DNA Flashcards
What does DNA stand for?
DeoxyriboNucleic Acid
What is it?
DNA is the chemical that all genetic material in a cell is made up from, it contains codes that are instructions for protein synthesis and bodily functions. It determines your inherited characteristics.
Where is it found?
In long structures that usually come in pairs called chromosomes, they are found in the nucleus of cells.
What shape and type of molecule is DNA?
A polymer in a double helix shape
What are genes?
A gene is a small section of DNA
What does MRNA do?
They code for a particular sequence of amino acids which are put together to make a specific protein by telling what order to put the amino acids together
How many amino acids are there?
20 but they make up thousands of proteins
How does DNA determine cell type?
It determines what proteins the cell produces, such as keratin in hair or nail cells
What is the genome?
The genome is the entire set of genetic material in an organism, scientists have worked out the complete genome.
Why is it important to understand?
It allows scientists to identify genes in the genome that are linked to diseases, knowing which genes are linked to inherited disease helps us to understand them and develop better treatments for them. Scientists can also look at genomes to trace the migration of certain populations of people worldwide
What are nucleotides?
Nucleotides are parts of a DNA strand consisting of a sugar, a phosphate (these two make the backbone) and a base
What are the four base letters?
A-T G-C
What is this pairing called?
Complimentary base pairing
What do the order of bases determine?
The order of amino acids in a protein, coded for in triplets
What do parts of DNA do if they don’t code for proteins?
They control whether or not a gene is expressed (used to make a protein).
Where are ribosomes located?
In the cytoplasm
Why can’t DNA move out of the cell, what is used instead?
DNA is too large to move out of the cell so a molecule called mRNA is used instead. It is made by copying the code from DNA and moving through the cell to the ribosomes in the cytoplasm.
What is a carrier molecule?
Molecules that bring the correct amino acid to the ribosome
Three examples of different proteins
Enzymes, hormones and structural proteins
Enzymes
Act as biological catalysts to speed up chemical reactions in the body
Hormones
Used to carry messages around the body, such as insulin which is a hormone in the blood released by the pancreas to regulate blood sugar levels
Structural Proteins
Physically strong such as collagen which strengthens connective tissues like ligaments
What are mutations?
Mutations are random changes in an organism’s DNA and they can sometimes be inherited.
When do they occur?
Mutations occur continuously, they can occur spontaneously such as when a chromosome isn’t replicated properly but the chance of mutation is increased by exposure to specific substances or radiation types
What do mutations do?
Mutations change the sequence of DNA bases in a gene which produces a genetic variant, because this sequence codes for amino acids that make up a protein- mutations sometimes change the protein the DNA codes for
What effects does a mutation have?
It depends on the type of mutation, some can be harmless and have little to no effect on the protein whereas others can be severe and affect its shape so the protein cannot perform its function
What is an example of a protein that cannot function without the correct shape?
Enzymes cannot function without the correct shape as their active sit is changed so a substrate won’t bind to it
Name the three different mutation types
Insertion, deletion, substitution
What are insertions?
Insertions are where a new base is added, they can have a knock on effect in the base code further down the sequence so they can have severe effects
What are deletions?
Deletions are where a base is removed from the base code so they can also severely affect the protein produced because they can have a knock on effect
What are substitutions?
Substitutions are where a base is swapped to a different base, they do not have a knock on effect so they are often less severe.
