BIOCHEMISTRY Flashcards
(26 cards)
What are micelles?
micelles are aggregates of surfactant molecules where the single hydrophobic tails are sequestered from water
starch in plants is stored as
granules in chloroplasts
what is cellulose
cellulose is a structural plysaccharide, helps maintain structure, made of unbranched straight chains of beta glucose. H bonds between chains give strength and rigidity.
what is a peptidoglycan
complex polysaccharide linked with proteins used in bacterial cells walls for stability.
what are glycosaminoglycans
hetero polysaccharides which act as lubricants or shock absorbers. found in bacteria and ECM of animals but not in plants.
highly polar
uronic acid and an N-acetylated amino sugar.
what is a glycoprotein
protein + sugar chain
cell communication
markers on cell membranes
what is a proteoglycan
glycosaminoglycans + protein predominantly carbohydrate tissue organisers growth factors regulate ECM assembly
what cell does not have DNA and RNA
red blood cells
What are the components of a nucleotide
nitrogenous base
phosphate group
deoxyribose or ribose sugar
what are the 5 nitrogenous bases
adenine thymine cytosine guanine uracil (T in rna)
what is the difference between deoxyribose and ribose
deoxyribose is just ribose deoxygenated. It has lost its Oxygen on C2
What are purines
2 ring nitrogenous bases
A and G
What are pyrimidines
1 ring nitrogenous bases
T, C and U
Describe phosphate bonds in DNA
a Phosphate group P and 3O bond between C3 and C5 of the sugar molecules in nucleotides. The bases then come off the sugar
What is the convention of writing DNA
from 5’ to 3’ end. The complimentary strands are called sense and anti-sense and run anti-parallel.
How many hydrogen bonds in G-C
3
How many hydrogen bonds in A-T
2
How is the double helix shape formed
Hydrophobic bases held together by h bonds, are stacked causing the winding pattern. The wider section of winding is the major groove and the smaller is the minor. DNA is then coiled around histones to form chromatin and chromosomes
Outline DNA replication
specific enzymes replicated DNA before cell division. There is a high fidelity process due to checkpoints where errors are fixed so they arent passed on to the daughter cells. Genes are transcripted to produce messenger RNA (mRNA) which then travels to the cytosol where it is translated to proteins by ribosomes
what are waxes
waxes are esters of fatty acids and alcohols. They act as food storage, water repellent, prevent excessive evaporation and make up lotions polishes etc.
what are the main components of phospholipids
amphipathic molecules made of glycerol, 2 fatty acids and a phosphate group.
describe the bonding between the phospholipid bilayers
there is no covalent bonding between the floating phospholipids. they are in constant lateral motion and only flip vertically about once a month. Unsaturated proteins enhance fluidity.
how is cholesterol related to fluidity of membrane
in high temps cholesterol levels decrease and therefore lateral movement decreases. vice versa for low temp
why do some organelles have membranes
so reactions can occur independently and safely from the cell as a whole
