Nucleic Acids Flashcards
covers the second half of section one
Describe the structure of a nucleotide.
Made up of a pentose sugar and a nitrogen-containing base
How is a polynucleotide formed?
A polynucleotide is formed when two nucleotides join together by a condensation reaction between the phosphate group of one nucleotide and the sugar of another. The chain of phosphates and sugars is known as the sugar-phosphate backbone.
What is the bond formed between two nucleotides?
A phosphodiester bond.
What is DNA?
DNA (Deoxyribonucleic acid) is a molecule found in all organisms. It holds all the genetic information.
What is the structure of each DNA nucleotide?
each DNA nucleotide consists of a deoxyribose sugar an organic base and a phosphate group
What is the structure of a DNA molecule?
A DNA molecule is twisted into a double helix composed of two separate strands of polynucleotides joined together by hydrogen bonds between complementary bases.
What are the 4 possible bases that can be found in a DNA molecule and which bases are complementary to each other?
the possible bases are adenine guanine cytosine and thymine
How does the structure of the DNA lead to their properties?
The double stranded feature helps DNA to become more stable and act as a template in semi-conservative replication. The coiled feature helps the DNA to be more compact. The complementary base pairing ensures semi-conservative replication occurs as the hydrogen bonds between the bases are weak and can easily be broken during semi-conservative replication.
Describe the process of DNA replication.
DNA replication occurs in interphase by semi-conservative replication. DNA helicase is used to separate strands and break the hydrogen bonds between both strands. Both strands act as templates and free complementary nucleotides bind to the exposed bases of the template strands. Complementary base pairing occurs between adenine and thymine and guanine and cytosine. DNA polymerase joins nucleotides and the hydrogen bonds reform. Semi-conservative replication is finally done with new DNA molecules containing one old strand (template strand) and one new strand.
What is RNA?
RNA (Ribonucleic acid) is a molecule found in all organisms. It transfers genetic information from the DNA to the ribosomes. There are two types of RNA: mRNA (messenger RNA) and tRNA (transfer RNA).
What is the structure of each RNA nucleotide?
Each RNA nucleotide consists of a ribose sugar an organic base
What is the structure of an RNA molecule?
An RNA molecule is relatively short and it is single stranded.
What are the 4 possible bases that can be found in an RNA molecule and which bases are complementary to each other?
possible bases are adenine guanine complementary to uracil and cytosine
What is ATP?
ATP (Adenosine triphosphate) is an energy carrier molecule that delivers energy for life processes.
What is the structure of ATP?
ATP is made from 1 adenine base
and 3 phosphates and a ribose sugar
How does ATP help release energy?
ATP gets broken down into ADP (Adenosine Diphosphate) and Pi (Inorganic phosphate ion) in a hydrolysis reaction using ATP hydrolase meaning energy is released from the bonds.
How is ATP reformed?
ATP gets reformed when ADP (Adenosine Diphosphate) and Pi (Inorganic phosphate ion) join together during a condensation reaction using ATP synthase meaning energy is carried and stored in its bonds.
What makes ATP a good deliverer of energy?
ATP is an immediate source and only needs to break one weak bond. It is also a manageable source as it releases small amounts of energy.
What are the different uses of ATP in organisms?
- Protein synthesis - Organelle synthesis - DNA replication - Cell division (mitosis) - Active transport - Metabolic reactions - Movement - Maintaining body temperature - To add inorganic phosphate to other substances and make them more reactive and change their shape. This is known as phosphorylation.
Describe the structure of a water molecule?
A water molecule is made up of two atoms of hydrogen and one of oxygen. Water molecules are dipolar since hydrogen has a slightly positive side and the oxygen has a slightly negative side. Therefore water molecules can form hydrogen bonds with each other.
State the properties of water?
- Water is an important metabolite used in many important metabolic reactions including condensation and hydrolysis. - Water has a high specific heat capacity as it takes a lot of heat energy to heat it up due to the presence of hydrogen bonds
What is the importance of water in living organisms?
The high specific heat capacity allows certain habitats to not be affected. For example when water freezes
What are inorganic ions?
Inorganic ions occur in solution in the cytoplasm and body fluids of organisms
some in high concentrations and others in very low concentrations.
What are the examples of inorganic ions?
- Hydrogen ions to determine pH; higher hydrogen concentration means lower pH. - Iron ions are a component of haemoglobin. - Sodium ions are involved in the co-transport of glucose and amino acids. - Phosphate ions are a component of DNA and ATP.
