unit 2 Flashcards
(64 cards)
what’s the difference between nucleotides and nucleosides?
- nucleotides are composed of 3 parts: sugar/phosphate/heterocyclic base
- nucleosides are composed of 2 parts: sugar + heterocyclic base
what is the function of nucleic acids?
store genetic information
what’s the difference between DNA & RNA
what types of bases are there
monocyclic pyrimidines: cytosine/thymidine/uracil
bind at n1
aromatic
bicyclic purines: adenine/guanine
bind at n9
aromatic
organize from polymer to smallest monomer
1- nucleotides
2-nucleoside
3-nucleic acids
nucleic acids > nucleotides > nucleosides
what is the function of phosphate in nucleotides?
it is able to form stable bonds between molecules and builds new active molecules upon increasing phosphate bonds
what are the properties of phosphate?
- good leaving groups
- stable anions
why is it that ATP has high reactivity?
because phosphates are stable anions and good leaving groups, thus they are able to be attacked fromhard or soft nucleophiles from the ch2 group
why is DNA so named?
because the 2’ position at the ribose ring is vacant, lacking a hydroxyl group, therefore it is known as 2-deoxyribonucleic acid
why is it that purine must bind to pyrimidine in nucleic acids?
because only the combination of larger purines and smaller pyrimidines bridges the gap between the nucleic acid coils, allowing each nucleotide to recognize its pair
how are purines connected to pyrimidines?
via 2 or 3 hydrogen bonds of two kinds (amine-carbonyl group) or (amine-imine)
why do cells need to extract energy from sources and store it?
- cells needs to move in the environment;
- to build molecules that require, DNA, proteins and enzymes for cells living,
- reproduction and growth and also energy is involved in transport of ions/molecules in/out of cells, for example balance Na/K to keep isotonic (inside=outside) pressure, to take sugars/aminoacids/vitamins (nutrients) inside the cell
what does ATP consist of?
triphosphate, deoxy-ribose (sugar, OH) and adenine (H).
deoxy-ribose (sugar, OH) and adenine (H) are one of 4 basis DNA called “adenosine”. other bases are ___, _______ &_____
guanosine
cytidine
uridine
what are the energy reach compounds
- guanosine triphosphate (GTP)
- cytidine triphosphate (CTP)
- uridine triphosphate (UTP)
what molecule is this
ATP
where is ATP located in the cell?
cytoplasm
in ATP, 5 carbons are bound to oxygen of phosphate to form phosphate ester bond and other bonds are _________
phosphoanhydride bonds
describe bonding in ATP
1 phosphate ester bond formed by linkage between the alpha-phosphoryl group to the 5’-oxygen of ribose and Phosphoanhydride bonds formed by alpha, beta and beta, gamma linkages between phosphoryl groups. Usually present as complexes magnesium cations.
metabolism is divided into two sets of reactions known as:
anabolic (producing molecules)
catabolic (producing energy)
describe the sequence of catabolic and anabolic processes within the cell
- simple sugars go through glycolysis where sugars are broken down and pyruvate is produced and small amount of ATP.
- Pyruvate is then converted in Acetyl Co enzyme A that enters citric acid cycle (Krebes cycle), where CO2 and electrons are produced and the electrones are transported to the oxidative phosphorylation stage, ATP is produced during oxidative phosphorylation.
- Fats are broken down into glycerine that enters the catabolic routes at glycolysis stage, whereas the fatty acids are broken down and they enter catabolism as acetyl Co enzyme A.
- Proteins are broken down in the amino acids and depending on amino acid they enter catabolism in different places.
true or false
anaerobic reactions produce a small amount of ATP whereas aerobic reactions produce w larger amount
true
For most organisms the main supply of energy is by metabolism of glucose and other sugars. what happens when sugar/glucose is depleted?
Metabolism of fats and proteins becomes more important for energy production when the supply of glucose and other sugars is limited.
what is the initial stage of metabolism known as?
glycolysis
- it takes place in the cytoplasm
- it does not require oxygen
- it is not efficient
- the reaction also produces two molecules of NADH (Nicotinamide Adenine Dinucleotide)
