Nucleic Acids Flashcards
What are the nucleic acids?
RNA and DNA
Individual nucleotides are made up of 3 components:
Pentose sugar
Phospate group
Nitrogen containing base
What are the nitrogen containing bases?
Cytosine
Thymine
Uracil
Adenine
Guanine
How is the pentose sugar, phosphate group and organic bases joined together? And to form what?
By condensation reactions to form a single nucleotide
Two mononucleotides may, in turn, be joined as a result of a ______________ reaction between the deoxyribose sugar of one mononucleotide and the _________ group of another.
Condenstation,
Phosphate
What bond is formed between 2 mononucleotides joined together after a condensation reaction?
A phosphodiester bond
What is the continued linking of mononucleotides called?
A polynucleotide
What is RNA?
It is a polymer made up of nucleotides
What is the structure of RNA?
Single, short, polynucleotide chain in which the pentose sugar is always ribose and organic bases are Adenine, guanine, cytosine, and uracil
One type of RNA transfers genetic information from ___ to the ribosomes
DNA
The ________ themselves are made of proteins and another type of RNA. A third type of RNA is involved in _______ _________.
Ribosomes
Protein synthesis
In DNA, the _______ sugar is deoxyribose and the ________ bases are Adenine, Thymine, _______ and cytosine.
Pentose
Organic
Guanine
DNA is made up of? (structure wise)
Two strands of nucleotides (polynucleotide)
Each of the two strands is _______ _____, and they are joined together by _______ bonds formed between certain bases.
Extremely long,
Hydrogen
The bases on the two strands of ___ attach to each other by ___________ bonds
DNA,
Hydrogen
Adenine always pairs to?
Thymine
Guanine always pairs with?
Cytosine
Adenine is complementary to ______ and guanine is complementary to _______
Thymine
Cytosine
It follows that the _________ of adenine and thymine in DNA are always the same, and so are the ________ of guanine and ________.
Quantities,
Quantities,
Cytosine
However, the ____ of adenine and thymine to guanine and cytosine _____ species to species
Ratio
Varies
The uprights of __________ and deoxyribose wind around one another to form a ______ _______.
Phosphate
Double helix
DNA is a stable molecule. Give a reason related to the phophosidester backbone.
Phosphodiester backbone protects the more chemically reactive organic bases inside the double helix
DNA is a stable molecule. Give a reason related to the hydrogen bonds.
The hyrogen bonds link the organic base pairs forming bridges between the phosphodiester uprights.
DNA is the _________ material responsible for passing genetic information from ____ to _____ and generation to generation
Hereditary,
Cell,
Cell
How many base pairs are in the DNA of a typical mammalian cell?
3.2 billion
DNA is a very _____ molecule which normally passes form generation to generation without _____. Only rarely does it ______.
Stable,
Change,
Mutate,
DNA’s two separate strands are joined only with _______ bonds, which allow them to separate during DNA _________ and protein synthesis
Hydrogen
Replication
DNA is an extremely _____ molecule and therefore _______ an immense amount of _______ information
Large
Carries
Genetic
DNA has the base pairs within the ______ cylinder of the ______________–phosphate backbone, the genetic information is to some extent ___________ from being corrupted by outside chemical and _________ forces.
Helical
Deoxyribose
Protected
Physical
DNA base pairing leads to DNA being able to __________ and to transfer information as _____
Replicate
mRNA
What does ATP stand for?
Adenosine Triphosphate
A single molecule of ATP is a derivative of a ___________
Nucleotide
How is ATP formed?
A molecule of adenine, a molecule of ribose and three phosphate groups
What catalyses the hydrolysis of ATP?
The enzyme ATP hydrolase
After the hydrolysis of ATP what is formed?
Adenosine diphosphate and an inorganic phosphate group
The hydrolysis of ATP can be coupled to energy-requiring reactions within cells. Name a few.
Active transport, secretion (exocytosis) production of polymers and muscle contraction.
The _________ phosphate released during the __________ of ATP can used to ________________ other compounds, often making them more reactive.
