Nucleic Acids Flashcards
What does nucleotide structure look like
Circle attached to pentagon attached to rectangle
What is the circle in the DNA structure
Phosphate
What is the pentagon in a nucleotide
Pentose sugar
What does a nucleotide contain
Phosphate
Pentose sugar
Organic base
Name the bases in DNA
Adenine
Guanine
Cytosine
Thymine
Which bases pair up together
Adenine and Thymine
Cytosine and Guanine
What is the rectangle in a DNA structure
Organic base
What reaction forms the nucleotide together
Condensation
Bond, formed between the phosphate, pentose sugar and base
Phosphodiester bond
Whats a dinucleotide
2 nucleotides
What is RNA
Single polypeptide chain instead of a double helix
Pentose sugar in RNA called
Ribose
Pentose sugar in DNA
Deoxyribose
Base in RNA
Uracil
3 types of RNA
mRNA
rRNA
tRNA
What is mRNA
Messenger
Used in protein synthesis
What is rRNA
Ribosomal RNA
Part of ribosomes
What is tRNA
Transfer RNA
Used to make proteins at ribosomes
Shape of mRNA
Curly line
Shape of tRNA and why
Clover leaf shape
Hydrogen bonds form due to some sections of the tRNA complementary to base pairing
Role of ATP
Transfers energy
How is DNA stable
Backbone = protects bases inside double helix
Hydrogen bonds = form bridges between phosphodiester uprights
How ATP is formed from ADP
Rectange pentagon P - P + Pi
<=>
Rectange pentagon P - P - P +H2O
Forward and backward reaction in formation of ATP
ADP => ATP = ATP catalyses reaction
ATP => ADP = ATP hydrolase catalyses
What does DNA and RNA do
DNA = holds genetic information
RNA = transfers genetic information from DNA to ribosomes
What are ribosomes formed from
RNA and proteins
What bond forms when a condensation reaction between two nucleotides takes place
Phosphodiester
Bond between two polynucleotide chains
Hydrogen between base pairs
Process of semi-conservative replication of DNA
1) double helix unwinds
2) Hydrogen bonds break between complementary bases in polynucleotide strands using DNA helicase
3) new DNA nucleotides attracted to exposed bases on template strands, base pairing occurs
4) DNA polymerase joins adjacent nucleotides
What do the enzymes dna helicase and dna polymerase do
DNA helicase = unwinds dna and breaks h2 bonds
DNA polymerase = joins adjacent nucleotides
The conservative and semi-conservative model by who
Watson-Crick model
Watson and Crick
Conservative model
Original dna molecule remained intact and that a separate daughter dna copy was built from new molecules
Semi conservative
Original dna molecule splits into two separate strands each replicated mirror image
What is the phosphate released during hydrolysis of ATP used for
Phosphorylate other compounds
What happens when you hydrolyse atp to adp
Inorganic phosphate group is catalysed by ATP hydrolase
What does atp hydrolase do
Catalyse hydrolysis of atp -> adp
How to form atp
Condensation reaction of ADP and Pi
Structure of atp and how its drawn
Adenine
Ribose
Phosphates
Three phosphates attachment to ribose
Adenine attached to ribose
Same structure as dna
What are each of atp’s components
Adenine = nitrogen containing organic base
Ribose = sugar molecule acts as a backbone
Phosphates = chain of three phosphate
Describe the bonds between the phosphate groups
Unstable
Have low activation energy
Easily broken
equation for forming adp
ATP + H2O -> ADP + Pi (inorganic phosphate) + E (energy)
what is this reaction catalysed by
Atp hydrolase
Three ways synthesis of ATP from ADP happens
1) In chlorophyll-containing plant cells during photosynthesis
2) Plant and animal cells during respiration
3) Plant and animal cells during substrate-level phosphorylation
When is ATP used
1) metabolic processes = provides energy to build macromolecules from basic units e.g. starch
2) movement = energy for muscle contraction
3) active transport = shapes carrier proteins in plasma membranes allowing molecules to move against conc gradient
4) secretion = form lysosomes for secretion
5) activation of molecules = inorganic phosphate released during hydrolysisused to phosphorylate other molecules
Bond between two bases
hydrogen
bond between deoxyribose and phosphate group
phosphodiester
Describe the whole process of semi-conservative replication
1) DNA helicase separates two strands of DNA by breaking hydrogen bonds that join complementary bases
2) Free nucleotides are that are activated are joined by DNA polymerase making phosphodiester bonds. Remaining unpaired bases continue to attract complementary nucleotides
3) Nucleotides join to form complete polynucleotide chain using DNA polymerase. Two identical strands of DNA are formed, each strand contains half of original DNA strand
Energy requiring processes in cells
Metabolic process
Movement = muscle contraction
Active transport
Secretion = form lysosomes
Activation of molecules = phosphorylate other compounds to make them reaction, lowering activation energy in enzyme-catalysed reactions
DNA s functin
To hold or store genetic information
Molecule that contains the instructions for frowth and development of all organisms
Rnas function
Transfer the genetic cde found in DNA out of the nucleus and carry it to the ribosomes in the cytoplasm
Difference between purine and pyrimidine bases
Purine = adenine and guanine, double ring structure
