topic 2. 1-7

Metabolic rate

Rate at which metabolism (biochemical reactions) occur in an organism

Lumen

Inner open space or cavity of a tubular organ, such as a blood vessel or an intestine

Gas exchange air flow

Air - nose - nasal cavity - trachea - bronchi - bronchioles - alveoli - capillaries

Trachea structure

• Lined by ciliated epithelium

• Supported by c-shaped rings of cartilage to prevent collapse and allow food to pass down the oesophagus behind trachea

Bronchi structure

• lined with ciliated epithelium

• Supported by C shaped rings of cartilage to prevent collapse

Bronchioles structure

• lined by ciliated epithelium

• Compromised of smooth muscle and elastic fibres

Alveoli structure

• Alveoli surfaces moist as oxygen has to be dissolved in water to move across membrane

• Alveoli walls made up of squamous cells that are one cell thick

• Alevoli walls contain elastic fibres that stretch and recoil during respiration

• Large difference in concentration

Primary structure of a protein

• sequence of amino acids linked together by peptide bonds

Secondary structure of a protein

• weak hydrogen bonds form between the negative oxygen of the c=o group and the positive hydrogen of the nh group

• the hydrogen bonds cause a regular 3D shape (like an alpha helix or b pleated sheet)

Tertiary structure

• the conformational change of secondary structure leads to additional bonds between different parts of the polypeptide chain

• the bonds are: hydrogen, disulphide and ionic bonds

• the new bonds cause it to fold into a more complex 3D structure

Quaternary structure

• 3D arrangement of more than one polyptode

Fibrous proteins

• long parallel polypeptides

• Insoluble due to hydrophobic R groups

• Used for structure and support

• Hydrogen bonds between the chains

• Example: collagen

Globular proteins

• fold into a 3D spherical structure

• Soluble due to hydrophilic R groups

• Example: insulin

Globular protein (conjugated)

• Conjugated proteins contain a non protein component called a prosthetic group

• Soluble

• Example: haemoglobin

Glycoprotein

A group of proteins which have carbohydrate groups attached to a polypeptide chain

Functions of the plasma membrane

• form a barrier between cell and external environment

• Controls movement in and out the cell

• Isolates organelles from the rest of the cytoplasm allowing cellular processes to occur separately

• Cell signalling

• Allows cell to change shape

Why are some molecules hydrophobic and some hydrophilic

In phospholipids the phosphate group is polar, therefore one end is slightly positive and the rest is negative.

Therefore it attracts other polar molecules - it is hydrophilic

Label diagram

Properties of phospholipid bilayer

Membrane is fluid meaning Proteins are not fused and parts of the membrane can easily break away to form vesicles, or new cell surface membranes

Simple diffusion

Net movement of molecules of ions from a region of high concentration to low concentration

Facilitated diffusion

Movement of molecules often lower down their conc. gradient through membrane proteins w/o using energy

Osmosis

movement of water from a high concentration to a low concentration

Movement of water from a low solute concentration to a high solute concentration

Active transport

Movement of molecules/ions against a conc gradient

Exocytosis

• involves vesicles (small membrane bound sacs) fusing with the cell surface membrane to release their contents outside the cell

Endocytosis

• cell engulfs substances by folding its membrane to form a vesicle

Beetroot practical (Temp)

• beetroot cubes already cut

• Left overnight to wash away excess dye

• Place 8 labelled boiling tubes each containing 5cm distilled water into water bath at temperature (0-70 degrees), leave for 5 minutes

• Add a beetroot cubes to each tube and leave for 15 minutes

• Decant liquid into second boiling tubes and shake the boiling tube

• Set up the colorimeter using a cuvette containing distilled water, to put the absorbance to 0

• Using the Pipette take out 2cm of dye solution from the boiling tubes

• Take a reading for each dyes absorbance

beetroot practical alcohol

• beetroot cubes already cut

• Left overnight to wash away excess dye

• Place one beetroot section into each of 8 labelled boiling tubes. The tubes contain 0-70% alcohol concentration

• leave for 15 minutes

• Decant liquid into second boiling tubes and shake the boiling tube

• Set up the colorimeter using a cuvette containing distilled water, to put the absorbance to 0

• Using the Pipette take out 2cm of dye solution from the boiling tubes

• Take a reading for each dyes absorbance

Osmosis definition

• movement of free water molecules through a partially permeable membrane from an area of low solute concentration to an area of high solute concentration

Passive transport

Not requiring energy

Types:simple diffusion and facilitated diffusion

Simple diffusion

Movement of molecules down the conc gradient. Small non-polar molecules diffuse across the membrane easily, larger molecules diffuse slower.

Facilitated diffusion

Diffusion of molecules across membrane via channel proteins or carrier proteins embedded in the membrane, molecules move down the concentration gradient

Active transport

Movement of molecules against the concentration gradient using carrier proteins and ATP as a source of energy

Exocytosis

• involves vesicles (small membrane-bound sacs) fusing with the cell surface membrane to release their contents outside the cell

Endocytosis

• cell engulfs substances by folding its membrane to form a vesicle

Explain why mutations in the CFTR channel protein result in thicker mucus.

1. CFTR is absent or non-functional.

2. Na+ channel is permanently open

3. Cl- diffuse down electrical gradient into the tissue fluid

4. Water is continuously removed from mucus by osmosis - MUCUS BECOMES DRY + STICKY.

Mono-nucleotide structure

• a pentose sugar - deoxyribose (DNA) or ribose (RNA)

• A phosphate group

• An organic base: T,C,G,A (DNA) OR U,C,G,A (RNA)

Pyrimidines

C AND T (U - RNA)

PURINES

A AND G