Inorganic
Hydrolysis
Phosphorylate
ATP is resynthesised by what?
the condensation of ADP and Pi
This condensation reaction is catalysed by the enzyme ATP _______ during photosynthesis, or during respiration.
Synthase
During the hydroylus of ATP, it releases a small quantity of energy, why?
So it doesn’t overwhelm the cell and distort it.
The bond between the second and third phosphate is hydrolysed easily, why?
It is unstable, so it can be hydrolysed easily.
ATP is found in all what?
Living things
ATP is an _________ source of energy by cells
Immediate
When ATP breaks down, it does what?
Releases energy in small manageable steps
Cells constantly make ATP from ADP and inorganic phosphate in what?
Respiration, photosynthesis and substrate level phosphorylation
In metabolic processes, ATP provides energy needed to build up what?
The macromolecules from their basic units.
In the energy-requiring process of movement, ATP provides the energy for what?
Muscle contraction
In muscles contraction, ATP provides the energy for the?
Filaments of muscle to slide past one another, to shorten the overall length of a muscle fibre
In active transport, ATP provides energy to do what?
Change the shape of carrier proteins in plasma membranes to allow molecules/ions to be moved against a concentration gradient.
In secretion, ATP is needed to form what?
Lysosomes necessary for the secretion of cell products.
A water molecule is made up of what?
Two atoms of hydrogen and one of oxygen
Does an oxygen atom have a slightly negative charge? Yes or No.
Yes
Water is described as what?
Dipolar
Different poles attract, which means what? (water and hydrogen bonding)
Positive pole of one water molecule will be attracted to the negative pole of another water molecule.
Water acts as a buffer against sudden what?
Temperature variations, making the aquatic environment a temperature-stable one.
Water has a high specific heat capacity, what does this mean?
It takes a great deal of energy to separate water molecules from eachother.
___________ bonding between water molecules means that it requires a lot of energy to evaporate _ gram of water. This energy is called ______ _____ __ ________________
Hydrogen,
1,
Latent heat of vapourisation
What is cohesion?
The tendancy of water molecules to stick together
Water has larger cohesive forces and the allow it to be?
Pulled up through a tube
What is surface tension?
Where water molecules meet air and tend to be pulled back into the body of water rather than ecsaping from it
Water in metabolism: water is used to break down many complex molecules by what?
Hydrolyis
Water is produced in what?
Condensation reactions
Water readily dissolves other substances, give 5 types.
Gases, waste products, inorganic ions, small hydrophillic molecules, and enzymes
Evaporation of water does what for organisms?
Cools them down and allows them to control their temperature
Water is not easily compressed so this means what?
It can provide support
Water is transparent, why is this useful for aquatic plants?
So they can photosynthesise
Where are inorganic ions found in organisms?
Cytoplasm of cells and in body fluids
Iron ions are found where and what do they do?
Found in haemoglobin and play a role in transport of oxygen
Where is a phosphate ion found and whats their role?
Found to form structural old in DNA molecules and a role in storing energy in ATP molecules
Hydrogen ions are important for what?
Determine the pH of solutions and therefore the functioning of enzymes.
Sodium ions are important for what?
In the transport of glucose and amino acids across plasma membranes
What is nuclear division?
The process by which the nucleus divides : mitosis and meiosis
What is cytokinesis?
Follows nuclear division and is the process by which the whole cell divides
Before a nucleus divides its DNA must be what? And why?
Replicated, to ensure all daughter cell have the genetic information to produce the enzyme and other proteins that they need.
Semi-conservative replication: what is step 1?
Enzyme DNA helicase breaks the hydrogen bonds linking the base pairs of DNA, leaving the double helix to separate into 2 strabds and unwinds
Semi-conservative replication: what is step 2?
Each exposed polynucleotide strand acts as a template to which complementary free nucleotides bind by specific base pairing
Semi-conservative replication: what is the last step?
The nucleotides are then joined together in a condensation reaction by the enzyme DNA Polymerase to form the missing polynucleotide stand on each of the 2 original polynucleotide strands of DNA
