DNA Flashcards
How is a nucleotide or a mononucleotide made?
In a condensation reaction, joining together all the main components.
What happens when two mononucleotides undergo a condensation reaction?
A dinucleotide is formed.
What type of bond is between polynucleotides?
Phosphodiester bond.
How is a polynucleotide formed?
Dinucleotides joining in a condensation reaction.
Why can Adenine join with a Thymine?
They are complementary to one another.
What is RNA?
A single-stranded polynucleotide.
What type of pentose sugar does RNA have?
Ribose pentose sugar.
What is RNA’s role?
To transfer genetic info from DNA to ribosomes.
What contributes to the stability of DNA?
- Phosphodiester backbone protects more chemically reactive organic bases in the double helix.
- Multiple hydrogen bonds between bases create strength.
How does the stability of DNA help it be passed on through each generation?
Means it can be passed from generation to generation without changing, mutations are very rare.
What 3 features of DNA help it perform its function?
- it’s large, so can hold a lot of information.
- the 2 strands are joined by hydrogen bonds which can separate during DNA replication and protein synthesis.
- base pairing allows DNA to replicate and transfer info as mRNA.
What the components of a nucleotide?
A pentose sugar,
A phosphate group,
A nitrogen-containing base, either A C G U or T
What are the stages of cell division and what happens in each?
Nuclear division - nucleus divides
Cytokinesis - continues nuclear division, process where the cell divides
What must have occurred before nuclear division can happen?
The DNA must be replicated.
Why must DNA be replicated?
To ensure daughter cells have the genetic info necessary to produce the enzymes and proteins they need.
What enzyme is involved in separating the two polynucleotide strands in DNA replication?
DNA helicase
What happens after the double helix has unwound into 2 strands during DNA replication?
Each exposed polynucleotide acts as a template to which complementary base pairs bind by specific base pairing.
What enzyme joins nucleotides together in a condensation reaction during DNA replication?
DNA polymerase
What does ATP contain?
- Adenine (nitrogen-containing base)
- Ribose (sugar molecule with a 5 carbon ring structure that acts as a backbone
- Phosphates (a chain of 3 phosphate groups)
what is ATP abbreviated from?
Adenosine triphosphate
Why is ATP suitable for releasing energy?
It has unstable bonds between the phosphates, so it has a low activation energy.
What is the general equation for the release of energy from ATP?
ATP + H2O –> ADP + Pi + E
What is released from ATP other than ADP and Energy?
Pi, Inorganic Phosphate
What type of reaction is ATP being converted to ADP and why?
Hydrolysis reaction, because water is used.
What is the reverse of the reaction of ATP being converted to ADP known as?
ATP synthesis
What enzyme is used in ATP synthesis?
ATP synthesase
What type of reaction is ATP synthesis?
Condensation reaction
How does ATP synthesis occur in chlorophyll?
By photosynthesis
Why is ATP a better alternative for releasing energy than some fats or carbohydrates?
It is an immediate energy source.
Give 3 reasons why ATP is a better immediate energy source than Glucose?
- ATP produces smaller amounts of energy than glucose
- ATP can be released in smaller, more manageable amounts
- the hydrolysis of ATP is a single step reaction
What energy-requiring processes in cells is ATP used for?
- metabolic processes
- movement
- active transport
- secretion
- activation of molecules
What is a gene?
A section of DNA containing coded info for making polypeptides and RNA.
What is a locus?
A section of DNA located at a particular location.
What does a gene code for?
- the amino acid sequence of a polypeptide
- RNA
The genetic code is degenerate, what does this mean?
Most amino acids are coded for by more than one triplet.
What makes a stop code?
3 triplets.
The genetic code is non-overlapping, what does this mean?
Each base is read only once.
The genetic code is universal, what does this mean?
Each triplet codes for the same amino acid in all organisms.
What are coding sequences called?
Exons
What are non-coding sequences called?
Introns
Is RNA a monomer or a polymer and what is it made from?
Polymer made up of nucleotides.
What part of the DNA structure does the phosphodiester backbone protect?
The more chemically reactive organic bases in the double helix.
