Edexcel AS Biology - Topic 2 - Genes + Health Notes

Complete notes for Edexcel biology at A level.

HideShow resource information
  • Created by: Einstein
  • Created on: 18-02-13 19:19
Preview of Edexcel AS Biology - Topic 2 - Genes + Health Notes

First 109 words of the document:

Organs affected by cystic fibrosis:
Sinusitis (infection)
Thick, sticky mucus build up, bacterial infection and widened airways
Sweat glands produce salty sweat
Blocked biliary ducts
Blocked pancreatic ducts
Cannot fully absorb nutrients
Reproductive organs
(male and female) complications
Order in which air flows through the lungs:
1. Nasal/oral cavity
2. Pharynx
3. Larynx
4. Trachea
5. Bronchus
6. Bronchioles
7. Alveoli
Adaption's for gas exchange:
Millions of tiny alveoli
Alveolus are folded to increase surface area
Very good blood supply

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Net movement of molecules from an area of a high concentration to a area of low
concentration across a partially permeable membrane
Due to the random movement of molecules
The molecules move down their concentration gradient
Until dynamic equilibrium is reached
Protein structure:
There are 20 different R groups
There are 20 different amino acids
Hydrophilic (water attracting)
Hydrophobic (water repelling)
Non ­ polar
They are joined by condensation reactions and broken by hydrolysis
They form peptide bonds…read more

Page 3

Preview of page 3

Here's a taster:

A chain of amino acids is a polypeptide chain
The 4 structures:
Fick's Law:
Membrane structure:
Main component of a membrane
Phosphate head…read more

Page 4

Preview of page 4

Here's a taster:

Lipid tail
does not interact with water
not attracted to polar water
Cell membrane
arranged into a bilayer 7nm thick
aqueous solution on either side maintains the
Fluid mosaic model:
phospholipids always moving
proteins are studded on its surface
helps maintain fluidity and permeability of the phospholipid bilayer
integral proteins that often have an attached carbohydrate
carbohydrates on the membrane surface may also have a lipid component
Both are used for:
cell signalling
cell recognition
channels/pores…read more

Page 5

Preview of page 5

Here's a taster:

Simple diffusion
Net movement of molecules from an area of high concentration to an area of low
concentration across a partially permeable membrane.
continues until dynamic equilibrium
small uncharged molecules fit between phospholipids
Facilitated diffusion
Still molecules moving down their concentration gradient
using proteins to transport polar molecules across membrane
Either channel or carrier proteins
Net movement of water molecules from a solution with a low concentration
to a solution with a higher concentration through a partially permeable
membrane.…read more

Page 6

Preview of page 6

Here's a taster:

has same concentration as cell
looses same amount as it gains
higher solute concentration
loses more water than it gains
has a lower solute concentration
gains more water than it loses
Active transport
pumping molecules along their concentration gradient
requires carrier protein, energy ATP
into the cell
membrane engulfs substance and takes vesicle into the cytoplasm
Phagocytosis (larger molecules/organisms)
Pinocytosis (smaller, soluble molecules)
Exocytosis…read more

Page 7

Preview of page 7

Here's a taster:

The body works by chemicals reacting together.…read more

Page 8

Preview of page 8

Here's a taster:

Proteins are GLOBULAR
They have a TERTIARY structure
The active site of an enzyme:
· Specific region on the enzyme
· That allows only one substrate to bind to it:
­ Complementary fit
How enzymes catalyze reactions:
1. The specific substrate with the complementary shape collides with the active site
of an enzyme
2. Enzymesubstrate complex is formed
3. Lowers the activation energy and reaction proceeds
4.…read more

Page 9

Preview of page 9

Here's a taster:

Induced fit
­ Active site is not rigid
­ Once substrate collides with active site
­ Active site changes shape
­ Reduces the activation energy needed.…read more

Page 10

Preview of page 10

Here's a taster:

T + C have single rings (pyrimidines)
Genes act as the code for protein synthesis
· All of the genes in an individual make up its genome
· 2 strands of DNA (deoxyribonucleic acid) twisted to form a double helix
­ They rung in opposite directions, called antiparallel strands.…read more


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all resources »