in nucleotides, what components contain carbon
- nitrogen containing bases
what is the role of cholesterol
-binds to phospholipids fatty acid tails, increasing packing of membrane thus reducing the fluidity of the membrane.
why do single celled organisms not need a specialised surface for gaseous exchange
- it has a short diffusion pathway- easy for gasses to diffuse in and out
describe the structure of the plasma membrane
-primarily made of phospholipid bilayer that contains proteins. hydropho9bic tails face inwards and hydrophilic heads face outwards. cholesterol bound to fatty acid tails. Extrinsic and intrinsic proteins present. Glycoproteins stick out the bilayer.
why are different enzymes involved in different processes
enzymes are SPECIFIC and the substrates have diff shapes. the active site and a substrate have to be complimentary to form ESC.
what forms enzyme product complex
destabilizing of bonds
what improves reliability
-repeating experiment
explain the induced fit hypothesis
what is the detailed structure of cells visible with only an electron microscope
ultrastructure
what do xylem vessels contain
lignin
2 types of cells found in phloem tissue
-companion cells and sieve tube elements
how to see amino acids in chromatography
spray with ninhydrin
what are the coils of amylose and amylopectin held by?
hydrogen bonds
difference in amino acid structure in fibrous and globular
fibrous- repetitive amino acid sequence
globular- varied in amino acids- hydrophilic and hydrophobic
what can stem cells be used for
whats the point of lignin
whats the function of bordered pits
allow water to move between xylem vessels, lateral flow and allow for supply of water through the plant and to other cells
state 3 roles of membranes inside cells
whats the term organ
more than 1 type of tissue working with many tissues to perform a specific function
what side does the bhor shift cause the sigmoid to move
to the right
what allows for the movement of cillia
what structure allows for secretion of mucus
- centriole
how is hydrostatic pressure generated in the heart
by the contraction of ventricles
explain why the hydrostatic pressure drops as u move away from the heart
as you move away, there are more smaller vessels, the vessels have a larger total lumen. Arteries can also stretch and expand and at the capillaries, there is loss of fluid.
describe how the action of the heart is initiated and coordinated
-SAN initiates impulse which is excitation across the atrial walls causing the atria to contract (atrial systole). The impulse is then received at the AVN, delayed then conveyed down the bundle of His into the purkinje fibres which reach along the apex of the heart causing the ventricle to contract bottom upwards