Chapter 2 Nucleic Acids Flashcards
What are the components of a nucleotide?
Phosphate group
Pentose sugar (5 C atoms)
Nitrogen-containing organic base
How is a nucleotide formed?
Condensation reaction
Pentose sugar + Phosphate Group + Organic base
How is a dinucleotide formed?
Deoxyribose sugar + ,Mononucleotide
How are dinucleotides held together?
Phosphodiester bond
What is a long chain on mononucleotides?
Polynucleotides
Describe the RNA structure?
Single, relatively short polynucleotide chain
Pentose sugar = Ribose
Organic Bases = Adenine, Uracil, Guanine, Cytosine
What is the RNA function?
Transfers genetic info from DNA to other ribosomes
Protein Synthesis
Describe the DNA structure?
Pentose sugar = Deoxyribose
Organic bases = Adenine, Thymine, Guanine, Cytosine
What are the complementary base pairings in DNA?
Adenine + Thymine
Guanine + Cytosine
How are the base pairings joined together and what does it form?
Hydrogen Bonding Forms bridges (rings) between phosphodiester uprights
What are the features of the double helix?
2 polynucleotides twisted
Extremely long
How is the double helix structured?
Phosphate + deoxyribose wind around one another = double helix
Forms a structural backbone of DNA
What protects chemically organic bases inside the double helix?
Phosphodiester backbone
A higher proportion of C-G pairings…
…Creates a more stable DNA (3 H bonds)
What is base stacking?
When interactive forces between base pairs hold up a molecule
What is the function of DNA?
Is a hereditary material responsible for passing genetic info from cell to cell, from generation to generation
How does the adaptation of 2 separate strands joined by H bonding support the function of DNA?
Allows them to separate during DNA replication + protein synthesis
How does the adaptation of being an extremely long molecule support the function of DNA?
Allows to carry an immense amount of genetic info
How does the adaptation of base pairing support the function of DNA?
DNA is able to replicate + transfer info as mRNA
How does the adaptation of base pairs being within the helical cylinder of deoxyribose, phosphate backbone support the function of DNA?
Genetic material is protected from being corrupted by outside chemical and physical forces
Before a cell divides DNA must be…
Replicated
Why should DNA be replicated?
It ensures that all daughter cells have genetic info to produce enzymes and other proteins they need
What phase does DNA replication happen?
S phase (Interphase)
What are the 4 requirements needed for Semiconservative replication to take place?
1) 4 types of nucleotides must be present
2) Both strands of DNA act as a template for attachment of nucleotides
3) Enzyme Polymerase
4) Source of energy required to drive process
Describe the process of SCR?
1) Enzyme DNA helicase breaks H bonds linking bases pairs in DNA
2) Therefore, double helix separates + unwinds into 2 strands
3) Each polynucleotide strand acts as a template to which complementary free nucleotides bind by specific base pairing
4) Nucleotides are joined by a condensation reaction by enzyme DNA polymerase to form ‘missing’ polynucleotide strand of each 2 original strands of DNA
5) Each new DNA contains one original DNA and one build into a new DNA molecule
What does ATP stand for?
Adenine Triphosphate
What is the function of ATP?
The main energy source to carry out processes within a cell
Is a phosphorylated macromolecule
Describe the structure of ATP?
Adenine (N containing organic base)
Ribose (Acts as a backbone)
Phosphates (Chain of 3 phosphate groups)
How does ATP store energy?
Bonds between the 3 unstable phosphate groups which causes lower activation energy causing it to be easily broken.
When broken it releases energy
What is the equation of ATP converting to ADP?
ATP + H2O -> ADP + Pi + E
What is used to convert ATP -> ADP?
Water = Hydrolysis
What enzyme is catalyzed in the reaction where ATP is converted to ADP?
ATP hydrolase
The conversion of ATP to ADP is a ________ reaction
reversible
How is ADP reformed into ADP?
Energy is used to add inorganic phosphate to reform to ATP
What enzyme is used the reaction of ADP -> ADP?
ATP synthase (Condensation rection)
The addition of a phosphate molecule occurs in what 3 ways?
1) In chlorophyll-containing plants cells during photosynthesis
2) Plant + animal cells during respiration
3) Plant + animal cells when phosphate groups are transferred from a donor molecule to ADP
Why is ATP not a good long-term energy store?
The phosphate base is unstable therefore it is used as an immediate energy source of cell
Cells don’t store large quantities of ATP and therefore ______
maintain a few secs supply
Give three examples of why ATP is a better immediate energy source than glucose?
1) Each ATP molecule releases less energy than Glucose, therefore, energy is released in smaller manageable quantities
2) Hydrolysis of ATP -> ADP is a single reaction and releases immediate energy
3) Breakdown of glucose takes a long series of reactions, energy release takes longer
ATP cannot be stored therefore it needs to be_____
made continuously in mitochondria of cells that need it
Why do metabolic processes require energy?
ATP provides energy to build up macromolecules from basic units
Why does movement require energy?
Energy for muscle contraction
Provides energy for muscle filaments to slide past one another
Why does active transport require energy?
Energy to change the shape o carrier proteins in the plasma membrane.
Allows ions + molecules to move against conc gradient
Why does secretion require energy?
Form lysosomes
Why does activation molecules require energy?
Inorganic phosphate released from hydrolysis of ATP used to phosphorylate other compounds to make them more reaction by lowering activation energy in an enzyme-catalyzed reaction
How is the water molecule dipolar?
2 atoms of H (slightly positive)
1 atom of O (slight negative)
How is water bonded by H bonding?
different poles ( + , -) attract between different charges
What causes unusual properties in the water?
Each bond is fairly weak together causes water to stick together
Why are waters boiling point higher than expected?
Because H2O stick together more energy is needed to separate
It requires more energy to heat a given mass of H2O therefore_________
you can use it to buffer against sudden temp variations which can make aquatic environments stable
What is the energy called that is required to evaporate water? (due to H bonding with H2O)
Latent heat of vaporization
How is evaporation effective for cooling?
Because body heat is used to evaporate H2O
What is cohesion?
The tendency of molecules to stick together
How can water be pulled up the xylem?
With its Hydrogen bonding, H2O has large cohesive forces which allow it to be pulled up the xylem
What is surface tension?
When water surface acts like skin and is strong enough to support small organisms
Why is water important to organisms?
The main constituent of all organisms (e.g 70% of humans)(
The environment where species may live
How is water used in metabolism?
It’s used to break down complex molecules by hydrolysis + produced in condensation reactions
Chemical reactions take place in an aqueous medium
Water major raw material for photosynthesis
How is water used as a solvent?
Readily dissolves in substances:
Gases (O2 + CO2)
Wastes (NH3 + urea)
Inorganic ions + small hydrophobic (molecules / amino acids, monosaccharides ATP)
Enzymes (Reaction takes place in solution)
What is the advantage of water evaporating?
cools organisms
What is the advantage of water not easily compressed?
Provides support
What is the advantage of water being transparent?
Aquatic plants can photosynthesize
What are inorganic ions?
found in organisms where they occur in solution in the cytoplasm of cells + bodily fluids, larger molecules
Concentration ranges from very high -> very low
What is the function of inorganic ions?
Related to its properties
