Nucleic acids Flashcards
What does RNA stand for?
Ribonucleic acid
What does DNA stand for
Deoxyribonucleic acid
What is a nucleotide structure?
— a pentose sugar
— a phosphate group
— a nitrogen containing base.
What is the bond called that is formed between two nucleotides?
Phosphodiester bond
What is the reaction called that joins two nucleotides together?
Condensation reaction
What is the pentose sugar for RNA?
Ribose sugar
What are the organic bases found in RNA?
Adenine, guanine, cytosine, uracil
What type of pentose sugar is found in DNA?
Deoxyribose
What are the bases found in DNA?
Adenine, thymine, guanine, cytosine
What bonds join together the two strands of DNA?
Hydrogen bonds
What are the base pairings in DNA?
A+T
G+C
What makes DNA a stable molecule?
— phosphodiester backbone protects the more chemically reactive organic bases
— hydrogen bonds link the organic base pairs forming bridges.
What are the functions of DNA?
— very stable structure which passes from generation to generation
— two separate strands joined with hydrogen bonds so easily separated
— extremely large molecule and therefore carries immense amount of genetic information
— having the base pairs within the helical cylinder of deoxyribose-phosphate backbone
— base pairing leads to DNA being ankle to replicate and transfer information as mRNA
What are the two main stages of cell division?
— nuclear division
— cytokinesis
What are the 4 requirements for semi-conservative replication
— 4 types of nucleotides
— both strands of DNA molecule act as a template for the attachment of these nucleotides
— the enzyme DNA polymerase
— a source of chemical energy is required to drive the process
Describe the process of semi-conservative replication
- The enzyme DNA helicase breaks the hydrogen bonds linking the base pairs of DNA
- Double helix separates
- Each exposed polynucleotide strand then acts as a template which complementary free nucleotides bind by specific base pairing
- Nucleotides join together in a condensation reaction by DNA polymerase
- Each of the new DNA molecules contain one of the original DNA strands.
What are the three components of ATP?
— adenine
— ribose
— phosphates
what reaction converts ATP to ADP and what enzyme catalyses this reaction?
— hydrolysis reaction
— ATP hydrolase
In what 3 ways does the synthesis of ATP from ADP occur?
— (photophosphorylation) in chlorophyll-containing plant cells during photosynthesis
— (oxidative phosphorylation) in plant and animal cells during respiration
— (substrate-level phosphorylation) in plant and animal cells when phosphate groups are transferred from donor molecule to ADP
In which two ways is ATP a better immediate energy source than glucose for the following reasons:
— each ATP molecule releases less energy than each glucose molecule so released in more manageable quantities
— hydrolysis of ATP to ADP is a single reaction that releases immediate energy.
How is ATP used in energy-requiring processes in cells (5):
— metabolic processes - ATP provides the energy needed to build up macromolecules from their basic units
— movement - ATP provides the energy for muscle contraction.
— active transport - ATP provides the energy to change the shape of carrier proteins in plasma membranes
— secretion - ATP is needed to form the lysosomes necessary for the secretion of cell products
— activation of molecules - the inorganic phosphate released during the hydrolysis of ATP can be used to phosphorylase other compounds
What does it mean that water is dipolar?
It has both positive and negative charges
why is hydrogen bonding important in water?
Allows important forces to form that cause the water molecules to stick together, giving water it’s unusual properties
describe the specific heat capacity of water.
It takes more energy to separate water molecules due to the hydrogen bonds, which is important so water can last in high temperatures so allows life to exist on earth.
What does the latent heat of vaporisation of water describe?
Hydrogen bonding between water molecules means that it requires a lot of energy to evaporate 1 gram of water.
Describe the cohesion and surface tension of water?
The tendency of molecules to stick together is know as cohesion.
What are the different ways water is important to living organisms?
— water in metabolism ( break down complex molecules my hydrolysis)
— water as a solvent (readily dissolves other substances)
— cools organisms
— not easily compressed
— transparent so aquatic plants can photosynthesis
