Life at the Cellular Level 2 Flashcards
What are the 10 elements that are normally found in structural parts of organisms?
H, C, N, O, Na, P, S, Cl, K and Ca
How many trace elements are needed in small amounts?
12
What are 99% of our cells composed of?
H, N, C and O
What are H, N, C and O found in 99% of our cells?
Because they are the lightest atoms which can form the strongest bonds (H forms 1, O forms 2, N forms 3 and C forms 4)
Why does carbon form the bases of all biomolecules?
Because it is so versitle, being able to form 4 bonds
What defines a molecules function?
Its functional group
What are some functional groups?
Hydroxyl (polar, hydrogen bonds, linkage by dehydration)
Aldehyde (C=O very reactive)
Keto (C=O very reactive)
Carboxyl (hydrogen bonding, polar)
Amide (hydrogen bonds)
What does the hydroxyl functional group look like?
What does the aldehyde functional group look like?
What does the keto functional group look like?
What does the carboxyl functional group look like?
What does the amide functional group look like?
Why is the polarity of carbon critical to function?
C-C and C-H are relatively stable or share e- evenly
C-O or C-N o C-functional group are highly polar which allows carbons bond reactivity
Does funcition also depend on how groups are arranged in a molecule?
Yes
What is configuration?
The final arrangement of atoms in a molecule
Why is C=C a rigid conformation?
Because cannot move freely around a double bond so can only have two distinct configurations
trans
cis
How do you convert between trans and cis configurations?
By breaking and reforming the bonds
C an be a chiral centre, what are the two forms?
Laevo (left handed)
Dextro (right handed)
Is the difference between laevo and dextro important?
Yes, all proteins are made from L-amino acids
What is conformation?
The precise arrangement of atoms in a molecule
What is a property of bonds that can rotate freely?
They can form many different conformations without breaking and reforming bonds
What dictates how freely bonds can rotate?
Interaction of groups, certain conformations are favoured
What are the five chemical reactions of life?
Redox reactions
Making and breaking C-C bonds
Internal rearrangement
Group transfers
Condensation and hydrolysis reactions
What are redox reactions?
Redox reactions involve oxidation (loss of electrons) or reduction (gain of electrons)
Is every reduction accompanied by oxidation and vice versa?
Yes
What is condensation?
Addition reaction that produces water
What is hydrolysis?
Reaction involving breaking a bond in a molecule using water
What are proteins?
Polymers of amino acid monomers linked by peptide bonds
What is a monomer?
A molecule that is able to bond in a long chain
What is a polymer?
A substance whose molecular structure is built up from a large number of similar units bonded together
What are nucleic acids?
Polymers of nuceotide monomers linked 3’, 5’-phosphodiester bonds
What does a diagram of a nucleotide look like?
What are the two kinds of bases in nucleic acids?
Pyrimidines (flat single rings such as cytosine, thymine and uracil)
Purines (flat double ring such as adenine and guanine)
What does a diagram showing the conversion of a base to a nucleotide look like?
What does the flat planer structure of bases allow DNA to do?
Form the double helix
What is the reason behind base pairing?
A and T can form two bonds
G and C can form three bonds
How is RNA different form DNA
Single stranded
Ribose sugar instead of deoxyribose
Uracil (U) base replaces thymine (T)
How do double stranded segments of RNA form?
Sequences of RNA nucleotide pair with one another
What are polyaccharides?
Polymers of sugar monomers linked by glucosidic bonds
What are examples of polysaccharides?
Starch and glycogen
Why is D-glucose terms a reducing sugar?
Linear form containing an aldehyde can be oxidised
What are properties of glycose polymers?
Formed from condensation reaction between glucose monomers
Monomers are in cyclic form except the end monomer which is linear and known as a reducing end
What are lipids?
Molecules that contain hydrocarbons and is souble in nonpolar solvents
What do saturated and unsaturated lipids look like?
What do more double carbon bonds do to a lipid?
Molecule becomes less linear and more bent
What are some classes of lipids?
Triacylglycerides
Phopholipids
What are properties of triacylglyderides?
Act as storage lipids, releasing a lot of energy when broken down
Non polar
Three fatty acid chains linked to glycerol
What are properties of phospholipids?
Have a hydrophilic head group attracted to glycerol, making them polar
Tail composed of two hydrophobic fatty acid chains