Pyrimidine = thymine, uracil, cytosine, single ring structure
Similarities and differences between DNA and RNA structure
Similar = polynucleotide and contains AGC
Difference = RNA uracil DNA thymine and RNA ribose DNA deoxyribose, RNA single stranded
Examples of rna
TRNA
MRNA
RRNA
What are ribosomes
Small organelles free in cytoplasn or attached to rough endoplasmic reticulum
Site of protein synthesis
Formed from RNA and proteins
What is rRNA
Ribosomal RNA
RNA forms structure of ribosomes (rRNA)
Catalyses formation of peptide bonds between amino acids
Each ribosome is a mixture of rRNA and proteins
Describe the two types of ribosomes
80S - eukaryotic (larger)
70S - prokaryotic, mitochondria and chloroplasts of eukaryotic (smaller)
What is r RNAs function
RRNA and proteins hold tRNA molecules in place
Condensation enzymes linked to rRNA can then catalyse the formation of peptide bonds between amino acids
Who confirmed the double helix structure of DNA
Watson and Crick
WHat does semi conservative replication do
Each new DNA molecule produced one polynucleotide DNA strands from original DNA is copied
New DNA conserved half of the original DNA and used to create a new strand
Why is it important to retain one original DNA strand
It ensures new cells inherit all their genes from the parent cell
Cells replaced regularly so the new cells to same role as old ones
Replication of DNA and cell division occurs during growth
When does DNA replication occur
-In preparation for mitosis = when parent cell divides to form daught cells, number of molecules in parent cells must double before mitosis takes place
-S phase of cell cycle (interphase when cell not dividing)
Process of DNA semi conservative replication
1) Helicase (enzyme) unwinds DNA double helix by breaking H2 bonds between base pairs on polynucleotide DNA strands forming two single polynucleotide DNA strands
2) Base pairing = single polynucleotide DNA strands act as a template for forming a new strand made of free nucleotides that are attracted to exposed DNA bases
3) New nucleotides joined by DNA polymerase catalysing condensation reactions to form a new strand
4) Original strand and new strand joined through H2 bonding between base pairs forming new DNA moleucule
How does DNa polymerase form two template strands
Catalyses condensation reaction between deoxyribose sugar and phosphate groups of adjacent nucleotides within the new strands
Forming sugar-phosphate backbone of new DNA strand
IT breaks off two extra phosphates and uses energy released to make phosphodiester bonds
H2 bonds then form between complementary base pairs
What are the leading and lagging strand
Leading = synthesis of strnad is continuous
Lagging = synthesis of strand is not continuous and created in short segments that are joined by DNA ligase
Where is energy requieed
Anabolic reactions = building large from small molecules
Active transport
Muscle contraction
Nerve impulse conduction
Advatantaged of atp
Hydrolysis of ATP is rapid using ATPase
Useful quantity released so not wasted
Relatively stable at cellular pH levels
Recylable = reversible reaction
Soluble and moves easily = transported to different areas easily
Ways ATP can be made
Substrate phosphorylation and electron transport chain of respiration
Why are hydrogen bonds important in water
Solvent = many substances can dissolve in water
High specific heat capacity
High latent heat of vaporisation
Less dense when solid
High surface tension
Acts as a reagent
Advantage of high specific heat capacity of water
Suitable habitats
Able to maintain constant temeprature to absorb heat without big temperature fluctations
Enzyme activity
Water in blod vital for transfering heat around the body maintaining temperature
Why is the latent heat of vaporisation important in water
Cooling effect for living organisms
Types of inorganic ions
Hydrogen ions H+
Iron Fe2+/Fe3+
Sodium ions Na+
Phosphate ions PO43-
Calcium Ca2+
Why are hydrogen ionsi important
Concentration of H+ determines pH
More H+ lower pH
Enzyme controlled reactions
Iron ions importance
Haemoglobin contain Fe2+ for O2 binding
Cytochromes (component of electron transport chians)
Iron switches between Fe3+ and Fe2+ to allow electrons to be accepted and donated
Sodium ions importance
Na+ transports glucose and amino acids across cell surface membranes
Co transport
Na+ actively transported out of epithelial cells, Na+ conc inside lower than in lumen so Na+ re enter through co transport proteins allowing glucose and amino acids to enter with them
Nerve impulses
Phosphate ions importance
PO43- attaches to other molecules to form DNA RNA ATP
Nucleotides to join up
ATP bonds allow phosphate to easily attach or detach
Phospholipids
Calcium ions importance
Ca2+ movement in organisms, synapses
Muscle contraction (Ca2+ released from sarcoplasmic reticulum, binds to troponin removing tropomysin from myosin binding sites)
Regulate protein channels permeability
Enzymes activated by Ca2+
Important for forming blood clots
Main role of DNA
Carry genetic code
Instructions for making proteins
What is DNA
A molecule with a double helix structure which consists of hydrogen bonds between specific complementary base pairs on two antiparallel polynucleotide chains.
