neutrophils engulf pathogens by phagocytosis, a type of endocytosis --> after digestion, the waste materials are released back out of the leucocyte by exocytosis

• is taken into cells by endocytosis
• transported through the blood attatched to proteins as it is non-polar
• in the form of lipoprotein particles (low density lipoproteins LDPs)
• LDLs bind to proteins which are taken into the cells themselves

• contain test ***** with either glucose dehydrogenase or glucose oxidase
• these enzymes turn the glucose in blood into gluconolactone
• gluconolactone gives off electrical impulse that is detected by meter

1. wash hands throughly

2. swab hands with alcohol-based solution

3. ***** the top of the finger with a sterile lancet

4. place a small drop of blood on the glucose test *****

5. reading appears in 15 - 30 seconds

3 TYPES

1. Monosaccharies

• simple sugars
• GLUCOSE - repsiratory substrate, broken down easily by repsiration; soluble so transported in blood plasma

2. Disaccharides

• 2 monosaccharides
• GLUCOSE + GLUCOSE --> MALTOSE in condensatino reaction, forming glycosidic links (type of bond)

3. Polysaccharides

• many monosaccharides joined by condensation reaction
• many alpha glucose --> glycogen
• glucose residue + 3 glucose molecules = branched molecule

• stored in liver and muscle cells
• insoluble so doesn't dissolve in cytoplasm etc. and affect water potential
• compact so a lot can fit in a small space
• branched molecule so many areas where glucose can be released at a fast rate when needed

  Fats and Oils

  • are types of triglycerides

  TRIGLYCERIDE = 3 fatty acids + glycerol molecule (condensation reaction)

  FATTY ACID = hydrocarbon chain + carboxylic acid group

  AND FATTY ACID STUCTURE PIC

  

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